Neuro-vestibular rehab: new developments.

Objectives: To investigate the ameliorating effects of sinusoidal galvanic vestibular stimulation (GVS) on vestibular compensation from unilateral vestibular deafferentation (UVD) using a mouse model of unilateral labyrinthectomy (UL).Methods: Sixteen male C57BL/6 mice were allocated into two groups that comprise UL groups with GVS (GVS group, n = 9) and without GVS intervention (non-GVS group, n = 7). In the experimental groups, we assessed vestibulo-ocular reflex (VOR) recovery before (baseline) and at 3, 7, and 14 days after surgical unilateral labyrinthectomy. In the GVS group, stimulation was applied for 30 min daily from postoperative days (PODs) 0–4 via electrodes inserted subcutaneously next to both bony labyrinths.Results: Locomotion and VOR were significantly impaired in the non-GVS group compared to baseline. The mean VOR gain of the non-GVS group was attenuated to 0.23 at POD 3 and recovered continuously to the value of 0.54 at POD 14, but did not reach the baseline values at any frequency. GVS intervention significantly accelerated recovery of locomotion, as assessed by the amount of circling and total path length in the open field tasks compared to the non-GVS groups on PODs 3 (p < 0.001 in both amount of circling and total path length) and 7 (p < 0.01 in amount of circling and p < 0.001 in total path length, Mann–Whitney U-test). GVS also significantly improved VOR gain compared to the non-GVS groups at PODs 3 (p < 0.001), 7 (p < 0.001), and 14 (p < 0.001, independent t-tests) during sinusoidal rotations. In addition, the recovery of the phase responses and asymmetry of the VOR was significantly better in the GVS group than in the non-GVS group until 2 weeks after UVD (phase, p = 0.001; symmetry, p < 0.001 at POD 14).Conclusion: Recoveries for UVD-induced locomotion and VOR deficits were accelerated by an early intervention with GVS, which implies that GVS has the potential to improve vestibular compensation in patients with acute unilateral vestibular failure.

OPINION article Front. Neurol., 06 January 2012 | https://doi.org/10.3389/fneur.2011.00090

Conclusion: The age-related changes in ocular vestibular-evoked myogenic potentials (oVEMPs) elicited by galvanic vestibular stimulation (GVS) and bone-conducted vibration (BCV) might be attributed to the morphological degeneration of the vestibular system. Objective: This study employed GVS and BCV modes for eliciting oVEMPs in healthy subjects to explore the effect of aging on the vestibulo-ocular reflex (VOR) pathway. Methods: Sixty-nine healthy subjects (aged 22–69 years) were divided into 5 groups of 12–19 subjects by decades of age. All subjects underwent oVEMPs using GVS and BCV modes. The prevalence and parameters of oVEMPs, including nI latency, pI latency, nI-pI interval, and nI-pI amplitude were measured and compared. Results: The prevalences of GVS-oVEMPs had nonsignificant differences among all age groups, whereas that of BCV-oVEMPs in the over-60 group was significantly lower than those in the under-60 groups. In GVS-oVEMPs, the group over 60 years had significantly longer nI, pI latencies, and smaller amplitudes when compared with those under 60 years. In BCV-oVEMPs, the nI and pI latencies in the over-60 group were significantly longer than those of the under-60 groups, while the nI-pI amplitudes of groups over 50 years were significantly smaller than those of groups under 50 years. All oVEMP parameters exhibited significant differences between GVS- and BCV-oVEMPs in each age group.

Healthy subjects (N = 10) were exposed to 10-min cumulative pseudorandom bilateral bipolar Galvanic vestibular stimulation (GVS) on a weekly basis for 12 weeks (120 min total exposure). During each trial subjects performed computerized dynamic posturography and eye movements were measured using digital video-oculography. Follow up tests were conducted 6 weeks and 6 months after the 12-week adaptation period. Postural performance was significantly impaired during GVS at first exposure, but recovered to baseline over a period of 7–8 weeks (70–80 min GVS exposure). This postural recovery was maintained 6 months after adaptation. In contrast, the roll vestibulo-ocular reflex response to GVS was not attenuated by repeated exposure. This suggests that GVS adaptation did not occur at the vestibular end-organs or involve changes in low-level (brainstem-mediated) vestibulo-ocular or vestibulo-spinal reflexes. Faced with unreliable vestibular input, the cerebellum reweighted sensory input to emphasize veridical extra-vestibular information, such as somatosensation, vision and visceral stretch receptors, to regain postural function. After a period of recovery subjects exhibited dual adaption and the ability to rapidly switch between the perturbed (GVS) and natural vestibular state for up to 6 months.

