Following test is most useful in diagnosing
Brainstem involvement in stroke
A clinically occult lesion in multiple sclerosis
Large hemispheral strokes
Spinal cord compression
The testing of evoked potentials is of the greatest utility in detecting subclinical spinal cord and optic nerve lesions. Up to two-thirds of persons with multiple sclerosis have neurologic deficits that are evident on visual or personal somatic evoked potentials but not on physical examination. A "second lesion" of this type frequently establishes the diagnosis of multiple sclerosis. Evoked potentials may be ab­normal in the other conditions listed in the question.