Cognitive Profile of Patients with Thalamic Hemorrhage according to Lesion Localization.

Background: The thalamus is known as the central sensory and motor relay station of the brain generally. However, cognitive decline due to thalamic lesions has been previously reported in different studies. Also, it has been observed that different cognitive subdomains are affected according to the localization of the lesion in the thalamus.

Objectives and methods: Detailed neurophysiological tests were performed on 28 patients with thalamic hemorrhage and the control group. Patients were grouped according to lesion localization. The results were compared with both the control group and the hemorrhage groups themselves.

Results: The performance of patients in all neuropsychological tests was significantly worse than that of the control group. Of the 28 patients, 15 had anterolateral, 5 had posterolateral, 5 had dorsal, and 3 had an anteromedial thalamic hemorrhage. The anteromedial group had the worst scores of almost all tests. Also, 2 situations came to notice in these tests. First, the posterolateral group achieved a remarkably low mean in the recall subgroup of the MMSE tests and verbal memory process tests. Second, the anterolateral group was found to have a low mean in both the language subgroup of the MMSE tests and the phonemic subgroup of the verbal fluency tests.

Conclusion: It was concluded in this study that thalamic hemorrhages affect cognition entirely regardless of the lesion localization. It was also observed that the lateral part of the thalamus was associated with language, the posterior part with memory, and the anteromedial part with the rest of the cognitive subdomains.