“Look straight ahead”—A new test to diagnose spatial neglect by computed tomography

PLOS ONE RESEARCH ARTICLE “Look straight ahead”—A new test to diagnose spatial neglect by computed tomography Joel Coelho-Marques1,2, Jens Hanke3, Caroline Schell1, Frank Andres1, HansOtto Karnath ID2* 1 Department of Neurology and Early Rehabilitation, Kreiskliniken Reutlingen GmbH, Reutlingen, Germany, 2 Division of Neuropsychology, Center of Neurology, Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany, 3 Diagnostic and Interventional Radiology, Kreiskliniken Reutlingen GmbH, Reutlingen, Germany a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 OPEN ACCESS Citation: Coelho-Marques J, Hanke J, Schell C, Andres F, Karnath H-O (2023) “Look straight ahead”—A new test to diagnose spatial neglect by computed tomography. PLoS ONE 18(4): e0284033. https://doi.org/10.1371/journal. pone.0284033 Editor: Zhentian Wang, Tsinghua University, CHINA Received: August 23, 2022 Accepted: March 22, 2023 Published: April 6, 2023 Copyright: © 2023 Coelho-Marques et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: Data are provided with anonymization of the participants and are available on G-Node (https://doi.org/10.12751/gnode.8zwmk4). Funding: This work was supported by the Deutsche Forschungsgemeinschaft (KA1258/231). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing interests: The authors have declared that no competing interests exist. * Abstract Spatial neglect is the dominant behavioral disorder after right hemisphere brain lesions. Reliabel diagnosis by formal neuropsychological testing is often achieved only later during hospitalization, leading to delays in targeted therapies. We propose a way to diagnose spatial neglect right at admission. We measured the conjugated eye deviation (CED) on the initial computed tomography (CT) scans, in combination with the verbal instruction “Please look straight ahead” during the scan. The command was implemented in the scanner program and automatically played before a cranial CT started. This prospective study included a total 46 consecutive subjects (16 patients with first ever right brain damage and no spatial neglect, 12 patients with first ever right brain damage and spatial neglect, and 18 healthy controls). The right brain damaged groups were submitted to paper pencil tests to access the diagnosis of a spatial neglect after radiological confirmation of the brain damage during the initial phase of their hospitalisation. This procedure allowed us to define a cut-off value of 14.1 degrees of CED to the ipsilesional side to differentiate right hemispheric stroke patients with versus without spatial neglect with a confidence interval of 99%. This simple addition to a radiological routine procedure provides a new tool to help diagnose spatial neglect at the earliest stage possible and thus offers the possibility of providing patients with optimized rehabilitative therapy from a very early stage on. Introduction Despite declining incidence and mortality [1], cerebrovascular disease stays of upmost importance as a health indicator, especially in terms of resulting disability, associated healthcare, and nursing costs [2, 3]. Along with hemiparesis, the two most dominant clinical symptoms of stroke are aphasia after a lesion of the human left hemisphere and spatial neglect after right hemisphere damage [4]. Early diagnosis of these disorders is important for several reasons: Studies have shown that early onset rehabilitative therapy within the first 24 hours after stroke can improve the outcomes of the neurological deficits [4, 5] − aphasia and spatial neglect included [5] − if the interventions are frequent and short [5]. Furthermore, spatial neglect has PLOS ONE | https://doi.org/10.1371/journal.pone.0284033 April 6, 2023 1 / 11 PLOS ONE “Look straight ahead”—A test to diagnose neglect been shown to increase hospitalization times and slow down the recovery from additional deficits [6], which highlights the importance of an early diagnosis. While early assessment of language disorders in awake patients is straightforward, the diagnosis of spatial neglect is not so well established in this (hyper)acute phase of admission, i.e. when paper-and-pencil testing is often not yet feasible. Two early clinical signs in neglect patients are the spontaneous and sustained deviation of the eyes (conjugate eye deviation [CED]) and of the head toward the ipsilesional side [7–9]. Becker and Karnath [7] observed that the horizontal eye-in-head deviation is specifically associated with spatial neglect rather than with brain damage per se and that it can be detected already in clinical imaging scans taken at admission. Using the latter observation for a clinical test of spatial neglect seemed obvious. However, the retrospective analysis of routine clinical scans by Becker and Karnath [7], i.e., scans obtained without further modifications of the typical neuroradiological imaging procedure, did not allow a control of the patients’ eye-in-head position; they were free to direct their eyes in any direction. In the present prospective study, we tried to maximize the discrepancy between horizontal eye-in-head deviation between stroke patients with and without spatial neglect by giving the simple verbal command “Please look straight ahead” during the scan. While this instruction can easily be followed by stroke patients without neglect, it will not help patients with neglect to overcome their tonic horizontal eye-in-head deviation. This simple verbal instruction could therefore serve to maximize the discrepancy between these two groups and might allow to build a formal cut-off for differentiation between them. Methods Subjects Neurological patients with the suspicion of an acute stroke consecutively admitted between February 2018 and March 2020 to the Department of Neurology in Reutlingen were screened for a first ever right-hemisphere stroke. Patients with tumors, patients in whom MRI or CT scans revealed no obvious lesions, as well as patients with disturbed awareness at admission were not included. Patients who were not able to perform the paper/pencil tasks and patients who underwent any type of revascularization therapy were also excluded (see below). We also did not include patients with left-sided stroke to exclude any conflicts between the here newly applied (verbal) procedure in the scanner (see below) and possible disturbances of language processing [10]. A group of control subjects consisted of 18 subjects in whom CT imaging had been conducted due to headache, but no pathological findings had been revealed. Clinical and demographic data of all subjects are presented in Table 1. All subjects provid (...truncated)