An investigation into the utility of wearable sensor derived biofeedback on the motor control of the lumbar spine

Lower back pain (LBP) is a disability that affects a large proportion of the population and treatment for this has been shifting towards a more individualized, patient-centered approach. There has been a recent uptake in the utilization and implementation of wearable sensors that can administer biofeedback in various industrial, clinical, and performance-based settings. The overall aim of this Master’s thesis was to investigate how wearable sensors can be used in a sensorimotor (re)training approach, including how sensory biofeedback from wearable sensors can be used to improve measures of spinal motor control and proprioception. Two complementary research studies were completed to address this overall aim. As a systematic review, Study #1 focused on addressing the lack of consensus surrounding wearable sensor derived biofeedback and spine motor control. The results of this review suggest that haptic/vibrotactile feedback is the most common and that it is administered in an instantaneous real-time manner within most experimental paradigms. Further, study #1 identified clear gaps within the research literature. Specifically, future research would benefit from more clarity regarding study design, and movement instructions, and explicit definitions of biofeedback parameters to enhance reproducibility. The aim of Study #2 was to assess the acute effects of wearable sensor-derived auditory biofeedback on gross lumbar proprioception. To assess this, participants completed a target repositioning protocol, followed by a training period where they were provided with auditory feedback for two of four targets based on a percentage of their lumbar ROM. Results suggest that mid-range targets benefitted most from the acute auditory feedback training. Further, individuals with poorer repositioning abilities in the pre-training assessment showed the greatest improvements from the auditory feedback training. This suggests that auditory biofeedback training may be an effective tool to improve proprioception in those with proprioceptive deficits. Collectively these complimentary research studies will improve the understanding surrounding the ecological utility of wearable sensor derived biofeedback in industrial, clinical, and performance settings to enhance to sensorimotor control of the lumbar region

The Role of the Central Nervous System in the Integration of Proprioceptive Information

The proprioceptive system provides feedback on human performance that makes it possible to learn and perform novel tasks. Proprioception predominately arises in the peripheral nervous system at the muscle spindle organ. Mechanical stimulus such as vibration has been implicated in altering muscle spindle afferent signals used as feedback. Researchers have utilized this understanding to document gross performance changes resulting from a muscle spindle disruption paradigm. Findings of this work have demonstrated that the altered proprioceptive feedback alters performance both during and after vibration exposure. This has also led many to postulate that altered proprioceptive feedback due to environmental working conditions may be responsible for many incidences of musculoskeletal injury, including low back pain. In order to more fully understand how proprioceptive feedback is integrated into a motor response it was required to investigate activity within the central nervous system, itself the target of the spindle afferent, both before and after receiving a modulate afferent. We developed a protocol based on measures of average velocity to test for this activity. Our investigation began we examining whether or not average velocity, in the form of seated sway velocity, would be sensitive to applied vibration. We found that while vibration was applied; mean sway speed increased significantly above pre vibration levels, regardless of feedback and task difficulty. A computer based pursuit task was then implemented in order to investigate performance relative to timing of vibration exposure. Our results revealed a significant decrease in pursuit velocity during vibration from pre-vibration velocity. Additionally, subjects demonstrated an equal magnitude but opposite increase in pursuit speed after vibration was removed. This protocol was then replicated in a functional-MRI to compare the gross motor pursuit task performance with the corresponding BOLD imaging data. We observed a similar decrease/increase pattern of joystick pursuit velocity. The corresponding cortical activity revealed patterns of inhibition consistent with cognitive inhibition. The current findings support proprioception as a central inhibitory control mechanism that shifts cortical networks dependent on available sensory stimulus

Design and Assessment of Vibrotactile Biofeedback and Instructional Systems for Balance Rehabilitation Applications.

