Post-Stroke Visual Dependence and Early Intervention of Multisensory Balance Rehabilitation (2/3)

Visual dependence is to describe overly reliance on visual information rather than other sensory systems to maintain effective spatial orientation and postural control. It has been reported that subjective visual vertical was easily affected by static or dynamic visual inputs in stroke patients. Their postural sway measured by center of gravity displacement became bigger and faster in exposure to a rotating visual environment. Both indicate high level of perceived and postural visual dependence in stroke patients. However, only one study investigated the prevalence of visual dependence after stroke but the data was speculated by limited sample size. Post-stroke visual dependence is strongly associated with balance problems, however, the majority of studies examined the effects of visual dependence on static balance rather than dynamic balance and gait, which are relatively functional in daily life. It is therefore important to understand the influence of visual dependence on motor functions especially dynamic balance and gait. More than half of stroke patients have at least once fall experience and instability is one of risk factors. Thus, which assessment tool can distinguish fallers from non-fallers stroke is crucial. The Rod and Frame test and the Rod and Disc test, are commonly used for visual dependence measurement, can discriminate between fallers and non-fallers in community-dwelling elderly. It is unclear whether two tests have similar discrimination in stroke patients. Visual dependence could be associated with sensory reweighting deficit, and thus multisensory balance exercise could be beneficial to decrease the levels of visual dependence. Multisensory balance rehabilitation is an exercise to improve sensory reweighting and organization by manipulating visual, vestibular and proprioceptive inputs. Initial months since onset time are important period for sensory systems recovery and adaptation. Early intervention of multisensory balance exercise could improve perceptual motor adaptation in order to prevent from developing abnormal sensory organization and compensatory strategy of visual dependence. This proposal is 3-year research with 2 aims: 1) investigating the prevalence of post-stroke visual dependence, the effects of visual dependence on balance and gait in stroke patients, and whether the visual dependence measurements could distinguish fallers from non-fallers stroke; 2) investigating the effectiveness of multisensory balance rehabilitation on visual dependence, balance and gait in acute stroke patients. Aim 1 will recruit 160 chronic stroke patients to assess their fall history, levels of visual dependence, motor function such as balance and gait. Aim 2 will recruit 160 acute stroke patients with less than 1 month onset time. They will be randomly allocated into control and experimental group. The former will receive FaME (Fitness and Mobility Exercise) exercise while the latter will receive combination exercise of FaME and multisensory balance rehabilitation for 16 weeks. Assessment will be carried out before the exercise, immediately after exercise and follow-up (one year after stroke) including visual dependence, fall experience, balance and gait.