Comorbidity in severe developmental language disorders: Neuropediatric and psychological considerations

Abstract

To explore possible patterns of comorbidity in children with severe developmental language disorders (DLD). A retrospective investigation of the clinical records of 28 children relating to oral motor and language problems, psychological profiles, medical history and EEG findings. 36% of all the children had pure expressive language problems, 64% had combined expressive-receptive language problems and 57% had additional oral motor problems. Girls predominated in expressive-receptive problems, while boys predominated in oral motor problems. Children with expressive-receptive disorders were over-represented at the lower end of normal full-scale IQ (p = 0.015). Lower verbal than non-verbal IQ levels were almost as common as equal levels, but a lower non-verbal IQ than verbal IQ was also found. Pre/perinatal problems were found in 21%, and heredity for developmental language problems or dyslexia in 39%. There was a higher proportion of attention and motor problems, EEG abnormalities, and epileptic syndromes than in the general population (p < 0.001). In severe DLD, both pure expressive and mixed expressive-receptive problems are found, and oral motor problems are common. Gender differences regarding symptoms are present. Receptive language ability is associated with the full-scale IQ level. A high proportion of EEG abnormalities and epilepsy is found. There is a complex pattern of comorbidity between speech-language symptoms, psychological characteristics, heredity and EEG findings.