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Application of vibrotactile feedback of body motion to improve rehabilitation in individuals with imbalance. J Neurol Phys Ther 2010; 34:98-104. [PMID: 20588096 DOI: 10.1097/npt.0b013e3181dde6f0] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND AND PURPOSE Balance rehabilitation and vestibular or balance prostheses are both emerging fields that have a potential for synergistic interaction. This article reviews vibrotactile prosthetic devices that have been developed to date and ongoing work related to the application of vibrotactile feedback for enhanced postural control. A vibrotactile feedback device developed in the author's laboratory is described. METHODS Twelve subjects with vestibular hypofunction were tested on a platform that moved randomly in a plane, while receiving vibrotactile feedback in the anteroposterior direction. The feedback allowed subjects to significantly decrease their anteroposterior body tilt but did not change mediolateral tilt. A tandem walking task performed by subjects with vestibulopathies demonstrated a reduction in their mediolateral sway due to vibrotactile feedback of mediolateral body tilt, after controlling for the effects of task learning. Published findings from 2 additional experiments conducted in the laboratories of collaborating physical therapists are summarized. RESULTS The Dynamic Gait Index scores in community-dwelling elderly individuals who were prone to falls were significantly improved with the use of mediolateral body tilt feedback. DISCUSSION AND CONCLUSIONS Although more work is needed, these results suggest that vibrotactile tilt feedback of subjects' body motion can be used effectively by physical therapists for balance rehabilitation. A preliminary description of the third-generation device that has been reduced from a vest format to a belt format is described to demonstrate the progressive evolution from research to clinical application.
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Janssen M, Stokroos R, Aarts J, van Lummel R, Kingma H. Salient and placebo vibrotactile feedback are equally effective in reducing sway in bilateral vestibular loss patients. Gait Posture 2010; 31:213-7. [PMID: 19926286 DOI: 10.1016/j.gaitpost.2009.10.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Revised: 10/15/2009] [Accepted: 10/17/2009] [Indexed: 02/02/2023]
Abstract
This study explores the effect of vibrotactile biofeedback on body sway in stance in patients with severe bilateral vestibular losses in a placebo-controlled study. A tilt sensor mounted on the head or trunk is used to detect head or body tilt and activates via a microprocessor 12 small vibrators that are placed around the waist with a mutual distance of 30 degrees. Two positions of the tilt sensor (head and trunk) and three types of biofeedback (normal, full and random) were evaluated, besides no biofeedback. Body sway during stance was assessed in 10 patients with bilateral vestibular areflexia and performance was scored in the seven different conditions. Inter-individual and test-retest variability without biofeedback was assessed in 10 additional patients with bilateral vestibular areflexia. In six patients no significant change in body swaypath was observed using biofeedback. In four patients body swaypath decreased significantly using biofeedback and sensor on the head in all three activation modes, whereas with sensor on the trunk only one patient showed a significant improvement in swaypath in all three activation modes. The patients rated the functionality of the AVBF system and its effect on balance on average 6.5 on a scale from 0 to 10. Thus, body sway improved in 4 out of 10 patients using biofeedback, but the improvement with true biofeedback was only observed in those subjects where an improvement was present in placebo mode as well. The improvement was, at least partially, caused by other effects than biofeedback, like training, increased self-confidence or alertness.
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Affiliation(s)
- Maurice Janssen
- Department of Biomedical Engineering, University Hospital Maastricht, The Netherlands.
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Grierson LEM, Zelek J, Carnahan H. The Application of a Tactile Way-finding Belt to Facilitate Navigation in Older Persons. AGEING INTERNATIONAL 2009. [DOI: 10.1007/s12126-009-9039-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Verhoeff LL, Horlings CGC, Janssen LJF, Bridenbaugh SA, Allum JHJ. Effects of biofeedback on trunk sway during dual tasking in the healthy young and elderly. Gait Posture 2009; 30:76-81. [PMID: 19356934 DOI: 10.1016/j.gaitpost.2009.03.002] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2008] [Revised: 03/03/2009] [Accepted: 03/07/2009] [Indexed: 02/02/2023]
Abstract
We examined the effect of biofeedback of trunk sway on balance control while walking and performing a simultaneous cognitive or motor task. Thirteen healthy elderly (mean age (+/-S.E.M.) 70.8+/-2.0 years) and 16 healthy young (mean age 21.5+/-0.7 years) subjects performed three gait tasks while wearing body-worn gyroscopes, mounted at L1-3, to measure trunk sway. The gait tasks were walking normally, walking and counting backwards in 7's, and walking while carrying a tray with cups of water. Differences in trunk sway were examined when subjects performed the gait tasks with or without a head mounted actuator system which provided subjects with vibro-tactile, auditory and visual biofeedback of trunk sway. In the young, trunk pitch (fore-aft) angles, and trunk roll (sideways) and pitch angular velocities were significantly reduced using biofeedback across all three gait tasks. In the elderly, the same angle and angular velocities were also significantly reduced while walking normally. During walking while carrying a tray, only trunk sway velocities were significantly reduced, whereas no improvements were seen for walking while counting backwards. Counting backwards ability significantly improved with feedback. Young participants were able to perform a dual task during gait and employ biofeedback to reduce trunk sway. Elderly participants were not able to reduce sway using biofeedback during the cognitive task but were able to reduce sway velocities with biofeedback during the motor task.
