Three cases of parietal lobe epilepsy with axial and axorhizomelic tonic posturing

Abstract

Tonic posturing in parietal lobe epilepsy was studied by closed-circuit video electroencephalogram (EEG) monitoring in three patients. The diagnosis of parietal lobe epilepsy was based chiefly on electroanatomic findings. Interictal and ictal epileptogenic discharges were predominant in distribution and amplitude over the bilateral centroparietooccipital areas. Magnetic resonance imaging (MRI) suggested epileptogenic lesions in the parietal lobe. Notably, single photon emission computed tomography (SPECT) showed the transformation of interictal hypoperfusion to ictal hyperfusion in the parietal lobe of two patients. SPECT seems to be useful for confirming the parietal lobe origin of seizures. On magnetoencephalogram (MEG), equivalent current dipoles of interictal discharges were localized to an atrophic lesion in the left parietal lobe in one patient. Seizures occurred daily, often in clusters, and manifested bilateral tonic facial contraction, or axial or axorhizomelic tonic posturing with (two patients) or without (one patient) sensory aura. Consciousness was intact or secondarily impaired during the seizures, and there was no postictal confusion. Seizure duration was short in two patients and prolonged in one patient. Tonic posturing appeared variably at the beginning or after a seizure onset. In conclusion, tonic posturing seems to be due to seizure progression from the mesial parietal lobe to the mesial frontal lobe (two patients) or to a widespread epileptogenic zone in both lobes (one patient).