Long-term follow-up study of Lennox–Gastaut syndrome in patients with severe motor and intellectual disabilities: with special reference to the problem of dysphagia

A long-term follow-up study of Lennox-Gastaut syndrome (LGS) ( > 10 years) was conducted with 38 patients with severe motor and intellectual disabilities (SMID) to clarify the relationship between the rapid development of dysphagia and epileptic seizures, and to elucidate the long-term evolution of LGS in patients with SMID. Those who showed a relatively favourable seizure outcome were compared to those with a poor seizure outcome. Poor seizure outcome correlated strongly with: (a) an early appearance of dysphagia and additional deterioration of the already retarded mental function; (b) a predominance of atypical absence seizures; and (c) persistent frequent epileptiform discharges during electroencephalographic evaluations. Neither age at seizure onset nor intelligence level at the time of the last examination was correlated with seizure prognosis. Further, seizure prognosis was not related to the aetiology of LGS. Repeated seizures apparently caused development of progressive epileptic encephalopathy, in addition to the underlying severe brain damage. Since development of dysphagia burdens an already severely handicapped patient with intensive medical care, efforts to reduce the seizures and design a long-term care plan are of great importance.