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Goodworth AD, Wall C, Peterka RJ. Influence of feedback parameters on performance of a vibrotactile balance prosthesis. IEEE Trans Neural Syst Rehabil Eng 2009; 17:397-408. [PMID: 19497820 DOI: 10.1109/tnsre.2009.2023309] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
We investigated the influence of feedback conditions on the effectiveness of a balance prosthesis. The balance prosthesis used an array of 12 tactile vibrators (tactors) placed on the anterior and posterior surfaces of the torso to provide body orientation feedback related to several different combinations of angular position and velocity of body sway in the sagittal plane. Control tests were performed with no tactor activation. Body sway was evoked in subjects with normal sensory function by rotating the support surface upon which subjects stood with eyes closed. Body sway was analyzed by computing root mean square sway measures and by a frequency-response function analysis that characterized the amplitude (gain) and timing (phase) of body sway over a frequency range of 0.017-2.2 Hz. Root mean square sway measures showed a reduction of surface stimulus evoked body sway for most vibrotactile feedback settings compared to control conditions. However, frequency-response function analysis showed that the sway reduction was due primarily to a reduction in sway below about 0.5 Hz, whereas there was actually an enhancement of sway above 0.6 Hz. Finally, we created a postural model that accounted for the experimental results and gave insight into how vibrotactile information was incorporated into the postural control system.
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Affiliation(s)
- Adam D Goodworth
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR 97239, USA.
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Janssen LJF, Verhoeff LL, Horlings CGC, Allum JHJ. Directional effects of biofeedback on trunk sway during gait tasks in healthy young subjects. Gait Posture 2009; 29:575-81. [PMID: 19157877 DOI: 10.1016/j.gaitpost.2008.12.009] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2008] [Revised: 12/04/2008] [Accepted: 12/08/2008] [Indexed: 02/02/2023]
Abstract
Biofeedback of trunk sway is a possible remedy for patients with balance disorders. Because these patients have a tendency to fall more in one direction, we investigated whether biofeedback has a directional effect on trunk sway during gait. Forty healthy young participants (mean age 23.1 years) performed 10 gait tasks with and without biofeedback. Combined vibrotactile, auditory and visual feedback on trunk sway in either the lateral or anterior-posterior (AP) direction was provided by a head-mounted actuator system. Trunk roll and pitch angles, calculated from trunk angular velocities measured with gyroscopes, were used to drive the feedback. A reduction in sway velocities occurred across all tasks regardless of feedback direction. Reductions in sway angles depended on the task. Generally, reductions were greater in pitch. For walking up and down stairs, or over barriers, pitch angle reductions were greater with AP than lateral feedback. For tandem and normal walking, reductions were similar in pitch and roll angles for both feedback directions. For walking while rotating or pitching the head or with eyes closed, only pitch angle was reduced for both feedback directions. These results indicate that the central nervous system is able to incorporate biofeedback of trunk sway from either the AP or lateral direction to achieve a reduction in both pitch and roll sway. Greater reductions in pitch suggest a greater ability to use this direction of trunk sway biofeedback during gait.
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Affiliation(s)
- Lindy J F Janssen
- Division of Audiology and Neurootology, Department of ORL, University Hospital, Basel, Switzerland
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57
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Effectiveness of Head-Mounted Vibrotactile Stimulation in Subjects With Bilateral Vestibular Loss. Otol Neurotol 2009; 30:210-6. [DOI: 10.1097/mao.0b013e318194f84d] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Giansanti D, Dozza M, Chiari L, Maccioni G, Cappello A. Energetic assessment of trunk postural modifications induced by a wearable audio-biofeedback system. Med Eng Phys 2008; 31:48-54. [PMID: 18602331 DOI: 10.1016/j.medengphy.2008.04.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2007] [Revised: 04/08/2008] [Accepted: 04/09/2008] [Indexed: 10/21/2022]
Abstract
This paper investigates the trunk postural modifications induced by a wearable device which assesses the trunk sway and provides biofeedback information through sonification of trunk kinematics. The device is based on an inertial wearable sensing unit including three mono-axial accelerometers and three rate gyroscopes embedded and mounted orthogonally. The biofeedback device was tested on nine healthy subjects during quiet stance in different conditions of sensory limitation eyes closed on solid surface, eyes open on foam cushion surface, eyes closed on foam cushion surface. Five trials were performed for each condition; the order of the trials was randomized. The results reported in this paper show how subjects reduced their rotational kinetic energy by using the biofeedback information and how this reduction was related to the limitation of sensory information.
