Comparisons of Word Comparisons of Word Recognition Performance Recognition Performance in Normal-Hearing in Normal-Hearing ChildrenChildren

A Pilot Project by Tiffany A Pilot Project by Tiffany Skinner and Stephanie TaylorSkinner and Stephanie Taylor

Spring 1999Spring 1999

To compare word recognition scores To compare word recognition scores in normal-hearing five year olds using in normal-hearing five year olds using the WIPI under the following four the WIPI under the following four conditions:conditions:

– Use of the WIPI as a closed-set test in quietUse of the WIPI as a closed-set test in quiet– Use of the WIPI as a closed-set test in the Use of the WIPI as a closed-set test in the

presence of background noisepresence of background noise– Use of the WIPI as an open-set test in quietUse of the WIPI as an open-set test in quiet– Use of the WIPI as an open-set test in the Use of the WIPI as an open-set test in the

presence of background noisepresence of background noise

According to Papso and Blood (1989), According to Papso and Blood (1989), word recognition testing, usually word recognition testing, usually administered in quiet, has been administered in quiet, has been criticized because of its lack of criticized because of its lack of difficulty and insensitivity to hearing difficulty and insensitivity to hearing loss. As a result, the introduction of loss. As a result, the introduction of background noise to word recognition background noise to word recognition testing has been advocated to reduce testing has been advocated to reduce scores and increase test sensitivity.scores and increase test sensitivity.

In a study by Hodgson (1973), it In a study by Hodgson (1973), it was found that children attained was found that children attained significantly higher scores when significantly higher scores when the WIPI was given as a picture the WIPI was given as a picture test (closed-set test) compared to test (closed-set test) compared to open-set testing using the WIPI open-set testing using the WIPI word lists.word lists.

SubjectsSubjects

Five children (3 female, 2 male) Five children (3 female, 2 male) participated in this study. All were participated in this study. All were five years of age and had normal five years of age and had normal hearing as evidenced by the hearing as evidenced by the results of the annual hearing results of the annual hearing screenings conducted at the screenings conducted at the preschool.preschool.

Test StimuliTest Stimuli

Word Intelligibility by Picture Word Intelligibility by Picture Identification (WIPI)Identification (WIPI)

ProcedureProcedure

Prior to testing, an experimental schedule Prior to testing, an experimental schedule was developed for each child to was developed for each child to randomize the order in which the word randomize the order in which the word lists were presented for each condition.lists were presented for each condition.

The conditions were presented in the The conditions were presented in the following order for each child:following order for each child:

– WIPI, closed-set in quietWIPI, closed-set in quiet– WIPI, closed-set in noiseWIPI, closed-set in noise– WIPI, open-set in quietWIPI, open-set in quiet– WIPI, open-set in noiseWIPI, open-set in noise

Test OrderTest Order

I II III IVClosed, Closed, Open, Open,

Child Quiet Noise Quiet Noise A List 1 List 2 List 3 List 4B List 4 List 1 List 2 List 3C List 3 List 4 List 1 List 2D List 2 List 3 List 4 List 1E List 1 List 2 List 3 List 4

ProcedureProcedure

All speech stimuli were presented at 60 All speech stimuli were presented at 60 dB HL.dB HL.

When testing in noise, a +6 When testing in noise, a +6 signal/noise ratio was used (60 dB HL signal/noise ratio was used (60 dB HL speech, 54 dB HL noise).speech, 54 dB HL noise).

All testing was conducted in the All testing was conducted in the soundfield via two loudspeakers.soundfield via two loudspeakers.

All testing was conducted at 45 All testing was conducted at 45 degrees azimuth.degrees azimuth.

Summary of Performance Summary of Performance in Each Test Conditionin Each Test Condition

Condition Avg % Score Avg # Missed

Closed quiet 94.4 % 1.4

Open quiet 93.6 % 1.6

Closed noise 88.8 % 2.6

Open noise 80.0 % 5.0

As shown in the summary of results, the As shown in the summary of results, the children performed the worst in the children performed the worst in the open-set with noise condition (80%) open-set with noise condition (80%) followed by the closed-set with noise followed by the closed-set with noise condition (88.8%).condition (88.8%).

According to Papso and Blood (1989), According to Papso and Blood (1989), scores falling within 88-100% are scores falling within 88-100% are considered normal on the WIPI. considered normal on the WIPI.

– The only condition whose score fell outside of the The only condition whose score fell outside of the normal range was the closed-set in noise (80%).normal range was the closed-set in noise (80%).

From these results, it is apparent From these results, it is apparent that noise is the biggest predictor that noise is the biggest predictor of performance, and open-set of performance, and open-set versus closed-set does not seem to versus closed-set does not seem to be as relevant.be as relevant.

Summary of Individual Summary of Individual PerformancePerformance

Closed, Closed, Open, Open,

Child Quiet Noise Quiet Noise

A 92% 92% 84% 88%

B 100% 84% 92% 84%

C 92% 100% 100% 76%

D 96% 76% 100% 64%

E 92% 92% 92% 88%

The result of this pilot project shows that The result of this pilot project shows that word recognition tasks administered to word recognition tasks administered to normal-hearing children in noise yields normal-hearing children in noise yields worse scores than the same tasks worse scores than the same tasks administered in quiet. This is relevant administered in quiet. This is relevant because it indicates that currently used because it indicates that currently used word recognition tasks (given in quiet) word recognition tasks (given in quiet) may not accurately reflect how children may not accurately reflect how children will perform in their everyday will perform in their everyday environments which have poor S/N ratios.environments which have poor S/N ratios.

Furthermore, these results support the Furthermore, these results support the importance of improving the S/N ratio in importance of improving the S/N ratio in noisy environments where speech noisy environments where speech intelligibility is critical, such as in the intelligibility is critical, such as in the classroom.classroom.

– A +12 S/N ratio is considered minimally acceptable A +12 S/N ratio is considered minimally acceptable for hard of hearing students; yet, S/N ratios of 0 to for hard of hearing students; yet, S/N ratios of 0 to +6 dB are fairly common in typical classrooms.+6 dB are fairly common in typical classrooms.

– Optimally the S/N ratio should be +30 dB for Optimally the S/N ratio should be +30 dB for hearing impaired students and +20 dB for students hearing impaired students and +20 dB for students with normal hearing (Berg, 1987).with normal hearing (Berg, 1987).

Berg, F.S. (1987). Room Acoutics. Berg, F.S. (1987). Room Acoutics. In In Facilitating Classroom Facilitating Classroom ListeningListening (pp. 89-116). Boston, (pp. 89-116). Boston, MA: College Hill Press.MA: College Hill Press.

Papso, K.F. & Blood, I.P. (1989). Papso, K.F. & Blood, I.P. (1989). Word Recognition Skills of Children Word Recognition Skills of Children and Adults in Background Noise. and Adults in Background Noise. Ear and Hearing, 10Ear and Hearing, 10 (4), 235-236. (4), 235-236.