CLINICAL UTILITY OF MAGNETIC CORTICOSPINAL TRACT STIMULATION AT THE FORAMEN MAGNUM LEVEL

We applied magnetic stimulation of the corticospinal tract at the fora men magnum level to 19 patients with various neurological disorders. R esults were consistent with our previous speculation that activation o ccurs at the foramen magnum level. This method was clinically useful f or the following conditions. (1) Detection of subclinical lesion: one patient who had transient ischemic attack that caused no clinical symp toms at examination was shown to have dysfunction of the corticospinal tract. (2) Multiple lesions: our method disclosed at least one lesion above and below the foramen magnum in two patients with multiple scle rosis. (3) Unmasking of dysfunction of the corticospinal tract masked by peripheral neuropathy: magnetic stimulation showed conduction delay in the corticospinal tract in two patients in whom no pyramidal signs were evident because of muscular atrophy due to neuropathy. One patie nt had multiple sclerosis and chronic inflammatory demyelinating polyr adiculoneuropathy, the other had degenerative ataxia and neuropathy. ( 4) Association of disorders: conduction delay rostral to the foramen m agnum, which should not occur-in patients with only cervical myelopath y, was shown in a patient with cervical myeloradiculopathy and amyotro phic lateral sclerosis. We conclude that this magnetic stimulation met hod which is less painful than electrical stimulation has extensive cl inical usefulness.