M. Maziade et al., Prolongation of brainstem auditory-evoked responses in autistic probands and their unaffected relatives, ARCH G PSYC, 57(11), 2000, pp. 1077-1083
Background: Brain function, as indexed by brain electrical activity, is her
itable in humans, and it may be impaired in autism. Autism also has strong
genetic determinants, and like all major psychiatric disorders, its complex
clinical phenotype renders genetic studies difficult. Innovative strategie
s focused on alternative biological phenotypes are needed.
Methods: The early brain auditory-evoked response was assessed in 73 autist
ic probands and 251 relatives who were compared with 521 normal controls.
Results: We first confirmed in the autistic probands the presence of a slow
ing in nerve conduction in the auditory system as expressed by the prolonga
tion of early brain auditory-evoked response under the form of I-III interp
eak latencies (IPLs). Furthermore, we observed the same I-III IPL prolongat
ion in the unaffected first degree relatives of the autistic probands compa
red with controls. Despite clear evidence of a coaggregation of autism and
I-III IPL prolongation in families, the IPLs did not seem to be the sole li
ability factor for autism as suggested by the observation of 52% of familie
s in which the autistic proband and relatives showed normal IPLs.
Conclusion: A prolongation of the early brain auditory-evoked response IPLs
may be a marker for one of several deficits underlying autism and deserves
further analysis as a potential alternative phenotype for the disorder.