Studies on the sensory changes and somatosensory evoked potential in thalamic stroke

Jung, Doo Gyo; Kim, Jong Yeol; Suh, Chung Kyu

Abstract

BACKGROUND: The thalamus is a subcortical gray-matter composed of several groups of nuclei. Though there are some characteristic clinical findings in thalamic stroke syndrome, it is not easy to identify their own function in each nuclei. We demonstrated this study to figure out the relationships between anatomic nucleus, sensory symptoms, and electrophysiologic findings in thalamic stroke.
METHODS
Sixteen thalamic stroke patients were studied. Fifteen cases showed thalamic lacunar infarction by magnetic resonance imaging and one case showed thalamic hemorrhage by computed tomography. We compared their sensory symptoms and signs, somatosensory evoked potentials(SSEP), the size of lesions, and the location of lesions on imaging studies.
RESULTS
There were 12 cases of a lesion on ventroposterolateral(VPL) nucleus(Group I) and 4 cases of a lesion on the other nuclei(Group II). All 8 cases which had a sensory deficit in Group I, and 2 cases - one with sensory deficit and the other without in Group II, showed abnormal SSEP findings. There were 9 cases in Group I and 3 cases in Group II with thalamic pain and there was no relationship between SSEP and thalamic pain. Five were pure sensory strokes in 6 patients with a small lesion(less than 0.5 cm), and pure sensory strokes were only 3 in 10 patients with relatively a large lesion (between 0.5 and 1.5 cm).
CONCLUSION
There was significant relationship between sensory deficit and SSEP. SSEP can be used as a objective method in estimating the sensory deficit of thalamic stroke. We could ascertain the fact that other nuclei as well as VPL nucleus were associated with the development of pain in thalamic stroke, and there was significant relationship between the size of lesion and the clinical feature of stroke.