Comparison of a Low-Cost Miniature Inertial Sensor Module and a Fiber-Optic Gyroscope for Clinical Balance and Gait Assessments.

Objective: To investigate whether a microelectromechanical system (MEMS) inertial sensor module is as accurate as fiber-optic gyroscopes when classifying subjects as normal for clinical stance and gait balance tasks.

Methods: Data of ten healthy subjects were recorded simultaneously with a fiber-optic gyroscope (FOG) system of SwayStar™ and a MEMS sensor system incorporated in the Valedo® system. Data from a sequence of clinical balance tasks with different angle and angular velocity ranges were assessed.

Vibro-tactile and auditory balance biofeedback changes muscle activity patterns: Possible implications for vestibular implants.

Background: The two different types of balance prostheses being developed, implants and vibro-tactile/auditory feedback prostheses, rely on different measures to prove efficacy (those based on vestibular ocular reflexes versus balance control, respectively). Here we provide evidence that examining muscle activity might provide a useful alternative for both.

Methods: The muscle activity of 6 bilateral vestibular loss (BVL) and 7 age-matched healthy controls (HC) was examined while standing eyes closed on a foam support surface.

Benefits of multi-session balance and gait training with multi-modal biofeedback in healthy older adults.

Real-time balance-relevant biofeedback from a wearable sensor can improve balance in many patient populations, however, it is unknown if balance training with biofeedback has lasting benefits for healthy older adults once training is completed and biofeedback removed. This study was designed to determine if multi-session balance training with and without biofeedback leads to changes in balance performance in healthy older adults; and if changes persist after training. 36 participants (age 60-88) were randomly divided into two groups.

Recovery of Vestibulo-Ocular Reflex Symmetry After an Acute Unilateral Peripheral Vestibular Deficit: Time Course and Correlation With Canal Paresis.

Background: We investigated how response asymmetries and deficit side response amplitudes for head accelerations used clinically to test the vestibular ocular reflex (VOR) are correlated with caloric canal paresis (CP) values.

Methods: 30 patients were examined at onset of an acute unilateral peripheral vestibular deficit (aUPVD) and 3, 6, and 13 weeks later with three different VOR tests: caloric, rotating chair (ROT), and video head impulse tests (vHIT). Response changes over time were fitted with an exponential decay model and compared with using linear regression analysis.

The Effect of Age on Improvements in Vestibulo-Ocular Reflexes and Balance Control after Acute Unilateral Peripheral Vestibular Loss.

Background: An acute unilateral peripheral vestibular loss (aUVL) initially causes severe gaze and balance control problems. However, vestibulo-ocular reflexes (VOR) and balance control are nearly normal 3 months later as a result of peripheral recovery and/or central compensation. As pre-existing vestibular sensory loss is assumed to be greater in the healthy elderly, this study investigated whether improvements in VOR and balance function over time after aUVL are different for the elderly than for the young.

Recovery times of stance and gait balance control after an acute unilateral peripheral vestibular deficit.

Background: Acute unilateral peripheral vestibular deficit (aUPVD) patients have balance deficits that can improve after several weeks. Determining differences in vestibulo-spinal reflex (VSR) influences on balance control and vestibular ocular reflex (VOR) responses with peripheral recovery and central compensation would provide insights into CNS plasticity mechanisms. Also, clinically, knowing when balance control is approximately normal again should contribute to decisions about working ability after aUPVD.

Cochlear implantation in children and adults in Switzerland.

The cochlear implant (CI) is one of the most successful neural prostheses developed to date. It offers artificial hearing to individuals with profound sensorineural hearing loss and with insufficient benefit from conventional hearing aids. The first implants available some 30 years ago provided a limited sensation of sound.

Influence of perturbation velocity on balance control in Parkinson's disease.

Underlying somatosensory processing deficits of joint rotation velocities may cause patients with Parkinson's disease (PD) to be more unstable for fast rather than slow balance perturbations. Such deficits could lead to reduced proprioceptive amplitude feedback triggered by perturbations, and thereby to smaller or delayed stabilizing postural responses. For this reason, we investigated whether support surface perturbation velocity affects balance reactions in PD patients.

The effect of prosthetic feedback on the strategies and synergies used by vestibular loss subjects to control stance.

Background: This study investigated changes in stance movement strategies and muscle synergies when bilateral peripheral vestibular loss (BVL) subjects are provided feedback of pelvis sway angle.

Methods: Six BVL (all male) and 7 age-matched male healthy control (HC) subjects performed 3 stance tasks: standing feet hip width apart, eyes closed, on a firm and foam surface, and eyes open on foam. Pelvis and upper trunk movements were recorded in the roll and pitch planes.

Improving gait and balance in patients with leukoaraiosis using transcranial direct current stimulation and physical training: an exploratory study.

Background: Leukoaraiosis describes ischemic white matter lesions, a leading cause of gait disturbance in the elderly.

Objective: Our aim was to improve gait and balance in patients with leukoaraiosis by combining a single session of transcranial direct current stimulation (tDCS) and physical training (PT).

Methods: We delivered anodal tDCS over midline motor and premotor areas in 9 patients with leukoaraiosis.