Partial or total unilateral vestibular loss is the third most common cause of peripheral vestibular dysfunction. Dysfunction of one or both of the vestibular mechanisms can manifest physically as abnormalities of posture, balance, and/or visual acuity. This case report describes physical therapy examination and individualized intervention with vestibular rehabilitation for a patient with unilateral vestibular hypofunction. The patient was an 80-year-old male with electronystamographically confirmed unilateral vestibular loss of 98.3%. He demonstrated altered balance and gaze stability classifying him as having an increased risk for falling. After 5 weeks of individualized vestibular rehabilitation, the patient significantly decreased his fall risk from 11 to 20 of 24 on the Dynamic Gait Index. His gaze stability also improved from a 4 to 1 line disparity with dynamic visual acuity testing. The patient also had a decrease in perceived disability on the Dizziness Handicap Inventory from 30/100 at evaluation to 12/100 at discharge. Individualized vestibular rehabilitation decreased fall risk and improved gaze stability for a patient with significant unilateral vestibular hypofunction.

Recent neurophysiological findings, cited in previous publications imply that some vestibular commissural pathways may form positive feedback loops across the midline. It has already been shown theoretically that such feedback coupling of the vestibular nuclei could play an important role in the realization of the central integrator in the vestibuloocular reflex (VOR). In addition, it was found that known commissural plasticity during vestibular compensation, if placed at the level of such cross-midline loops, could reconcile findings after labyrinthine lesions. This paper examines theoretically the role such commissural feedback loops could play in the adaptation of the dynamics of the VOR in normal behaving animals. A simple static example is used to illustrate that changes in synaptic efficacy along cross-midline feedback loops could serve to adjust both balance and gain in vestibular reflexes. A bilateral model of the VOR and its interactions with vision is used to explore analytically the consequences of parametric changes along cerebellar and/or commissural pathways in three protocols: VOR in the dark, visual pursuit, and visual VOR suppression. Model predictions are systematically related to published findings after short- and long-term adaptation of the VOR. Conclusions arising from the theoretical results point to specific strategies that can be used in experiments on intact alert animals, in the further study of vestibular adaptation, and in the diagnosis of possible sites of plasticity. This should be relevant to arguments on cerebellar versus brain stem sites for vestibular adaptation, currently a highly controversial issue. For example, it is found that observations of responses in the adapted VOR in the dark are not sufficient to distinguish between a brain stem or cerebellar site for VOR plasticity. Also, the analysis shows that, in the model, changes in the VOR gain would often be associated with parallel changes in VOR dynamics; this has often been reported, but previously left unexplained. Model predictions of response changes in the adapted VOR, during VOR suppression, do provide a means of distinguishing between brain stem or cerebellar sites of plasticity; only the brain stem site, postulated here in the commissural loops, would produce cerebellar response changes compatible with the observations of Miles and Lisberger, during long-term adaptation of the VOR. A cerebellar site for VOR adaptation in the model would produce changes in cerebellar responses that would only be compatible with observations to date during rapid, or short-term (hours), modification of the VOR, as reported by Ito and his group.(ABSTRACT TRUNCATED AT 400 WORDS)

16. Psychophysical assessment of vestibular function and vestibular disorders

Cathodal galvanic currents activate primary vestibular afferents, whereas anodal currents inhibit them. Pulsed galvanic vestibular stimulation (GVS) was used to determine the latency and initiation of the human vestibuloocular reflex. Three-dimensional galvanic vestibuloocular reflex (g-VOR) was recorded with binocular dual-search coils in response to a bilateral bipolar 100-ms rectangular pulse of current at 0.9 (near-threshold), 2.5, 5.0, 7.5, and 10.0 mA in 11 normal subjects. The g-VOR consisted of three components: conjugate torsional eye rotation away from cathode toward anode; vertical divergence (skew deviation) with hypertropia of the eye on the cathodal and hypotropia of the eye on the anodal sides; and conjugate horizontal eye rotation away from cathode toward anode. The g-VOR was repeatable across all subjects, its magnitude a linear function of the current intensity, its latency about 9.0 ms with GVS of >or=2.5 mA, and was not suppressed by visual fixation. At 10-mA stimulation, the g-VOR [x, y, z] on the cathodal side was [0.77 +/- 0.10, -0.05 +/- 0.05, -0.18 +/- 0.06 degrees ] (mean +/- 95% confidence intervals) and on the anodal side was [0.79 +/- 0.10, 0.16 +/- 0.05, -0.19 +/- 0.06 degrees ], with a vertical divergence of 0.20 degrees . Although the horizontal g-VOR could have arisen from activation of the horizontal semicircular canal afferents, the vertical-torsional g-VOR resembled the vestibuloocular reflex in response to roll-plane head rotation about an Earth-horizontal axis and might be a result of both vertical semicircular canal and otolith afferent activations. Pulsed GVS is a promising technique to investigate latency and initiation of the human vestibuloocular reflex because it does not require a large mechanical apparatus nor does it pose problems of head inertia or slippage.

