Stroke is a global health-care problem that is common, serious, and disabling in most countries, the 2nd or 3rd most common cause of death and one of the main causes of acquired adult disability. Patients with stroke have number of impairments but usually present with difficulty maintaining balance. Balance is described as the ability to maintain equilibrium in a gravitational field by keeping or returning the center of body mass over its base of support. Body balance is the result of a harmonious interaction between the afferents from sensory systems (vestibular, proprioceptive and visual). The somatosensory system organizes proprioceptive information, while the visual system provides information about the position of the body in relation to the external environment. When the functions of the sensory triad are disrupted, unpleasant sensations occur, e.g. dizziness, nausea, feeling of imbalance and, sometimes, nystagmus, Balance is a complex process in which the maintenance of a position is regulated by postural adjustments to voluntary activity and in response to external perturbation. Impairments of postural control result in increased rates of unintentional falls. In fact, falls are the leading cause of injuries and subsequent deaths among people 65 years and older, and generate a fundamental financial burden to the healthcare system.Stroke survivors present with deficits in different systems, including sensory, musculoskeletal, perceptual, and cognitive, which decrease postural stability. The lack of postural stability can lead to falls during hospitalization, both in the acute care and rehabilitation stages, and after discharge. Because of the importance of postural instability in this population, a systematic evaluation of balance is needed to identify specific problems.The measures most commonly used with stroke patients are different parameters extracted from the center of pressure (COP) and weight distribution of the vertical reaction force. After a stroke, patients have demonstrated a significant increase in sway and weight-bearing asymmetry. The relearning of postural control through external visual and auditory biofeedback is believed to be an effective therapy for improving balance control. In a Cochrane review, the results of seven randomized clinical trials and indicated that providing feedback from a force platform resulted in improved stance symmetry after stroke but did not improve balance during active functional activities, nor did it improve overall independence. A study conducted on elderly population was concluded that Balance training reduced elderly subjects' overactive proprioceptive feedback and enhanced vestibular orientation Previous studies only assess the effect of balance training on elderly population or stroke population. But the role of these trainings on vestibular and proprioception function were not assessed among stoke population while in the current study we aimed to assess the effect of balance training of simple physical therapy exercises on sensory channel (vestibular function, proprioception feedback mainly). In 2011 on Stroke rehabilitation was concluded by Ongoing trials of repetitive task training, early mobilization, treadmill training, physical fitness training, and speech and language training for aphasia and dysarthria are high-quality, multicenter, multidisciplinary studies of complex interventions, which meet many of the above recommendations.

In 2004 a comparative study to compare clinical and biomechanical measures of balance in elderly stroke patients with those of healthy elderly people. This study concluded as postural stability in quiet stance, as measured by COP-COM amplitude, was related to functional measures of balance as well as physiologic factors relating to balance, such as visual conditions, lower-extremity peripheral sensibility, motor recovery, and simple reaction time Another study on dynamic balance ability through stair gait training where in proprioceptive neuromuscular facilitation (PNF) was applied and for the four weeks of the experiment, each group received training three times per week, for 30 min each time. Berg Balance Scale (BBS) values were measured and a time up and go (TUG) test and a functional reach test (FRT) were performed for a comparison before and after the experiment which is concluded that gait training group to which PNF was applied saw improvements in their balance ability, and a good result is expected when neurological disease patients receive stair gait training applying PNF.(10) A systematic review evaluated recent evidence related to the effect of balance training on balance performance among individuals post stroke across the continuum of recovery. On the basis of this evidence, we also provide recommendations for exercise prescription in such programs. Review evaluated recent evidence related to the effect of balance training on balance performance among individuals post stroke across the continuum of recovery. On the basis of this evidence, we also provide recommendations for exercise prescription in such programs.

In 2o18 on to investigate the effect of customized vestibular rehabilitation training on gait stability of patients with sub-acute stroke. An instrumented 10- Meter Walk Test together with traditional clinical scales were used to assess VR effects. Which is concluded by VR could be included into a rehabilitation program for patients with stroke for improving their gait and dynamic balance acting on their vestibular system as facilitator of recovery.

Another study in 2014 virtual reality (VR) proprioception rehabilitation system was developed for stroke patients to use proprioception feedback in upper limb rehabilitation by blocking visual feedback. To evaluate its therapeutic effect, 10 stroke patients (onset \> 3 month) trained proprioception feedback rehabilitation for one week and visual feedback rehabilitation for another week in random order. Proprioception functions were checked before, a week after, and at the end of training.it was concluded that effectiveness and possible use of the VR to recover the proprioception of stroke patients In 2020 A pilot study to find out the effects of COP (center of pressure) movement tracking training conducted using the Biodex Balance System SD in static and dynamic modes on balance ability in stroke patients. The result of study concluded that COP movement tracking training in dynamic mode was found to be a more effective intervention for improving the static balancing abilities of stroke patients than training in static mode.

In 2000 A comparative study was done by walker et al to compared the relative effectiveness of visual feedback training of center-of-gravity (COG) positioning with conventional physical therapy following acute stroke result show that Visual feedback or conventional balance training in addition to regular therapy affords no added benefit when offered in the early stages of rehabilitation following stroke