+ All Categories
Home > Documents > Current Status of Treatments for Dyslexia_critical Review

Current Status of Treatments for Dyslexia_critical Review

Date post: 07-Apr-2018
Category:
Upload: edith-lo
View: 221 times
Download: 0 times
Share this document with a friend

of 16

Transcript
  • 8/3/2019 Current Status of Treatments for Dyslexia_critical Review

    1/16

    744 Journal of Child Neurology I Volume liJ, Num ber 10, Octo ber 2004

    79. Bnick M: Word recognition skills of adults witli chikiiiood diagnosesof dyslexia. Dev Psychol 1990;26:439-454.80. Bnick M: C omponent spelling skills of college sttidents witli childhooddiagnoses ofdyslexia. Learn Di.'iabil Q 1993:1(5:171-184.81 . Elbro C, Nielsen I, Petersen DK: Dyslexia in adult-s: Evidence fordeficits innon-word reading and in the plionological representationof lexical items. Ami Di/shu-ia 1994:44:205-226.82 . Felton RH, Naylor CE, Wood FB: Neuropsychological profile of adultdyslexics. Brain Lang 1990;39:48.5-497.83 . Maiitner TS: Dyslexia-My "invisible handicap." Ann Dyslexia1984:34:299-311.84 . Satz P, Buka S,Ups itt L, Seidman L: The long-term progno sis of learn-ing disabled children : A review of studies (1054-1993), in Shapiro BK,Accard o PJ, Capu te AJ (efis): Specific Reading Disability: A Vteiv oflltf Spectrum. New York. York Press, 1998, 223-250.85 . Sundheim STPV. Voeller KKS: Psychiatric im plications of language dis-ordei-s and lesiming disabilities: Risks and mana gem ent../ Child Neii-m/2004;I9:814-826.86. Flax .IF. Realpe-Bonilla T, Hirsch LS, et al: Specific language inipaii-ment in faiiUlies: Evidence for co-occu rrence with reading iiupairm ents../ Speech Lang Hear Res 2003;46:530-543,87. Molfese DL: Predicting dyslexia at 8 years of ^ e using neonatal brainresponses. Brain Lamj 2000;72:238-245.88 . Leppanen PH, Richai-dson t', Pihko E, et al: Brain responses to changesin speech soun

  • 8/3/2019 Current Status of Treatments for Dyslexia_critical Review

    2/16

    Current Slalus of Trealnients for Dyslexia / Atexartde'r and Slinger-Cojistanl 74

    Over the last 15 to 20 years, there h as been a great deal of resea rchfocused on finding Ihe most effective methods lor treating read-ing disability (dyslexia). We have had the opportunity to evaluatenot only the effect of specific interve ntion s on reading skill but alsoto devise technologie.s thai make it possible to study the way inwliicli the brain responds to these interventions. This body ofknow ledge is complex, in paii b ecau se although all iudividutUs withdyslex ia hav e a similai- pitbleni, namely, difficulty ceading, they haveheterogeneous characteristics, and depending on the child's devel-opm ental level, the dem imds of reading and the required skills arequite different. As Torgesen pointed oiit, even the defmition of agood rea der varies: Is it being able to orally decod e accurately andfluently? Is it simply being able to g et the gist of what is read? Oris it being able to analyze, synthesize, and c onve rt information frommultiple source s into a meaningful wh ole?' Torgesen noted th at allof these factoi-s have contribu ted to the challenge of designing inter-ventioii studies, interiJreting the outcomes of treatment, andanswering the following crucial questions:

    1. What types of prevention or intervention treatment will bemost effective? The answer depends on what children need toknow to read at a given grade level and the reading levelexpei'ted for their (leveloilmental stage feg, mechan ics of wordreading, fluency, or text reading and comprehen sion of reading).

    2. What level of intensity is most effective? There are two typesof intensity: one referring to the frequency of the intei-vention(daily, two to th ree times per w eek, once per week) and the otherreferring to tlie instructor to studen t ratio (1:1, small group, class-room).

    3. How many hours are needed to complete the intervention?Wliat is the optimal duration of treatment?

    4. How well aie gains and skills maintained after the interventionhas ended?5. What therajjist or teacher skills are tteeded?{) . What child cha racteris tics coTUribute to the succe ss or failure

    of the intervention (type of language involvement, severity,age, and comorbidity)?

    7 . In wha t educa t iona l con tex t can these in te rven t ions beimplemented?

    To address so me of these questions, the National R esearch( ouncil, the research arm of tiie National Academy of Science, pub-lished a report in 1998 summarizing available research fmdings thatcould be used to prevent reading tlifficult ies in young cliildren.- Theleport, emphasized the im portance of eaiiy childhood language andliteracy experience as the foundation on which systematic phono-logic decodin g should be taught. To explore ho w reading researchcould be more spocificatly applied to classroom implementation,the National Institute for Child Health and Human Development

    Recoivod Juno 23. 2003. Accepted for publication June 23. 2004.From The Morris Center, Department of Dpvelopmenta! Ped iatrics {DrAlex;uider) aiid The Univoi-sity of Florida. Depaitnient of Cliild Neurology(Dr. Slinger-Constant), Gaiiies^illp. FLAddress correspondeiicp to Dr Ann W Alexander, The Morris C eiiter, 2035SW 75th S treet. Suite B, Gainesville, FL 32607. Tel: 352-332-2629; fax: 352-332-3012: e-mail: [email protected].

    and the Department of Education convened the N ational ReadingPanel to conduct a meta-analysis of reading research since 1990in the areas of alphabetics, fluency, comprehension, teacher edu-cation, and the effects of com puter t echnology. Only studies m eet-ing tigorou s research m ethodologic criteria were analyzed. Althouglimuch of the research in the field did not meet these criteria, andin some instances there w ere too few studies to conduct a m eta-analysis, Ihe N ational Reading Panel ditl find rot)iist eviden ce in theareas of alphabetics (phonologic awareness, reading and spellingskills).-'

    Specifically, direct and systematic phonologic awaieness andphonics instruction produced significant effects for at-risk read-ers (ie, young children in kimiergaiten or first grade wlio have hadminimal exposure to reading and aie deficient iti phonologic aware-ness and letter knowledgeprecursors for the acquisition ofphonologic decoding), as well as disabled readers (those whohave had exposure to adetiuate reading mstruction and have notlearned to read). The panel noted that the re were differences in thetype of instruction and the respon se of these two group s of < hildren to instruction:One type of instruction involved the prevention of reading dis-ability in the young, at-risk child:1. The younger the child {kindergarten throug h first grade), the

    better the outcome.2. Tlie at-ilsk child resp onds best to small-group instructioti (2:1 or

    3:1), with phonologic awareness training being combined withIett,er knowledge an d explicit pho nics instruction.

    3. Ti'ained teachers achieved good results.4. More frequent instruction (4-5 days/week) was more effec-

    tive.5. Gains were maintained in most of the children at long-term fol-low-up.6. Tlie following characteris tics of the child were assoc iated with

    poor outcome in reading and spelling: poor rapid naming, poorverbal ability, and attention or beha\ior overall. Low socio-economic statu s wa s also associated w ith poor spelling achieve-ment. Com puter programs were helpful aids.

    The second tyiie of instruction, remediation, was directed atthe older, reading-disabled child (second to sixth grade):1. Although the older, reading-disabled children respo nded witli

    improved w ord reading to similar intensive, diret t. and explicitinstruction, they were less responsive, and gains were nol asmarked.

    2. Tliey did b etter w ith one-to-one or small-group instruction.3. More intensive work for a longer duration wiis required.4. Spelling and fluency did not respond well, but there was some

    improvement in reading com prehension.5. GaiJis were m aintained in most children at follow-up.6. (Characteristics that imp eded leadin g and siieiling gains included

    poor attention and behavior control, rapid naming deficits, andweak verbal ability. Low socioeconomic status affected read-ing gains; trained teachere achieved good resitlts, but tliey w eretypically not as robust as the results when working withresearchers. Com puter instruction served a s an effective aiti butwas not effective by itself.

  • 8/3/2019 Current Status of Treatments for Dyslexia_critical Review

    3/16

    746 Journal of Child Neurology I Volume 19. Number ID, Ociobt'r 2(K)-1

    The skills needed for normal reading development w ere foundto enco mpas s five essential doniaiits:1. Phonem ic aware ness: awarenes s of the sound struc ture of spo-

    ken language and the basic units of speech (phonemes)2. Phonics: knowledge of relationships between letters and sound s

    and spelling-sound correspondences; allows fluent phonologicdecoding3. Sight word acquisition: automaticity of reading words by sightwithout havinj; to decode sound by sound; leads to ortho-graphic decoding tluency

    4. Vocabulary: the storage of word m eanings and the ability to flu-ently access that infoi-mation

    5. Comprehension of text: the ability to tliink abou t and extractthe information provided in text while reading, a fluent inte-gration ofmultiple processes.

