Clinical Differences between Radiographic and Physical Horizontal Gaze Deviation: Utility of Using the Two in Patients with Ischemic Stroke.

Background and Purpose: Radiographic horizontal gaze deviation (RHGD) has been identified as a useful finding on computed tomography (CT) that indicates the affected side in supratentorial ischemic stroke; however, it remains unclear whether RHGD is essentially the same phenomenon as physical horizontal gaze deviation (PHGD). To resolve the issue, this study was conducted. Methods: Retrospective analyses were performed for 671 patients with ischemic stroke and 142 controls who were hospitalized and underwent head CT. First, clinical findings were examined to find differences between RHGD-positive and RHGD-negative patients. Second, patients were classified by their stroke mechanisms and/or affected vascular territories. For each subgroup, RHGD was compared with PHGD in frequency. Third, the proportions for patients divided by positivity for PHGD and RHGD were calculated in the subgroups. Results: Patients with RHGD had PHGD more often than those without. In all stroke subgroups, RHGD was more frequent than PHGD. The frequency difference was prominent in small-artery occlusion (SAO) and posterior inferior cerebellar artery (PICA) stroke. In SAO of the basilar artery pontine perforator, RHGD was positive in 25% and largely contralesionally-directed. In PICA stroke, lesions in the vestibulocerebellum were associated with contralesional RHGD. Moreover, lesions in the lateral medulla also caused RHGD, which was mainly directed to the ipsilesional side. PHGD-positive stroke without RHGD was infrequent, whereas RHGD-positive stroke without PHGD was commonly observed (PICA stroke, 45.9%; other subgroups, 21.1%-27.5%). Conclusions: RHGD had different characteristics from PHGD; therefore, assessments of both PHGD and RHGD may lead to more accurate diagnoses.