Lesion Localization of Time Disorientation in Patients With Focal Brain Damage

Background and ObjectivesTime orientation is a fundamental cognitive process in which ones personal sense of time is matched with a universal reference. Assessment of time orientation is a ubiquitous component of neurological mental status examinations and neuropsychological assessments, yet its neural correlates remain unclear. Large bilateral lesions have been associated with deficits in time orientation, but more specific regions of the brain implicated in time disorientation following focal unilateral damage are relatively unknown. The current study investigates the anatomy of time disorientation and its network correlates in patients with focal brain lesions. Methods550 patients with acquired, focal brain lesions participated in this study, identified retrospectively from the Iowa Neurological Patient Registry. Time orientation was assessed 3 months or more after lesion onset using the Benton Temporal Orientation Test (BTOT), and 39 patients were identified as having chronic impairment in time orientation defined as a score of 3 or worse on the BTOT. Multivariate lesion-symptom mapping and lesion network mapping were used to evaluate the anatomy and networks associated with time disorientation. Performance on a variety of neuropsychological tests was compared between the time oriented and time disoriented group. Results39 patients were identified as having chronic impairment in time orientation. Multivariate lesion-symptom mapping showed that lesions of the posterior cortices were associated with impaired time orientation, including medial temporal lobes, occipitotemporal cortex, and precuneus (r=0.21, p<.001). Individuals with time disorientation tended to have concomitant impairments in memory, visuospatial ability, and naming. Follow-up analyses of individuals with unilateral lesions and those with relatively unimpaired cognition in other domains implicated the precuneus and parahippocampal gyrus in time orientation. Lesion network mapping demonstrated that these regional findings occurred at nodes of the default mode and visual networks. Individuals with time disorientation tended to have concomitant impairments in memory, visuospatial ability, and naming. DiscussionWe interpret these findings as novel evidence for the role of posteromedial cortices extending from the precuneus to the medial temporal lobe in supporting time orientation.