title: Altered autonomic nervous system reactivity to pain in trigeminal neuralgia.
abstract: BACKGROUND
  In the past two decades, there has been increasing evidence to suggest that trigeminal neuralgia (TN) may be linked to a dysfunction of the autonomic nervous system (ANS). The aim of the present study was to formally test this hypothesis by comparing the reactivity of the ANS to experimental pain in a population of TN patients and healthy controls.
  
  
  METHODS
  Twelve patients diagnosed with classical TN and 12 healthy controls participated in the study. Cardiac activity was assessed while participants were instructed to rest and again during a cold pressor test (CPT). Heart rate variability analyses were performed off-line to obtain parasympathetic (high-frequency) and sympathetic (low-frequency) indices.
  
  
  RESULTS
  At baseline, ANS measures did not differ between healthy controls and TN patients, and both groups showed a similar increase in heart rate during the CPT (all p values >0.05). However, TN patients showed a greater increase in cardiac sympathetic activity and a greater decrease in cardiac parasympathetic activity during CPT compared with healthy controls (all p values <0.05). Importantly, changes in sympathetic reactivity, from baseline to CPT, were negatively associated with the number of pain paroxysms experienced each day by TN patients in the preceding week (r=-.58, p<0.05).
  
  
  CONCLUSIONS
  These results suggest that TN, like many other short-lasting, unilateral facial pain conditions, is linked to ANS alterations. Future studies are required to determine if the altered ANS response observed in TN patients is a cause or a consequence of TN pain.
authors: 1Centre de Recherche sur le Vieillissement,CSSS-IUGS,Sherbrooke,Québec,Canada.
authors: Guillaume
authors: G
authors: Léonard
authors: 2Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke,Sherbrooke,Québec,Canada.
authors: Philippe
authors: P
authors: Chalaye
authors: 2Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke,Sherbrooke,Québec,Canada.
authors: Philippe
authors: P
authors: Goffaux
authors: 2Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke,Sherbrooke,Québec,Canada.
authors: David
authors: D
authors: Mathieu
authors: 2Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke,Sherbrooke,Québec,Canada.
authors: Isabelle
authors: I
authors: Gaumond
authors: 2Centre de Recherche du Centre Hospitalier Universitaire de Sherbrooke,Sherbrooke,Québec,Canada.
authors: Serge
authors: S
authors: Marchand
mesh_terms: D000368:Aged; D001341:Autonomic Nervous System / Q000503:physiopathology*; D003080:Cold Temperature; D005157:Facial Pain / Q000503:physiopathology; D005260:Female; D006321:Heart / Q000503:physiopathology; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000209:etiology / Q000503:physiopathology*; D058748:Pain Perception; D010275:Parasympathetic Nervous System / Q000503:physiopathology; D011312:Pressure; D013564:Sympathetic Nervous System / Q000503:physiopathology; D014277:Trigeminal Neuralgia / Q000150:complications / Q000503:physiopathology*
keywords: trigeminal neuralgia