Preliminary report on cognitive and adaptive behaviors of preschool-aged males with fragile X

Preliminary results are presented of 18 males with fragile X (fra X) syndrome between the ages of 16 and 64 months compared to non-fra X males individually matched on age and overall IQ. Cognitive assessments were conducted with either the Bayley Scales of Infant Development or the Stanford-Binet, 4th edition. Adaptive and maladaptive behaviors were assessed by the Vineland Adaptive Behavior Scales and the Child Behavior Checklist, respectively. Forty-four percent of the fra X group had overall IQs in the borderline to average ranges. In cognitive assessments with the Stanford-Binet, the fra X group scored lower than controls in quantitative and short-term memory areas. There was no evidence, however, that overall IQ declined among the fra X children across the 16 through 64 month age period. Older (≥ 40 months) fra X males scored lower in the communication and socialization adaptive behavior domains than younger (< 40 months) fra X males and older controls. Among maladaptive behaviors, social withdrawal behaviors were most problematic for the young males with fra X. These preliminary findings indicate that a neurobehavioral profile in fra X males was observed as early as 3-5 years of age and adaptive behavior development appeared to slow during this same age period.