SPECT abnormalities in Landau-Kleffner syndrome

Five right-handed children with acquired aphasia elipepsy syndrome (Landau-Kleffner, LKS), were investigated with 99^m TcHMPAO single photon emission computed tomography (SPECT) and the results were correlated with their EEGs and clinical history. The childrens' ages ranged from 2 to 5 years and the aphasia had been present for 6 to over 12 months. No clinical seizure had ever been onserved in the younger two children and their waking EEGs showed infrequent central spikes. Both children had areas of low intensity on SPECT, involving the left temporal lobe in one and the right temporal lobe in the other, which has also been reported in children with congenital dysphasia who have normal EEGs. The three older children presented with frequent generalized seizures, with the aphasia occurring 3–6 months later. The SPECT scans in these children were performed either in the ictal state, or when electrographic seizure activity was very frequent on EEG. All three children had hyperintense foci on SPECT involving the left posterior temporal region corresponding to Wernickes area. We conclude that LKS may be initially a unilateral seizure disorder of Wernickes area, with EEG discharges in the contralateral hemisphere representing propagation from the unilateral focus.