Event Abstract Back to Event Effect of visual field motion on vestibulo-myogenic response during upright stance: A pilot study Yawen Yu1, 2* and Emily A. Keshner1 1 Temple University, Physical Therapy, United States 2 Shriners Hospitals for Children - Philadelphia, United States BACKGROUND Maintaining upright stance requires the continuous update on sensory information from the primary systems in order to estimate the current state of postural orientation (Peterka, 2002). While each sensory system is responsible for unveiling a specific aspect of body motion, changes in one sensory system can also alter sensory input from another sensory system. This process of adjusting sensory contributions to balance control is referred to as sensory reweighting (Asslander & Peterka, 2014). Sensory reweighting would explain why the magnitude of the postural response due to galvanic vestibular stimulation (GVS) is dependent upon non-vestibular sensory signals (Fitzpatrick & Day, 2004). A much greater postural response can be elicited by GVS, when visual information is made unavailable (Welgampola & Colebatch, 2001). Individuals standing quietly in an immersive virtual environment where the visual surround is continuously moving exhibit postural sway in the direction of the visual flow (Wang, Kenyon, & Keshner, 2010). Thus, vestibular reafference could be modulated by visual flow as it is by fear of falling (Naranjo, Allum, Inglis, & Carpenter, 2015) and weakened muscle strength around the ankle (McIntosh, Power, & Dalton, 2018). The purpose of the current study was to explore whether vestibular reafference would be modulated by visual field motion. Results of this study provide a physiological interpretation for changes in the postural response due to visual field motion. METHODS Subjects: Eight healthy young adults (8 females; 28.0 ± 6.0 years) with no history of neurological disorder gave informed consent to participate in the current study. All subjects had no known history of vestibular or hearing deficit. All participants had a minimum of 20/40 corrected vision. The experimental protocol was approved by the Temple University Ethics Board. Using the Rod-and-Frame test, all participants were identified as visually independent (Yu, Lauer, Tucker, Thompson, & Keshner, 2018). Virtual Environment: The immersive virtual environment consisted of three screens facing the front, right, and left of the subject. The overall dimension of the virtual environment was 3.5m (width), 3.5m (depth), and 6.1m (height). One Panasonic PT-DX610 DLP-based projectors positioned behind each screen projected a full-color field with the resolution of 1024x768 pixels at a 60 Hz refresh rate. The image of the virtual environment was created in Unity (Unity Technologies SF, San Francisco, CA, USA). Vestibular Evoked Myogenic Potential (VEMP): Acoustic air-conducted stimulation consisting of 500Hz, 125dB SPL tone bursts, with 1ms rise/fall time, 2ms plateau, at a repetition rate of 5 Hz, was delivered monaurally though in-ear earphones (ER-3C, Etymotic Research Inc., Elk Grove Village, IL, USA). The electromyogram (EMG) signals representing cervical vestibular evoked myogenic potential (cVEMP) responses were recorded with disposable, self-adhesive, pre-gelled, Ag/AgCl electrodes with 40-inch safety leadwires (GN Otometrics, Schaumbaurg, IL, USA), which were amplified (2500x) and band-pass filtered (20 – 2000Hz) for cVEMPs. A non-inverting electrode was placed at the mid-point of the sternocleidomastoid (SCM) muscle on each side. An inverting electrode was placed at the sternoclavicular junction on each side. A ground electrode was placed on the manubrium sterni. Procedure: Participants were instructed to perform quiet stance in the center of the virtual environment. For left cVEMP testing, for example, participants were asked to look over the right shoulder to face the front screen with their body parallel to the left screen and actively contract the left SCM throughout the trial. During each 20-second trial, the visual field motion was kept either stationary (EO) or continuously rolling about the nasion-to-inion axis (RU) at 30°/s. Additionally, the acoustic air-conducted stimulation (100 tone-bursts) was delivered over the 20-second period. Three trials were performed for each condition on each side. Response parameters: The cVEMP waveform consists of a positive peak (p13), identified as the first distinctive valley in the waveform that appears 11ms – 16ms post tone burst, and a negative peak (n23), identified as the first distinctive peak in the waveform that appears 18ms – 26ms post tone burst. Mean values for cVEMP latencies and amplitudes were calculated separately for p13 and n23; peak-to-peak (p13-n23) amplitudes were also calculated. Muscle background activity of each SCM was calculated using the area under the curve of the rectified EMG over the 10ms window pre-stimulus. Statistical Analysis: Paired-sample t-tests were used to compare differences between EO and RU conditions for all dependent measures with the level of statistical significance set at p = 0.05. RESULTS A significant effect of visual field motion emerged in cVEMP amplitudes (p=.014). Specifically, the p13 amplitudes were significantly reduced by the RU visual scene condition (Figure 1; EO: 21.1±4.2 uV; RU: 17.7±3.7 uV). No significant differences between the stationary and roll visual conditions were found in n23 amplitudes, p13 and n23 latencies, and p13-n23 peak-to-peak amplitudes or in the background EMG activity (ps>.05). DISCUSSION Changes in the magnitude of the cVEMP suggest that vestibular reafference was modulated by visual field motion in the virtual environment even though all of the healthy participants in this study were identified as visually independent. To our knowledge, this is the first study to elicit and record VEMPs during upright stance with different conditions of visual field motion. These results provide a foundation for future studies examining vestibulo-myogenic responses in individuals with visual dependence due to neurological disorders (e.g., stroke, cerebral palsy). Comparison of vestibulomyogenic responses as a function of illusion of self-motion due to visual field motion (or vection) could further explain how the nervous system weights these signals in the natural environment. Figure 1 Acknowledgements This work is supported by the Shriners Hospitals for Children Postdoctoral Fellowship (#84308-PHI) to Yawen Yu. References Asslander, L., & Peterka, R. J. (2014). Sensory reweighting dynamics in human postural control. J Neurophysiol, 111(9), 1852-1864. doi: 10.1152/jn.00669.2013 Fitzpatrick, R., & Day, B. (2004). Probing the human vestibular system with galvanic stimulation. Journal of Applied Physiology, 96, 2301-2316. doi: 10.1152/japplphysiol.00008.2004. McIntosh, E. I., Power, G. A., & Dalton, B. H. (2018). The vestibulomyogenic balance response is elevated following high-intensity lengthening contractions of the lower limb. Neurosci Lett. doi: 10.1016/j.neulet.2018.03.056 Naranjo, E. N., Allum, J. H., Inglis, J. T., & Carpenter, M. G. (2015). Increased gain of vestibulospinal potentials evoked in neck and leg muscles when standing under height-induced postural threat. Neuroscience, 293, 45-54. doi: 10.1016/j.neuroscience.2015.02.026 Peterka, R. J. (2002). Sensorimotor integration in human postural control. J Neurophysiol, 88(3), 1097-1118. Wang, Y., Kenyon, R. V., & Keshner, E. A. (2010). Identifying the control of physically and perceptually evoked sway responses with coincident visual scene velocities and tilt of the base of support. Exp Brain Res, 201(4), 663-672. doi: 10.1007/s00221-009-2082-0 Welgampola, M. S., & Colebatch, J. G. (2001). Vestibulospinal reflexes: quantitative effects of sensory feedback and postural task. Exp Brain Res, 139(3), 345-353. Yu, Y., Lauer, R. T., Tucker, C. A., Thompson, E. D., & Keshner, E. A. (2018). Visual dependence modifies postural sway responses to continuous visual field motion in individuals with cerebral palsy. Dev Neurorehabil. doi: 10.1080/17518423.2018.1424265 Keywords: virtual environment, posture and balance, sensorimotor integration, Vestibular evoked myogenic potential (VEMP), Vection Conference: 2nd International Neuroergonomics Conference, Philadelphia, PA, United States, 27 Jun - 29 Jun, 2018. Presentation Type: Oral Presentation Topic: Neuroergonomics Citation: Yu Y and Keshner EA (2019). Effect of visual field motion on vestibulo-myogenic response during upright stance: A pilot study. Conference Abstract: 2nd International Neuroergonomics Conference. doi: 10.3389/conf.fnhum.2018.227.00086 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 03 Apr 2018; Published Online: 27 Sep 2019. * Correspondence: PhD. Yawen Yu, Temple University, Physical Therapy, Philadelphia, PA, United States, yawen.yu@colostate.edu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Yawen Yu Emily A Keshner Google Yawen Yu Emily A Keshner Google Scholar Yawen Yu Emily A Keshner PubMed Yawen Yu Emily A Keshner Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

