Automatic Pre-Attentive Auditory Responses: MMN to Tone Burst Frequency Changes in Autistic School-Age Children

OBJECTIVE: Autism is a pervasive developmental disorder that includes deficits in socialization, communication, and adaptive functioning. The mismatch negativity (MMN) is a component of evoked response potentials that reflects pre-attentive change detection. The purpose of this study was to determine whether a group of autistic school-age children had abnormal changes in auditory MMN and to analyze and compare the results with an age-matched group of normal children. MATERIALS and METHODS: This prospective study was carried out on 31 autistic school-age children. Thirty age-, gender-, and IQ-matched children served as a control group. The children were evaluated through diagnostic procedures that included psychometric and speech language tests and audiological assessments. Auditory MMNs were recorded from all participants, and the peak amplitudes and latencies were measured. RESULTS: The mean ages were 11.3 +/- 2.8 and 11.2 +/- 3.2 years for the autistic and normal children, respectively. The MMN amplitudes obtained from the two groups were found to be statistically significantly different. The MMN amplitudes were reduced, and latencies were prolonged in autistic versus normal children. CONCLUSION: Our results suggest that children with autism do have auditory changes at the level measured by MMN, mainly pre-attentive response, which argues for a doubt on affection of the supposed origin of auditory MMN in those children.