    Although the National Reading Panel's review of the re searchliterature answered some of the questions about word readinginstillction, the re were not enough data to draw firm conclusionsabout the best way to teach fluency, vocabulary, and text com-prehension or to train teachers, illustrating the need for morestringent research in the field. Nonetlieless, preliminary findingssuggested that:1. Fluency is better achieved by repeated guided oral reading

    thaiT bysilent reading practice.2. Vocabulary instruction should be taught by both direct and

    indirect methods, with computer programs as ac^uncts.3. Comprehension is developed byfluent word reading, vocabu-

    lary strength, and a combination of strategies for helping thechild connect with and think abo ut the text.

    The most rigorous methodologic studies resulted in veryrobust effect sizes for reading gains; however, even the studies withthe weakest methodology also yielded significant gains in phono-logic awareness. With the impetus to improve the quality of theexperimental studies to arrive at more definitive answers to ourquestions, research has continued to advance our understandingof how children develop skilled reading and to learn more aboutthe factors that hinder that deve lopm ent'' M ore recent findings aresiunmarized below.C U R R E N T R E SE A R C HThis article focuses on research studies that compare treatm ent effi-cacy forprevention (ie, working with young children who ar e "atrisk") and the efficacy of various approaches to remediation (ie,treating older children who have already been identified as reafi-ing disabled). Pre- and post-treatment functional brain imaging stud-ies have been conducted in some of these studies, and these arediscussed. Behavioral studies in combination with neuroimagingstudies allow us to develop an miderstanding of the neurobiologiccoiTelates ofbehavioral responses to treatment. Finally, develop-ment of compu tational m odels, computer sim ulations of how read-ing is acquired, has not only provided additional insight into theprocess of reading acquisition but has also offered explanations forspecific intei-vention outcomes.'

    Prevention StudiesTorgesen, in an overview of research on the effectiveness of inter-ventions with at-risk children, in the classroom and with smallgroups, noted that two programs pro\'iding relatively direct, systematic instruction inpho nem ic decroding skills, "Direct Instruc-tion" and "Success for All," were effective for this at-risk group buno t for already impaired readers. ' Tmmier and Chapman con-ducted a longitudinal study using the Reading Recoveiy Method,which has been a popular ear ly intervention program in theschools.^" It offere one-to-one, daily, puil-out tutoring for 12 to 20weeks for 6*year-old children performing at or below the .'JOth per-centUe in reading . Although it has been reported to be helpful forstruggling readei-s. its effectiveness has not been documented byrigorous research. Tuimier and Chapman found tliat 30M) of tlie children were referred out of the program because they were notresponding.'' These children were found to have significant phono -logic deficits, wWch probably accoimts in part for their lack ofresponse. When the children who did show a good response to theintervention at the end of the treatment were tested 1 year latertheir perfomiance was no better than that of the controls. Thesefindings indicate that intensive treatment alone is not enoughdespite one-to-one instm ction, th e at-i isk children did not respondas well as Ihose receiving appropriate classroom interventionThis study illustrates that the content or method of interventionis itself a critical factor in treatm ent efficacy The Reading Recov-ery Metliod is a top-down, more whole-language approach usingsemantic or syntactic clues for word reading and d oes not containI he explicit phonics or phonoiogic awareness instmction neededby these younger at-risk children.

    Denton and Mathes reported the effectiveness of foiu: pri-mary classroom treatment projects that followed the NationaReading Panei reconmien dations." The study taigeted at-risk chil-dren wh o fell betw een tlie 18th and 25th percen tiles in phonolog icand letter knowledge skills. After intervention. 18 to 31% of the children still had not reached the benclimark of the 30th percentile forword-level reading and would require a h ^ e r level of interventionDenton and Mathes also evaluated Ihe effectiveness of five interventions that involved a more intensive approach (one to onesmall group with m ore hours of instruction) with students w ho w eremore impaired (12-18th percentile). They found that 4 to 30%remained below the 30th percentile benchmark after tliis tieatnientOn extrapolating their findings to the general population for bothgroups, they noted that only 0.7 lo 4.5% of the more severelyimpaired gi oup aiid 5 to G% of the mild to m oderately impaii ed grouremained in the impaired range, a significant difference from the15 to 20% rate currently reported. Both tyjies of intervention yieldedsignificant result s, with the itioie intensive administration moviiigeven the more severely at-risk children into the average range.

    Torgesen and colleagues conducted a study of kindergartners who were severely at risk (10th percentile for prereadingskills).^ The study compared the effect of three types of intensiveinterventions that were delivered: one on one, 20 minutes/dayand 4 days/week through the end of second grade. There was alsoa no-treatment control group. The interventions w ere (1) a regular classroom reading curriculum, which was more whole lan-guage in nature; (2) embedded plionics training, which provided

  • 8/3/2019 Current Status of Treatments for Dyslexia_critical Review

    4/16

    Current Status of TYeatments for Dyslexia / Alexander and S linger-Constant 747

    more implicit, nonsequential phonics instruction when the oppor-timity presented itself in text: text reading and writing instructionwere the predom inant com ponent; and (3) an explicit, sequentialdirect teaching of phonemic awareness using a multisensoryapproach, w hich brought in the motor perception of speech soim ds{the IJndamoo d Auditory Discrimination in Depth program)^ to facil-itate Ihe development of fine grained phonetnic representations.Decoding and encoding of words with direcl phonics instructioncomprised m ost of the instruction, with little emphasis o n text read-ing. Tliis appro ach w as a predo min antly bo ttom-u p, sen soryapproach for the development of more distinct phoneme repre-sentations, in contrast to the more top-down orthographic-seman-tic approach of the o ther interventions. It also offered more explicitphonics instruction.

    The bottom-up, sensory, more explicit approach was signifi-cantly superio r to all of the other gro ups at. the end of the inter-vention period. The more top-down inteinventions resulted inoutc om es similar to those of the no-treatm ent controls. Long-termfollow-up revealed that the more explicitly trained group (thosereceiving Ihe Lindamood Auditory Discdniitiation in Depth pro-gi'am) wa s performing solidly in the average range for accuracy an dfluency at the end of the fouith grafle. These findings sugges t th atthese young, impaired cMldren required much more salient inter-vention to improve their phoneme maps, combined w ith explicitinstnictio n for letter and sound mapping. The more Implicit phon-ics approach that laiighl phon ics rtiles was ineffeclive. Perha ps tliiswas due to the more abstract, top-down nature of teaching the phon-ics rules, without establishing fme-grained phonetnic representa-tions. With deficient ph onologic processin g, less explic it instructionwould place greater demands on executive ftmction. Because nei-ther execu tive fimction nor abstra ct thinking ability isfiillydevel-oped at this youtiger age, a more concrete intervention programwould be expected to be most effective for the struggling reader.

    Denton and Mathes also addressed the question of which cri-teria are most useful for predicting sticcess with future leadingacquisition following early intervention." They found that fiuency(or words read per minute) w as more significantly related to futureoutcome than otlier reafiing measures, and the rate of response tointervention w as also a predicto r of future reading developmenttlie slower the learning cnrve, the more difficult it was for thechild to become an adequate reader.

    Vellutino and colleagues also foimd the rate of response totreatm ent to be a significant predic tor of ou tcom e. TTieir (i-yeai' lon-gitudinal study of at-risk first-graders revealed that the children inIhe "limited response to inten'ention" group (treatment resisters)differed from t he cliildren who were readily rem ediable.'" Althoughall of the subjects had significant difficulty with phonologic skillssuch as phoneme awareness and with letter and number Tumting,there were differences between tlie readily remediated readers ;uidthe most difficult-t.o-remediate readers in tlieir cognitive and lan-guage-based abilities: rapid naming, confrontational naming, ver-bid working memory (synlac tJc word order, nonword repetition),short'tenn verbal memory (digit span), and articulation speed.The readily remediated group performed more like the normalreading group on these meas ures. These children were mo re likelyto have had limitations in their early language experiences and/orinstruction. Thus, although all of the children had phonoiogically

    based deficits, there were two different types of deficient phono-logic sensitivity. One group lacked the enviroimiental ex postire nec-essary for the development of a strong phonologic system (an"experiential reading disability"); the o ther grou p of children hadbeen exposed to appropriate etivironmental stimulation but hadatypical development of the neural systems underlying phono-logic sensitivity (characteristic of the typical individual withdyslexia). With the appropriate input, the fonner group coulddevelop the brain m aps of the norm al reader. The cognitive and lin-guistic deficits of the individual with dyslexia suggest a more per-vasive difficulty, w hich is constitutional in natitre and prese nts adistinct therapeutic challenge.I n t e r v e n t i o n S tu d i e sIntervention studies have demonstrated that intensive (daily, oneon one, and small group), phonoiogically bjised treatm ents can closethe gap for reading accuracy, even in tho se children falling as lowas the 2nd perc entile in word-level reading skills. In his interven-tion study. Torgesen and co!!eagti(i contrasted the two treatmentapproaches described in the prevention study above: (1) a nuilti-sensory, bottom-up, explicit approach for developing phonemicawareness and phonemic decoding and encoding skills with min-imal text instruction (the Lindamood program, described above)and (2) the embedded photiics instruction approach in which only209 ) of the time was sp ent on single-word phon emic decod ingactivities and the rest on text readin g and sight word training .'' ' "-Tlie children w ere 8 to 11 years old and fell in the 2nd percentilefor word-level reading ability and the 10th percentile on a broadreading measure, combining word reading with comprehension(Broad Reading Score, Woodcock Johnson Tests of Achievement,Revised).'' Intensive remediation was delivered on a one-to-onebasis, 5 days a week for 100 minu tes a day for 8 weeks , and th e cliil-dren then returned to their special education classroom s.

