Bilateral painful hand-moving fingers: Electrophysiological assessment of the central nervous system oscillator

We describe a 35-year-old woman who presented with the syndrome of painful hand-moving fingers on the right side. Eight months later, she developed si milar finger movements and hand discomfort on the left side. She had a hist ory of hand trauma and recurrent shoulder dislocation on the right side. Ki nesiologic electromyography suggested a common central oscillator for finge r movements in both hands. Electrophysiological assessment of spinal alpha motor neuron excitability, reciprocal inhibition, and Renshaw cell inhibiti on failed to show any abnormalities. Somatosensory evoked potential test sh owed marked attenuation of N20 potential recorded from the left somatosenso ry cortex; paired transcortical magnetic stimulation of the left motor cort ex suggested failure of cortical facilitation. The data suggest that the ce ntral oscillator responsible for finger movements is located above the spin al cord level in this patient.