Somatosensory evoked potentials in lesions of central structures of the skin-motor analyzer

To assess the role of different mechanisms in increasing the amplitude of the early components of cortical somatosensory evoked potentials (SSEPs) in lesions of central structures of the skin-motor analyzer in humans, SSEPs of the hand cortical projection zones (the points and) and the spinal dorsal column nuclei (DCN) were recorded in parallel in response to trancutaneous electrostimulation of the median nerve in the carpal region in two groups of subjects. The control group included 26 healthy volunteers aged 39-62 years; the other group included 12 patients aged 45-63 years with hemiplegia and sensory disorders due to a stroke experienced 8-24 months before the electrophysiological studies. A significant (from < 0.05 to < 0.01) increase in the amplitude of the early SSEP components of the intact hemisphere and several early SSEP components of the affected hemisphere (with a decrease in the amplitude of the other components) and no changes in DCN SSEPs were observed in the patients compared to the control group, which was interpreted as a manifestation of local mechanisms causing an isolated increase in cortical excitability without changes in the reactivity of DCN.