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Letters to the Editor
March 2002

Prolonged Brainstem Auditory Evoked Potentials: An Autism-Specific or Autism-Nonspecific Marker

Arch Gen Psychiatry. 2002;59(3):288-289. doi:

In their study, Maziade et al1 presented challenging data concerning a possible early brainstem auditory evoked potential response marker for an autistic phenotype. The authors demonstrated that the I-III interpeak latency (IPL) of brainstem auditory-evoked potentials (BAEP) was prolonged not only in persons with autism, but also in their unaffected first-degree relatives compared with age-matched controls. By providing a neurophysiological marker of the autistic phenotype, this finding could be very important to our understanding of autism. However, the authors reported that in 52% of families, neither the proband nor the relatives showed an abnormally prolonged IPL. This finding suggests that BAEP-impaired and -nonimpaired subjects might represent subgroups, and that they should be separated for analysis. If prolonged ILP is not a continuous but a dichotomous variable, and thus indicates subgroups rather than a continuous spectrum, then neither a correlation with autistic symptoms for the whole sample nor the average IPL is likely to be informative in revealing the exact nature of this phenomenon.