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Affiliation(s)
- D Giansanti
- Technology and Health Department, The Italian National Institute of Health, Viale Regina Elena 299, 00161 Roma, Italy.
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Jones LA, Sarter NB. Tactile displays: guidance for their design and application. HUMAN FACTORS 2008; 50:90-111. [PMID: 18354974 DOI: 10.1518/001872008x250638] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
OBJECTIVE This article provides an overview of tactile displays. Its goal is to assist human factors practitioners in deciding when and how to employ the sense of touch for the purpose of information representation. The article also identifies important research needs in this area. BACKGROUND First attempts to utilize the sense of touch as a medium for communication date back to the late 1950s. For the next 35 years progress in this area was relatively slow, but recent years have seen a surge in the interest and development of tactile displays and the integration of tactile signals in multimodal interfaces. A thorough understanding of the properties of this sensory channel and its interaction with other modalities is needed to ensure the effective and robust use of tactile displays. METHODS First, an overview of vibrotactile perception is provided. Next, the design of tactile displays is discussed with respect to available technologies. The potential benefit of including tactile cues in multimodal interfaces is discussed. Finally, research needs in the area of tactile information presentation are highlighted. RESULTS This review provides human factors researchers and interface designers with the requisite knowledge for creating effective tactile interfaces. It describes both potential benefits and limitations of this approach to information presentation. CONCLUSION The sense of touch represents a promising means of supporting communication and coordination in human-human and human-machine systems. APPLICATION Tactile interfaces can support numerous functions, including spatial orientation and guidance, attention management, and sensory substitution, in a wide range of domains.
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Affiliation(s)
- Lynette A Jones
- Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave., Room 3-137, Cambridge, MA 02139, USA.
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Asseman F, Bronstein AM, Gresty MA. Using vibrotactile feedback of instability to trigger a forward compensatory stepping response. J Neurol 2007; 254:1555-61. [PMID: 17641814 DOI: 10.1007/s00415-007-0587-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2006] [Revised: 03/06/2007] [Accepted: 03/13/2007] [Indexed: 11/25/2022]
Abstract
We evaluated the effectiveness of vibrotactile feedback to enhance protective stepping with a view to developing a prosthesis for patients with balance disorders. Subjects standing on a moving walkway were exposed to an unpredictable, abrupt backwards translation of the support surface that required a step response to remain standing. The subjects were 15 normal young, 15 normal elderly and 9 patients with either bilateral vestibular loss or peripheral neuropathy. The initial passive displacement of the body was recorded by a gyroscope placed on the leg which triggered a vibration pulse to the trigeminal distribution on the forehead to cue a forwards step. Stepping responses and postural sway, with and without vibration feedback, were compared. Vibration produced significantly shorter stepping reaction times only in the elderly normals with naturally slower stepping. Patients did not benefit in any way. We conclude that the effectiveness of vibration biofeedback appears limited. Any enhancement of compensatory stepping might be triggered by speeding the decision to step rather than by creating a specific stimulus-response loop.
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Affiliation(s)
- François Asseman
- Imperial College London, Department of Clinical Neuroscience, Charing Cross Campus, Fulham Palace Road, London W6 8RF, UK.
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Wall C, Oddsson LE, Horak FB, Wrisley DW, Dozza M. Applications of vibrotactile display of body tilt for rehabilitation. CONFERENCE PROCEEDINGS : ... ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL CONFERENCE 2007; 2004:4763-5. [PMID: 17271374 DOI: 10.1109/iembs.2004.1404318] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Body-mounted motion sensors have been shown to decrease subject sway when a tilt estimate is fed back to the user by means of an array of tactile vibrators which display estimated tilt magnitude and direction. Vestibulopathic subjects who are tested using computerized dynamic posturography show significantly reduced sway in both the sensory motor and the motor control portions of that test. This result suggests potential application as an assistive balance aid. Another potential application of vibrotactile tilt feedback is in rehabilitation. Two lines of research have yielded promising, albeit very preliminary, supporting results. The first of these is the response of subjects to a toes-up pitch maneuver. At critical pitch velocities, vestibulopathic subjects are unable to maintain stability during or after a perturbation without tilt feedback, but are able to stand when feedback is provided. The second line of research involves perturbations during locomotion. Vibrotactile tilt feedback again reduces subjects sway. Preliminary results of both of these on-going experiments indicate that this increase in performance may be retained.