    Figure 1 provides a snapshot of the findings. The growth ofthe children's reading skills in both conditions was m easured ona broad nieasure combining word reading accuracy and passagecomp rehension into a single stai\dard sco re (mean 100. SD 15;thus, a value from 85 to 115 is in the average range).

    For the 16 mo nths before tlie intervention, th e children w erein special education classes, where the instruction maintainedtheir level but did tiot close the gap. The intensive intervention pro -duced a steep rate of reading growth, regardless of the interven-tion, and gains continued over the 2 years, with the childrenreaching mean standard scores above 90, approximately the 30ttipercenlile, which was also their mean Wechsler Verbal IQ. Eventhe children with the lowest verbal shori-temi memory (standardscore 70-85) as meastired by the Digit Spmi subtest of the WechslerIntelligence Scale for Childien-Revised (WISC-R)" made gains inphonem ic decoding similai' to those of the group as a whole (meanstanda rd score 70.2 to 93.5). At follow-up, 4O! i of the children hadbeen staffed out of the special education classrooms, a consider-ably higher percentage than t he county's record of less than TfA,.

    Whereas almost all of the children made significant gainsduring Ihe intervention period, only a little more than half susta inedor increased their gains diu-ing follow-up. Furthermore, about afourth of the children lost most of the gains made during th e inter-vention during th e 2-year follow-up period. The variable s predict-

  • 8/3/2019 Current Status of Treatments for Dyslexia_critical Review

    5/16

    748 Journal of Child Npumlogy I Volume 19, Number 10, October 2004

    G RO \\TH IN TOTAL READING SKILL BEFORE,G, .AND FOLLO \MN G INTE NSI\ EINTER\ENTIONM EA N C K O U P !Q

    Mk . . *

    i LIPSJ EP

    P-Piel("j | P I P I'OSI 1 yesu 2 yemInterval in Months Between Measurem ents

    Figure 1. Treatment effects: broad reading skill measures (WoodcockJohnson Test of Achievement, Th ird E dition, standard score mean 100,SD + 15) before 16 mon ths of special educ ation (P-Pretest), before 9weeks of intensive remediation (Pre), immediately after 9 weeks ofreme diation (Post), and at 1- and 2-year follow -up . The dotted hori-zontal line represents the group mean IQ, EP = embe dded phonic s;LIPS = Lindamood Phoneme Sequencing.

    ing growth during the follow-up were attention, receptive lan-guage ability, and socioecon omic status. Of note, the more implicittop-down approach was as effective as the nnillisensory bottom-up approach, suggesting that the children could harn ess the p hon-ics niles despite having weak phonologic representations. Thiswould suggest that they now had the executive function andabstract thinking abilities to com pensate.

    L'nfommately, the fluency gap could not be narrowed with thisintensive intervention, and the children remained severely impairedin reading rate (2nd percen tile). To explo re this further, Torgesenand colleagues conducted small-groti]i intervention studies witholder (11-12 years) reading-disabled childi en. ''Al l children wereseverely impaired in word reading fluency (2nd percentile), but onegroup was mildly impiiired (30th percentile) and the other mod-erately impaired (10th percentile) for word reading skills. Theintervention used the Spell, Read Phonological Auditory TVain-ing."' which provided systematic instruction in phonemic aware-ness and phonemic decoding combined with fluency-orientedpractice from the start. The mildly impaired group evidenced sig-nificant gains in both accuracy and fluency, with fluency improv-ing from the 2nd perceutile to approximately the 50th percentileafter only (iO hours of treatment. The moderately impaired read-ers were further subdivided into two groups, which receiveddifferent duratio ns of treatmen t. One group received 50 hoiu^ oftreatme nt, and th e othe r received 100 hours . Although the gains intext reading accuracy and fluency on the Gray Oral Reading Test,Third Edition,'' were significant in both groups, the longer instruc-tion period prod uced gi eater gains in accuracy (19 vs 8 stand ardscore point improvement) and fluency. The group exposed to thelonger dui at ion of treatm ent improved in tluency from a m ean stan-dard score of 65 to 79 (14 standard score pointsnearly 1 SD),whereas the group exposed to a shorter duration of treatmentshowed a 9 standard score point improvement (68 to 78). Clearly,fluency remained a sigitificant problem for both groups.

    Figure 2 illustrates the results from the prevention study ofthe yoimg at risk cliildren as well as the remediation study of theolder, reading-disabled children.'' TVeatment of the young at-riskchildren in the prevention study resulted in normal accuracy andfluency at the end of fourth grade, emphasizing the importajice oearly identification and treatment. ' Although th e mildly intpairedreaders (30tli percentile) expe rienced ve iy significant grow th aftetreatm ent, they still evifienced a gap betw een acc uracy aiiti fluencyThe more severely impaired readers (10th percentile) made significant gains in accuracy but remained impaired in fluency. Thlonger duration of treatinent in tlie moderately imjjairetl readerresulted in more gains but was still inadequate. The most severelimpaired (2nd percentile) readers ft'otn Torgesen et al's intervention study also mad e signific ant gains in accuracy but no g ains influency."

    Torgesen and colleagues condu cted a subsequent intert'entionstudy with two groups of severely impaired (2nd percentile) 9-1(311-year-old children using two interventions: (1) the LindamoodPhoneme Sequencing program'- for 67.5 houiK, followed by 67.5hou rs of fltiency instruction (repeated reading and word d rills) andcomp rehension instruction , and (2) an accuracy-only group, wh ichreceived only tiie Lindamood Phon eme Secjuencing instruction, withequal time in comprehension instniction. ' ' Prelinuiiary fmdingbased on 45 of the 60 children who fmished the study reveal similar accuracy and fluency outcomes for both groups, with significant gains in accuracy but none in fluency. Neither fluencyinstruction nor a longer duration could close the gap.

    Tlie studie s by Torgesen et al suppo it the need for early intervention for the developiuent of fluent w ord reading. Torgesen proposed that because the acquisition of sight words occurs withrepeated exposure to words in print, individuals witli dyslexia do[lot read, antl Ihe fltiency gap w idens .' Tliose older child ren w ho a rremediated and acquire the phonologic decoding ability for accurate reading wottid liave to read more than other c hildren to closthe sight word gap. Other factore contributing to poor automaticword reading and text reading fluency can be child characte risticsuch as rapid naming, attention deficit, executive function deficitsor recep tive lajiguage ability, hi theu" 2001 study, Torgesen et al fotmthat attention, receptive language ability, and socioeconomic status were predictive factors in this population." Indeed, the childrein the 2001 study were fotuid to have significant laiigtiage impairment as measured by the Clinical Evaluation of I^anguage I-Xindamentals, Thijd Revision,'^ witlt a mean total language standardscore of 76.3 (-t- 9.0) for tlie giwup receiving tJie Lindamood PhonemSequencing, and of 81 (-^ 12) in the embedded phonics group. Interestingly, these language-impaired children showed a significanimprovei\ient \w he total language standard score at l-yeai^ followLiij: the Lindamood Phoneme Sequencing group standard scoriuiproved to 89.7 (+ 14), and the emb edded ph onics group standarsco re im proved to 89.9 (-H 19.3). Both tiie explicit an d the mo rimplicit phonologic interventions were effective in significantleiiliancing spoken language processing and written language.

    Poko mi et al reported minimal gains in language ;uid readingrelated skills in a group of 18 yoimger, langitagt'-impairetl. poo r readers, aged 7.5 (o 9 years. " Their scores on the Clinical Evaluatioof Laiigtiage Fundamentals, Third Edition,"^ fell more than 1.5 SDbelow the mean, and they were moderately reading impaire

  • 8/3/2019 Current Status of Treatments for Dyslexia_critical Review

    6/16

    Current Status of TVeatments for Dyslexia / Alexander and S linger-Constant 749

    80 -

    70 -

    %ileTypeRx h r s30''RD

    GOhis10'"RD50hrs

    10"'RDlOOhrs

    ^ii 1

    RDeShrs

    At Risk88hfE

    Figure 2- The fluency gap: a comparison of word-level fluency gainsimm ediately after intensive, phonofogically based treatment in groupsof reading disabled (RD) children, with varying severity of difficulty priorto treatment. The two groups of RD children in the 10th percentiie illus-trate that longer treatment duration (Rx hrs) yielded greater gains inaccuracy but no response with fluency. A contrast grou p of at-risk chil-dren, who had received intensive intervention through second grade,illustrates m aintenance of gains through fo urth grade, with norm al flu-ency. The horizontal line represents the 30th percentile benchmark.

