Electrodermal level asymmetry in a unilateral brain-damaged patient

The purpose of this article is to report on a patient with right frontal damage who exhibited a strong left > right asymmetry of skin conductance levels (SCLs). Comparison with a control group indicates that this asymmetry resulted only from a higher SCL on the left hand. Such a result suggests that the frontal lesion has induced a contralateral disinhibition and is consistent with the idea of a contralateral inhibitory control of tonic electrodermal activity in the case of a healthy hemisphere. Peripheral factors, such as sweating or temperature seem unrelated to the SCL asymmetry and a possible influence of motor weakness is also rejected following comparison with a second patient who presented the same motor disorder without atypical SCL asymmetry. In contrast to SCLs, no asymmetry in skin conductance response amplitudes was observed in the former patient. This discrepancy is in line with previous observations showing that tonic and phasic EDA could depend on different neurophysiological controls.