Rhythmic cortical myoclonus in Niemann-Pick disease type C

Mov Disord. 2006 Sep;21(9):1453-6. doi: 10.1002/mds.20984.

Abstract

We here describe a patient with late-infantile Niemann-Pick disease type C (NPC) presenting with worsening myoclonus, seizures, cerebellar symptoms, mild mental impairment, and gaze palsy. Electroencephalographic (EEG) -polymyographic examinations showed abnormally high and diffuse background alpha-activity, enhanced by intermittent photic stimulation. The electromyographic (EMG) showed quasirhythmic myoclonic jerks during motor activation. EEG-EMG frequency analysis (better than jerk-locked back-averaging) demonstrated the cortical origin of the myoclonus. Our observations indicate that cortical myoclonus may occur as the main symptom of NPC.

Publication types

  • Case Reports

MeSH terms

  • Adolescent
  • Alpha Rhythm
  • Beta Rhythm
  • Cerebral Cortex / physiopathology*
  • Consanguinity
  • Dominance, Cerebral / physiology
  • Electroencephalography*
  • Electromyography*
  • Epilepsies, Myoclonic / diagnosis
  • Epilepsies, Myoclonic / genetics
  • Epilepsies, Myoclonic / physiopathology*
  • Epilepsy, Generalized / diagnosis
  • Epilepsy, Generalized / genetics
  • Epilepsy, Generalized / physiopathology
  • Female
  • Fourier Analysis
  • Humans
  • Muscle, Skeletal / innervation
  • Niemann-Pick Disease, Type C / diagnosis
  • Niemann-Pick Disease, Type C / genetics
  • Niemann-Pick Disease, Type C / physiopathology*
  • Photic Stimulation
  • Pyramidal Tracts / physiopathology
  • Reaction Time / physiology
  • Signal Processing, Computer-Assisted