Responses to median and tibial nerve stimulation in patients with chronic neuropathic pain.
Somatosensory evoked magnetic fields and electrical potentials were measured in eight patients with unilateral neuropathic pain. After median nerve stimulation on the painful side, the amplitudes of the evoked responses were enhanced 2 to 3 times at a latency of about 100 ms compared to the responses of the contralateral, unaffected side. After posterior tibial nerve stimulation an enhancement was found at latencies around 110 ms and 150 ms. The scalp distribution of the magnetic field at the latencies of "abnormal" responses was dipolar and the responses could be ascribed to a current dipole. Three (of the eight) patients underwent spinal cord stimulation (SCS) for their pain. The enhancement of the evoked responses to stimulation of the painful side decreased after spinal cord stimulation. After a long period of spinal cord stimulation only (e.g., a year) during which the patient reported to be pain free, these "abnormal" responses were no longer observed.
Theuvenet
P J
PJ
Department of Anesthesiology, Medical Centre of Alkmaar, The Netherlands.
Dunajski
Z
Z
Peters
M J
MJ
van Ree
J M
JM
D000059:Accidents; D000328:Adult; D000368:Aged; D000671:Amputation, Surgical; D001921:Brain / Q000503:physiopathology*; D001931:Brain Mapping; D002908:Chronic Disease; D004569:Electroencephalography; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005260:Female; D005385:Fingers; D007839:Functional Laterality; D006801:Humans; D015225:Magnetoencephalography; D008297:Male; D008475:Median Nerve / Q000503:physiopathology*; D008875:Middle Aged; D009437:Neuralgia / Q000503:physiopathology*; D013497:Sural Nerve / Q000293:injuries / Q000503:physiopathology; D013710:Tendons / Q000601:surgery; D013979:Tibial Nerve / Q000503:physiopathology*