title: Differences in central facilitation between episodic and chronic migraineurs in nociceptive-specific trigeminal pathways.
abstract: BACKGROUND
  The trigeminal nociceptive system plays a pivotal role in the pathophysiology of migraines. The present study investigated whether there are differences between patients with episodic migraine (EM) and patients with chronic migraine (CM) in trigeminal pain processing at the brainstem and cortical levels using the nociceptive blink reflex (nBR) and pain-related evoked potentials (PREP).
  
  
  METHODS
  This study assessed 68 female migraineurs (38 EM patients and 30 CM patients) and 40 age-matched controls using simultaneous recordings of nBR and PREP during the interictal period.
  
  
  RESULTS
  In terms of the nBR, EM patients displayed significantly decreased latencies and larger amplitudes and area-under-the-curve (AUC) values for the R2 component, whereas CM patients showed significantly prolonged latencies and smaller amplitudes and AUC values for the R2 component (p < 0.05). In terms of PREP, both the EM and CM patients had decreased latencies (N1, P1), with larger amplitude compared with the controls (p < 0.05), which indicates facilitation at the cortical level. Additionally, the amplitude and AUC values of the R2 component exhibited a negative correlation, whereas the latency of the R2 component for the nBR showed a positive correlation, with the frequency of headaches in migraineurs (p < 0.01).
  
  
  CONCLUSIONS
  In the present study, the facilitation in the trigeminal nociceptive pathway of the EM group suggests the occurrence of migraine-specific hyperexcitability. Additionally, the suppression of R2 at the brainstem level in the CM group may relate to impaired or dysfunctional descending pain modulation. These findings suggest that there are adaptive or maladaptive responses due to the chronification of migraine attacks.
authors.affiliation: Department of Neurology, Chuncheon Sacred Heart Hospital, Hallym University College of Medicine, 153 Gyo-dong, Chuncheon-si, Gangwon-do, 200-704, Republic of Korea. deepfoci@hallym.or.kr.
authors.forename: Jong-Hee
authors.initials: JH
authors.lastname: Sohn
authors.affiliation: Department of Neurology, Chuncheon Sacred Heart Hospital, Hallym University College of Medicine, 153 Gyo-dong, Chuncheon-si, Gangwon-do, 200-704, Republic of Korea.
authors.forename: Chul-Ho
authors.initials: CH
authors.lastname: Kim
authors.affiliation: Department of Neurology, Chuncheon Sacred Heart Hospital, Hallym University College of Medicine, 153 Gyo-dong, Chuncheon-si, Gangwon-do, 200-704, Republic of Korea.
authors.forename: Hui-Chul
authors.initials: HC
authors.lastname: Choi
mesh_terms: D000328:Adult; D001933:Brain Stem / Q000503:physiopathology*; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006261:Headache / Q000503:physiopathology*; D006801:Humans; D008875:Middle Aged; D008881:Migraine Disorders / Q000503:physiopathology*; D009434:Neural Pathways / Q000503:physiopathology; D010147:Pain Measurement; D012018:Reflex / Q000502:physiology; D055815:Young Adult
keywords: Chronic migraine; Episodic migraine; Nociceptive blink reflex; Pain-related evoked potential; Trigeminal pathway