Relation between head impulse tests, rotating chair tests, and stance and gait posturography after an acute unilateral peripheral vestibular deficit.

Background: Vestibulo-ocular reflex (VOR) deficits and balance instability during stance and gait are typical for an acute unilateral peripheral vestibular deficit (AUPVD). The relation between different VOR measures with recovery is unknown, as is the relation of VOR measures to balance control. To answer these questions, we examined changes over time in caloric canal paresis (CP), head impulse tests (HIT), whole body rotation (ROT) tests of the horizontal VOR, and changes in trunk sway during stance and gait tests, for cases of presumed vestibular neuritis.

Strategies and synergies underlying replacement of vestibular function with prosthetic feedback.

This study investigated changes in movement strategies and muscle synergies when bilateral peripheral vestibular loss (BVL) subjects are provided prosthetic feedback of their pelvis sway during stance. Six BVL subjects performed 3, for them, difficult stance tasks: standing eyes closed, on a firm surface, on a foam surface, and standing eyes open on foam. Movement strategies were recorded as roll and pitch ratios of upper and lower body velocities with body-worn gyroscopes.

Balance control in multiple sclerosis: correlations of trunk sway during stance and gait tests with disease severity.

Objective: To investigate which measures of trunk sway taken during stance and gait tasks are best correlated with Expanded Disability Status Scale (EDSS) scores of multiple sclerosis (MS) patients.

Methods: We studied 37 MS patients (mean age 43±10 years; 76% female; 81% relapsing-remitting MS; mean EDSS score 2.8±1.

Improving impaired balance function: real-time versus carry-over effects of prosthetic feedback.

This study investigated whether training with realtime prosthetic biofeedback (BF) of trunk sway induces a carry-over improvement in balance control once BF is removed. 12 healthy older adults and 7 uncompensated unilateral vestibular loss patients were tested. All participants performed a battery of 14 balance and gait tasks (pre-test) upon their initial lab visit during which trunk angular sway was measured at L1-3.

Screening for balance disorders in mildly affected multiple sclerosis patients.

Multiple sclerosis (MS) patients often complain about balance problems when Romberg's test and tandem gait are normal. The aim of the study was to determine if measures of trunk sway taken during a battery of stance and gait tasks could be used to detect subclinical balance disorders. We recorded trunk angular sway in the pitch and roll directions from 20 MS patients (EDSS 1.

Trunk sway in mildly disabled multiple sclerosis patients with and without balance impairment.

Multiple sclerosis (MS) causes a broad range of neurological symptoms. Most common is poor balance control. However, knowledge of deficient balance control in mildly affected MS patients who are complaining of balance impairment but have normal clinical balance tests (CBT) is limited.

First trial postural reactions to unexpected balance disturbances: a comparison with the acoustic startle reaction.

Unexpected support-surface movements delivered during stance elicit "first trial" postural reactions, which are larger and cause greater instability compared with habituated responses. The nature of this first trial reaction remains unknown. We hypothesized that first trial postural reactions consist of a generalized startle reaction, with a similar muscle synergy as the acoustic startle response, combined with an automatic postural reaction.

Directional effects of biofeedback on trunk sway during stance tasks in healthy young adults.

Biofeedback has been shown to improve balance in a number of different populations. As certain clinical populations have a tendency to fall in one direction, the provision of biofeedback in the impaired direction may improve balance in that direction but not in others. The purpose of this study was to determine the effects of uni-directional biofeedback on stance tasks in healthy young adults.

Trunk sway reductions in young and older adults using multi-modal biofeedback.

This study investigated whether real-time biofeedback of angular trunk displacement could alter balance performance among healthy older and young adults. Healthy community-dwelling older adults (n=32) and healthy young adults (n=32) were included in the randomized control trial study. The intervention group received combined vibrotactile, auditory and visual biofeedback of angular trunk displacement in real-time during training on a battery of static and dynamic balance tasks and during the subsequent post-training balance re-assessment.

Differentiating malingering balance disorder patients from healthy controls, compensated unilateral vestibular loss, and whiplash patients using stance and gait posturography.

Differentiating balance disorder patients who are malingering from those with organic balance disorders is difficult and costly. We used trunk sway measured during several stance and gait tasks in 18 patients suspected of malingering in order to differentiate these from 20 patients who had suffered unilateral vestibular loss 3 months earlier, 20 patients with documented whiplash injuries, and 34 healthy controls. Classification results ranged from 72 to 96% and were equally accurate for task or criteria variables based on 90% sway values.

Effects of biofeedback on trunk sway during dual tasking in the healthy young and elderly.

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.

Directional sensitivity of "first trial" reactions in human balance control.

Support-surface movements are commonly used to examine balance control. Subjects typically receive a series of identical or randomly interspersed multidirectional balance perturbations and the atypical "first trial reaction" (evoked by the first perturbation) is often excluded from further analysis. However, this procedure may obscure vital information about neurophysiological mechanisms associated with the first perturbation and, by analogy, fully unexpected falls.

Directional effects of biofeedback on trunk sway during gait tasks in healthy young subjects.

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.