title: Transcranial magnetic stimulation reveals cortical hyperexcitability in episodic cluster headache.
abstract: Evidence shows involvement of the cerebral cortex in the pathophysiology of cluster headache (CH). Here we investigated cortical excitability in episodic CH patients by using transcranial magnetic stimulation. In 25 patients with episodic CH and 13 healthy subjects we evaluated the motor cortical response to single-pulse (ie, motor threshold, input-output curves, cortical silent period) and paired-pulse (ie, intracortical facilitation, short intracortical inhibition) transcranial magnetic stimulation in both hemispheres. Thirteen patients were evaluated outside bout and the remaining 12 patients inside bout. Our results showed increased slope of the input-output curves after stimulation of both hemispheres in patients outside bout and in the hemisphere contralateral to the headache side in patients inside bout. Increased intracortical facilitation was observed in the hemisphere ipsilateral to the headache side in patients evaluated both outside and inside bout; reduced short intracortical inhibition was observed in patients inside bout ipsilateral to the side of pain. In conclusion, we provide evidence of increased cortical excitability in episodic CH both outside and inside bout, especially in the hemisphere ipsilateral to the side of headache attacks. Our results suggest that an abnormal regulation of cortical excitability could be involved in the pathophysiology of CH.
  
  
  CONCLUSIONS
  We investigated cortical excitability in episodic cluster headache by using transcranial magnetic stimulation, providing evidence of cortical hyperexcitability in patients both inside and outside bout. We suggest that an abnormal state of cortical excitability could be involved in the pathophysiology of the disease.
authors.affiliation: Department of Experimental Biomedicine and Clinical Neurosciences (BioNeC), University of Palermo, Palermo, Italy.
authors.forename: Guiseppe
authors.initials: G
authors.lastname: Cosentino
authors.affiliation: Department of Experimental Biomedicine and Clinical Neurosciences (BioNeC), University of Palermo, Palermo, Italy. Electronic address: filippo.brighina@unipa.it.
authors.forename: Filippo
authors.initials: F
authors.lastname: Brighina
authors.affiliation: Department of Experimental Biomedicine and Clinical Neurosciences (BioNeC), University of Palermo, Palermo, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Brancato
authors.affiliation: Department of Experimental Biomedicine and Clinical Neurosciences (BioNeC), University of Palermo, Palermo, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Valentino
authors.affiliation: Department of Experimental Biomedicine and Clinical Neurosciences (BioNeC), University of Palermo, Palermo, Italy.
authors.forename: Serena
authors.initials: S
authors.lastname: Indovino
authors.affiliation: Department of Experimental Biomedicine and Clinical Neurosciences (BioNeC), University of Palermo, Palermo, Italy.
authors.forename: Brigida
authors.initials: B
authors.lastname: Fierro
mesh_terms: D000328:Adult; D003027:Cluster Headache / Q000503:physiopathology*; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D009044:Motor Cortex / Q000503:physiopathology*; D050781:Transcranial Magnetic Stimulation / Q000379:methods
keywords: Episodic cluster headache; cortical excitability; motor cortex; pathophysiology; transcranial magnetic stimulation