ObjectiveTo compare sensory reweighting for upright stance between collegiate collision and non-contact sport athletes.BackgroundThe potentially adverse effects of repetitive head impact (RHI) exposure through routine collision sport participation have become a major public health concerns.Design/MethodsThirty male collegiate athletes were grouped by sport type, including collision (n = 15, 21.2 ± 2 years, 85.9 ± 13.8 kg, 179.7 ± 8.2 cm) and non-contact (n = 15, 20.8 ± 2.1 years, 72.9 ± 4.8 kg, 178.3 ± 4.3 cm) sport athletes. Participants underwent a standing balance assessment; they experienced simultaneous perturbations to visual, vestibular, and somatosensory systems. The visual stimulus consisted of 500 pyramids displayed on a virtual reality cave and translated in the anterior-posterior direction at 0.2 Hz in a sinusoidal waveform. The vestibular stimulus consisted of binaural-monopolar galvanic vestibular stimulation (GVS) at 0.36 Hz in a sinusoidal waveform. The somatosensory stimulus consisted of bilateral Achilles’ tendon vibration at 0.28 Hz in a square waveform with equal on/off times. Different frequencies were chosen for each modality so that we could calculate the gain to each stimulus independently. There were four conditions: two conditions of each high amplitude (0.2 m) and low amplitude (0.8 m) visual scene translation and two conditions of each vibration on and vibration off. The leg segment gain to each modality was compared between groups and across conditions using a repeated-measures ANOVA.ResultsThere were no changes in leg segment gain to vision (i.e. group effect; F = 2.624, p = 0.094, η2 = 0.086), gain to GVS (F = 1.341, p = 0.266, η2 = 0.46), or gain to vibration (F = 3.124, p = 0.088, η2 = 0.100). In addition, there were no changes in sensory reweighting for any modality (i.e. condition X group effect; vision, F = 0.074, p = 0.788, η2 = 0.003; GVS, F = 0.547, p = 0.46, η2 = 0.019; vibration, F = 0.734, p = 0.399, η2 = 0.026).ConclusionsOur findings suggest that there are no differences in sensory reweighting between collegiate collision and non-contact sport athletes. Despite concerns that RHI exposure through routine collision sport participation may result in balance disturbances, our results do not support this association.

