title: Experimental activation of the sphenopalatine ganglion provokes cluster-like attacks in humans.
abstract: BACKGROUND
  High frequency (HF) stimulation of the sphenopalatine ganglion (SPG) is an emerging abortive treatment for cluster headache (CH) attacks. HF SPG stimulation is thought to exert its effect by physiologically blocking parasympathetic outflow. We hypothesized that low frequency (LF) SPG stimulation may activate the SPG, causing increased parasympathetic outflow and thereby provoking cluster attacks in CH patients.
  
  
  METHODS
  In a double-blind randomized cross-over study, seven CH patients implanted with an SPG neurostimulator were randomly allocated to receive HF or LF stimulation for 3 min on 2 separate days. We recorded headache characteristics and autonomic symptoms during and after stimulation.
  
  
  RESULTS
  Six patients completed the study. Three out of six patients (50%) reported ipsilateral cluster-like attacks during or within 30 min of LF SPG stimulation. These cluster-like attacks were all successfully treated with the therapeutic HF SPG stimulation. One out of six reported a cluster-like attack with 3 min HF SPG stimulation, which was also successfully treated with continued HF therapeutic SPG stimulation.
  
  
  CONCLUSIONS
  LF SPG stimulation may induce cluster-like attacks with autonomic features, which can subsequently be treated by HF SPG stimulation. Efferent parasympathetic outflow from the SPG may initiate autonomic symptoms and activate trigeminovascular sensory afferents, which may initiate the onset of pain associated with CH.
authors: Danish Headache Center and Department of Neurology, Glostrup Hospital, Denmark.
authors: Henrik W
authors: HW
authors: Schytz
authors: Mads
authors: M
authors: Barløse
authors: Song
authors: S
authors: Guo
authors: Juliette
authors: J
authors: Selb
authors: Anthony
authors: A
authors: Caparso
authors: Rigmor
authors: R
authors: Jensen
authors: Messoud
authors: M
authors: Ashina
mesh_terms: D000328:Adult; D003027:Cluster Headache / Q000209:etiology* / Q000503:physiopathology* / Q000628:therapy; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004599:Electric Stimulation Therapy / Q000009:adverse effects* / Q000295:instrumentation / Q000379:methods; D004567:Electrodes, Implanted / Q000009:adverse effects*; D005260:Female; D005725:Ganglia, Autonomic / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement / Q000295:instrumentation / Q000379:methods*; D056739:Pterygopalatine Fossa / Q000503:physiopathology
keywords: Cluster headache; autonomic nervous system; headache model; neurostimulation; sphenopalatine ganglion