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Affiliation(s)
- C Wall
- Harvard Medical School, Boston, MA, USA
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Johannsen L, Wing AM, Hatzitaki V. Effects of Maintaining Touch Contact on Predictive and Reactive Balance. J Neurophysiol 2007; 97:2686-95. [PMID: 17303815 DOI: 10.1152/jn.00038.2007] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Light touch contact between the body and an environmental referent reduces fluctuations of center of pressure (CoP) in quiet standing although the contact forces are insufficient to provide significant forces to stabilize standing balance. Maintenance of upright standing posture (with light touch contact) may include both predictive and reactive components. Recently Dickstein et al. (2003) demonstrated that reaction to temporally unpredictable displacement of the support surface was affected by light touch raising the question whether light touch effects also occur with predictable disturbance to balance. We examined the effects of shoulder light touch on SD of CoP rate (dCoP) during balance perturbations associated with forward sway induced by pulling on (voluntary), or being pulled by (reactive), a hand-held horizontal load. Prior to perturbation, SD dCoP was lower with light touch, corresponding to previous findings. Immediately after perturbation, SD dCoPAP was greater with light touch in the case of voluntary pull, whereas no difference was found for reflex pull. However, in the following time course, light touch contact again resulted in a significantly lower SD dCoP and faster stabilization of SD dCoP. We conclude that shoulder light touch contact affects immediate postural responses to voluntary pull but also stabilization after voluntary and reflex perturbation. We suggest that in voluntary perturbation CoP fluctuations are differentially modulated in anterioposterior and mediolateral directions to maintain light touch, which not only provides augmented sensory feedback about body self-motion, but may act as a “constraint” to the postural control system when preparing postural adjustments.
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Affiliation(s)
- Leif Johannsen
- Behavioural Brain Sciences Centre, School of Psychology, University of Birmingham, Birmingham, B15 2TT, UK
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63
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Weinberg MS, Wall C, Robertsson J, O'Neil E, Sienko K, Fields R. Tilt determination in MEMS inertial vestibular prosthesis. J Biomech Eng 2007; 128:943-56. [PMID: 17154697 DOI: 10.1115/1.2378922] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND There is a clear need for a prosthesis that improves postural stability in the balance impaired. Such a device would be used as a temporary aid during recovery from ablative inner-ear surgery, a postural monitor during rehabilitation (for example, hip surgery), and as a permanent prosthesis for those elderly prone to falls. METHOD OF APPROACH Recently developed, small instruments have enabled wearable prostheses to augment or replace vestibular functions. The current prosthesis communicates by vibrators mounted on the subject's trunk. In this paper we emphasize the unique algorithms that enable tilt indication with modestly performing micromachined gyroscopes and accelerometers. RESULTS For large angles and multiple axes, gyro drift and unwanted lateral accelerations are successfully rejected. In single-axis tests, the most dramatic results were obtained in standard operating tests where balance-impaired subjects were deprived of vision and proprioceptive inputs. Balance-impaired subjects who fell (into safety restraints) when not aided were able to stand with the prosthesis. Initial multiaxis tests with healthy subjects have shown that sway is reduced in both forward-back and sideward directions. CONCLUSIONS Positive results in initial testing and a sound theoretical basis for the hardware warrant continued development and testing, which is being conducted at three sites.
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Dozza M, Chiari L, Horak FB. A portable audio-biofeedback system to improve postural control. CONFERENCE PROCEEDINGS : ... ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL CONFERENCE 2007; 2004:4799-802. [PMID: 17271384 DOI: 10.1109/iembs.2004.1404328] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
This paper introduces a portable audio-biofeedback (ABF) system that encodes the signals provided by a linear accelerometric sensor into a stereo sound. This sound is relayed to the subjects via headphones and can enhance the ability of subjects to perceive trunk accelerations. We tested this system on nine healthy subjects while they stood in three conditions listening to the ABF representation of their trunk accelerations. The ABF significantly improved the subjects' balance in all three conditions. The subjects reported that they were comfortable wearing and using the ABF device. Results suggest that devices such as this ABF system may be used for balance training and balance rehabilitation therapy.
