P300-amplitudes in upper limb amputees with and without phantom limb pain in a visual oddball paradigm.
The aim of the study was to investigate to what extent cortical hyper-reactivity to visual stimuli is present in upper limb amputees. Five amputees with phantom limb pain (PLP), five amputees without PLP (Non-PLP) and 10 healthy controls (HC) were investigated using a visual oddball paradigm. Two hundred visual stimuli were presented with target stimuli occurring at a probability of 25% and standard stimuli at a probability of 75%. Event-related potentials were recorded from nine scalp positions (F3, F4, Fz, C3, C4, Cz, P3, P4, Pz). The PLP-patients had significantly higher P300-amplitudes to both types of stimuli compared to the non-PLP-patients. The HC were not significantly different from both amputee groups. P300-amplitude to targets at frontal sites in the hemisphere contralateral to the amputation was higher in the PLP patients. P300-latencies to target stimuli differed only at frontal sites with PLP-patients showing significantly longer latencies than non-PLP-patients. To standard stimuli, however, they showed significantly shorter latencies at central and parietal scalp positions. The HC had significantly shorter latencies than both amputee groups. The size of the P300-amplitude was positively correlated with the intensity of PLP. These findings suggest a higher magnitude of non-specific cortical excitability in amputees with PLP and a reduced excitability in amputees without PLP. This extends previous findings of differences in cortical excitability in PLP and non-PLP patients in the sensorimotor domain.
Karl
Anke
A
Biopsychology, University of Technology Dresden, Zellescher Weg 17, D-01062 Dresden, Germany. karl@psy2.psych.tu-dresden.de
Diers
Martin
M
Flor
Herta
H
D000328:Adult; D000367:Age Factors; D000368:Aged; D000674:Amputees; D000704:Analysis of Variance; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000503:physiopathology; D004569:Electroencephalography / Q000379:methods; D018913:Event-Related Potentials, P300 / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000503:physiopathology*; D010591:Phantom Limb / Q000503:physiopathology*; D010775:Photic Stimulation / Q000379:methods; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D034941:Upper Extremity / Q000503:physiopathology*