Event-related potentials in the segmental exclusion syndrome of the upper limb.

Upper limb segmental exclusion syndromes are frequent after traumatic or infections affections. They can be defined as an insufficient utilization of a limb segment - fingers or hand - reversible on verbal exhortation and arising in subjects with no other neurologic or psychiatric disorder. Our hypothesis was that the segmental exclusion syndrome could be likened to a neglect behavior. To verify the validity of this hypothesis, we measured digital nerve short-latency SEP and SEP-P300 waves in response to odd-ball task target stimuli in healthy volunteers (n = 11) and patients with digit exclusion syndromes (n = 19). For N20 latency, there was no significant difference (Wilcoxon's test: p = 0.52) between normal and excluded digits. Stimulation of the excluded vs normal digit resulted in a significant lengthening in SEP-P300 latency (p = 0.0003). The implications of these results and means of extending our knowledge of the pathophysiology of exclusion syndromes are discussed.