Although anatomically well described, the functional role of the mammalian efferent vestibular system (EVS) remains unclear. Unlike in fish and reptiles, the mammalian EVS does not seem to play a role in modulation of primary afferent activity in anticipation of active head movements. However, it could play a role in modulating long-term mechanisms requiring plasticity such as vestibular adaptation. We measured the efficacy of vestibuloocular reflex (VOR) adaptation in α9-knockout mice. These mice carry a missense mutation of the gene encoding the α9 nicotinic acetylcholine receptor (nAChR) subunit. The α9 nAChR subunit is expressed in the vestibular and auditory periphery, and its loss of function could compromise peripheral input from the predominantly cholinergic EVS. We measured the VOR gain (eye velocity/head velocity) in 26 α9-knockout mice and 27 cba129 control mice. Mice were randomly assigned to one of three groups: gain-increase adaptation (1.5×), gain-decrease adaptation (0.5×), or no adaptation (baseline, 1×). After adaptation training (horizontal rotations at 0.5 Hz with peak velocity 20°/s), we measured the sinusoidal (0.2-10 Hz, 20-100°/s) and transient (1,500-6,000°/s(2)) VOR in complete darkness. α9-Knockout mice had significantly lower baseline gains compared with control mice. This difference increased with stimulus frequency (∼ 5% <1 Hz to ∼ 25% >1 Hz). Moreover, vestibular adaptation (difference in VOR gain of gain-increase and gain-decrease adaptation groups as % of gain increase) was significantly reduced in α9-knockout mice (17%) compared with control mice (53%), a reduction of ∼ 70%. Our results show that the loss of α9 nAChRs moderately affects the VOR but severely affects VOR adaptation, suggesting that the EVS plays a crucial role in vestibular plasticity.

Application of intermittent galvanic vestibular stimulation reveals age-related constraints in the multisensory reweighting of posture

