Brainstem hyperexcitability during cataplexy.

The exact cause of narcolepsy-cataplexy syndrome remains unclear; however, the recent discovery of hypocretin deficiency in the lateral hypothalamus of narcoleptic patients has increased our understanding of its etiology. The authors performed masseter reflex, tibial F response, and blink reflex excitability studies during and between attacks in a 66-year-old man with status cataplecticus. Masseter reflex and F responses were inhibited while the blink reflex R2 component was enhanced during attacks, suggesting either hyperexcitability or disinhibition of pontine and/or medullary interneurons but hypoexcitability of pontine and spinal motor neurons during cataplexy.