    (18-25th percent i le) . These chi ldren received the LindamoodPhoneme Sequencing intervention for approximately the samenum ber of hours of daily treatme nt, bu t in a small group (four chil-

  • 8/3/2019 Current Status of Treatments for Dyslexia_critical Review

    7/16

    750 Journal of Child Neiimlogy /Vo\ume 19, Number 10, October 2004

    for Children. Third Edition [WISC-IIT])," Six of the eight werediagnosed with attention-defirit disorder and were treated withpsychostinmlant medication throughout the study period. Thefomparison group consisted of eight children aged 8 to 14.2 yearsold (mean age 10.3 years) with reading scores above the 50th per-centile and a mean IQ score of 107 (+ 10.5). One of the eight was(tiagnosed wil h attention-deficit d isorde r ajid w as treated w ith med-ication. All lG subjects were right-handed, native English speak-ers. Following intervention, reading accuracy in all subjects wasabove the 37th percentile. On the imaging studies prior to inter-vention, the subjects witli dyslexia displayed the ch aracteristic COT-tical activation profile of the individual with dyslexia: little to noactivation in the left temporoparietal areas and strong activationin the homotopic right hemisphere. In contrast, the controls liadlittle activation on the right and strongly activated the tem-poroparietal areas on the left, believed to be involved in phono-logic processing. After treatment, the cortical activation patternsof tlie subjec:ts with dyslexia resem bled m uch m ore closely tho seof the nonnal controls- A dramatic increase was noted on the left,most pronouitced in tlie left su perior temporal gynis, and increasedactivation in the inferior parietal area s approach ed significance.There was a moderate decrease in homotopic right hemisphereactivation. The cortical activation patterns of the normal con-trols did not change. Of note, the imping study also revealedthat the subjects with dyslexia engaged the left superior tempo-ral gyms more slowly than did the controls, despite remediation,stiggesting that the new circuitry might not be as efficient, and flu-ency would remain a problem. The authors stated that the smallsample size calls for caution in interpreting the results. However,with the significant improvement noted both behaviorally andl^hysiologically, they suggested tliat these findings indicate a "nor-malization" of functional brain organization following intensiveintervention.

    Tliese findings have been replicated in a methodo logically rig-orou s longitudinal study by Shaywitz and colleagues.^' A large cohort(77 (j- to 9-year-old child ren) with readin g disabilities received 86 to115 hours of daily, individual, aiui evidence-based phonoIogicaUymediated reading intervention at school. There were two controlgroups: a group of reading-disabled children who received the typ-ical interventions of the school ;md private tutoring and a group ofnom ial read ers. Tlie children were assessed before, following, and1 year after treatmen t ended. Behavioral gains on the Gray Oral Read-ing Test, Tliird E dition, we re fomid to be significant in compariso nwith the control reading-disabled group ajul the nonnal readersimmediately post-treatment. The scale score improved fr^om 5.4 to7,0 for the treatment group; the scale score d ecreased from 5.4 to4.9 for the reading-tlisabled control group on the passage score, acombination of accuracy and rate (mean 7, SD 3). There could beno comparison at 1 year because only two of the reading-disabledcontrol group and two of the nonnal reading group retumed. Thetreatment grou p evidenced a decline in performance from a standa rdsco re of 7.0 to 6,4, However, an effect size calculation of tlie group'sgains dming treatment and of gains maintained from pretreatmen tto 1-year follow-up revealed an effect for both periods (effect, size0.52 a nd 0.43, respectively). Effect size in the 0.5 to 0.79 range is c on-sidered moderate.-" Of note, tlie mean readi:ig conipi'ehension as mea-sured by the Gray Oral Reading Test, Tliird Edition, improved during

    the treatment and at the 1-year follow-up, moving into and stayingin the average range (pretest mean standaid score 5.7; post-testmean standard score 8.0; standard score at 1-year follow-i^i 8.5). OUiestudies have demonstrated a greater ability witli text comprehensionthan with word-level reading before treatment'' anfl tliat, followingti'eatment, comprehension exceeds t he 30th percentile, although woi-dreading ability still lags behind in the 13tli to 22nd percentile. Thissuggests tliat enlianced phonologic decoding allows the pereon withdyslexia to better use other top-down p rocessing strategies, whichcan be strengths.

    Physiologic measu res also revealed significant chan ges. Usingfunctional magnetic res onance imaging (MRI) during a letter identification task, Shaywitz et al also demonstrated the shift from righhemisphere to increased left heimsphere activation reported bySimos et aL^-^ Interestingly, although the treatment subjects remainedin the impaired range on reading measures (Gmy Oral Reading TestThird Edition, passag e score: 5.4 preintervention, 7.0 inunediatelyposUntervention, and 6.4 1 year later) in contras t to the normareaders, both groups demonstrated similar brain activation patterns, with increased activation in the left inferior gyms and posterior middle temporal gyms immediately after treatment. At the1-year follow-up, only the treatment group underwent a repeatedimaging stutiy, which revealed that tliese chiid ien activated the fastpaced occipitotemp oral w ord form area serving skilled reading, thebilateral inferior frontal gyri, and left superior temporal regions,

    Richards et al used magnetic resonance spectros copy (specifically, proton echo-planar spectroscopy) to evaluate the responseto a less intensive but phonologically based intervention on brainlactate metabolism during "reading-related tasks" in eight boywith dyslexia and seven control boys between the ages of 10 and13 years.-'^ After the 3-week intervention p eriod, which consistedof 15 2-honr group sessions, pertonn ance on behavioral m easureof phonologic processing improved. Prior to intervention, thedyslexic v)articipajits manifested significantly greater la ctate m etabolism in the anterior quadrant of the left hemisphere during areading task compared with controls, suggesting that they hadgreater difficulty with the task that necessitated increased use othe frontal cortex. One year iifter intervention, repeat magnetic resonance spectroscop y revealed a m etabolic patt.em similar to th aof controls during the phonologic task.

    To evalua te the effects of treatm ent using two different linguistic interventions, phonologic and morphologic, Beminger et aconducted a .study with children in fourth to sixth grade who werepart of a family gen etics stud y aiifi were found to be dyslex ic."' Thecliildren were of nonn al intelligence (mean Wechsler Verbal IQ wa110,6 11), and although they did not have oral language problemsor attention deficit, rapid naming deficits were present. The subjects w ere randomly assigned to a phonologic aw arenes s or a morphologic awareness treatment group. They received daily treatmenamounting to 28 hours over a period of 3 weeks. The behavioraresults revealed significant gains in phonemic decoding skill anthe rate from pretest to post-test for both groups. Phonologicdecoding (the Woodcock-Johnson Reading Mastery Test WordAttack subtest) improved significantly for both groups. Interestingly, the moiphology treatment group showed a significantlygreater level of improvement than the phonology treatment grouin phonologic decoding efficiency, as measu red by the Pseudow ord

  • 8/3/2019 Current Status of Treatments for Dyslexia_critical Review

    8/16

    Current S tatus of Treatments for Dyslexia / Alcrander and Slinger-Constanl 751

    Reading Efficiency subtest of the Test of Word Reading Efficiency.'"'Beniinger et al suggested tha t the efficiency of phono logic decod-ing depend s on an interaction betw een phonologic, m orphologic,and orthographic representations, as described by Harm and Sei-denberg's computer simulation studies below." Moreover, fol-lowing morphology treatment, magnetic resonance spectroscopyrevealed decre ased lactate activation in the left frontal region du r-ing a rhyming task in all but one child with dyslexia, and the acti-vation pattern resembled that of normal readers. However, in thephonologic treatment, group, the pattern of activation remained thesame or increased in ail of the subjects. A reduction in lactate acti-vation might reflect increased efficiency of mental processing.Good rea ders h ave less activation in the left frontal region duringthis phon olo gic ,ju

