title: Cluster analysis of clinical seizure semiology of psychogenic nonepileptic seizures.
abstract: OBJECTIVE
  To develop an objective classification of psychogenic nonepileptic seizures (NES) based on cluster analysis of clinical seizure semiology.
  
  
  METHODS
  We studied the clinical seizure semiology in 27 patients with psychogenic NES documented by prolonged video-EEG monitoring. We analyzed the following clinical symptoms: clonic and hypermotor movements as well as trembling of the upper and/or lower extremities, pelvic thrusting, head movements, tonic posturing backward of the head, and falling. We used cluster analysis to identify symptoms occurring together in a systematic way and thus tried to achieve a clinical classification of psychogenic NES.
  
  
  RESULTS
  We could identify three symptom clusters. Cluster 1 was characterized by clonic and hypermotor movements of the extremities, pelvic thrusting, head movements, and tonic posturing of the head, and therefore was named "psychogenic motor seizures." Cluster 2 comprised trembling of the upper and lower extremities and was termed "psychogenic minor motor or trembling seizures." Cluster 3 consisted of falling to the floor as the only symptom and was referred to as "psychogenic atonic seizures."
  
  
  CONCLUSIONS
  Our study represents the first study to analyze the clinical semiology of psychogenic NES by cluster analysis, which should be useful for an objective classification of psychogenic NES. This classification should allow both a better characterization of psychogenic NES and an easier differential diagnosis against specific epileptic seizures.
authors.affiliation: Universitätsklinik für Neurologie, University of Vienna, Austria.
authors.forename: G
authors.initials: G
authors.lastname: Gröppel
authors.forename: T
authors.initials: T
authors.lastname: Kapitany
authors.forename: C
authors.initials: C
authors.lastname: Baumgartner
mesh_terms: D000328:Adult; D016000:Cluster Analysis; D003937:Diagnosis, Differential; D004569:Electroencephalography / Q000706:statistics & numerical data; D004827:Epilepsy / Q000145:classification / Q000175:diagnosis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000706:statistics & numerical data; D009069:Movement Disorders / Q000145:classification / Q000175:diagnosis; D011602:Psychophysiologic Disorders / Q000145:classification* / Q000175:diagnosis*; D012640:Seizures / Q000145:classification* / Q000175:diagnosis*; D009626:Terminology as Topic; D014741:Video Recording