Key WordsGerstmann’s syndrome W Spatial imagery W Stroke
AbstractGerstmann’s syndrome comprises finger agnosia, pe-ripheral agraphia, anarithmetia, and right-left confusion.We here report a single-case study of an 85-year-oldambidextrous man who exhibited pure Gerstmann’ssyndrome (i.e., without aphasia) 10 weeks after a strokeinvolving the angular gyrus in the left parietal lobe. Wehypothesize that, in this case, the main cognitive denom-inator of Gerstmann’s tetrad was a severe dysfunction inmental rotation and translation. This report provides fur-ther evidence for the spatial nature of Gerstmann’s syn-drome.
Acquired Gerstmann’s syndrome is defined by thetetrad of finger agnosia, right-left confusion, apraxic agra-phia, and anarithmetia, and is associated with lesion [1]or dysfunction [2] of the left angular gyrus. This syndromeis rarely dissociated from aphasia, and whether it is anautonomous entity continues to be debated. Multiple cog-nitive failures can account for each component of the syn-drome and only a few studies have provided significantevidence for the existence of an underlying spatial disor-der [3, 4].
Case Report
An 85-year-old ambidextrous man (E.K.), a skilled viticulturistwho had been retired for 10 years, was admitted to hospital with rightfacial-brachial paresis, psychomotor slowing, transcortical sensoryaphasia, and right spatial neglect. Magnetic resonance imaging(fig. 1) showed acute ischemic lesions involving the left angular gyrus(area 39) and the left precentral gyrus (areas 4 and 5), due to embolioriginating from severe left carotid stenosis.
Ten weeks after stroke, aphasia completely disappeared and themain clinical features were mild right facial-brachial paresis and thecardinal signs of Gerstmann’s syndrome. The patient’s examinationrefers to this period. At this time, E.K. was fully oriented and cooper-ative and had a good insight into his deficits. Immediate familymembers indicated a high level of functioning and no signs of cogni-tive deterioration before stroke.
Finger Recognition Failure, Autotopagnosia, Somatagnosia, andRight-Left ConfusionThe examination results relating to these deficits are summarized
in table 1.Under visual control, finger knowledge was relatively spared.
When E.K. was unable to see his hands, there were few errors in fin-ger recognition when his fingers were touched, but he showed severeimpairment in indicating on his own hand the finger moved by theexaminer facing him, both in the crossed condition (e.g. the patient’sright hand and the examiner’s right hand) and the uncrossed condi-tion (e.g. patient’s right hand and examiner’s left hand).
Naming of, and pointing to, body parts were impaired comparedto control subjects. Nevertheless, the errors were close to the targetand he corrected them when he was told he had made a mistake, andno difficulties were observed in everyday life actions requiring spa-tial knowledge of body parts (dressing and putting glasses). This sug-gests a mild degree of autotopagnosia and somatagnosia.
In contrast, there were marked errors in decision about left andright in terms of the examiner’s body with the examiner facing him(incongruous condition) after both simple commands (e.g. ‘touch my
Fig. 1. T2-weighted MRIs and Damasio’stemplates showing the lesion sites.
right shoulder’) or double commands in the crossed condition (e.g.‘touch my right shoulder with your right hand’) or uncrossed condi-tion (e.g. ‘touch my left shoulder with your right hand’). These errorswere reduced when the examiner was facing away from the patient(congruous condition).
Apraxic AgraphiaDue to residual mild right hand paresis, E.K. spontaneously used
his left hand for all writing tasks, but made the same errors whenwriting with either hand. Curiously, E.K. was unable to rememberwhether he wrote with his right or left hand before his stroke,although his relatives said he was ambidextrous, but used to writewith his right hand.
