Siniatchkin, M Contingent negative variation in patients with chronic daily headache. [electronic resource] - Cephalalgia : an international journal of headache Oct 1998 - 565-9; discussion 531 p. digital Publication Type: Journal Article ISSN: 0333-1024 Standard No.: 10.1046/j.1468-2982.1998.1808565.x doi Subjects--Topical Terms: Adaptation, PsychologicalAdultContingent Negative Variation--physiologyFemaleHabituation, PsychophysiologicHeadache--physiopathologyHumansMaleMigraine Disorders--physiopathologyPeriodicity