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Affiliation(s)
- M Dozza
- Department of Electronic, Computer Science & Systems, Bologna University, Italy
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65
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Yoo WG, Yi CH, Kim MH. Effects of a proximity-sensing feedback chair on head, shoulder, and trunk postures when working at a visual display terminal. JOURNAL OF OCCUPATIONAL REHABILITATION 2006; 16:631-7. [PMID: 17086500 DOI: 10.1007/s10926-006-9059-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
INTRODUCTION This study was designed to identify the effects of feedback from a proximity-sensing chair on head, shoulder, and trunk postures when working at a visual display terminal (VDT). METHODS Twenty healthy adults were asked to perform VDT work, and their forward head, forward shoulder, and trunk flexion angles were analyzed using a 3-D motion analysis system. The statistical significance of differences between without and with an auditory feedback device was tested by paired t-tests, with the significance cutoff set at alpha=0.05. RESULTS The forward head, forward shoulder, and trunk flexion angles significantly decreased during VDT work when using the proximity sensor with auditory feedback. CONCLUSION We suggest that a feedback device promotes the adoption of beneficial postures, which may be effective in preventing VDT-work-related neck and upper-limb disorders.
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Affiliation(s)
- Won-gyu Yoo
- Department of Rehabilitation Therapy, The Graduate School, Yonsei University, 134 Shinchon-dong, Seodaemun-gu, Seoul, 120-752 Republic of Korea.
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Vuillerme N, Chenu O, Demongeot J, Payan Y. Controlling posture using a plantar pressure-based, tongue-placed tactile biofeedback system. Exp Brain Res 2006; 179:409-14. [PMID: 17136521 DOI: 10.1007/s00221-006-0800-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2006] [Accepted: 11/07/2006] [Indexed: 10/23/2022]
Abstract
The present paper introduces an original biofeedback system for improving human balance control, whose underlying principle consists in providing additional sensory information related to foot sole pressure distribution to the user through a tongue-placed tactile output device. To assess the effect of this biofeedback system on postural control during quiet standing, ten young healthy adults were asked to stand as immobile as possible with their eyes closed in two conditions of No-biofeedback and Biofeedback. Centre of foot pressure (CoP) displacements were recorded using a force platform. Results showed reduced CoP displacements in the Biofeedback relative to the No-biofeedback condition. The present findings evidenced the ability of the central nervous system to efficiently integrate an artificial plantar-based, tongue-placed tactile biofeedback for controlling control posture during quiet standing.
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Affiliation(s)
- Nicolas Vuillerme
- Laboratoire TIMC-IMAG, UMR CNRS 5525, Faculté de Médecine, 38706, La Tronche Cédex, France.
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Dozza M, Horak FB, Chiari L. Auditory biofeedback substitutes for loss of sensory information in maintaining stance. Exp Brain Res 2006; 178:37-48. [PMID: 17021893 DOI: 10.1007/s00221-006-0709-y] [Citation(s) in RCA: 113] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2005] [Accepted: 09/07/2006] [Indexed: 11/27/2022]
Abstract
The importance of sensory feedback for postural control in stance is evident from the balance improvements occurring when sensory information from the vestibular, somatosensory, and visual systems is available. However, the extent to which also audio-biofeedback (ABF) information can improve balance has not been determined. It is also unknown why additional artificial sensory feedback is more effective for some subjects than others and in some environmental contexts than others. The aim of this study was to determine the relative effectiveness of an ABF system to reduce postural sway in stance in healthy control subjects and in subjects with bilateral vestibular loss, under conditions of reduced vestibular, visual, and somatosensory inputs. This ABF system used a threshold region and non-linear scaling parameters customized for each individual, to provide subjects with pitch and volume coding of their body sway. ABF had the largest effect on reducing the body sway of the subjects with bilateral vestibular loss when the environment provided limited visual and somatosensory information; it had the smallest effect on reducing the sway of subjects with bilateral vestibular loss, when the environment provided full somatosensory information. The extent that all subjects substituted ABF information for their loss of sensory information was related to the extent that each subject was visually dependent or somatosensory-dependent for their postural control. Comparison of postural sway under a variety of sensory conditions suggests that patients with profound bilateral loss of vestibular function show larger than normal information redundancy among the remaining senses and ABF of trunk sway. The results support the hypothesis that the nervous system uses augmented sensory information differently depending both on the environment and on individual proclivities to rely on vestibular, somatosensory or visual information to control sway.
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Affiliation(s)
- Marco Dozza
- Neurological Sciences Institute, Oregon Health & Science University, 505 NW 185th Ave, Beaverton, OR 97006, USA
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Abstract
Balance dysfunction remains a significant contributing factor for disability in the elderly. A wide variety of surgical, pharmaceutical, medical, and rehabilitation treatment options exists for these patients. The complexity of the balance system, however, often requires a thorough, multidisciplinary approach to the evaluation and successful treatment of balance impairment.
