The long term objective of this research is to develop reliable and sensitive subjective judgment procedures that can provide important information to the fitting and verification of hearing aid performance in children.
The specific aims of the proposed investigation are as follows: (1) to determine the effects of sensory and cognitive processes on the formation of subjective judgments in normal-hearing and hearing- impaired children, (2) to investigate the interaction between development and degree of hearing loss on the ability to form subjective judgments, and (3) to implement a subjective judgment procedure in the perceptual evaluation of two hearing aid prescriptive strategies. In the first of three experiments, the perceptual dimension of clarity will be judged by normal-hearing and mild to moderately hearing-impaired children (ages 8-12 years) for sentences that are equated in bandwidth and loudness but vary in spectral shaping (uniform vs. high-frequency emphasis vs. low-frequency emphasis), spectral slope (6 dB/octave vs. 3 dB/octave) and number of talkers (one versus six). Subjective judgments will be measured by a paired comparison procedure that incorporates a confidence rating. Testing will be conducted over a number of sessions to measure the effects of learning and to document the inter-and intrasubject variability. Demonstration of the child's ability to discriminate from among pairs of stimulus conditions that differ in spectral shape and slope will determine the sensory component. The cognitive component will be ascertained through the existence of transitivities (logical operations) in response patterns, quantifiable by the confidence ratings. The same design will be implemented in a second experiment, but will evaluate hearing-impaired children of younger ages (5-8 years) and with different degrees of hearing loss (mild to severe). The third experiment will incorporate the subjective judgment procedure into the pediatric hearing aid evaluation process. Hearing-impaired children will judge the clarity of sentences processed by two hearing aid prescriptive strategies, one developed for linear amplification (NAL-R) and another developed for wide dynamic range compression (DSL[i/o]). Subjective judgements will be measured systematically using different talkers presented at soft, medium, and loud input levels. Results should determine whether hearing-impaired children are able to distinguish between different prescriptive strategies and whether clarity preferences are reliable and sensitive.
| Winter, M; Eisenberg, L (1999) Amplification for infants: selection and verification. Otolaryngol Clin North Am 32:1051-65 |
