title: Comparison between pharmacologic evaluation and repetitive transcranial magnetic stimulation-induced analgesia in poststroke pain patients.
abstract: BACKGROUND
  It has been reported that poststroke pain has a complex pharmacologic background and that only about one-half of poststroke pain patients are sensitive to motor cortex stimulation induced by repetitive transcranial magnetic stimulation (rTMS).
  
  
  OBJECTIVE
  The relationship between pharmacologic background and effects of rTMS of the primary motor cortex was investigated to clarify the pharmacologic basis of rTMS-induced analgesia in poststroke pain patients.
  
  
  METHODS
  Changes in visual analog scale (VAS) score for pain following drug challenge tests using ketamine, morphine, and thiopental were compared with the changes in VAS score following rTMS of the primary motor cortex (frequency 5 Hz, at 100% resting motor threshold, 500 pulses per session) in 20 poststroke pain patients.
  
  
  RESULTS
  In our drug challenge test, 10 of 20 (50%) patients in ketamine test, 7 of 20 (35%) in thiopental test, and 3 of 20 (15%) in morphine test showed more than 40% reduction of VAS score. VAS score decreased immediately after rTMS of motor cortex and persisted for 300 min (p < 0.05, Bonferroni's multiple comparisons). Comparison of the magnitude of VAS score reduction between drug challenge test and rTMS showed significant correlations with ketamine test (r = 0.503, p = 0.012), morphine test (r = 0.526, p = 0.009), and thiopental test (r = 0.609, p = 0.002) by regression analysis.
  
  
  CONCLUSIONS
  rTMS-induced VAS score reduction correlated well with morphine, ketamine, and thiopental tests. However, ketamine sensitivity was observed in more cases compared with morphine and thiopental in poststroke pain patients. We speculate that additional pharmacologic therapy using ketamine as determined on the basis of the ketamine test may be useful for enhancing the efficacy of rTMS in poststroke pain patients.
authors: Department of Neurological Surgery, Nihon University School of Dentistry at Matsudo, Chiba, Japan.
authors: Yuhei
authors: Y
authors: Matsumura
authors: Teruyasu
authors: T
authors: Hirayama
authors: Takamitsu
authors: T
authors: Yamamoto
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000698:Analgesia / Q000379:methods*; D000704:Analysis of Variance; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000188:drug therapy / Q000209:etiology; D059408:Pain Management; D010147:Pain Measurement; D012044:Regression Analysis; D020521:Stroke / Q000150:complications; D050781:Transcranial Magnetic Stimulation / Q000379:methods*
keywords: Morphine; motor cortex stimulation; neuropathic pain; poststroke; transcranial magnetic stimulation