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Affiliation(s)
- Brittany A Matsumura
- Department of Rehabilitation Medicine, Mount Sinai School of Medicine, 1425 Madison Avenue, New York, NY 10029-6574, USA
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van Erp JBF, Groen EL, Bos JE, van Veen HAHC. A tactile cockpit instrument supports the control of self-motion during spatial disorientation. HUMAN FACTORS 2006; 48:219-28. [PMID: 16884044 DOI: 10.1518/001872006777724435] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
OBJECTIVE We investigated the effectiveness of a tactile torso display as a countermeasure to spatial disorientation (SD) and compared inside-out and outside-in codings. BACKGROUND SD is a serious threat to military as well as civilian pilots and aircraft. Considerable effort has been put into SD countermeasures such as training programs and advanced cockpit displays. Tactile displays have been considered a promising technology. METHOD Twenty-four participants were assigned to the two coding groups (12 per group and matched for age and gender). We used a rotating chair to build up a state of SD by rotating participants around their yaw axis followed by a sudden stop. During the following recovery phase a random disturbance signal was added to the chair's orientation. Participants actively controlled their orientation and were instructed to maintain a stable orientation. RESULTS Statistical analyses revealed that recovery from SD was improved with support of the tactile instrument, but tracking performance was reduced. The effects were the same whether the instrument was available full time or during the recovery phase only. There were no differences between outside-in and inside-out coding. CONCLUSION The present study demonstrates the potential of tactile cockpit instruments in controlling SD, even in the presence of strong but misleading self-motion information from the vestibular sense. APPLICATION Actual or potential applications of this research include spatial disorientation countermeasures for pilots, divers, and astronauts.
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Affiliation(s)
- Jan B F van Erp
- Human Interface Department, TNO Human Factors, P.O. Box 23, NL - 3769 ZG, Soesterberg, Netherlands.
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71
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Chiari L, Dozza M, Cappello A, Horak FB, Macellari V, Giansanti D. Audio-Biofeedback for Balance Improvement: An Accelerometry-Based System. IEEE Trans Biomed Eng 2005; 52:2108-11. [PMID: 16366234 DOI: 10.1109/tbme.2005.857673] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
This paper introduces a prototype audio-biofeedback system for balance improvement through the sonification using trunk kinematic information. In tests of this system, normal healthy subjects performed several trials in which they stood quietly in three sensory conditions while wearing an accelerometric sensory unit and headphones. The audio-biofeedback system converted in real-time the two-dimensional horizontal trunk accelerations into a stereo sound by modulating its frequency, level, and left/right balance. Preliminary results showed that subjects improved balance using this audio-biofeedback system and that this improvement was greater the more that balance was challenged by absent or unreliable sensory cues. In addition, high correlations were found between the center of pressure displacement and trunk acceleration, suggesting accelerometers may be useful for quantifying standing balance.
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Affiliation(s)
- Lorenzo Chiari
- Dipartimento di Elettronica, Informatica e Sistemistica, Università di Bologna, Viale Risorgimento 2, 40136 Bologna, Italy.
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Dozza M, Chiari L, Horak FB. Audio-biofeedback improves balance in patients with bilateral vestibular loss. Arch Phys Med Rehabil 2005; 86:1401-3. [PMID: 16003671 DOI: 10.1016/j.apmr.2004.12.036] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJECTIVE To evaluate the effectiveness of an audio-biofeedback (ABF) system for improving balance in patients with bilateral vestibular loss (BVL). DESIGN Before-after trial. SETTING University balance disorders laboratory. PARTICIPANTS Nine subjects with BVL and 9 unaffected subjects as controls. INTERVENTION Trunk acceleration ABF while standing on foam with eyes closed. MAIN OUTCOME MEASURE Balance stability was evaluated according to the following parameters: the root mean square of (1) the center of pressure (COP) displacements and of (2) the trunk accelerations; the COP bandwidth; the time spent by the participant within +/-1 degrees threshold from their baseline COP position; and the mean accelerations of the trunk while the participant was swaying outside this +/-1 degrees threshold. RESULTS Participants with BVL had significantly larger postural sway than did unaffected participants. Those with BVL, while using ABF, decreased sway area by 23%+/-4.9%, decreased trunk accelerations by 46%+/-9.9%, and increased time spent within +/-1 degrees sway threshold by 195%+/-34.6%. CONCLUSIONS ABF improved stance stability of participants with BVL by increasing the amount of postural corrections.