  • 8/3/2019 Current Status of Treatments for Dyslexia_critical Review

    9/16

    752 Journal of Child Neurology I Volume 111 Number 10, October 2004

    Simos and colleagues described above and resulted in significantbehavioral and physiologic gains in the six patients who weretreated.^^ However, n o othe r scientifically con trolled st udie s on tliisprogram have been reported. A word of caution is necessary: theSimos et al study delivered the intervention in a one-to-one dailyintensive manner using a trained teacher. However, the programwas designed to be ca nied out by pai ents at home, with 1 to 2 lioursper week of teacher support, m aking the intensity considerably less.No reliable study h as validated th is form of delivery. Intensity is akey ingredient to successful remediation, and the intensity needsto increase w hen th e deficit is severe. Home program s in tliis dayand age in families in which both paren ts are w orking are not real-istic if intensity is required.N O N L I N G U I ST I C I N T E R V E N T I O N SThe remedial intervention stud ies discussed th us far have been lin-guistically driven. Individuals with dyslexia have bee n reported tohave co-occurring nonlinguistic deficits as well. Heilman andAlexander sununarized the most commonly reported aJid consid-ered them to be deterrents to the efficient mapping of phonemicrepresentations, which are essential as the building blocks for astrong plwnoiogic system. ' Tliese nonlinguistic road block s include:a) impaired temporal processing of rapidly presented brief audi-tory, visual, and soma tosenso ry stimuli; b) a slowed respo nse timeatross domains, whicli is thought to compromise working mem-oiy with its time-bm ited capacity; and c) an attention d eficit com-promising working memoiy as well as executive fimctions andsustained a ttention. Children with dyslexia can evidence poor sen-sorimotor coordination requiring bimanual and/or rhythmic out-put"; poor postural stability and low tone in the upper body andlabored acq uisition of skilled m otor task s, such its sl\oe tying andhandwriting*"; and difficulty w ith temp oral seq uential o rdering inshort-temi auilitory memory and working memory,^'* Subtle impair-me nts in visual function include impaired binocu lar vergence con-trol, with inefficient fixation on near targets and less accuratelocalization of small do ts on a scree n; difficulty recognizing sev-eral visual items presented simultaneously; trouble with letters orwords "swimming" or jumping around on the page; and trouble withleft-right discrimination.^'T R E A T ME N T S T A R G E T I N GAUDITORY PROCESSINGIntervention studies exploring auditory temporal processing deficitsin children with reading problems and the impact of interventionsdesigneii to remediate thes e low-level perceptual processing deficitsrepoited in some subsets of subjects witii dyslexia have yieldedinteresting fmdings."'*"^' There are few methotioiogically soundresearch studies on th e efficacy of these nonlinguistic interventionstrategies. Earobics-" and FastForWord^' were used in some ofthe studies reviewed above. These programs are cond ucted usingcoiTunercially developed computer programs to address the audi-toiy pro cessing deficit found in a subset of subjects w ith dyslexia.They use acoustically modified speech to remediate the auditoryprocessing deficit but also tap phonologic skills. FastForWordwas developed based on scientific evidence of the relationship

    betw een auditory p rocessing and language.*** It is prese nted throu ghthe auditory channel but also trains syntactic and semantic com-prehension. Earobics incorporates graphemes and written wordsinto the prognu n.

    Hayes et al studied 27 children e d 8 to 12 years old with learning in\pairments (as defmed by a discrepancy of at least 1 SD ormore between measures of mental ability and reading, spelling,phonologic awareness, or auditory processing}.'^' Tlie subjects,who received 8 weeks of auditory perceptual training with Earo-bics Step I and Step il, exliibited improvements in auditory pro-cessing skills and altered cortical responses to speech syllableswith a more mature pattern in quiet and increased resistance todegradation in backgrotmd noise compared with normal co ntrolsand an untreated le;irning-disabled group . However, these changesditi not result in improvement in perfonnance on measures ofreading and spelling ability. The possible implications of theseresults for children with dyslexia are unclear because the sub-jects included children with attention deficit alone.

    Agnew and colleagues s tudied th e impact of a language reme-diation program using acoustically modified speech (FastForWord), designed to improve auditory temporal processing andlanguage skills.' '- Their primary aim was to as ses s its effect on theaccuracy with which seven children (being seen in a private clinicfor FastForWord treatment based on parental concern, clinicianrefeiral, or poor schoo l perfomiance) could judge i elative durationof auditory and visual stimuli, Tlieir second ahii was to ascertainits effect on pho nologic decoding. Following 4 to 6 weeks of intensive daily inten^ention. the subjects dem ons trated imjjrovem entsin the auditory, but not visual, modality on duration Judgmentasks. This was interpreted as evidence that the program indeedimproved auditoiy processing and that gains were not due toimproved attention. This improvement in auditory temporal discrimination was not associated with improvement in phonologicawareness or nonword reading, results that Agnew and colleaguesinterpreted as "illustrating the need for further research to establish the relationship betw een reading and auditory temp oral pro-cessing." They proposed that the auditory temporal processingdiffic'ulty that children with specific- language impairment anddyslexia exhibit is the result of poor phonologic representatio nsrath er than aji auditory tem poral proce ssing deficit or, as has beensuggested by other researchers, a generalized nervous systemdeficit in the process ing and integ ration of rapidly successive a ndtransient signals.

    In the study described above by Pokom i et al, Earobics StepII and FastForWord were compared w ith the Lindamood PhonemeSequencing program. '* After approxim ately GO hours of daily intevention delivered in a small-group setting, reading gains were nonoted in either group. Children exposed to Lindamood PhonemeSequencing were significantly better in improving phonologicawareness with gains in segmenting imd blending, and the Earo-bics group also showed significant gains attributed to phonemicsegm entation. N o signifit ant gains were foimd in the FastForWordgroup.

    Temple and colleagues compai'ed the cortical activation patterns of 20 children with dyslexia before and after 8 weeks ofFastForWord remediation.'' Left teniporoparietal cortex and leftinferior frontal gyms activation increased following the interven

  • 8/3/2019 Current Status of Treatments for Dyslexia_critical Review

    10/16

    Current Status ofiVeatments for Dyslexia / Alexander and Stinger-CoTtstanl 753

    tion. In co ntras t to oth er studies,"""'- Temjile aiici colleagues demon-strated gioup improvement in both oral language and reading per-formance in association witli these chan ges in cortical activity. Theirsubje cts w ere ni(}(ierately impaired in nonw ord reading (stand ardsco re 85.5, SD 7.9), average in oral language (receptive lajigiiagestandai d score 92.5, SD 12.1), and severely impaired in rapid nam -ing (staiidaid score 79.1, SD 14.5). Significant gains were found innonword reading, word identification and passage comprehen-sion, receptive and expressive language, and rapid naming. Onlynonword reading reached the 30th percentile benchmark, with aposi-treatment score of 93.7 (range 82-109). Oral Umguage alreadyexceeded it before treatment. However, there were no significantgains in oral language for Ifl (5(M0 of the subjects. Similarly, therewere n o significant reading gains for 9 (45%) of the s ubjects. Sim-ilai- data for rapid naming ar e not rep orted. T he amo unt of activa-tion in the left temporoparietal area correlated with improvementiji oral language ability. Increased Jictivity in the right hem ispherefrontal and temporal regions, as well as the bilateral anterior cin-gulate, was noted. Temple et al suggested that the cingulate niighlrepresent improved attention and that the hom otopic right hemi-sphere area s might represent compen satory activity, which mightdecrease with improved function.

    Whereas gains in auditory, phonologic, and language pro-cessing have been noted with these programs, the gains in read-ing skills have been, at best, incon sistent ;uid have not matched thegains in reading reporteti by programs using systematic phonologicawarene ss and pho nics interventions. Both programs have devel-oped new software that includ es phonics and language instruction.The efficacy of these additions has yet to be reponed.T RE A T ME N T S I N V O LV I N G T H E V I S U A L S Y S T E MStein and Talcott showed that a subset of subjects with dyslexiamight have abnormal magnocelluiar systems, causing decreasedvi-siia! mot Inn sensitivity, witli poo r visual guid ance of t he eye move-ments that result in inferior binocular vergence control. ' Tliis prob-lem with vergence control results in difficulty fixating on neartargets antl might explain why the childi-en reported trouble withlettere moving around on the page. This visual motion sensitivityhas been found to be a predictor of orthographic skill, accountingfor more than 15%of tlie vaiiance in the reading accuracy of irreg-ulai' sight words.'' ' Stein et al repo rted on a large in terventio n study(twogi 'oupsof 70 children, average age 8 years, 9 months, of nor-mal intelligence, with reading skills more than 2 SD below theme an). " Tlie subjects met th e criteria for severe dyslexia and un sta-ble binocular \1sion aiad were randomly assigned to wear yellow-tinted glasses with or without occlusion of the left lens (becausemost of the ( hiklren were right han ded). Yellow tinting was ch osenbecause the magnocellulai' system, felt lo be deficient in these cliil-th-en, gets a boost in the yellow ran ge. Stein et al reported that sh ort-tenn monocular occlusion helped the children to overcome theirbinocular fixation instability, and, while using only one eye to read,visual inconsistency and confusion resolved. Tlie cliildren were seenevery 3 m onths Tor 9 months and were assessed for binocular sta-bility and reading ability. Both groups b egan treatm ent reading atthe 6.8- to 6.10-year-old level. At the end of 9 mo nths, the group withmonocular occlusion had gained 16.1 m onth s in reading ability but

