LACK OF COGNITIVE IMPAIRMENT IN 1ST-DEGREE RELATIVES OF CHILDREN WITHPERVASIVE DEVELOPMENTAL DISORDERS

Objective. The objective of this study was to test the hypothesis that mild cognitive impairments aggregate in the unaffected first-degree r elatives of probands with autism or pervasive developmental disorders (PDD). Method: The unaffected siblings and parents of 52 PDD probands and 33 Down syndrome and low birth weight controls were administered a battery of psychometric tests- The tests included measures previously found to be depressed in siblings of autistic children as well as cog nitive deficits seen in PDD subjects of normal IQ. In addition, the Vi neland Adaptive Behavior Scales were administered to siblings to measu re the social-communication impairments found in PDD. Results: Neither the siblings nor parents of the PDD probands demonstrated lower cogni tive or adaptive behavior scores compared with controls. Developmental histories did not reveal greater rates of social, cognitive, or langu age delays, nor was there evidence to suggest that relatives of subgro ups of PDD probands were different from each other. Conclusion: These findings indicate that, apart from relatives with PDD, cognitive and s ocial impairments do not aggregate in the families of PDD probands.