Intellectual functioning and behavior in Dravet syndrome: A systematic review

Area of Science:

• Neuroscience
• Developmental Pediatrics
• Genetics

Background:

• Dravet syndrome (DS) is a severe developmental and epileptic encephalopathy.
• Onset occurs in the first year of life, with neurodevelopmental slowing observed in the second year.
• Associated challenges include intellectual disability, behavioral problems, autistic features, and attention/hyperactivity issues.

Purpose of the Study:

• To systematically review the prevalence of cognitive/developmental quotients (DQs) indicative of intellectual disability (ID).
• To assess the prevalence of deficits in adaptive behavior, autism spectrum disorder (ASD), attention-deficit hyperactivity disorder (ADHD), and behavioral difficulties in DS.
• To explore factors associated with intellectual and behavioral outcomes in individuals with DS.

Main Methods:

• Systematic review of studies indexed in PubMed and Scopus.
• Adherence to Preferred Reporting Items for Systematic Review (PRISMA) guidelines.
• Quality assessment of included studies using National Institutes of Health (NIH) tools.

Main Results:

• Pooled prevalence of ID was 86%; ASD prevalence was 31%.
• Adaptive behavior was significantly below average (more than 2 SDs).
• Behavioral difficulties ranged from 37% to 100%; age was linked to cognitive decline, and health-related quality of life (HRQoL) to behavioral issues. Study quality was predominantly poor or fair.

Conclusions:

• High prevalence of ID and significant deficits in adaptive behavior in DS patients.
• Elevated ASD prevalence compared to the general population, though with wide study variations.
• Need for more robust, large-scale studies using standardized instruments for intellectual and behavioral disorders in DS.