    still remained significantly behind (at the 8.1-year-oId reading levelat the age of 9.5 years). The children who made tlie greatest gainswere those achieving binocular stability. In fact, when a childdemo nstrated uiconsistent stability over time, the reading gaiiLs fort he 3-montli period of uistability were 1.2 montlis per m ontli, in con-trast to an average of 2.1 months per m onth wh en stability was pre-sent. The ^o u p with t inted lenses alone manifested only an S-uionthgain over the 9-month period. Stein et al noted that the grouptreated witli tinted glasses alone achieved a greater than expectedra!e of binocular stability over the 9 month s (54%, in contrast to asimiliii- study using clear glasses, with a rate of20 tcj 24%). They won-dered if this difference could be du e to the color giving a boost tothe magnocelluiar .system. They noted that most children withdyslexia have a core deficit in the phonolo gic system of languagebut propo sed that in a subs et of subjects with dyslexia, visual pro-cessing difficulties might account for otthographic mapping prob-lems owing to the inconsistency of the \isual input.TREATM ENTS RELATED TO THE C EREBELLAROR MOTOR SYSTEMFawcett et al ajid Nicolson and Fawcett reported that many chil-dren with dyslexia peifonii poorly on tests assessing cerebellai" pro-cessing. ^' The cerebellum helps control eye m ovem ents thatimpact reading and might also have a role m. phonologic process-ing (mentally sounding out ttie letters in a word}.'" Tliis is support edby the connection between the right cerebellum and left tem-poroparietal areas. Structural MRI studies by Eckert and col-leagues found a decreased right cerebellar volume in their dyslexicpopulation."** Based on this hypothesis of the role of the cerebel-lum in phonologic and other reading-related processes, an intei-vention ha s been developed, tlie Dyslexia, Dysprtuda and A ttentionDeficit Treatmentan exercise-based app roach to the remediationof dyslexia and related disorders. R eynolds et al conducted a studyusing this approach iji a popu lation of juni or high school stud ents(mean age 9 years, 4 months) identified as being at potential riskof dyslexia by th e D yslexia Screening Test/'"'*^ Although significantimprovements in balance, dexterity, and eye movement control,along with reported improvements in reading, were described,methodologic flaws in the research design and problematic analy-sis and interpreta tion of the results rendered these fuidings ol' lim-ited use in determining whether these interventions aimed atimproving cerebellar fimction indeed result in improvement inthe oral and w ritten language sk ills of children w ith reading diffi-culties. Tlie program is available commercially at tlie Do re Achieve-ment Centers. It involves a home program admii^istered daily bythe parents, with supervision by the center. The InternationalDyslexia Association does not endorse it but encourages futuremethodologically sound studies to validate the efficacy of thisintervention.QUESTIONS TO ASK IN EVALUATINGT R E A T ME N T P R O G R A MSEden and Moats reviewed conmiercial programs that have beenfueled by neiu-oscientific theo ries of dyslexia*' Some a re effective,whereas others are less so. It is important that the child u ndergo

  • 8/3/2019 Current Status of Treatments for Dyslexia_critical Review

    11/16

    7. 4 JounifJl of Child Neurology I Volume lfl. Numb er 10, Octobe r 2004

    a thorou gh evaluation to define what, is likely to bo the best treat-ment modality. Without such an evaluation arid caieful assess-ment of the child's needs and the nature of the program, p arentsmight, invest time and m oney in a program th at is not ap prop riatefor their cliiltl. Tlie reseaich available to the neuroscieiitist is alsonot readily available to the public. Parents should be encouragedto seek help from Ihe International Dyslexia Association or theirpliysician, psychologist, huiguage therapist, or teacher. Howevor,they should also ask the following questions when co nsidering anyspecific iiiterx'ention: Wliat are the short- and long-term gains in accuracy, fluency,

    and comprehension of the intei'vention? Do they do baseline and post-treatment standardized assess-

    ments to measure outcome? Is it adntinistered intensively? Is there support following the intensive treatm ent to ensu re that

    the child practices and maintains gains? Is it a cost-effective solu tion ? Has the intervention been rigorously evaluated with scientifi-cally designed stud ies and rep orted in peer-reviewed studi es in

    reputable journals? Do these studies use standard readingassessments? Eden and Moats noted tliat only two commerciallyavailable program s fell into tha t category, emphasizing the needfor this research."'

    " Wliat ai'e the training requiremen ts to becom e a proficient ther-apist?

    Paren ts and professionals can also find reviews of reading pro-grams offered in the schoo ls by going to Torgesen's Center forReading Research Web site,

  • 8/3/2019 Current Status of Treatments for Dyslexia_critical Review

    12/16

    Current Status of Treatments for Dyslexia / Alexander and Slinger-Coitstunl 755

    PHONOLOGYiPERfEPTION P R OE FUNCTION / rNTENTION

    READINGiPER'/EPTION PROIiUCTICiNi

    Figure 3. The development of the phonologic system: a visualschematic illustrating the neural substrates and networks needed forthe optimal development of the phonologic system. The stoplightsserve to illustrate whether th e neural substrates allow for e fficient net-working Igreen), as is shown here. The stoplights can be used toexplain treatment plans, illustrating when substrates are subop timal,resulting in a "bott leneck" (yellow), orare nonexistent, requiring a"detour."

    niajjping, and red represents a lack of input from that neuralcompon ent, requii-ing the overreliance on other comp onents andthe wiring of atypical networks. With impaired inputs, bottle-necks or "roadblocks" to learning occur. The more distinctcomp onents of sensory input or cortical representations mustbe relied on m ore frequently for skill acquisition; the less dis-tinct are ignored. It is hypothesized that a tyjie of "Mattheweffect" occurs: the strong become stronger , and the weakbecome weaker."'^^ Thus, children with phono logic weaknes sdo not ch oose to engage in activities that use this system . Theymust be immersed in it in an explicit and systematic fashion,as noted above, to develop the necessary neural networks.Therefore, an analytic app roach as to whic h pathw ays are welldeveloped iind which are not is essential for the plamiiiig ofeffective intervention strategies.

    The working memory block, which repre sents the time-sensi-tive "slave" systems of the central executive system that areresponsible for retrieving, holding, and manipulating informa-tion for processin g. It has a different developm ental tim etablethan that of executive function, wMch is represented as a higherlevel of processing on the sche ma tic.* The role of executive func-tion as strategist, top-down processor, and controller of atten-tion to tasks and regulator of motor intention is illustrated bybroken lines to signify that it is not as fully developed in theyoung child. Deficits in these executive functions are beingconsid ered as a possible third c ore tleficit in dyslexia after thephon ologic and rapid nam ing core deficits (Bem inger VW, per-sonal communication, 2003).

    C O M P O N E N T S IN T H E D E V E L O P M E N TO F T H E P H O N O L O G I C S Y S T EM

    If the assessment reveals that the individual with dyslexia hasdifficulty in the phonologic system, one should consider iill of

    F. FrWT ION /TNTFNTION

    Figure 4. The development of skilled oral read ing: a visual schematicillustrating the neural substrates and networks needed for the opti-mal development ofskilled (fluent, with appropriate expression andcomprehension) oral reading. The stoplights serve to illustrate whetherthe neural substrates allow for efficient networking {green), as isshown here. They can be used toexplain treatment plans, illustrat-ing when substrates are suboptimal, resulting in a "bottlenec k" {yel-low), or are nonexistent, requiring a "detour."

    the poss ib le bo t t lenecks h inde r ing s t rong synapt ic connec -t ionsthe l inguist ic and the nonlinguist ic. Are moto r ic pho ne-mic sequences produced eas i ly and cons is ten t ly? Does theindividual have soivialosensory awareness of the aiticulatoiy ges-tures? Is the weaker pro cess a lower-level auditory processinginefficiency? Does the child look at your mouth when auditoryinput is not clear? Is the environ ment a factor? Has the child hadmultiple bout s of hearing loss owing to effusions? Is ther e a pos-sibility of subclinical seizures? Are the re comorbid affectivedisorders? Is the child inattentive to all sensory stimuli? Is thechild impulsive, disorganized, or unable to use strateg ies? Inter-ventions should be designed accordingly to addres s any of thesefactors.

