PURE SENSORY STROKE CAUSED BY A PONTINE INFARCT - CLINICAL, RADIOLOGICAL, AND PHYSIOLOGICAL FEATURES IN 4 PATIENTS

Background and Purpose We conducted this retrospective study to evalua te the clinical, neuroradiological, and neurophysiological findings in patients with pure sensory stroke due to pontine lacuna. Summary of R eport Four patients with pontine lacuna, three men and one woman (mean age, 64.5 years; range, 55 to 75 years), were evaluated. Magnetic res onance images were obtained with a 0.5-T superconducting magnet using the SE technique. Short-latency somatosensory evoked potentials were e valuated by unilateral stimulation of the median nerve at the wrist. T hese tests were done at a mean of 22.5 months (range, 9 to 34 months) after symptom onset. Deep sensory disturbances were present in one hal f of the patient's body with no other neurological deficits found. The sensory deficit was characterized by a prolonged period of refractory dysesthesia and a discrepancy between the superficial and deep sensor y disturbances. Lesions were localized in the medial lemniscus of the middle and lower pens, with a sparing of the spinothalamic tracts. The central conduction times of short-latency somatosensory evoked potent ials were prolonged (patients 1, 2, and 4), and the amplitudes were si gnificantly reduced (patients 1 and 2) when stimulating the parestheti c-sided median nerve (contralateral side of the lesion) compared with stimulating the other side. Conclusions In all cases, the clinical and radiological findings indicated a dysfunction of the medial lemniscal tract in the pens. The observed somatosensory evoked potentials were probably related to the persistent refractory dyesthesias present in t hese patients.