Head Position of Patients with Right Hemisphere Damage during a Visual Search Task in a Large Field

Ken Nakatani,Kiyoe Sakai,Masako Notoya,Shusuke Takahashi,Daisuke Kimura,Takashi Fujita,Naoe Mori,Shinya Fuwa,Shinya Fukunaga,Nobuyuki Sunahara,Minoru Toyama

doi:10.4236/wjns.2018.82018

Abstract

Spatial neglect syndrome with cerebral lesions is characterized by the ina-bility to orient, report, or respond to relevant visual stimuli contralateral to the lesions. In this study, we investigated the pattern of horizontal visual search in a large space; this search was performed by patients with right hemisphere damage caused by cerebrovascular disease. The neck rotation angle and search time in each increment were continuously recorded during the task, and quantitative data of the measurements were collected. Head position during the visual search task in a large space (%) was then calculated. We set angular bands in increments of 5 degrees from the midline on the left and right sides, and calculated the total search time in each angular band. In patients with unilateral spatial neglect (USN), the search time in the angular band of 5 - 9 on the right side was significantly longer (with USN 16.7%, without USN 4.5%, t = 2.52, df = 16, p < 0.05). Furthermore, in patients with neglect in the leftmost end area in a large space, the search time was significantly shorter in the angular band of 1 - 4 degrees to the left (with neglect 13.1%, without neglect 23.7%, t = 2.13, df = 16, p < 0.05), and tended to be long in the angular band of 5 - 9 to the right. The neck rotation angle and pattern during the search task in a large field deviated slightly to the right, and the search time slightly to the left was short. We believe that these results support the rightward deviation of the search pattern and frame of USN patients.

Highlights

Spatial neglect syndrome in patients with a cerebral lesion is defined as the failure to orient, report, or respond to relevant visual stimuli contralateral to the lesion [1]
We have previously reported on the diversity of unilateral spatial neglect (USN) symptoms, wherein we focused on a sound lateralization ability using auditory tasks [6], as well as on a visual search ability and horizontal neck rotation angle during visual search tasks in a large space [7]
By analyzing horizontal visual search ability, head position, and neck rotation pattern during the search task in a large space, we reported a strong correlation between the number of visual search tasks performed in a large space and the total Behavioural Inattention Test Conventional Subtest (BITC) score

Summary

Introduction

Spatial neglect syndrome in patients with a cerebral lesion is defined as the failure to orient, report, or respond to relevant visual stimuli contralateral to the lesion [1]. We have previously reported on the diversity of USN symptoms, wherein we focused on a sound lateralization ability using auditory tasks [6], as well as on a visual search ability and horizontal neck rotation angle during visual search tasks in a large space [7]. We divided subjects into two groups, one with USN and one without USN, based on the score of Behavioural Inattention Test Conventional Subtest (BITC). By analyzing horizontal visual search ability, head position, and neck rotation pattern during the search task in a large space, we reported a strong correlation between the number of visual search tasks performed in a large space and the total BITC score. No significant difference was observed with respect to the neck rotation angle as well as the average and maximum values of the two groups [7]

Methods

Results

Discussion

Conclusion