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We evaluated the pattern of motor evoked potentials elicited by single-pulse and slow-rate (1 Hz) repetitive, transcranial, magnetic stimulation (RTMS) in minor head injuries. The motor response to a single magnetic stimulus in patients with minor head injury was characterized by a significantly higher threshold than in healthy subjects. However, central and peripheral motor conduction was normal in all patients. A stable pattern of MEP throughout the RTMS session was the most prominent feature in the control group. A progressive decrease in MEP amplitude and irregular alternation of large and very small MEPs over the course of RTMS was observed in minor head injury. The higher threshold of the motor response and the abnormal patterns of MEP behavior revealed by RTMS may reflect impaired excitability and enhanced exhaustion of the motor cortex in patients with minor head injuries, which improve with time.

Magnetic stimulation of the motor cortex and nerve roots in conjunction with F-wave recording was used for assessment of central and peripheral motor conduction times in 98 patients suffering from myelopathy and cervical or lumbo-sacral radiculopathy. Significant prolongation of the central motor conduction times was found in the myelopathy group. The Motor Evoked Potential was of low amplitude and distorted shape. The amplitude of the F-wave was markedly increased. The main feature of the radiculopathy group was prolonged motor root conduction time as evident by delayed F-wave. Motor evoked potentials proved to be a reliable objective tool in the functional evaluation of conduction along the spinal cord and its roots.