Atonic Seizure with Hypotonia in a Patient with Parietal Lobe Epilepsy

ABSTRACT

Atonic seizure shows characteristic features such as head drop because postural muscle tone is suddenly lost. Atonia of the seizure means no muscle tone and loss of electromyographic activities were reported. We report a left parietal lobe epilepsy patient with atonic seizure showing hypotonia on electromyography. A 27 year-old woman had intractable head drop seizures since 6 years old. Her brain MRI demonstrated cortical dysplasia in the left parietal lobe. During the video-EEG monitoring, she had 21 epileptic seizures which were atonic seizures. During her atonic seizures, simultaneous EMG recordings showed decreased muscle activities during the head drop attacks, instead of no muscle tone. This is the first case showing transient hypotonia during the atonic seizure, instead of atonia.