Backward and simultaneous masking in children with grammatical specific language impairment: no simple link between auditory and language abilities.

PURPOSE We investigated claims that specific language impairment (SLI) typically arises from nonspeech auditory deficits by measuring tone-in-noise thresholds in a relatively homogeneous SLI subgroup exhibiting a primary deficit restricted to grammar (Grammatical[G]-SLI). METHOD Fourteen children (mostly teenagers) with G-SLI were compared to age-, vocabulary-, and grammar-matched control children on their abilities to detect a brief tone in quiet and in the presence of a masking noise. The tone occurred either simultaneously with the noise or just preceding it (backward masking). Maskers with and without a spectral notch allowed estimates of frequency selectivity. RESULTS Group thresholds for the G-SLI children were never worse than those obtained for younger controls but were higher in both backward and simultaneous masking than in age-matched controls. However, more than half of the G-SLI group (8/14) were within age-appropriate limits for all thresholds. Frequency selectivity in the G-SLI group was normal. Within control and G-SLI groups, no threshold correlated with measures of vocabulary, grammar, or phonology. Nor did the language deficit in the G-SLI children vary with the presence or absence of auditory deficits. CONCLUSION The auditory processing deficits sometimes found in children with SLI appear unlikely to cause or maintain the language impairment.