    C O M P O N E N T S IN T H E D E V E L O P M E N TO F R E A D I N GRiUTieUiart et al observed that reading can be viewed as an inter-active process between information processed from current sen-sory information (bo ttom up ) and the meaning of what has been read(top down)."' The connectionist models support this \iew. Oralreading is the most demanding, and P^igure 4 represents the neiu-alcomponents necessary for the development of this skill. A combi-nation and integration of distinct phonologic, morphologic, ortho-graphic, and semantic rcpresentiitions for the decoding of a wordare optimal for nonnal readiiig development (accurate and auto maticdecoding) according to Snowling and Nation.'^ Harm and Seiden-berg's computer simulations coufuiu the need for tliis iuten^lay,"Ardculatory and prosodic representations are necessary for appro-priate oral production but also for enhancement of phonologic,mo rphologic, antl seman tic m aps. Without efficient phono kigic aaidmoqahologic decoding ability, the reader must rely on context(semantic and syntactic cues).*^' The transition into flueril reading

  • 8/3/2019 Current Status of Treatments for Dyslexia_critical Review

    13/16

    75(i Jounial of Child Nearnlmjy I Volume 19. Number 10, Octobe r 2004

    with comprehension depends on developing orthographic auto-maticity but also on syntactic competence and se mantic strength.

    To confound the issue further, an appreciation of the devel-opmental course is essential. Snyder and Downey found that S- to9-year-old children's syntactic knowledge, followed by their abil-ity to retell a story and th eir wo rd retrieval ability on a co nfronta-tion naming task, accounted for better reading comprehension.""Older cMldren (11-14 years) w ere found to rely on bottom-up andtop-down strategies, depending on the m aterial being read. Bottom-up ])lu)nrtic processes are used to decode isolated unfamiliarwords ill less fainiUar text; more top-down strategies are usedwhen reading stories and text on familiar topics. At this age, theirdiscoui"se processing skills, followed by their phonolog ic aware-ness abilities, accounted for the greater variance in their readingscores. Weak phonemic representations result in weak phono-logic represen tations, Ihottght to be tiie con ' deficit in developmentaldyslexia'' ' Orthograpiiic representations are acquired more effi-ciently if there is an appreciation of the phonologic componentsof the word. Likewise, phon ics rules aj'e difficult to apply withou ta strong phonologic base. Some children might also complain ofthe wo rds swimm ing or mo\i ng on the page, making it difficult tokeep their place and causing fatigue, as well as placing them at riskof orlhograp liic mappiitg deficits.

    Single-word reading is typically more markedly affected indyslexic indi\i(luals owing to the weakness of the phoneme, mor-pheme, and orthographic representations. However, children withstrong cognitive and semantic abilities (lexical-semantic repre-sentations) can offset the severity of the decoding deficit in con-textualized text reading. They make good use of context for thedecoding of unknown words and exliibit greater strength in com-prehension than would be expected. Unfoitiinately, this stratejjvalone is less efficient than the com bination of phono logic decod-ing and orthograp hic kn owledge b ecause reading material is oftenon unknown topics (decontextualized).

    As content becomes more sj-iitactically complex, the childrcquiies a facility with syntax to be able to read and understandthe m aterial, especially if its conten t is not familiar. Dyslexic indi-viduals often have a liistory of poor morphosyntactic develop-ment. Thus, more ambiguous and abstract language presentsobstacles to comprehension. Similarly, the impoverished vocabu-lary stores of sonte children seriously impact their reading com-prehers ion; althougli they might be able to decode the w ord, theydo not know w hat it means.

    If a child pre sent s w ith a reading disability, cons ideration ofeach factor on the schem atic might clarify which factors a re play-ing a role and need to be addressed ui the treatment plan. Weak-ness hi the representation of articulatoi-y gestui"es ;UM1 phonologicreprese ntation s implicates lower-level sensory processing, as do dif-ficulties with auditory processing. Do the chikiren complain ofwords moving on tiie page? Talcott et al found a unique vaiiancetor visual motion sensitivity and orthographic skills and a similarvariance for auditory sensitivity to change and phonolog ic skills ina subset of subjects with dyslexia.'"* Rapid word retrieval is oftena factor in inefficient reading an d is thought to b e the result of deficitsin phonologic, morphologic, and semantic processing; attention;executive function; articulatoiy processing; and/or a weak visual-verbal coimection.^'^ There is presumed to be an interplay between

    all of these neural com ponen ts, so that a breakdown in ;my one coulresult in proble ms. Wolf et al poin ted out tliat tiiese same n etw orksubserv e reading and might acco unt for the word retrieval deficitbeing found in the poorest readers.- Children with these retrievadeficits progress more poorly and have significant difficulty witlsight word reading, especially with fluency. A poor vocabulaiy suggests weak scmiintic representations, creating fewer resources focomprehension. A weak syntactic system would contribute lo difficulty with comprehension as well. Impaired attention, workingmemoty, and executive function and intention resources couldcontribute to inefficient acquisition of reading from both a bottom-up and a top-down app roach. Slow temporal processing strainthe time-sensitive working memory system too. lnter\ 'entiondesigned to add ress t he need s of the iiiclivickuii cliikl should consider all of these factors.

    Tlie most prevalent comorbid condition impacting the development of the individual with dyslexia is attention deficit. Optimaattention increases leaming. Attention deficit results in inconsistent perception of stimuh hampering tjte development of stronneural connections and weakens the working memory necessarfor processing multiple perceptions. Optimal treatment of thattention deficit is an imp erative. The child who is stmggling withcognitive and linguistic development places mo re demand on theattention system when leaming, and research has found it to be deterrent to a good response to intervention.SUMMARYAltliougli treatment studies iiave shown that tiie m^ority of children respond to evidence-based treatment interventions, therare still a signific;uit num ber of ciiildren wh o m e resistant to treatment. They are the challenge s for future research and t he cliildrewho require more comprehensive evaluation and individualizedinten.'entions. As described by Heilman ;uid Alexan der,'' altho ughappropriate language intervention is tiie key component in thtreatment plan for the child with oral and/or written languagimpairments resulting from a faulty foundation in the phonologisystem, otlier factors mu st be considered for optimal outco me . Thchild's attention, working memory, and executive functions musbe assessed and treated optimally. Sensorimotor deficits, includingdysgiapliia, can impact skill acquisition and should also be remediated. The linguistic and social emotional environm ents at homand school must be evaluated and addressed with treatment inecessaiy. Is ther e evirtence of an associated p sychiatric disorder(Considering the high degree of comorbidity between attentiondeficit hyperactivity disorder |ADHD|. mood disorders, and anxiety disorders, a careful assessment of the child's psychologic andemotional s ta tus is of ten extremely important . The reader ireferred to the aiticle by Sundheim and Voeller in this issue.'Related to this is the child's ability to persev ere in the face of frustration, which is an extremely valuable asset. Some children arbom with that trait, others have to be encom aged to develop it, ansome have decided that they will never learn to read and have giveup. Reinforcement of the approp riate work ethic will allow the chilto become successful in spite of i)eing less dextrous with language, fine motor skill, or organizational abilities. Compensatoraccomm odations should be considered; does the child need mor

  • 8/3/2019 Current Status of Treatments for Dyslexia_critical Review

    14/16

    Current Status of Treatmenls for Dyslexia / A/^ranrffr (iiiil Slingo-Corislaul 757

    time, a quiet room for test taking, an FM ajuplifier, a scribe, avoice-activated word processing program, or Books on Tape fromthe Library for the B lind and D yslexic?

    A child's language development is a dynamic process. The clin-ician's challenge is optimally tracking this process, identifyingdeficits tha t can h inder optim al acquisition of critical language skills,and guiding interventions to ad dress them , Tlie clinic ijui should con-tinue to mon itor progress even aft er Intensive treatment has moveda child's performance into the average range. Behavioral and imag-ing studies have deinoiistrated that the newly strengttiened languagesystems might continue to have subtle weaknesses that mightimpede acquisition of Xi\e skills called for at the next level. The sam eprocess of assessnienl and thoughtful evaluation of all of the fac-tors that need to be in place for optimal development must berepeated. With the advent of more rigorous intervention research,the outlook for the child with dyslexia is much more optimistic.As the science of intprvention grows, more refined and sophisti-cated techniques will become available, and the individual withdyslexia will be free to function even more efficiently at school,at home, and in the workplace.References1. Torgcseii .IK: Lessons learned from respiirch on intervention for stu-dents with difficulty leaniing to read , in Mc( 'ardie P, Chhabra V (eds):nc . Voice of Evidence In Reading Resea rcli. Baltimore, MD, BrookesPublisiung Co, 2004, 355-382.