Complementary and Alternative Medicine (CAM) covers a heterogeneous spectrum of ancient to new-age approaches that purport to prevent or treat disease. By definition, CAM practices are not part of conventional western-style medicine because there is a perception of insufficient proof that they are safe and effective or because they are not taught in conventional medical and nursing schools. Complementary interventions are typically used together with conventional western-style treatments, whereas alternative interventions are used instead of conventional approaches. When combined with conventional practices they are often labeled Integrative Medicine (IM). Many people in the United States (US) use CAM and IM modalities1–7 and its use is increasing.2 In 1990, a national survey estimated that 33.8% of US adults used CAM modalities in the previous year,7 which increased to 42.1% in 19973 and 62% in the 2002 National Health Interview Survey (NHIS).1 These surveys included spiritual healing and "folk" medicine (remedies common, ethnically derived remedies used at home), in the CAM modality definition. Recently published results of the 2007 NHIS used a different CAM modality taxonomy and excluded these practices.2,8,9 When prayer specifically for health reasons was excluded, the 2002 and 2007 NHIS found 36% and 38.3%, respectively, of US adults reported using some form of CAM modality in the last 12 months.1,2 These national surveys only include civilian, noninstitutionalized individuals; they do not include our 1.8 million active duty military personnel and families. In the last 10 years, there has been an increase in interest and use of CAM modalities and IM in the military.9 This important segment of the US population receives health care from both military and civilian practitioners; and is subject to similar health risks as civilians plus additional physical, emotional, and cognitive stress of deployment with associated family separations for both the active duty member and families, and the consequences of combat.10,11 It would not be unexpected for military personnel to seek to improve their health through complementary practitioners, potentially at a greater extent due to health and performance expectations,10 and for the same reasons reported by civilians.1,2,11,12 This interest in CAM has been accelerated by the surge of chronic pain, chronic stress, and chronic symptoms associated with trauma and injuries from over a decade of wars in Iraq and Afghanistan.13 However, until recently there were little data to determine which CAM modalities are being used, how often, by whom, and for what purposes. Recently, these informational gaps are being filled in and the current picture is summarized below. USE OF CAM IN THE MILITARY The use of CAM in the military is higher than in the civilian population. Samueli Institute and Research Triangle International conducted the largest and most comprehensive survey of CAM use in over 16,000 active duty service members in all branches stationed both in the United States and overseas.14 Data were drawn from the 2005 Department of Defense (DoD) Survey of Health Related Behaviors among Active Duty Military Personnel, which draws on a worldwide, random sample of over 40,000 service members from all branches, sexes, races, and ranks.15 It asked about overall CAM use and 19 specific CAM therapies using a methodology that closely matched the NHIS used by the National Center for Complementary and Alternative Medicine.16 This military survey showed that approximately 45% of active duty military personnel reported using at least 1 CAM type in the previous 12 months. CAM use when not counting self-prayer was approximately 36%. The 8 most frequently reported CAM approaches included 4 mind body therapies (prayer for your own health: 24.4%; relaxation techniques: 10.8%; art/music therapy: 7.7%; exercise/movement therapy: 6.8%), 2 biologically based therapies (herbal medicine: 8.9%; high-dose megavitamins: 8.4%), and 2 manipulative and body-based methods (massage therapy: 14.1%; chiropractic: 5.2%). Eleven CAM types were used by <5.0% of respondents and 6 types were used by <1% of personnel. When both surveys were adjusted for the 2000 census bureau demographics, CAM use by military personnel was significantly higher than that of the general population (44.5% vs. 36.0% and 38.3% in the 2 NHIS surveys, respectively, P<0.001). Significantly more military personnel reported use of energy healing, guided imagery therapy, massage therapy, hypnosis, and relaxation techniques than civilians in both NHIS surveys (P<0.001) with more reported use of "folk" remedies, high-dose megavitamins, and spiritual healing by others than the 2002 NHIS survey (P<0.001) and more frequent use of biofeedback than the 2002 NHIS and 2007 NHIS surveys (P<0.001 and P<0.01, respectively). There were no statistical differences in reported use of acupuncture and homeopathy. Overall, the prevalence of CAM use in this study was consistent with smaller military surveys where 49.6% CAM use was reported by military veterans in the Southwestern United States,17 and with 37.2% use of 12 CAM modalities (excluding prayer) in US Navy and Marine Corps personnel.18 The vast majority of CAM health care occurs outside the military health system, some of it provided by TRICARE, the military's health insurance program. However, as in the civilian population, most CAM is paid for out of pocket by military personnel as TRICARE covers very few CAM modalities. Massage therapy, used by 14% or an estimated 137,000 personnel, is not a covered benefit, whereas biofeedback (for certain conditions) is covered. Chiropractic is the only CAM modality that is currently included in a systematic manner in the military health system; however, access to chiropractic practitioners is limited. In 2005, 54% of active duty personnel resided in areas served by chiropractic clinics, and the remaining 46% were not served by clinics because of living overseas (14%), in remote areas (5%), or in US installations without chiropractic clinics (28%).19 Herbal medicines and high-dose vitamins also are not covered by military health care. However, many military installations include a General Nutrition Center store on the premises where these products readily are available. Three CAM modalities (yoga, massage, and imagery), which are commonly used for stress management were used by military populations at an estimated 2.5–7 times the rate of civilians. The fact that military members and their families are seeking and personally paying for these therapies outside both direct military care system and the TRICARE System may reflect access problems in Military Treatment Facilities (MTF), a preference for CAM/IM over traditional modalities (ie, not turning away from traditional medicine but rather turning toward and preferring CAM/IM), growing concern about the results of traditional pharmacologically based treatments, and an increasing interest in and need for appropriate access to CAM modalities within the military health system to decrease symptoms and improve function for military members suffering from the "wounds of war." Unmonitored and uninformed use of CAM modalities in the military may have negative consequences on health and military performance. A number of large randomized, placebo controlled trials of herbal treatments20–22 and acupuncture7,23,24 have been negative, making the substitution of these CAM modalities for proven therapies risky. In addition, some CAM therapies, particularly herbal supplements, have been associated with potential harm through toxicity and herb/pharmaceutical interactions.25,26 Herbal medicines and nutrients in doses well above the Dietary Reference Intakes27 are 2 of the CAM modalities most commonly used by military personnel. With 45% of the over 1million active duty personnel reportedly using CAM modalities, and a steady increase globally, it is important to understand why military personnel are using CAM, the role these therapies should play in their health care, and for military health care providers to recognize, monitor, and integrate CAM modalities into their health care practices. OFFERINGS OF CAM IN MTF Two recent surveys have assessed the use of CAM across DoD medical facilities and evaluated their reported effects and attitudes by health care leaders in military MTFs. The first is in a report entitled "Integrative medicine in the military health system report to congress" by the DoD Undersecretary of Personnel and Readiness (P&R).28 In this survey, 29% (120) of 421 MTFs reported offering a total of 275 CAM programs including 213,515 CAM patient visits in calendar year 2012 for active duty members. The most visits were for chiropractic care (73%) and acupuncture therapy (11%). The report states that, of those doing evaluation of CAM they have found: (1) patients reporting a reduction in anxiety levels and improved sleep with meditation; (2) breath-based practices reportedly helped patients to remain sober and reduced overall stress levels; (3) patients using massage therapy