Haptic-based perception-empathy biofeedback system for balance rehabilitation in patients with chronic stroke: Concepts and initial feasibility study

Highlights

• We examined the feasibility of a haptic-based perception-empathy BF system.

• Clinical balance tests, in part, improved after the balance training with BF system.

• The regimen may be applicable for balance training in stroke rehabilitation.

• More studies are needed addressing limitations for future clinical use.

Abstract

Background

Most individuals have sensory disturbances post stroke, and these deficits contribute to post-stroke balance impairment. The haptic-based biofeedback (BF) system appears to be one of the promising tools for balance rehabilitation in patients with stroke, and the BF system can increase the objectivity of feedback and encouragement than that provided by a therapist.

Research question

Studies in skill science indicated that feedback or encouragement from a coach or trainer enhances motor learning effect. Nevertheless, the optimal BF system (or its concept) which would refine the interpersonal feedback between patients and therapist has not been proposed. Thus, the purpose of this study was to propose a haptic-based perception-empathy BF system which provides information regarding the patient’s center-of-foot pressure (CoP) pattern to the patient and the physical therapist to enhance the motor learning effect and validate the feasibility of this balance-training regimen in patients with chronic stroke.

Methods

This study used a pre-post design without control group. Nine chronic stroke patients (mean age: 64.4 ± 9.2 years) received a balance-training regimen using this BF system twice a week for 4 weeks. Testing comprised quantitative measures (i.e., CoP) and clinical balance scale (Berg Balance Scale, BBS; Functional Reach Test, FRT; and Timed-Up and Go test, TUG).

Results and significance

Post training, patients demonstrated marginally reduced postural spatial variability (i.e., 95% confidence elliptical area), and clinical balance performance significantly improved at post-training. Although the changes in FRT and TUG exceeded the minimal detectable change (MDC), changes in BBS did not reach clinical significance (i.e., smaller than MDC). These results may provide initial knowledge (i.e., beneficial effects, utility and its limitation) of the proposed BF system in designing effective motor learning strategies for stroke rehabilitation. More studies are required addressing limitations due to research design and training method for future clinical use.

Introduction

Stroke is the leading cause of long-term disability, annually experienced by approximately 250,000 individuals in Japan and remains a major healthcare and economic issue [1]. In stroke patients, a complex interplay of sensory, motor, and cognitive impairments causes balance issues [2]. Therefore, most stroke patients show increased postural sway during quiet standing and asymmetric weight distribution [2], [3], [4]. Regarding post-stroke balance disability, impaired balance reportedly predicts falls in elderly patients post stroke [5]. Therefore, an effective balance-training program for stroke patients with hemiplegia is required.

Recently, examination of balance-training incorporating supplementary tactile feedback revealed that vibrotactile biofeedback (BF) systems are effective at improving postural stability of healthy young adults in standing tasks [6], [7]. In a clinical trial, vibrotactile BF improved trunk sway during quiet standing in patients with vestibular disorders [8], [9], [10], [11] and in patients with Parkinson’s disease [12]. Although the influence of vibrotactile BF on clinical balance performance in stroke patients remains unclear, we previously found that one-session balance-training with a device that provided supplementary sensory cues associated with center-of-foot pressure (CoP) displacement using vibrators attached to a pelvic belt had immediate effects on the improvement in static balance control in stroke patients [13]. Because stroke patients experience sensory disturbance in the lower limb [14], decline in sensory integration can lead to greater reliance on visual input to maintain balance [15], [16], [17]. Thus, the form of tactile BF may be preferable to avoid maintaining inadequate sensory integration; the system could realize the intervention without interfering visual or auditory information (i.e., communication and recognition of a person or an object).

Instruction related to the nature of the skill and one’s concept of self-efficacy during practice can influence motor behavior [18]. Regarding stroke patients, using a simple feedback manipulation demonstrated that individuals in stroke rehabilitation who were given feedback and encouragement during daily gait training had significantly faster walking speeds both at discharge and 3 months later than those provided with neither feedback on gait times nor encouragement [19]. Rehabilitation should preferably involve the repetition of simple tasks and include appropriate feedback and encouragement provided by a therapist [19]. Using a BF system can increase the objectivity of feedback and encouragement than that provided by a therapist and is presumably more effective for increasing the efficiency of training exercises. Nevertheless, the optimal BF system which would contribute in refining interpersonal feedback between patients and therapist has not been proposed.

Thus, this study aims to propose a haptic-based perception-empathy BF system, which provided information regarding a patient’s CoP pattern to the patient and the physical therapist to enhance the motor learning effects and validate the feasibility of proposed BF regimen with a 4-week balance-training in patients with chronic stroke. We hypothesized that a 4-week balance rehabilitation regimen using the device would improve clinical balance performance in patients with chronic stroke.