Although reading and copying were remarkably spared, hand-writing (either spontaneous or on dictation) was characterized bycontinuous perseveration of letters. No perseveration was seen usingmobile letters, but E.K. often erroneously reversed them on the hori-zontal or vertical axis. Despite flawless recognition of isolated lettersand numbers, when writing them, E.K. often made orientation errors(mirror-writing) on the horizontal or vertical axis (fig. 2a). Accordingto family members, his handwriting showed no mirror-writing fea-tures before stroke.
E.K. was often aware of the errors and, for the letters ‘K’ and ‘E’,after writing the vertical line first, he often said, ‘it is strange! I don’tknow where I should go’. When asked to orally describe letters, E.K.could recall most letters’ and numbers’ shapes, but often describedthem horizontally or vertically rotated (64% correct). Similar resultswere obtained in a ‘toothpick’ task in which he had to form lettersand numbers with sticks of different sizes (62% correct).
Semantic and orthographic knowledge of letters and numbers wascompletely spared, as shown by intact recognition in the visual
(100% correct) and tactile (98% correct) modalities even if the stimu-li were rotated. E.K. also recognized letters and numbers composedout of sight by guided movements of his finger (98% correct) and hehad no difficulty in oral spelling of written and spoken words (100%correct). E.K. was fully able to type on a keyboard spontaneously andon dictation.
E.K. was unable to write lower case letters and to transcode upperto lower case letters (but not vice versa), but forced choice betweenvisually presented upper case and lower case letters was substantiallycorrect (98% correct). He showed severe impairment in the ability todecide whether alphanumeric stimuli presented on a screen were nor-mally orientated or rotated by B90° or B180° on the horizontal orvertical axis (70% correct).
AnarithmetiaTranscoding tasks (visual-verbal) for units, tens, hundreds, and
operational signs were well executed. E.K. was able to read, repeat,and recognize numbers, but he wrote many reversed (fig. 2a). Com-prehension of numbers was normal: he was able to break down num-bers into hundreds and tens, to point to the larger of a number pair inverbal and in numeric formats, and to estimate prices, distances,weights, and quantities. He could count forwards and backwards andrecite multiplication tables without errors. Serial counting was possi-ble. In written operations, simple problems (e.g. 25 + 12 or 28 – 14)were solved. Number alignment in columns was normal and signs ofspatial neglect were not noted. With more complex operations ofaddition and multiplication involving the carrying of numbers (e.g.25 + 18, 36 – 19, 23 ! 16), E.K. made most errors in reporting theholding values. Mirror errors in writing numbers sometimes contrib-uted to computational errors. E.K. was completely unable to performdivision.
Spatial Imagery and Gerstmann’sSyndrome
Eur Neurol 2004;52:1–6 3
Table 1. Tests for finger recognition failure, autotopagnosia, somatagnosia and right-left confusion
Tasks Com-mands
Correct answers
E.K.a
VC no VC
5 male healthy subjectsb
VC no VC
Finger recognition failurePointing on verbal commandNaming on tactile stimulationIndicating on his own hand the finger corresponding
to that moved on the examiner’s handSubject’s right hand and examiner’s right handSubject’s left hand and examiner’s left handSubject’s right hand and examiner’s left handSubject’s left hand and examiner’s right hand
4040
20202020
4040
20191819
37
10131514
38B2.838.4B1.7
19.2B0.819.6B1.718.8B2.218.4B4.3
34.4B5.9
19B018.6B218.8B2.219.6B1.1
Autotopagnosia and somatagnosiaNaming body parts
On himselfOn the examiner
Pointing to body partsOn himselfOn the examiner
1414
1414
1412
1213
14B014B0
14B014B0
Right-left confusionOn himselfOn the examiner facing the subject
Simple commandsDouble commands
Uncrossed conditionCrossed condition
On the examiner facing away from the subjectSimple commandsDouble commands
Uncrossed conditionCrossed condition
20
20
2020
20
2020
18
10
1311
18
1716
18.8B4.3
19.4B1.7
17.6B518.6B1.1
19.8B0.9
20B018B5.1
VC = Visual control. Figures in italics indicate scores below the normal range.a E.K.: age 85 years, education 9 years.b Controls: age 81.2 B 4.1 (1 SD) years, education 7.8 B 1.6 (1 SD) years.c Scores are expressed as means B 2 SD.
