Cell phone based balance trainer

• Published in: Journal of neuroengineering and rehabilitation Vol. 9; no. 1; p. 10
• Main Authors: Lee, Beom-Chan, Kim, Jeonghee, Chen, Shu, Sienko, Kathleen H
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 08.02.2012; BioMed Central; BMC
• Subjects: Actigraphy - instrumentation; Adult; Advantages; Algorithms; American Recovery & Reinvestment Act 2009-US; balance; Biofeedback, Psychology - instrumentation; Biofeedback, Psychology - methods; Cell Phone; Computer engineering; Design; Equipment Design; Equipment Failure Analysis; Female; Health care access; Humans; Male; Management; Medicine, Physical; mobile phone; Postural Balance; Rehabilitation; sensory augmentation; smart phone; Smart phones; Smartphones; Software; Statistical analysis; Studies; Technological change; Therapists; Touch; Training; Treatment Outcome; Vestibular Diseases - diagnosis; Vestibular Diseases - physiopathology; Vestibular Diseases - rehabilitation; Vibration - therapeutic use; vibrotactile; Young Adult; United States; Ann Arbor Michigan
• ISSN: 1743-0003; 1743-0003
• DOI: 10.1186/1743-0003-9-10

In their current laboratory-based form, existing vibrotactile sensory augmentation technologies that provide cues of body motion are impractical for home-based rehabilitation use due to their size, weight, complexity, calibration procedures, cost, and fragility. We have designed and developed a cell phone based vibrotactile feedback system for potential use in balance rehabilitation training in clinical and home environments. It comprises an iPhone with an embedded tri-axial linear accelerometer, custom software to estimate body tilt, a "tactor bud" accessory that plugs into the headphone jack to provide vibrotactile cues of body tilt, and a battery. Five young healthy subjects (24 ± 2.8 yrs, 3 females and 2 males) and four subjects with vestibular deficits (42.25 ± 13.5 yrs, 2 females and 2 males) participated in a proof-of-concept study to evaluate the effectiveness of the system. Healthy subjects used the system with eyes closed during Romberg, semi-tandem Romberg, and tandem Romberg stances. Subjects with vestibular deficits used the system with both eyes-open and eyes-closed conditions during semi-tandem Romberg stance. Vibrotactile feedback was provided when the subject exceeded either an anterior-posterior (A/P) or a medial-lateral (M/L) body tilt threshold. Subjects were instructed to move away from the vibration. The system was capable of providing real-time vibrotactile cues that informed corrective postural responses. When feedback was available, both healthy subjects and those with vestibular deficits significantly reduced their A/P or M/L RMS sway (depending on the direction of feedback), had significantly smaller elliptical area fits to their sway trajectory, spent a significantly greater mean percentage time within the no feedback zone, and showed a significantly greater A/P or M/L mean power frequency. The results suggest that the real-time feedback provided by this system can be used to reduce body sway. Its advantages over more complex laboratory-based and commercial balance training systems in terms of cost, size, weight, functionality, flexibility, and accessibility make it a good candidate for further home-based balance training evaluation.