Impaired Cerebellar Learning in Children with Prenatal Alcohol Exposure: A Comparative Study of Eyeblink Conditioning in Children with ADHD and Dyslexia

Neuroanatomical and behavioral evidence indicate that the cerebellum is particularly vulnerable to the toxic effects of prenatal alcohol exposure. Recent research has shown impairments in eyeblink conditioning in rats following binge-like neonatal ethanol exposure. The neural substrates of eyeblink conditioning have been localized to the cerebellum and related brainstem mechanisms. The present study considered whether heavy prenatal alcohol exposure would result in similar impairments in eyeblink conditioning in children. A related purpose was to determine if eyeblink conditioning could discriminate between children with prenatal alcohol exposure and children diagnosed with attention deficit hyperactive disorder or developmental dyslexia. Fifty-three age-matched children [10 prenatal alcohol exposure (FAE), 16 attention deficit hyperactive disordered (ADHD), 14 children with dyslexia (DYS), 13 normal controls] were assessed on eyeblink conditioning in the delay paradigm. Children in the FAE and DYS groups failed to learn the conditioned response, producing longer latencies and poorly timed responses to the conditioning stimulus. Children with ADHD were impaired on measures of adaptively timed responses, although conditioned responses matched normal controls. The results suggest that children prenatally exposed to alcohol have deficits in cerebellar processing similar to those with dyslexia, and that these functional deficits are related to disabilities in learning.