General Cognitive AssessmentLinguistic, semantic, and general knowledge, visual imagery (de-
scription and comparisons of colors and shapes, details of animals,vegetables, and objects, and knowledge of places and historicalevents), abstract verbal reasoning (proverb interpretation, similari-ties and differences), and figural reasoning (Raven Progressive Ma-trices) were normal for his age and suggested a normal level of func-tioning before stroke. There were no signs of aphasia, memory dys-function, gestural or constructional apraxia, neglect (cancellationtests, visual tests and drawing), or visual agnosia. The patient onlyexhibited a mild psychomotor slowing revealed by the time neededfor test completion.
The standard examination is summarized in table 2. Severeimpairment was evident for the Hooper Visual Organization Testand some subtests of the Birmingham Object Recognition Battery.
Discussion
We here describe an ambidextrous man who present-ed, 10 weeks after an ischemic stroke of the left angulargyrus, ‘pure’ Gerstmann’s syndrome, as there were nosigns of executive dysfunction, aphasia, apraxia, or mem-ory or general intellectual disturbances.
‘Finger localization failure’ is the term that best fitsE.K.’s impairment in finger recognition and is probably amore clinically suitable and less interpretative term than‘finger agnosia’ to indicate the finger recognition deficitsin patients with pure Gerstmann’s syndrome [4, 5].
Fig. 2. Spatial errors. a Mirror errors in writing letters and numbers. b In this test, the patient decides whether theupper-case letters are correctly orientated. E.K.’s answers are random. c In this test, the patient chooses which of twostimuli will fit the target with the least number of rotations. E.K.’s answers are random. d No errors in locating townson a Swiss map. e Many errors in placing towns when the map of Switzerland is rotated 180° on the horizontal axis(only the location of Lausanne is correct).
Finger localization failure and right-left confusionwere more marked in the incongruous condition (examin-er facing the patient) than the congruous condition (exam-iner facing away from the patient), as the former obligesthe patient to rotate his egocentric perspective to adapt itto the examiner. In the absence of a significant body sche-ma or a semantic disorder, the patient’s impairment infinger recognition and in right-left judgments suggests adeficit in mentally represented movements.
E.K.’s errors in writing letters and numbers fit the pic-ture of apraxic agraphia (difficulties in writing single let-ters, while oral spelling, copying, and semantic and ortho-graphic knowledge of letters and numbers are preserved),and, more specifically, a peripheral type agraphia (a defi-cit of letter formation written by hand at a stage of periph-eral elaboration and not influenced by the lexical orsemantic properties of words). A peripheral type agraphia
is the writing disturbance typical of Gerstmann’s syn-drome [6]. E.K.’s peripheral agraphia was compatiblewith a dysfunction at the allographic level, the stage atwhich abstract information about letter identities is trans-lated into a written physical code. E.K.’s writing errorsmay correspond either to defective retrieval of the visuo-spatial characteristics of the allographic forms of lettersand numbers from a long-term store or to directionalerrors in executing the motor programs necessary for thewriting of specific letters and numbers.
E.K.’s errors in calculating were compatible with pureanarithmetia, as knowledge of numbers and arithmeticoperators was spared. The prevalence of errors in han-dling the carrying process, in the absence of any aphasicsigns or other cognitive failure, may suggest a spatialdefective manipulation of numbers in the working memo-ry. Although his total inability to perform division is more
Spatial Imagery and Gerstmann’sSyndrome
Eur Neurol 2004;52:1–6 5
Table 2. General cognitive examination
Domain Test Results
Language Montreal Toulouse Protocol [17] normal profile
Memory Digit Span Test [18]Corsi Spatial [18]Rey Auditory Verbal Learning Test (10 words) [19]
immediate recall (total in 3 trials)delayed recall (30 min)
Rey-Osterrieth Complex Figure Test [20, 21]immediate recalldelayed recall (30 min)
150 s, no errors330 s, no errors31 (90 percentile)
Scores below the range are shown in italics. The main impairment is in tasks requiring mental visuomotor manip-ulation of images.
difficult to explain on the unique basis of a spatial disor-der, this possibility cannot be excluded. In fact, the spatialnature of the organization of numbers in a mental map(the so-called SNARC effect) has been demonstrated inseveral studies [7, 8].
