Electrophysiological evidence for delayed mismatch response in infants at-risk for specific language impairment.

The present study investigated whether delayed auditory processing typically found in children with specific language impairment (SLI) can already be observed in the event-related potentials of 2-month-old infants. Infants with and without a family history of SLI were tested in a passive auditory oddball paradigm with CV-syllables differing in vowel duration. For the long syllable, a positive mismatch response occurred in the difference wave between deviant and standard. Its amplitude was higher in infants during quiet sleep than in awake infants, although its peak latency remained unaffected by alertness. Awake infants showed an adultlike mismatch negativity preceding the positivity. Risk for SLI was reflected in the latency of the positive mismatch response, which was delayed in infants with risk compared to infants without risk. This latency difference suggests that 2-month-old infants at risk for SLI are already affected in processing an auditory stimulus change of duration.