Peripheral and electrocortical responses to painful and non-painful stimulation in chronic pain patients, tension headache patients and healthy controls.
Sixteen chronic back pain (CBP) patients, 16 tension headache (THA) patients and 16 healthy controls (HC) were exposed to four series of ten electric stimuli at perception threshold, pain threshold and 10% below pain tolerance. The EEG was recorded from three sites, in addition, the EMG from the m. frontalis and m. erector spinae, heart rate and skin conductance were assessed. The CBP patients showed significantly lower pain threshold and pain tolerance values than the HC and the THA patients whereas the THA patients displayed a higher pain tolerance. Habituation was reduced in the CBP group. N150, P260, P300 and N500 were not significantly different between the groups nor were there significant group differences in the peripheral measures. However, since the stimulation intensity was significantly lower in the CBP patients, these data are indicative of both enhanced central and peripheral reactivity. The observed lack of habituation may contribute to the persistence of chronic pain.
Flor
Herta
H
Department of Clinical and Cognitive Neuroscience at the University of Heidelberg, Central Institute of Mental Health, Square J5, D-68159 Mannheim, Germany. flor@zi-mannheim.de
Diers
Martin
M
Birbaumer
Niels
N
D000328:Adult; D001288:Attention / Q000502:physiology; D001416:Back Pain / Q000503:physiopathology*; D002540:Cerebral Cortex / Q000502:physiology*; D002908:Chronic Disease; D004558:Electric Stimulation; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D005712:Galvanic Skin Response / Q000502:physiology; D006185:Habituation, Psychophysiologic / Q000502:physiology; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D006930:Hyperalgesia / Q000503:physiopathology*; D008297:Male; D009119:Muscle Contraction / Q000502:physiology; D009433:Neural Inhibition / Q000502:physiology; D009619:Nociceptors / Q000502:physiology; D010147:Pain Measurement; D017288:Pain Threshold / Q000502:physiology*; D010465:Perception / Q000502:physiology*; D012016:Reference Values; D012867:Skin / Q000294:innervation / Q000503:physiopathology; D018781:Tension-Type Headache / Q000503:physiopathology*