Unilateral neglect post stroke: Eye movement frequencies indicate directional hypokinesia while fixation distributions suggest compensational mechanism. Issue 1 (12th December 2018)

• Record Type: Journal Article
• Authors: Walle, Kjersti M.; Nordvik, Jan E.; Becker, Frank; Espeseth, Thomas; Sneve, Markus H.; Laeng, Bruno
• Is Part Of: Brain and behavior. Volume 9:Issue 1(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-12-12
• Subjects: divided attention -- eye‐tracking -- Multiple Object Tracking -- neglect -- nonspatial attention -- spatial attention; Neurology -- Periodicals; Neurosciences -- Periodicals; Psychology -- Periodicals; Psychiatry -- Periodicals; 616.8005
• DOI: 10.1002/brb3.1170
• Languages: English
• ISSNs: 2162-3279

Abstract

Abstract: Introduction: Eye movements and spatial attention are closely related, and eye‐tracking can provide valuable information in research on visual attention. We investigated the pathology of overt attention in right hemisphere (RH) stroke patients differing in their severity of neglect symptoms by using eye‐tracking during a dynamic attention task. Methods: Eye movements were recorded in 26 RH stroke patients (13 with and 13 without unilateral spatial neglect, and a matched group of 26 healthy controls during a Multiple Object Tracking task. We assessed the frequency and spatial distributions of fixations, as well as frequencies of eye movements to the left and to the right side of visual space so as to investigate individuals' efficiency of visual processing, distribution of attentional processing resources, and oculomotoric orienting mechanisms. Results: Both patient groups showed increased fixation frequencies compared to controls. A spatial bias was found in neglect patients' fixation distribution, depending on neglect severity (indexed by scores on the Behavioral Inattention Test). Patients with more severe neglect had more fixations within the right field, while patients with less severe neglect had more fixations within their left field. Eye movement frequencies were dependent on direction in the neglect patient group, as they made more eye movements toward the right than toward the left. Conclusion: The patient groups' higher fixation rates suggest that patients are generally less efficient in visual processing. The spatial bias in fixation distribution, dependent on neglect severity, suggested that patients with less severe neglect were able to use compensational mechanisms in their contralesional space. The observed relation between eye movement rates and directions observed in neglect patients provides a measure of the degree of difficulty these patients may encounter during dynamic situations in daily life and supports the idea that directional oculomotor hypokinesia may be a relevant component in this syndrome. Abstract : Our study investigated attention pathology in right hemisphere stroke patients with and without neglect. Patients had higher fixation frequencies compared to controls, suggesting they were less efficient in their visual processing. Neglect patients showed a spatial bias in their distribution of fixations that depended on neglect severity. This bias shifted from a rightward bias to a leftward bias as neglect symptoms decreased. This suggested that patients with less severe neglect were able to use compensational mechanisms in their contralesional space. The relation between direction of eye‐movements and their frequency in the neglect patients suggests that directional hypokinesia can be a relevant component in this syndrome.