Electroencephalographic abnormalities during sleep in children with developmental speech-language disorders: a case-control study.

Earlier research has suggested a link between epileptiform activity in the electroencephalogram (EEG) and developmental speech-language disorder (DSLD). This study investigated the strength of this association by comparing the frequency of EEG abnormalities in 45 language-normal children (29 males, 16 females; mean age 6y 11mo, SD 1y 10mo, range 4y-9y 10mo) and 54 community-ascertained children (35 males, 19 females; mean age 5y 7mo, SD 1y 6mo, range 4y-9y 11mo) with a diagnosis of severe DSLD, defined as a score at least 2 SD below the mean on at least one speech-language measure, and a performance IQ of at least 80 points. All participants underwent sleep EEGs after sedation. Children with DSLD also had detailed speech-language, hearing, and psychological assessments. Results failed to support the previously identified strong association between abnormal EEG and DSLD. There was a weak, non-significant relationship between DSLD and epileptiform EEG. Epileptiform EEG was significantly associated with low performance IQ (p=0.04). This study draws into question previously reported associations between epileptiform activity and DSLD probably because it examined a purer cohort of children with more severe language difficulties who did not have seizures.