Contribution of Muscle Strength and Integration of Afferent Input to Postural Instability in Persons with Stroke

Abstract

Objectives-To determine the relationship of muscle strength to postural sway in persons with stroke under standing conditions in which vision and ankle proprioception were manipulated.Methods-Forty persons with stroke and 40 healthy older adult controls were recruited from the community and underwent balance testing consisting of six conditions that manipulate vision and somatosensory information while standing. Postural sway was measured during each condition. In addition, lower extremity joint torques and cutaneous sensation from the plantar surface of the foot were assessed.Results-Postural sway was increased with more challenging standing conditions (i.e. when multiple sensory systems were manipulated) to a greater extent with the group with stroke compared to controls. Muscle strength was only correlated to sway during the most challenging conditions. Furthermore, a greater number of persons with stroke fell during the balance testing compared to controls.Conclusions-Impairments in re-weighting/integrating afferent information, in addition to muscle weakness appear to contribute to postural instability and falls in persons with stroke. These findings can be used by clinicians to design effective interventions for improving postural control following stroke.

Changes in Postural Sway According to Surface Stability in Post-stroke Patients

“…Although a stroke patient may survive with appropriate first aid and early treatment after the initial symptoms, stroke symptoms such as impairment of motor and sensory function, cognition, balance, and gait often persist 2) . Asymmetrical posture and weight bearing are the most common post-stroke symptoms, causing an increase in postural sway 3) . The increase in postural sway during standing is due to the degeneration of the nervous system and is more severe in elderly people than young adults.…”

“…In addition, Bowen et al 11) confirmed that stroke patients show increased anteroposterior postural sway when visual input is blocked in a standing posture. Furthermore, when integrating the sensory information in the central nervous system (CNS) for postural control, postural sway increases due to damage in the proprioception processing center in the upper spinal cord 3) . To investigate the influence of proprioception on postural sway for stroke patients in a sitting posture, van Nes et al 12) compared the difference in postural sway between sitting on stable and unstable surfaces.…”

“…They identified a significant difference in the mediolateral postural sway. Marigold et al 3) reported that when proprioceptive input was changed, the postural sway of stroke patients showed a significant increase compared with that of normal persons. In contrast, Bonan et al 11) reported that when proprioceptive input was changed, anteroposterior postural sway did not show a significant difference compared with that of normal persons.…”

Postural Stability and Balance Training Program in Hemiparetic Stroke Patients

“…Furthermore, Bonan IV et al [20] reported that parameters of posture stability in stroke patients were significantly lower than those from normal subjects. Marigold DS et al [21] reported that postural sway was increased in the stroke group.…”

The Immediate Effects of Inhibitive Gastrocnemius Kinesio Taping on Static and Functional Balance Performance in Subjects With Chronic Stroke Disorders

“…These patients suffer from impairment in static and dynamic balance [6] and have a high records of falling [3][4][5]. Stability in standing and walking is controlled by musculoskeletal, somatosensory, and vestibular systems [7][8][9][10]. Based on the results of various studies, stroke subjects are unable to control their standing balance and are at risk of falling [6,11,12].…”