HABITUATION OF ALPHA ATTENUATION RESPONSE IN CHILDREN AND ADULTS WITH PSYCHIATRIC DISORDERS

Duration and latency of the alpha attenuation response (AAR) to 50 consecutive single light flashes presented at irregular intervals of 5-20 sec were measured in 241 adults and children, comprising five experimental and four control groups. Visual and automatic analyses were employed. Habituation of AAR duration was demonstrable for all of the adult and children groups. Schizophrenics from the University Psychiatric Service did not differ from Medical School controls, but State Hospital schizophrenics differed from both these groups demonstrating earlier attenuation (shorter latency) and more persistent response (less habituation). Adult psychopaths did not differ from Medical School patient controls. Medical School Hospital schizophrenics manifested significantly shorter latencies than adult controls. Children with hyperkinetic behavior disorders demonstrated longer durations of AAR initially and throughout the consecutive trials compared with age-matched controls. Although habituation was evident, AAR duration never decreased to a level comparable to the controlschildren. Normal children differ from adult controls in demonstrating shorter latencies of AAR as well as a much flatter habituation curve (i.e., less change between initial and final values). Comparison of amount of alpha activity for 3 sec preceding each stimulus indicated that the significant differences obtained between the groups were not due to differences or variations in background activity. The findings are considered in relation to their maturational and clinical significance. © 1969.