Question

9. Children (approximately 11 years old) with cochlear implants (CI) and children with typical hearing (TH) were asked to listen to speech with a background of noise under different conditions in a classroom setting. The different conditions were the number of sound-absorbing acoustic panels hung on the walls in the classroom. This affected the reverberation time (RT). With more panels, there was less reverberation (0.3s). With fewer panels, there was more reverberation (0.9s). The signal-to-noise ratio was measured in decibels (dBA). The higher the number, the speech was louder than the noise. The lower the number (<0) the noise was louder than the speech.

a. Did children with cochlear implants score higher on speech perception at higher signal-to-noise ratios than children with typical hearing? Give data in support of your answer. [2]

b. You are in charge of classroom design for a school with mixed CI and TH children. What do you recommend? Give reasons with data. [2]

Answer 1

1. Cochlear implants (CIs) are used as a treatment for people with severe to profound hearing loss. In these devices the processing strategy is to deliver spectrally broad signals to the auditory system.

Speech recognition is the best in quiet places with sufficient word recognition. However, CIs struggle in noisy situations. However, listening in noise poses much greater difficulty to listeners with cochlear implants (CIs) than the listeners with typical hearing aid

2. In case of children noise effects hearing ability of all children equally irrespective of their current ability to recognize the signals. Thus, noise must be reduced overall for every student irrespective of finding targeted solution for children with CI. As a class in-charge, I would try to maintain the silence in the class as a whole. However, these panel based sound absorption must be tried in quiet environment as in quiet environment, a person with CI finds more difficulty in recognizing speech as compared to a normal child. Some of the common measures taken to improvise the classroom design include –

a) High end use of absorptive surfaces such as carpeting on the floor, soft materials on the walls and acoustical tile in the ceiling to have a higher reverberation rating

b) Use cork or felt pads to reduce noise

c) Placing of speakers at optimal distance