LANDAU-KLEFFNER SYNDROME WITH CONTINUOUS SPIKES AND WAVES DURING SLOW-WAVE SLEEP

The Landau-Kleffner syndrome is sometimes associated with continuous spike-waves during slow-wave sleep. The clinical significance of this association is unclear. In order to investigate differences in glucose metabolic patterns between awake and sleep states in two children with Landau-Kleffner syndrome and continuous spike-waves during slow-wave sleep, fluorodeoxyglucose positron-emission tomographic (PET) studies were performed in each state. In the first patient, the awake interictal PET study revealed moderate hypometabolism in the thalamus and frontal and temporal cortex and mild hypometabolism in the parietal and anterior cingulate cortex bilaterally. Occipital cortex was severely hypometabolic bilaterally. In a repeat PET study performed during sleep in which continuous spike-waves during slow-wave sleep were present, the only difference noted compared to the awake study was a marked bilateral increase in temporal cortex metabolism. The awake interictal PET in the second child was normal, except for mildly increased relative glucose metabolism in the left inferior temporal cortex. The sleep PET study with continuous spike-waves during slow-wave sleep in this child showed hypermetabolism in both temporal lobes; however, this was more pronounced, with a wider distribution in the left temporal cortex. In normal subjects, PET studies performed during awake and sleep states have not revealed such differences. Whether the temporal lobes are involved in the generation of continuous spike-waves during slow-wave sleep remains to be confirmed in a larger group of patients. The first child was treated surgically with multiple subpial transection, following which continuous spike-waves during slow-wave sleep disappeared and language function improved. The second child has had no recovery of speech, although she is seizure free, has discontinued anticonvulsants, and no longer shows continuous spike-waves during slow-wave sleep on the electroencephalogram. The role of PET in selecting suitable candidates for surgery in Landau-Kleffner syndrome requires further study.