Some Aspects of Temporal Processing Deficits in Individual with Learning Disability

Abstract

Individual with learning disability are likely to have auditory temporal processing deficit. Auditory temporal processing deficits lead to inability to process three main temporal features of speech sounds such as envelope, periodicity and fine structure cues. Since TMTF signal involves envelope, periodicity and fine structure, TMTF assessment would help in understanding the ability of the individual in perceiving the amplitude variation in continuous speech. To address this issue (a) TMTF function across different frequency modulation rates in individual with learning disability and individual with normal hearing, (b) age related changes in TMTF perception at different modulation rates in individual with normal hearing and children with learning disability, (c) comparison of phoneme recognition scores in the presence of noise between the normal hearing individual and individual with learning disability and (d) the correlation between TMTF perception and phoneme recognition scores in the presence of noise for children with learning disability on 24 individuals with learning disability and 20 normal hearing children were measured. TMTF threshold was obtained at different modulation frequency (fm: 4, 16, 32, 64 & 128 Hz). SPIN scores obtained in noise at 0 dB SNR and without noise in both the groups. TMTF threshold showed higher value for children with learning disability than normal hearing subjects with a peak sensitivity at 16 Hz and 4 Hz in normal and individuals with learning disability respectively. SPIN score showed no significant difference between normal and individuals with learning disability. Results suggest that TMTF is a better predictor of temporal processing deficit.