    2. Snow C. Bums M, Griffin P; Preventing Reading Difficulties inYoung Children. Washington, DC, National Academy Press, 1998.3. National Reading Panel: Teaching ChiUlren to Read: An Evidenced-Based Assessment of the Scientific Research Literature on Readingand Its Im.pliCOtioria for Rending fii-'^ti-iirlioti. Presented at theNationaJ Institutes of Child Health aiui Ihinuui Development, Wash-ington, DC, 2000.4. Rayner K, Foonnar BR, Perfetti CA. et at: How psychological scienceinforms the teaching of reading. PsgchnI Sci Public Interest2001;2:31-73.5. Tiinnier W Ch^man J: The reading recovery approach to preventiveearly interventio n: As good as ir gets? Read Psgchol 200;}:24:405-428.6. Clay M: The Early D etection of Reading D ifficulties. Auckland, NewZealand, Heinemann, 1985.7. Denton C, Mathes P: Intei-vention for struggling readers, in Foorm anBR (ed): Preventiriy and Remediating Reading Difficulties: Bring-ing Science to Scalp, "nnioniuni, MD. York Pres s, 2003, 229-252.8. Torgt'son .IK, Wagner RK, Rashotte t"A, et aJ: Preventing reading fjiil-ure in yoiuig children w ith phonological processing disabilities; Groupand individual response s to instruction. JEdvc Psychol 1999;4:579-593.9. Lindaniood V:Avdilo>fjDisci-imination in Depth. Austin, TX, PRO-

    ED, 1984.10. Vellutino K Scanion D. .lacoard J: Toward distinguishing betweencognitive and ex periontial deficits as |>riniai7 source s of tlifficulty inlearning to read: A two y ear follow-nji of tlifriciill t o rem ediat e and read-ily remediated poor readers, in Foorman BR (ed): Preventing andRemediating Reading D ifficulties: Bringing Science to Scale.Tim-onium, MD, York Pr ess, 2003, 73-120,11. Torgesen J. Alexander A. Wagiier R, ct al: Inlensivc rem edial instruc-tion for ch ildren with .'*e\'ere reading disabilities: Imm ediate and long-term outcomes from two instructional approaches. J Learn Disabil2001;34:33-58.12. Lindamood P: The Lindamood Phoneme Sequencing Program forReading, Spelling and Speech. Austin, TX, PRO-ED, 1998,13. Woodcock R, Matlier N: Woodcock-JoliriJton Tests of Achievement,

    Revised. Allen, TX, DLM Teacliing Resom-ces, 1989.14. Wechsler D: Wechsler hitelligencc Scale for Children-Revised. NewYork, Psychological Corp oration, 1974.

    15. Torgesen JK, Rashotte CA, Alexander A: Progress towai^ds under-standing the in structional condiUons necessar y for r;niodialing read-ing difficulties in older children, in Foorman BR (ed): Pifventingand Remediating Reading Difficnltics: Bringing Science to ScaleTlmonium, MD, York P iess, 2003, 275-298.16. MacPhee K: Spell, Read Phonological Auditory Training. Charlot-tetown. PEl, Learning Systems, 1998.17. Wied erholt .J, Bryant B: Gray Oral Reading Test, 3rd Edition. AustinTX, PRO-ED, 1992.IS. Seniel E, Wiig E, Kecord W: Cliiiicat Evaluation of Language Pun-damental% Timri Edition. SanAnton io,TX, Harcourt. Brace & Company, 1995.19. Pokom i J, Worthington C, Januson P: Phonological aware ness inter-vention: Comparison of Fast ForWord, Earobics, and LiPS. J Educ Res2004;97:147-157.20. Cognitive Concepts, Inc: Eai-obics Auditor^ Devetopment and Phonics Reading Pmgmm. Evaiiston, IL, Cognitive Co ncept s, 1998.21. Scientific Learning C oiitoi-ation: f n.sf ForWord. Berkely, CA, ScientifiLearning Corporation, 1996.22. Wolf M, O 'Brien B, DonneOy K, et al: Working for time: Reflections onnaming speed, readin g fluency, and interven tion, in Foorma n BR fed):Preventing and Remediating Reading Difficulties: Bringing Sciencto Scale, fimonium, MD, York Press, 2003, 355-380.23. Lovett M, Laterenza L, Boiden S,et al: Components of effective reme-diation for developmental reading disabilities: Combining phonolog-ical anti strategy-based instruction to improve outconie,s. J EducPsychol 2000;92:263-2S8.24. Wolf M, Miller L, Donnelly K: Retrieval, Automaticity, VocabtilaryElaboration. Orthography (RAVTI-O): A comprehensive fluency-basedre a d in g in t e rv e n t io n p ro g ra m. J Learn Disabil 2000:33 :322-324.25 . SiniosPG, Fletcher JM, Bergman E, et al : Dyslexia-specific brain acti-vation profile becomes non ual following successful renieetial traini i^.Neurology 2002;58:120;i-1213.26. Shaywitz BA, Shaywitz SE, Blachniaii B, et al: Development of leftocfipitotemponil systems for skilled reading in children after a phonol-ogy based intervention. Bioi Psychiatry 2004;55:926~933.27. CohpnJ: SkUi.stical PonH'rAnahfsis for tlie Behavioral Sciences. Hill

    dale, NJ, Lawrence Erlbaum, 1988.28 . Ricliards TI.,, Corina D, Serjifmi S, et al: Effects of a phonologically dri-veti treatment for dyslexia on lactate levels measuied by proton MRspectroscop ic imaging. Am J Neammiiiol 2000:21:916-922.29. BemingerVW, N^Ey WE, Carlisle J, et aJ: Effective trea tm ent for chil-dren with dyslexia: Behavior and brain evidence, in Foorman B (ed)Preventing and Remediating Reading Dijfic-ultix's: Bringing Sciento Scale, "nmonium, MD, York Press , 2003, 381-418.30. Torgesen .IK, Wagner RK. Rashotte CA: Test of Word Reading Efficienc(TOWRE). Au stin, TX, PRO-ED. 1999.31. Mann MW, Seidenberg MS: Phonology, reading acquisition, jind dyslexiaInsiglits from conneiiio nist m odels. Psychol Rev 19f)9; 106:491-528.32. Orton J: The Orton-GiUiiighan approach, in Money J (ed): Tlie Dis-abled Reader: Education of the Dyste.iic Child. Baltimore, MD. The

    John Hopkins Press, 1966,33. Mclntyre- C .Vtckeru\g,J i^dsy. Clinical Studies o f Mvltisensoi-y Structured Language Education for Students with Dyslea-ia and RelatedDisorders. Dallas, TX, International Multisensory Stnictured Lan-guage Education C ouncil, 2001.34. Guyer B, Bank.'s S, Guyer K: Spelling bnpiwement for College Stu-dents Who Are Dyslexic. Cliniral Studies of Multisensory Stt-uctiiredLangiiage Education for Stvdents With Dysle^ria and Related Di.torders. Presented at the International Multisensory Structured Lan-guage Education Council, Dallas, TX, 2001.35. Jast akS , Wilkinson G: Wide Range Achievement Test-Revised. Wilmington, DE, Jasktak Associates, 1984.36. Greene J: Systematic phonology: The critical element in teachingreading and lajiguage to dyslexics, in Mclntyre C. Pickering J (eds):Oinicai Studies of Multiseii.soifj Stnictured Language Education fo

    Students ivith Dysle.ria and Related Disorders. Dallas, TX, Interna-tional Multisensory Structured Language Education Council, 2001,17.3-188.

  • 8/3/2019 Current Status of Treatments for Dyslexia_critical Review

    15/16

    75 8 Journal of Child Neurology I Volume 19, Nu mb er 10, Oc tob er 2004

    37,

    38 .39,

    40 .41,

    42 .43 .

    44.

    45 .

    46.47.48.

    49,

    50.5 i.

    52.53.

    54.

    Maskel S, Felton R: Analysis of achievement at the Hill Learning Cen-ter: 1990-1994. in Mclntyre C, Pickering J (eds): Clinical Studies ofMultisensory Structured Language Education for Students withDyslexia and Related Disorders. Dallas, TX, Inteni ationa l M ultisen-sory StmcUired Language Education Council, 2001, 121-137,WoodcockR: Woodcock Reading Mastery Test-Revised. Circle Pines,MN, AGS, 1987,Oakland T, Black JL, Stajiford G, et al: An evaluation of the d yslexiatraining pn)gram: A multisensory method for pronujting reading in stu-dents with reading disabilities. J Learn Disabil 1998;31:140-147.Cox AR: Alphabetic Phonics. Cambridge, MA, Educational Publish-ing Service, 1992.Hook P, Jone s S, Macaruzo P: The efficacy of FastForWord trainingon facilitating acquisition of reading skills in children with specificreading disabilitiesA longitudinal study, Ann Dgsle.(ia 2001;51:McGniness C, McGuiness G: Reading Reflen-. Mt. Dora, FL. ReadAmerica Inc.,1998.Ileilmaii KM. Alexander AW: Treatment of developmental language dis-orders, in Noseworthy JH (ed): Neurotogicai Tlterapeulics: Prlnci-ptes and Practice. New York, Martin D unitz, 20t)3, 2751-2767.Wolff PH, Michel GF, Ovrut M: Rate variables an d autom atized nam-ing in developmental dyslexia. Brain Lang 1990;39:556-575.Fawcett A, NicoLson R, Dean P: Impaired performance of childrenwith dyslexia on a range of cerebellar task s. Ann Dyslexia 1996;46:253-2.59,Torgeson JK, Wagner RK, Rus hette CA: Longltu

  • 8/3/2019 Current Status of Treatments for Dyslexia_critical Review

    16/16


Recommended