Motor evoked potentials by transcranial magnetic stimulation of motor cortex and spinal regions were recorded from the biceps brachii, abductor digiti quinti and tibialis anterior muscles in 44 patients with cervical spondylosis. Abnormalities of central motor conduction time for at least one muscle were observed in all patient with myelopathy and these were closely correlated with clinical signs of upper motor neuron dysfunction. The amplitude of the motor evoked potentials were inversly correlated with central motor conduction time. Somatosensory evoked potentials were less frequently altered than motor evoked potentials. The magnetic brain stimulation is easy to perform, painless, safe and valuable test in evaluating of central motor pathway lesion in cervical spondylosis.
