Longitudinal assessment of adaptive and maladaptive behaviors in fragile Xmales: Growth, development, and profiles

As young fully mutated fragile X [fra(X)] males age, cognitive levels (IQ s cores) and adaptive behavior levels (DQ scores) decline. Given the variable behavioral profiles reported previously, we wondered whether changes in sp ecific attributes of adaptive behavior are related to declines in composite adaptive behavior levels. We also examined maladaptive behavior to determi ne if changes are related to age. Therefore, we evaluated three areas of ad aptive behavior, as well as maladaptive behavior, in 28 fully mutated fra(X ) males, ages 4-14 years. To develop a profile of adaptive behavior, we ana lyzed nine subscale scores from the Vineland Adaptive Behavior Scale (VABS) . To assess maladaptive behavior, we graded part I of the VABS Maladaptive Behavior Scale. Subjects were sorted into three age cohorts, according to t heir initial test age: younger than 6 years; 6 to 9 years; older than 9 yea rs. Results indicate that, in all age groups, the communications domain is the most severely impacted compared with either the socialization domain or daily living skills and that, in all age groups, the socialization domain is a relative strength compared with either the communications domain or da ily living skills. The youngest cohort manifested significant increases in age-equivalent community living skills. Significant differences in age-equi valent scores between cohorts were observed in written language and play sk ills. Maladaptive behavior scores were available from cross-sectional data only. Twenty males (74%) showed significantly higher maladaptive scores tha n expected from other children their age. Our data analysis also revealed a moderate and significant negative correlation between maladaptive behavior levels and age (r = -0.54; P < 0.01). Curiously, adaptive and maladaptive behaviors did not correlate with each other. (C) 1999 Wiley-Liss, Inc.