High amplitude delta rhythm related cataplexy in a boy with Niemann-Pick type C disease

•Cataplexy can be the only clinical manifestation in the early stage of NPC disease.•The electrophysiological feature of cataplexy is different between NPC and idiopathic narcolepsy.•High amplitude delta pattern correlates of cataplexy indicated the involvement of cortico-thalamo-cortical feedback loops.•Electrophysiological monitoring is of great significance to better understand the pathophysiology of cataplexy.