Significance of electrophysiology in brainstem ischemia and normal diffusion weighted and high resolution MRI

We analysed the significance of electrophysiologic testing in patients with acute signs of brainstem dysfunction without corresponding magnetic resona nce imaging (MRI) documented brainstem lesions. High resolution T-1- and T- 2-weighted and diffusion weighted MRI was done in 156 consecutive patients with clinical signs of acute brainstem dysfunction. MRI was normal in 22 of these. Seventeen of the 22 patients were diagnosed as TIA (10 patients) or PRIND (7 patients). Abnormal electrophysiologic findings were seen in 16 o f these 22 patients mainly affecting the masseter reflex, direct current el ectro-oculography or brainstem auditory evoked potentials. Re-examinations were done in 11 patients showing improvement or recovery in 8 of them. Elec trophysiological testing documents brainstem lesions in almost (3)/(4) of p atients with clinical signs of acute brainstem dysfunction but normal high resolution and diffusion weighted MRI. Although thinner slices and recently developed techniques have increased the sensitivity of MRI in the detectio n of brainstern lesions, electrophysiological testing remains a useful tool in the detection of brainstem lesions.