[Hearing and language ability in mild and moderate hearing impaired children]

102 children (mean age-7 years 9 mo.) with mild and moderate perceptive hearing impairment who had neither any auditory training nor had used a hearing aid were studied. Mean hearing level was 51.9 dB. Our findings: (1) Speech discrimination score (SDS) correlated with the hearing level at 2, 4 and 1 kHz, in that order. In all patients, SDS gradually worsened to 60 dB before registering a sharp decline; SDS was better than in patients who had acute unilateral hearing impairment and similar audiogram patterns, especially in vowels. (2) Correlation existed between the rate of accurate articulation and hearing levels at 2 and 4 kHz; it improved with age but plateaued at around 8 years. In children with a high tone loss, distortion and confusion of fricatives, explosives, unvoiced affricates and postconsonantal vowel /i/ were marked besides articulation errors commonly attributable to normal speech development. (3) On the WISC and WISC-R intelligence scale, verbal intelligence score had little correlation with performance intelligence and was influenced by hearing levels at 2, 4 and 1 kHz, in that order. When the mean hearing level was over 40 dB, verbal intelligence was frequently below par. Performance intelligence grew worse with age. (4) Children with a mild hearing loss exhibited a slight delay in vocalizing the 1st word and combining 2 words together while in those with a moderate loss, the delay in combining 2 words was pronounced. In both mild and moderate hearing loss, verbal intelligence was low when there was a delay in the ability to vocalize two words together.