noted 75% improvement of symptoms, including pain; and, (4) overall positive outcomes were reported by 50%–90% of patients using massage therapy. The Report also states that patients practicing yoga had declines in psychological symptoms and improvement in overall health. Over 30 research projects have been funded by DoD and have reported improvements in symptoms and sleep, reduction in anxiety and psychological symptoms across a number of CAM practices being used. The Report concluded that: "There is wide-spread use of CAM therapies across the [Military Health System] MHS. Providers and patients were interested in using CAM therapies even though many are not evidence-based. Some providers have added CAM therapies as an adjunct to conventional therapies for a holistic approach to patient management." The second survey, completed by Samueli Institute did a more in-depth survey of CAM availability across a more limited sample of both MTFs and morale, welfare, and recreation (MWRs) centers. The study examined the CAM services offered during the year 2013 in 47 DoD MTFs, and MWRs locations across all military service branches.29 Information was collected on the prevalence of CAM modalities provided; the attitudes and beliefs towards CAM among the leadership in the different facilities; the obstacles and barriers to access in military facilities; the funding sources for CAM offered at military facilities; and, whether CAM is part of the strategic plan for the future of health care delivery. In addition, information was collected on the provision of CAM treatments for highly prevalent conditions in military personnel (pain, combat-related stress, and rehabilitation), how beneficial medical leaders thought CAM was, and how practitioners were accredited to practice CAM modalities. The results of this survey showed that 30 (70%) of the 47 facilities surveyed provided some type of CAM service with most being provided for active duty service members (70%), followed by family members (43%) and retirees (36%). Less than 9% of the participants reported providing CAM services to federal employees, contractors, or members in the community. Overall, acupuncture and chiropractic were among the top 3 most prevalent practices followed by yoga and massage. For pain management the primary CAM modalities were acupuncture (36.2%), chiropractic or osteopathic medicine (27.7%), and breathing exercises (25.5%). For stress and stress-related conditions, the top modalities were acupuncture (25.5%), breathing exercises (21.3%), and biofeedback (17%). For wellness and fitness, offerings included weight management, diet-based therapies, and movement practices. In this Samueli Institute survey, 57% of medical leaders felt that CAM practices were either beneficial (40%) or highly beneficial (17%) with 40% being neutral on the benefit and 3.3% feeling CAM practices were not beneficial. Despite this generally favorable response, over 75% had no provision or guidelines for CAM use in their strategic plans. Still, 46% funded CAM services out of their general budget, with 12% receiving money from the Office of the Army Surgeon General, 8% receiving congressional money, and 4% private money for CAM. Only 10% reported any research or evaluation of CAM going on in their facility. This survey also examined the challenges to improving access to these practices. Although the majority of leadership responses (57%) rated CAM modalities as highly favorable or favorable, the identified obstacles and barriers for access to CAM in military facilities included (in order of frequency): (1) inadequate space to provide services; (2) patients do not know to ask for CAM; (3) CAM costs too much; (4) CAM is too time consuming; and (5) CAM does not contribute to workload coverage. The prevalence of CAM practices provided by MTFs and MWR across DoD shows 75% availability within MTFs, and 33% within MWR facilities and programs. There were no appreciable differences in availability of CAM across military branches. MINDING THE GAP: ALIGNING PATIENTS, PRACTICE, AND POLICY In the report to Congress by DoD P&R, it was recommended to evaluate CAM programs for safety and effectiveness, as well as cost-effectiveness and consider widespread implementation in the military health system if cost-effective. The criteria for how to do this are specified. Part 199 of Title 32, CFR, governs TRICARE benefits and restricts services to those medically necessary drugs, devices, treatments, or procedures for which safety and efficacy have been proven to be comparable or superior to established therapies. Established criteria state that unproven drugs, devices, treatments, or procedures may not be covered: (1) unless reliable evidence shows that any medical treatment or procedure has undergone well-controlled clinical studies that show maximum tolerated dose, toxicity, safety, or efficacy compared with standard treatment or diagnosis; (2) if the available reliable evidence is considered inadequate by experts who recommend further studies or clinical trials are needed. The criteria for making a determination of proven safe and effective to nationally accepted medical standards are evidence that comes from: (1) well-controlled studies of clinically meaningful endpoints published in referred medical literature; (2) published formal technology assessments; (3) published reports of national professional medical associations; and (4) published reports of national expert opinion organizations. However, these guidelines and criteria and not being applied appropriately to CAM modalities. Biofeedback is the only CAM practice currently covered under TRICARE guidelines, and TRICARE only covers biofeedback therapy for nerve injury, not stress management. The 2 most widely used CAM modalities (chiropractic and acupuncture) are excluded in Title 32 CFR section 199.4 (g) even though neither has been evaluated using TRICARE guidelines. In other words, none of the CAM modalities (with the possible exception of biofeedback) have been evaluated by the DoD or TRICARE using their own guidelines for determining which practices should be covered. Despite this, TRICARE declines to pay for acupuncture but will pay for biofeedback. Chiropractic (which also has not been evaluated by TRICARE guidelines) is provided to DoD beneficiates through MTFs but not through TRICARE. Chiropractic is currently being implemented across DoD even though research on the effectiveness of chiropractic in the DoD is only recently underway because of a Congressional mandate and special appropriation.30 Acupuncture is both widely accepted and used in the DoD and currently the Defense and Veteran's Pain Task Force is training medical practitioners in "Battlefield Acupuncture" (BA). BA is a specific auricular acupuncture protocol developed by Col (Ret) Richard Niemtzow, an Air Force physician, seeking to add a simple nonpharmacological pain management technique that could be used by a broad array of first responders and primary care providers to help reduce pain, reduce medication load, and improve function.31 Acupuncture has been shown to be superior to conventional therapy for several chronic conditions prevalent in the military, and has also been shown not to be due only to placebo effects.32 Samueli Institute has performed a comprehensive systematic review of acupuncture for the Trauma Spectrum Response, an important collection of comorbidities often experienced by service members after deployment.33 Recently, a comprehensive review of self-care CAM modalities for pain has been published in a special issue of Pain Medicine in which reasonable evidence for use of yoga, tai chi, and music were found for the treatment of pain.34 These areas are ripe for evaluation by the military and TRICARE Systems for possible inclusion into the array of services provided. CONCLUSIONS Over a decade of war has left hundreds of thousands of our service members and their families suffering from a range of psychological and physical injuries, many leading to or exacerbating chronic pain. They and their health care providers have surged ahead in seeking out drug-free and self-care healing practices to help them recover and return to wholeness in peacetime. The availability of efficacious CAM modalities adds needed access to a cadre of promising services and practices that promote healing and improved function with less medication and fewer unwanted side effects. However, DoD policy and priorities have not kept up with this surge, leaving the majority of active duty service members, veterans, and their families to fend for themselves, to pay for or go without the beneficial effects of CAM and IM practices. As stated in the DoD P&R report to Congress, "At this time, there are insufficient internal evaluations and reported results to determine whether the CAM programs being provided in the MTFs meet these [TRICARE] criteria." It is time for the DoD to step up their efforts to complete these evaluations and ensure that "sufficient evaluation" occurs in a more timely manner. Our long-suffering heroes deserve nothing less!