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Affiliation(s)
- Marco Dozza
- Department of Electronics, Computer Science and Systems, University of Bologna, Bologna, Italy
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73
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Giansanti D, Maccioni G, Macellari V. The Development and Test of a Device for the Reconstruction of 3-D Position and Orientation by Means of a Kinematic Sensor Assembly With Rate Gyroscopes and Accelerometers. IEEE Trans Biomed Eng 2005; 52:1271-7. [PMID: 16041990 DOI: 10.1109/tbme.2005.847404] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
In this paper, we propose a device for the Position and Orientation (P&O) reconstruction of human segmental locomotion tasks. It is based on three mono-axial accelerometers and three angular velocity sensors, geometrically arranged to form two orthogonal terns. The device was bench tested using step-by-step motor-based equipment. The characteristics of the six channels under bench test conditions were: crosstalk absent, non linearity < +/- 0.1% fs, hysteresis < 0.1% fs, accuracy 0.3% fs, overall resolution better than 0.04 deg/s, 2 x g x 10(-4). The device was validated with the stereophotogrammetric body motion analyzer during the execution of three different locomotion tasks: stand-to-sit, sit-to-stand, gait-initiation. Results obtained comparing the trajectories of the two methods showed that the errors were lower than 3 x 10(-2) m and 2 deg during a 4s of acquisition and lower than 6 x 10(-3) m and 0.2 deg during the effective duration of a locomotory task; showing that the wearable device hereby presented permits the 3-D reconstruction of the movement of the body segment to which it is affixed for time-limited clinical applications.
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Affiliation(s)
- Daniele Giansanti
- Dipartimento di Tecnologie e Salute, Istituto Superiore di Sanità, 00161 Roma, Italy.
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74
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Dozza M, Chiari L, Chan B, Rocchi L, Horak FB, Cappello A. Influence of a portable audio-biofeedback device on structural properties of postural sway. J Neuroeng Rehabil 2005; 2:13. [PMID: 15927058 PMCID: PMC1183240 DOI: 10.1186/1743-0003-2-13] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2005] [Accepted: 05/31/2005] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Good balance depends on accurate and adequate information from the senses. One way to substitute missing sensory information for balance is with biofeedback technology. We previously reported that audio-biofeedback (ABF) has beneficial effects in subjects with profound vestibular loss, since it significantly reduces body sway in quiet standing tasks. METHODS In this paper, we present the effects of a portable prototype of an ABF system on healthy subjects' upright stance postural stability, in conditions of limited and unreliable sensory information. Stabilogram diffusion analysis, combined with traditional center of pressure analysis and surface electromyography, were applied to the analysis of quiet standing tasks on a Temper foam surface with eyes closed. RESULTS These analyses provided new evidence that ABF may be used to treat postural instability. In fact, the results of the stabilogram diffusion analysis suggest that ABF increased the amount of feedback control exerted by the brain for maintaining balance. The resulting increase in postural stability was not at the expense of leg muscular activity, which remained almost unchanged. CONCLUSION Examination of the SDA and the EMG activity supported the hypothesis that ABF does not induce an increased stiffness (and hence more co-activation) in leg muscles, but rather helps the brain to actively change to a more feedback-based control activity over standing posture.
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Affiliation(s)
- Marco Dozza
- Department of Electronics, Computer Science, and Systems, University of Bologna, Bologna, Italy
- Neurological Science Institute, Oregon Health & Science University, Portland (OR), USA
| | - Lorenzo Chiari
- Department of Electronics, Computer Science, and Systems, University of Bologna, Bologna, Italy
| | - Becky Chan
- Neurological Science Institute, Oregon Health & Science University, Portland (OR), USA
| | - Laura Rocchi
- Department of Electronics, Computer Science, and Systems, University of Bologna, Bologna, Italy
| | - Fay B Horak
- Neurological Science Institute, Oregon Health & Science University, Portland (OR), USA
| | - Angelo Cappello
- Department of Electronics, Computer Science, and Systems, University of Bologna, Bologna, Italy
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75
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Cholewiak RW, Brill JC, Schwab A. Vibrotactile localization on the abdomen: effects of place and space. ACTA ACUST UNITED AC 2005; 66:970-87. [PMID: 15675645 DOI: 10.3758/bf03194989] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In this study, we explore the conditions for accurate localization of vibrotactile stimuli presented to the abdomen. Tactile orientation systems intended to provide mobility information for people who are blind depend on accurate identification of location of stimuli on the skin, as do systems designed to indicate target positions in space or the status of remotely operated devices to pilots or engineers. The spatial acuity of the skin has been examined for simple touch, but not for the types of vibrating signals used in such devices. The ability to localize vibratory stimuli was examined at sites around the abdomen and found to be a function of separation among loci and, most significantly, of place on the trunk. Neither the structures underlying the skin nor the types of tactor tested appeared to affect localization. Evidence was found for anatomically defined anchor points that provide localization referents that enhance performance even with wide target spacing.
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Affiliation(s)
- Roger W Cholewiak
- Tactile Research Laboratory, Naval Aerospace Medical Research Laboratory, Pensacola, Florida 32508-1046, USA.
