Adaptive and cognitive trajectories in adults with drug-resistant epilepsy and intellectual disabilities

Adults with epilepsy and intellectual disabilities (ID) may be at risk of adaptive and cognitive decline due to underlying genetic disorders, seizures, and complex comorbidity.

A follow-up study was performed in a cohort of adults with mostly drug-resistant epilepsy and mild-severe ID. Adaptive and cognitive functioning were re-assessed with the Vineland Adaptive Behavior Scales (VABS-II), Wechsler Adult Intelligence Scale short form (WAIS-SF-IV), and Picture Peabody Vocabulary Test (PPVT-III). Medical history, current antiseizure medication, and dementia diagnostics were retrieved from the medical files. Changes in adaptive and cognitive functioning were analyzed using mixed effects models and reliable change indexes. Chi square tests were used to explore associations with comorbidity.

A total of 72 adults were re-assessed after a mean of 5.4 (range 4.7-6.5) years, with a mean age of 52 (range 24-76) years. Raw scores of adaptive functioning declined significantly (daily skills: β_time = -1.45, df = 71, p < 0.001, social skills: β_time = -1.91, df = 71, p < 0.001). Re-assessment of cognitive functioning was successful in 55 individuals (77.8%) and remained stable in this group (WAIS: β_time = 0.75, df = 29, p = 0.51, PPVT: β_time = -0.02, df = 29, p = 0.64). A clinical suspicion of dementia was documented for 12 individuals (16.7%). Sensory impairments were associated with adaptive decline (visual: X² = 8.71, p = 0.003) and suspected dementia (hearing: X² = 11.63, p < 0.001).

Results show significant early adaptive decline and call for more awareness and frequent re-assessments.