Finally, in addition to Gerstmann’s tetrad, E.K. wasseverely and selectively impaired in all tasks requiringmental or visuomotor rotation and translation of images,such as left-right decisions for visually presented handshapes (33% correct), deciding if capital letters wererotated or not (42% correct; fig. 2b), and choosing whichof two figures would match the target with the least num-ber of rotations (60% correct; fig. 2c). Although he easilynamed the main cities in Switzerland, indicated theirlocation on a map (fig. 2d), and correctly estimated thedistance between them in space and time, he was unableto place them on a map that was rotated 180° on the hori-zontal axis (fig. 2e).
The Hooper Visual Organization Test requires the abil-ity to predict an image resulting from the rotation andtranslation of its randomly disposed pieces, as in the con-struction of a puzzle. The Birmingham Object RecognitionBattery length and gap match tasks require mental disloca-tion of lines and circles in order to compare them. In theabsence of significant executive dysfunction or basic vi-sual-perceptive disorders, we interpret defective scores inthe Hooper Visual Organization Test and some subtests ofthe Birmingham Object Recognition Battery as difficultiesin the visuomotor organization of mental images.
The neural model for spatial manipulations of repre-sented images, as proposed by Cohen et al. [9] on the basisof fMRI studies, includes the frontal eye fields (imagescanning), the superior parietal lobule (bulk of computa-tion for mental rotation), and the parieto-occipital border(motion-sensitive processing for computation based onobject motion).
Motor processes occurring in the frontal regions con-tribute to mental transformations of a spatial nature [10],but images of abstract objects seem to require less low-level motor processing than images of body parts, such ashands [11].
Activity in the superior parietal lobule and the intra-parietal sulcus in healthy subjects has been reported in allPET studies [11] and fMRI studies [9, 12, 13] that usedsimilar paradigms of mental rotation. The emerging hy-pothesis is that associative areas of the parietal lobe areprobably responsible for encoding spatial relationships,allocation of visual attention, and integration of sensoryand movement-related responses that are involved in ev-ery act of mental rotation. It is not clear if this neural sys-tem has a specific hemispheric dominance.
Our findings in this single-case study are in line withthose of previous clinical reports of patients showing poorperformance in mental rotation following damage to theposterior and superior parietal cortex [14, 15]. This caseconfirms the association between the left angular gyrus,Gerstmann’s syndrome, and a dysfunction in visuomotorimagery processing. According to Benton’s study [16], this
association could be considered causal and the associationof the four signs of Gerstmann’s syndrome to have morean anatomical than a functional basis. By searching forGerstmann’s syndrome signs in a population of 100brain-damaged patients with different cognitive failures,Benton showed that these signs are too weakly correlatedto consider Gerstmann’s syndrome as an autonomousentity. However, this postulate cannot be conceptuallyapplied to the ‘pure’ cases, such as E.K., which are excep-tionally rare and few of which have been adequately docu-mented.
The case of E.K. strongly reinforces the assumptions ofMayer et al. [4] that ‘when all the four elements of theGerstmann’s syndrome are found in a pure form, they willalways be accompanied by a defective process of mentalmanipulation of images’ and that ‘pure Gerstmann’s syn-drome without such a disorder will never be found’.
Acknowledgement
We thank Professor Luigi Pizzamiglio and the reviewers for theiruseful comments on an earlier version of the article.
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