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76
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Kadkade PP, Benda BJ, Schmidt PB, Wall C. Vibrotactile display coding for a balance prosthesis. IEEE Trans Neural Syst Rehabil Eng 2004; 11:392-9. [PMID: 14960115 DOI: 10.1109/tnsre.2003.819937] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Preliminary experiments have demonstrated the potential usefulness of a precursor balance prosthesis that displays the tilt of the subject using tactile vibrators (tactors) which are in contact with the subject's skin. The device consists of a motion sensing system mounted on the head or body whose signals are converted into estimates of head or body tilt. Tilt is displayed to the subject by coding the tilt estimate into signals that are sent to the tactors using one of several schemes. Because full blown, end-to-end balance experiments are relatively time consuming and expensive, and because there are many possible display schemes, we have developed a quantitative means to evaluate the display step separately. We used a modified version of the manual control critical tracking task (CTT) to help us make an initial selection of the more promising vibrotactile display schemes for further evaluation. The classic CTT is a compensatory form of tracking in which the operator attempts to control an increasingly unstable system using a joystick to regulate a tracking error signal (system minus joystick) that is visually displayed as a dot on a cathode ray tube. Our modification added vibrotactile display of the error signal. For a given subject and vibrotactile display scheme, the level of difficulty at which the subjects lost control, called the critical lambda (lambda(c)), was highly repeatable. Four different coding schemes were evaluated using an array of 16 vibrators that were attached to the lower backs of 11 healthy subjects. The first scheme, called interval-based coding, modulated the interval between pulses that were sent to single tactors mounted on the subject's right and left side. A greater tracking error magnitude was displayed as a faster pulse rate. A positive error was displayed on the right side while a negative one was displayed on the left. The remaining three schemes, called position-based coding, used a horizontal row of 14 tactors. Tracking error magnitude was mapped to position of the activated vibrator so that an error near zero corresponded to a vibrator near the center of the back. The three position-based schemes tested used three, four, or seven tactors per side. Averaged over all subjects, the value of lambda(c) for the interval-based scheme was significantly less than it was for each of the three position-based schemes. There was no significant change in lambda(c) as the number of position-based tactors was increased from three to seven per side. The prediction of better actual balance performance using position-based relative to interval-based vibrotactile display was validated by a preliminary study of six normal subjects that compared the body sway produced during quiet standing while providing head tilt estimates using both display modes. Our study provides basic characterization using lambda(c) for several vibrotactile display schemes in human subjects. The quantitative CTT measure of performance can logically be extended to other applications of vibrotactile displays and to other kinds of display schemes used for rehabilitation.
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Affiliation(s)
- Prajoy P Kadkade
- Department of Otolaryngology/Head & Neck Surgery, New York Presbyterian-The University Hospitals of Columbia and Cornell, New York, NY 10032, USA
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Kentala E, Vivas J, Wall C. Reduction of postural sway by use of a vibrotactile balance prosthesis prototype in subjects with vestibular deficits. Ann Otol Rhinol Laryngol 2003; 112:404-9. [PMID: 12784977 DOI: 10.1177/000348940311200503] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
To evaluate the effectiveness of a prototype vibrotactile balance prosthesis in maintaining balance during dynamic posturography, we studied 6 subjects with unilateral or bilateral vestibular deficit by means of Equitest computerized dynamic posturography (CDP). Their anterior-posterior (AP) sway at the small of the back was measured with a micromechanical rate gyroscope and a linear accelerometer. The resulting tilt estimate was displayed by a vibrotactile array attached to the torso. The vibration served as tilt feedback to the subject. Subject performance was evaluated with the tilt performance index (TPI), which is the inverse of the root-mean-square of tilt. We found that the balance prosthesis reduced the subjects' AP sway. The subjects' results without the balance prosthesis on CDP sensory organization tests (SOTs) 5 and 6 were compared to results with the prosthesis. The average TPI increased significantly (p < .05) when vibrotactile feedback was used as compared to the unaided condition. This finding was true for both SOTs 5 and 6. We conclude that vibrotactile feedback of estimated AP body tilt improved the subjects' ability to perform selected CDP tests. Some of the subjects were able to stand throughout the test with the device turned on, whereas they otherwise constantly fell.
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Affiliation(s)
- Erna Kentala
- Department of Otology and Laryngology and the Jenks Vestibular Diagnostic Laboratory Massachusetts Eye and Ear Infumary, Harvard Medical School, Boston 02114, USA
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78
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Wall C, Weinberg MS. Balance prostheses for postural control. IEEE ENGINEERING IN MEDICINE AND BIOLOGY MAGAZINE : THE QUARTERLY MAGAZINE OF THE ENGINEERING IN MEDICINE & BIOLOGY SOCIETY 2003; 22:84-90. [PMID: 12733464 DOI: 10.1109/memb.2003.1195701] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Conrad Wall
- Jenks Vestibular Diagnostic Laboratory, Massachusetts Eye and Ear Infirmary, 243 Charles Street, Boston, MA 02114-3096, USA.
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