Clinical Aspects of Screening Test Tools for Central Neuropathic Pain in Patients with Thalamic Stroke

[Purpose] The purpose of this study was to investigate clinical aspects of screen test tools for central neuropathic pain in thalamic stroke patients. [Subjects and Methods] Seven thalamic stroke patients were recruited as subjects. To classify the subjects into central neuropathic pain and non-neuropathic pain groups, the Leeds assessment of neuropathic symptoms and signs (LANSS) was used. Four patients were classified as having central neuropathic pain. To evaluate the central neuropathic pain, the quantitative somatosensory test, the median nerve somatosensory evoked potentials (SEPs), magnetic resonance imaging (MRI), and functional MRI (fMRI) were performed on average 31.5 months after stroke. [Results] The quantitative somatosensory test did not show a correlation between the central neuropathic pain group and the non-neuropathic pain group. The SEPs on the affected side showed a response in one of the patients without central neuropathic pain, and responses on the unaffected side were normal for all of the patients. M RI-based thalamic localization data indicate that this method is limited in its ability to distinguish the central neuropathic pain in thalamic stroke patients. Results of fMRI show that the secondary somatosensory areas of the central neuropathic pain group were more activated than those of nonneuropathic pain group. [Conclusion] Based on the results, we verified that functional MRI is useful for evaluating the central neuropathic pain in thalamic stroke patients.