Vestibular adaptation: How models can affect data interpretations

Background: Postural stability depends on the integration of multisensory inputs to drive motor outputs. When visual and somatosensory input is available and reliable, this reduces the postural control system’s reliance on the vestibular system. Despite this, vestibular loss can still cause severe postural dysfunction (1,2). Training one or more of the three sensory systems can alter sensory weighting and change postural behavior. Vestibular activation exercises, including horizontal and vertical headshaking, influence vestibular-ocular and -motor responses and have been showed to be effective in vestibular rehabilitation (3–8). &#x0D; Purpose/Hypothesis: To assess sensory reweighting of postural control processing and vestibular-ocular and -motor responses after concurrent vestibular activation with postural training. It was hypothesized that the effect of this training would significantly alter the pattern of sensory weighting by changing the ratio of visual, somatosensory and vestibular dependence needed to maintain postural stability, and significantly decrease vestibular responses.&#x0D; Methods: Forty-two young healthy individuals (22 females; 23.0+3.9 years; 1.6+0.1 meters) were randomly assigned into four groups: 1) visual feedback weight shift training (WST) coupled with an active horizontal headshake (HHS), 2) same WST with vertical headshake (VHS), 3) WST with no headshake (NHS) and 4) no training/headshake control (CTL) groups. The headshake groups performed an intensive body WST together with horizontal or vertical rhythmic headshake at 80 to 120 beats/minute. The NHS group performed the WST with no headshake while the controls did not perform any training. Five 15-minute training sessions were performed on consecutive days for one week with the weight shift exercises involving upright limits of stability activities on a flat surface, foam or rocker board (Fig. 1). All groups performed baseline- and post-assessments including sensory organization test (SOT) and force platform ramp perturbations, coupled with electromyographic (EMG) recordings. A video head impulse test was also used to record horizontal vestibulo-ocular reflex (VOR) gain. A between- and within-group repeated measures ANOVA was used to analyze five COP sway variables, the equilibrium and composite scores and sensory ratios of the SOT as well as EMG signals and horizontal VOR gain. Similarly, COP variables, EMG, as well as vestibular reflex data (vertical VOR, vestibulo-collic reflex [VCR] and vestibulo-spinal [VSR] gains) during ramp perturbations were analyzed. Alpha level was set at p&lt;.05.&#x0D; Results: The training showed a significant somatosensory downweighting (p=.050) in the headshake groups compared to the other groups. Training also showed significant decreased horizontal VOR gain (p=.040), faster automatic postural response (p=.003) (Figs. 2-4) with improved flexibility (p=.010) in the headshake groups. Muscle activation pattern in medial gastrocnemius (p=.033) was significantly decreased in the headshake.&#x0D; Conclusion: The concurrent vestibular activation and weight shift training modifies vestibular-dependent responses after the training intervention as evidenced in somatosensory downweighting, decreased VOR gain, better postural flexibility and faster automatic postural response. Findings suggest this is predominantly due to vestibular adaptation and habituation of VOR, VCR and VSR which induced sensory reweighting.&#x0D; Clinical relevance: Findings may be used to guide the development of a vestibular-postural rehabilitation intervention in impaired neurological populations, such as with vestibular disorders or sensory integration problems.