Sensory augmentation, a type of biofeedback, is a technique for supplementing or reinforcing native sensory inputs. In the context of balance-related applications, it provides users with additional information about body motion, usually with respect to the gravito-inertial environment. Multiple studies have demonstrated that biofeedback, regardless of the feedback modality (i.e., vibrotactile, electrotactile, auditory), decreases body sway during real-time use within a laboratory setting. However, in their current laboratory-based form, existing vibrotactile biofeedback devices are not appropriate for use in clinical and/or home-based rehabilitation settings due to the expense, size, and operating complexity of the instrumentation required. This dissertation describes the design, development, and preliminary assessment of two technologies that support clinical and home-based balance rehabilitation training. The first system provides vibrotactile-based instructional motion cues to a trainee based on the measured difference between the expert’s and trainee’s motions. The design of the vibrotactile display is supported by a study that characterizes the non-volitional postural responses to vibrotactile stimulation applied to the torso. This study shows that vibration applied individually by tactors over the internal oblique and erector spinae muscles induces a postural shift of the order of one degree oriented in the direction of the stimulation. Furthermore, human performance is characterized both experimentally and theoretically when the expert–trainee error thresholds and nature of the control signal are varied. The results suggest that expert–subject cross-correlation values were maximized and position errors and time delays were minimized when the controller uses a 0.5 error threshold and proportional plus derivative feedback control signal, and that subject performance decreases as motion speed and complexity increase. The second system provides vibrotactile biofeedback about body motion using a cell phone. The system is capable of providing real-time vibrotactile cues that inform corrective trunk tilt responses. When feedback is available, both healthy subjects and those with vestibular involvement significantly reduce their anterior-posterior or medial-lateral root-mean-square body sway, have significantly smaller elliptical area fits to their sway trajectory, spend a significantly greater mean percentage time within the no feedback zone, and show a significantly greater A/P or M/L mean power frequency.Ph.D.Mechanical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/91546/1/channy_1.pd

I-BaR: Integrated Balance Rehabilitation Framework

Neurological diseases are observed in approximately one billion people worldwide. A further increase is foreseen at the global level as a result of population growth and aging. Individuals with neurological disorders often experience cognitive, motor, sensory, and lower extremity dysfunctions. Thus, the possibility of falling and balance problems arise due to the postural control deficiencies that occur as a result of the deterioration in the integration of multi-sensory information. We propose a novel rehabilitation framework, Integrated Balance Rehabilitation (I-BaR), to improve the effectiveness of the rehabilitation with objective assessment, individualized therapy, convenience with different disability levels and adoption of an assist-as-needed paradigm and, with an integrated rehabilitation process as a whole, i.e., ankle-foot preparation, balance, and stepping phases, respectively. Integrated Balance Rehabilitation allows patients to improve their balance ability by providing multi-modal feedback: visual via utilization of Virtual Reality; vestibular via anteroposterior and mediolateral perturbations with the robotic platform; proprioceptive via haptic feedback.Comment: 37 pages, 2 figures, journal pape

Self versus Environment Motion in Postural Control

To stabilize our position in space we use visual information as well as non-visual physical motion cues. However, visual cues can be ambiguous: visually perceived motion may be caused by self-movement, movement of the environment, or both. The nervous system must combine the ambiguous visual cues with noisy physical motion cues to resolve this ambiguity and control our body posture. Here we have developed a Bayesian model that formalizes how the nervous system could solve this problem. In this model, the nervous system combines the sensory cues to estimate the movement of the body. We analytically demonstrate that, as long as visual stimulation is fast in comparison to the uncertainty in our perception of body movement, the optimal strategy is to weight visually perceived movement velocities proportional to a power law. We find that this model accounts for the nonlinear influence of experimentally induced visual motion on human postural behavior both in our data and in previously published results

Effects of sensory cueing in virtual motor rehabilitation. A review.

Objectives To critically identify studies that evaluate the effects of cueing in virtual motor rehabilitation in patients having different neurological disorders and to make recommendations for future studies. Methods Data from MEDLINE®, IEEExplore, Science Direct, Cochrane library and Web of Science was searched until February 2015. We included studies that investigate the effects of cueing in virtual motor rehabilitation related to interventions for upper or lower extremities using auditory, visual, and tactile cues on motor performance in non-immersive, semi-immersive, or fully immersive virtual environments. These studies compared virtual cueing with an alternative or no intervention. Results Ten studies with a total number of 153 patients were included in the review. All of them refer to the impact of cueing in virtual motor rehabilitation, regardless of the pathological condition. After selecting the articles, the following variables were extracted: year of publication, sample size, study design, type of cueing, intervention procedures, outcome measures, and main findings. The outcome evaluation was done at baseline and end of the treatment in most of the studies. All of studies except one showed improvements in some or all outcomes after intervention, or, in some cases, in favor of the virtual rehabilitation group compared to the control group. Conclusions Virtual cueing seems to be a promising approach to improve motor learning, providing a channel for non-pharmacological therapeutic intervention in different neurological disorders. However, further studies using larger and more homogeneous groups of patients are required to confirm these findings

