Effect of Optokinetic Stimulation on Spatial Neglect and Postural Stability in Patients With Stroke

In stroke patients the presence of spatial neglect predicts poor outcome in functional recovery, entailing a longer time of hospitalization, greater functional dependency, increased risk of falls and a long-term disability in Activities of Daily Living (ADL). This results in an overall increase of costs for the health system.

Spatial neglect patients' performance in self-care and household is usually compromised. Those patients had more problems in performing self-care and household tasks than non-spatially neglected patients. For example, spatial neglect patients forgot or could not find objects at one side when dressing or in the kitchen and had difficulty eating or using devices. VSN severity had a negative impact on the performance of ADL. Spatial neglect had a negative impact on walking and wheelchair navigation. Spatial neglect had a negative impact on exercise such as walking and jogging .

Patients with spatial neglect had an increased weight-bearing asymmetry favouring the non-paretic leg and increased mediolateral CoP excursions while standing. However, upright standing is an inherently more demanding posture owing to the height of the center of mass relative to the base of support.

Because of all those effects of spatial neglect on outcomes, it is a necessity to engage more neurological rehabilitative procedures focusing on neglect and its complications. One of the treatments used for neglect is optokinetic stimulation (OKS).

The vestibular apparatus is the primary organ of balance which is used mainly during motion when compared to somatosensation. Optokinetic stimulation is known to stimulate areas of the brain such as the brain stem and cerebellum that immediately process balance signals from the vestibular apparatus before they are transmitted to the cerebral cortex via the thalamus. Optokinetic chart stimulation has been reported to restore voluntary movement and mobility in an acute hemorrhagic stroke as well as restore postural control and independent mobility in an acute, ataxic, posterior temporal parietal ischemic stroke.

So, this study will be conducted to investigate the effect of optokinetic stimulation on neglect and balance measures in stroke patients rehabilitation.

• Optokinetic stimulation (Other): Patients will receive optokinetic stimulation (OKS) as an intervention for spatial neglect, based on observing moving visual stimuli to promote visual scanning of the neglected hemispace. With the patient properly positioned, the physiotherapist will apply virtual reality glasses supported by a mobile device displaying pre-prepared OKS videos. The videos will show vertical bars moving leftward at a fixed speed of 1 cm/s, with random color changes to maintain attention. Patients will be instructed to report each color change. OKS will be delivered in five 4-minute bouts separated by 1-minute rest intervals, totaling 20 minutes per session.
• Sham optokinetic stimulation (Other): A static image consisting of black-and-white vertical bars will be projected for patients in this group. The bars will undergo random color changes similar to those used in the intervention group; however, no movement will be present.
• Traditional therapy (Other): All participants in both groups will receive a selected physical therapy program for 30 min per session to enhance balance for 10 weeks.

Primary outcomes

• Albert test [10 weeks]: It is the test used for screening of unilateral spatial neglect .the examiner asked to cross all the lines. The more un crossed lines the worst degree of spatial neglect.
• Catherine bergego scale (CGS) [10 weeks]: It is a 4 point scale used to indicate the severity of neglect .the total score out of 30 . the higher scores indicate the more severe the spatial neglect

Secondary outcomes

• Limit of stability (LOS) [10 weeks]: It measures the examiner ability to shift center of gravity in eight directions. Lower scores indicated lower abilities to maintain dynamic balance.
• The Modified clinical test of sensory interaction on balance (m CTSIB) [10 weeks]: It measures sensory integration and its effect on stability and static balance. The higher scores indicates higher control.
• Center of pressure [10 weeks]: It examiner would maintain his center of pressure in the center of illustrated figure on the screen of HUMAC system . the longer the patient can maintain static balance the more control and stability patient has.

Sex: All, ages: 50 Years to 65 Years

Inclusion Criteria:

* Patient's age ranges from 50 to 65 years referred by neurologist.
* Patient's will be diagnosed as stroke in the subacute stage
* Patients will suffer from spatial neglect resulting from the stroke that screened by albert's test.
* Patients are medically stable and able to understand and follow instructions.

Exclusion Criteria:

* There is any previous neurological disability
* There is general unstable conditions, history of epilepsy, cardiac pacemakers
* There is sever cognitive disorder
* There is visual field deficit