Related Experiment Videos
Is fragile X syndrome a pervasive developmental disability? Cognitive ability and adaptive behavior in males with the
G S Fisch1, J J Holden, R Simensen
1Dept. of Psychiatry, Kings County Hospital Center, Brooklyn, NY 11203.
Abstract:
In addition to mental retardation (MR), fragile X [fra(X)] syndrome has been associated with various psychopathologies, although it appears that the link is secondary to MR. It has been proposed that individuals with the full mutation be classified as a subcategory of pervasive developmental disorders (PDD). If fra(X) males are to be categorized as PDD, how do they compare with other types of developmental disabilities? We examined 27 fra(X) males aged 3-14 years, from 4 sites in North America. Measures of cognitive abilities were obtained from the Stanford-Binet Fourth Edition (SBFE), while levels of adaptive behavior were evaluated using the Vineland Adaptive Behavior Scales (VABS). Control subjects were sex-, age-, and IQ matched children and adolescents ascertained from the Developmental Evaluation Clinic (DEC) at Kings County Hospital. At the DEC, control subjects were diagnosed as either MR (n = 43) or autistic disorder (AD; n = 22). To compare subjects' adaptive behavior (SQ) with their cognitive abilities (IQ), a ratio of [(SQ/IQ) x 100] was computed. Results graphed as cumulative distribution functions (cdf) revealed that the cdf for AD males, who by definition are socially impaired, was positioned to the left of the cdf for MR controls, as expected. Mean ratio for AD males (70) was lower than for MR males (84). On the other hand, the cdf for fra(X) males was positioned far to the right of either AD or MR controls (mean ratio = 125). Statistical tests showed that SQ of fra(X) males was significantly higher than controls.(ABSTRACT TRUNCATED AT 250 WORDS)
Insights
Fragile X syndrome (fra(X)) males show significantly higher adaptive behavior than individuals with mental retardation (MR) or autistic disorder (AD). This suggests fra(X) may represent a distinct developmental disability category.
Area of Science:
- Neurodevelopmental Disorders
- Genetics
- Psychopathology
Background:
- Fragile X syndrome (fra(X)) is associated with psychopathologies, often secondary to intellectual disability.
- A proposal suggests classifying full mutation fra(X) individuals within pervasive developmental disorders (PDD).
- Comparison of fra(X) males with other developmental disabilities is needed.
Purpose of the Study:
- To compare the adaptive behavior of fra(X) males with other developmental disabilities.
- To investigate if fra(X) males fit within a PDD classification.
- To analyze the relationship between cognitive abilities and adaptive behavior in fra(X) syndrome.
Main Methods:
- Examined 27 fra(X) males (aged 3-14) across North America.
- Assessed cognitive abilities using the Stanford-Binet Fourth Edition (SBFE).
- Evaluated adaptive behavior with the Vineland Adaptive Behavior Scales (VABS), comparing to MR and autistic disorder (AD) controls.
Main Results:
- Autistic disorder (AD) males had lower adaptive behavior (SQ/IQ ratio=70) than mental retardation (MR) controls (ratio=84).
- fra(X) males exhibited significantly higher adaptive behavior (SQ/IQ ratio=125) compared to both AD and MR controls.
- Adaptive behavior in fra(X) males surpassed expectations based on cognitive abilities.
Conclusions:
- fra(X) males demonstrate adaptive functioning considerably higher than predicted by their cognitive abilities.
- The adaptive behavior profile of fra(X) males differs significantly from both autistic disorder and mental retardation.
- Findings support further investigation into the distinct classification of fra(X) syndrome within developmental disabilities.