Advances in wearable technology and applications in physical medicine and rehabilitation

The development of miniature sensors that can be unobtrusively attached to the body or can be part of clothing items, such as sensing elements embedded in the fabric of garments, have opened countless possibilities of monitoring patients in the field over extended periods of time. This is of particular relevance to the practice of physical medicine and rehabilitation. Wearable technology addresses a major question in the management of patients undergoing rehabilitation, i.e. have clinical interventions a significant impact on the real life of patients? Wearable technology allows clinicians to gather data where it matters the most to answer this question, i.e. the home and community settings. Direct observations concerning the impact of clinical interventions on mobility, level of independence, and quality of life can be performed by means of wearable systems. Researchers have focused on three main areas of work to develop tools of clinical interest: 1)the design and implementation of sensors that are minimally obtrusive and reliably record movement or physiological signals, 2)the development of systems that unobtrusively gather data from multiple wearable sensors and deliver this information to clinicians in the way that is most appropriate for each application, and 3)the design and implementation of algorithms to extract clinically relevant information from data recorded using wearable technology. Journal of NeuroEngineering and Rehabilitation has devoted a series of articles to this topic with the objective of offering a description of the state of the art in this research field and pointing to emerging applications that are relevant to the clinical practice in physical medicine and rehabilitation

The Effects of Wearing Headscarves on Cervical Spine Proprioception and Range of Motion

Background: Wearing the headscarf is a part of an essential religious practice by females in Islamic cultures. Regular wear of the headscarf might have an influence on cervical proprioception and range of motion (ROM). The cervical spine is unique in providing multidirectional movement as well as providing the sense of awareness of movement of the head and neck in space. Impairments in cervical mobility and proprioception have been reported in subjects with whiplash-associated disorder as well as subjects having neck pain. Objectives: 1) To determine the effects of wearing the headscarf on cervical spine ROM and joint position error (JPE), 2) To analyze the influence of age at onset of wearing the headscarf and duration of hours per day wearing the headscarf on cervical ROM and JPE. Methods: Fifty-two females with mean age of 28.1±3.1 years were divided into two groups: Headscarf group (n=26) and control group (n=26). Cervical range of motion (CROM) device was used to measure cervical mobility in a seated position for flexion, extension, right lateral flexion, left lateral flexion, right rotation and left rotation. JPE was measured using the head-mounted laser method. Results: The headscarf group reported a significant limitation in cervical ROM in all six directions. JPE test revealed no significant difference between groups. Moreover, females in the headscarf group who wore the headscarf for more than 6 hours per day had significantly less left rotation compared to those who wear it for less than or equal to 6 hours (71.3±2.1 vs. 64.5±2.1, η2=2.2; p=0.045). Additionally, there was significantly more JPE when relocating from flexion (5.1±0.6 vs. 8.0±1.0, η2=1.5; p=0.048) compared to those who wear the headscarf for less than or equal to 6 hours. Conclusion: Wearing of the headscarf may result in cervical ROM limitation. The duration of wearing the headscarf daily is a key factor to limited cervical ROM an increase in cervical JPE. Key words: Cervical spine, range of motion, neck pain, mobility, proprioception, movement, joint position error test, headdress, headscarf, and Hijab

Investigation of the information provided by light touch for balance improvement in humans

This study investigates the information provided by Light Touch (LT) in improving human postural stability without mechanical assistance. Light Touch, an interaction force with a magnitude about 1 N, is known to improve postural stability in humans during quiet standing. However, the nature of the information from LT that helped improve balance is yet unknown. In this work, we hypothesized that LT provides information about one\u27s body kinematics. We used a haptic robot to provide modulated, measurable light interaction force on the high back haptic location of humans to provide body kinematics-dependent information through LT. Standing balance experiments were performed with different force conditions on a group of ten healthy young participants. Results from these experiments have shown significant improvement in standing balance in conditions that provided LT over the condition that had no touch/contact. No further improvement was observed with additional position information provided in the form of variable vibration. Further data analysis revealed that the embedded information in LT provided in this study was partly position-dependent and mostly velocity-dependent. This positive effect of LT on back advances the research on implementing LT into wearable devices that can help improve postural stability of humans --Abstract, page iv