van Wyk A.1, Eksteen C.A.2, Heinze B.M.3
1University of Pretoria, Department of Physiotherapy, Pretoria, South Africa, 2University of Pretoria, School of Health Care Sciences, Department of Physiotherapy, Pretoria, South Africa, 3University of Pretoria, Department of Speech-Language Pathology and Audiology, Pretoria, South Africa
Background: Saccadic eye movements are necessary to visually scan the surrounding environment to provide an individual with information that includes:
(a) the identification of objects' position in space;
(b) the determination of the objects' movement;
(c) the position of one's body in space;
(d) the relation of one body part to another and
(e) the motion of one's own body.
Impairment to control gaze or to shift gaze appropriately to scan the environment limits the visual system's input into postural-orientation processing and as a result affect postural stability and ultimately result in the inability to execute goal-directed activities accurately.
Clinical observations of patients with saccadic eye movement dysfunction following a stroke may include the following:
(1) head turn or tilt during near tasks;
(2) closing one eye during conversations and/or activities due to blurred vision or double-vision;
(3) having difficulty maintaining eye contact;
(4) neglecting one side of the body or space during functional activities;
(5) appears to misjudge distance due to a loss of depth perception;
(6) under or over reaching for objects; and
(7) decreased attention.
(a) the identification of objects' position in space;
(b) the determination of the objects' movement;
(c) the position of one's body in space;
(d) the relation of one body part to another and
(e) the motion of one's own body.
Impairment to control gaze or to shift gaze appropriately to scan the environment limits the visual system's input into postural-orientation processing and as a result affect postural stability and ultimately result in the inability to execute goal-directed activities accurately.
Clinical observations of patients with saccadic eye movement dysfunction following a stroke may include the following:
(1) head turn or tilt during near tasks;
(2) closing one eye during conversations and/or activities due to blurred vision or double-vision;
(3) having difficulty maintaining eye contact;
(4) neglecting one side of the body or space during functional activities;
(5) appears to misjudge distance due to a loss of depth perception;
(6) under or over reaching for objects; and
(7) decreased attention.
Purpose: To determine whether there is an association between visual impairment, specifically saccadic eye movement disorder and central vestibular dysfunction in sub-acute post-stroke patients' functional ability.
Methods: A cross-sectional survey (n = 70) was conducted to determine the association of saccadic eye movement dysfunction and functional ability in patients that sustained a stroke. An independent physiotherapist assessed the velocity of saccadic eye movements (SACCEM) with Video Nystagmography (VNG) to quantify saccadic eye movements and completed the Barthel Index.
Results: All stroke patients assessed presented with impaired saccadic eye movement velocity on SACCEM left eye left visual field (mean ± SD: 344.20±141.86°/s), SACCEM left eye right visual field (mean ± SD: 393.30±100.80 °/s), SPEM right eye left visual field (mean ± SD: 346.70±134.60 °/s) and SACCEM right eye right visual field (mean ± SD: 385.60±106.24 °/s). Pearson correlations (1% significant level) between SACCEM and Barthel Index were SACCEM left eye left visual field (r = 0.37496; p = 0.0014), SACCEM left eye right visual field (r = 0.38179; p = 0.0011), SACCEM right eye left visual field
(r = 0.38959; p = 0.0009) and SACCEM right eye right visual field (r = 0.26648; p = 0.0258).
Conclusion(s): Ocular motility and the interpretation of the visual input gathered during eye movements are important for aligning and maintaining the body in space. The ability to control the bodys position in space is fundamental to the successful performance of functional tasks in any particular environment. Visuomotor deficits and visual-perceptual impairments as result of visual impairments affect an individuals ability to respond to sensory input obtained from the environment and demands of the task. The inability to respond efficiently upon the sensory input from the environment and demands of the task results in a decrease in postural control that leads to increased functional dependence during ADL.
Implications: The study contributes to the diagnosis strategy that should be implemented in the rehabilitation of visual system dysfunction to optimise post-stroke rehabilitation.
Funding acknowledgements: National Research Foundation Innovation Doctoral scholarship for 2016 (Reference SFH150729132539) and the South African Society of Physiotherapy's Research Foundation (VAN180).
Topic: Neurology: stroke
Ethics approval: Ethics approval was obtained from the Ethics Committee of Faculty of Health Sciences at the University of Pretoria (UP) (374/2015).
All authors, affiliations and abstracts have been published as submitted.
