Search

Purpose: Visual vertigo (VV) is a type of dizziness triggered by visual stimuli. Despite a high incidence, its relationship with anxiety is not well-defined or understood. This study evaluated anxiety levels in subjects with VV compared to vestibulopathic subjects without VV and healthy individuals.Methods: A cross-sectional study to evaluate anxiety among individuals with VV was conducted twice. The first study included 72 participants (66 to 83 years of age) from senior residential centers. The second included 31 participants from a vestibular rehabilitation program (age range 35–82 years). Study 1 also used the Activities-Specific Balance Confidence (ABC) scale and study 2 the Dizziness Handicap Inventory (DHI).Results: Subjects were classified as VV positive (27 in study 1, 10 in study 2) or vestibulopathic without VV (30 in study 1, 11 in study 2) based on Head Impulse or Dynamic Visual Acuity Tests and the Dizziness Questionnaire. The remaining were age-matched healthy controls. The outcome of each study demonstrated significantly higher anxiety levels (p = 0.0001) in the VV group compared to the other groups. The results of the ABC test demonstrated that subjects in the VV group had significantly lower self-confidence (p = 0.001) than those in the Vest and Cont groups and performed fewer balance-related activities of daily life. DHI results showed that VV group expressed higher (p < 0.001) mean scores for self-perceived feelings of dizziness and imbalance (54%), compared to the Vest (9%) and Cont groups (1%).Conclusions: Anxiety related to VV requires special attention when assessing and managing vestibulopathy, regardless of patient age.Implications for RehabilitationAnxiety is a characteristic of subjects with visual vertigo (VV) and vestibulopathy.Anxiety in subjects with VV is not related to age.VV should be considered when subjects with anxiety complain of imbalance.Anxiety and vestibulopathy are often interrelated and should be considered in diagnostic evaluations. [ABSTRACT FROM PUBLISHER]

Copyright of Journal of Otolaryngology -- Head & Neck Surgery is the property of Sage Publications Inc. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: Objective: To investigate the postural adaptations to inclined walking in spinal cord injured (SCI) subjects. Methods: Eight subjects with an incomplete spinal cord injury and eight age- and sex-matched healthy control subjects walked on a treadmill at five different grades (from −10 to 10%) without any assistance. The movements of the trunk and pelvis were recorded with four high-resolution cameras. Results: The SCI subjects walked with greater forward tilt of both trunk and pelvic segments during level or inclined walking and could not adapt their body orientation to the inclination of the support surface as observed in healthy control subjects. Trunk and pelvic rotations as well as lateral excursions were maintained constant during inclined walking in both groups of subjects but total excursions were always greater in the SCI subjects. Conclusions: We argue that the forward bending posture observed in SCI subjects at any treadmill grade is adopted to compensate for a certain degree of instability due to lower-limb deficits and is a postural adaptation to the daily use of ambulatory assistive devices. Significance: The bent posture adopted by SCI subjects is not adequate when performing level or downhill walking and can lead to a loss of balance or a fall in these subjects. [Copyright &y& Elsevier]

The aim of the present study was to investigate the relationship between proactive and reactive components of postural control. We contrasted the kinematic and electromyographic (EMG) responses to multidirectional voluntary leg lifts with those elicited by unexpected surface tilts. In particular, we addressed the role of trunk stabilization following either a voluntary or forced weight shift from double to single limb support. Nine young female subjects stood with a standing posture of 45° toe-out and their arms abducted to shoulder level. On the experimenter’s signal, subjects either (1) lifted one leg as fast as possible in one of six directions (R/L side, R/L diagonal front, R/L diagonal back) to a height of 45° or (2) maintained standing as the support surface tilted at a rate of 53°/s to a height of 10° in one of six directions (R/L-up, R/L diagonal toes-up, R/L diagonal toes-down). For both tasks, our results showed that the center of pressure (COP) displacement began before or in conjunction with displacement of the center of mass (COM), after which the COP oscillated about the horizontal projection of the COM. In addition, the muscles were recruited in a distal-to-proximal sequence, either in anticipation of the voluntary leg lift or in response to the sudden surface tilt. Thus, the COP was being used dynamically to control displacement of the COM. The axial postural strategy comprising head, trunk, and pelvis movements was quantified by means of principal component analysis. More than 95% of the variance in the data could be described by the first two eigenvectors, which revealed specific coordination patterns dominated by pelvis rotation in one direction and head/trunk rotation in the opposite direction. Unexpected surface tilting elicited an automatic response strategy that focused on controlling the orientation of the head and trunk with respect to the vertical gravity vector while trunk verticality was compromised for movement generation and the recovery of postural equilibrium during leg lifting. In conclusion, regardless of the type (voluntary versus involuntary) or direction of perturbation, the strategy employed by the central nervous system to control the body COM displacement concerns mainly trunk stabilization. [ABSTRACT FROM AUTHOR]

Purpose: To develop a virtual reality (VR) based intervention targeting community walking requirements. Methods: Two focus groups each involving 7 clinicians allowed exploring optimal features, needed support and perceived favorable/unfavorable factors associated with the use of the VR-based intervention from the clinicians' perspective. Three stroke survivors and 2 clinicians further interacted with the intervention and filled questionnaires related to acceptability and favorable/unfavorable perceptions on the VR intervention. Stroke participants additionally rated their perceived effort (NASA Tax Load Index), presence (Slater-Usoh-Steed) and cybersickness (Simulator Sickness Questionnaire). Results: Results identified optimal features (patient eligibility criteria, task complexity), needed support (training, human assistance), as well as favorable (cognitive stimulation, engagement, representativeness of therapeutic goals) and unfavorable factors (misalignment with a natural walking pattern, client suitability, generalization to real-life) associated with the intervention. Acceptability scores following the interaction with the tool were 28 and 42 (max 56) for clinicians and ranged from 43 to 52 for stroke participants. Stroke participants reported moderate perceptions of effort (range:20-33/max:60), high levels of presence (29-42/42) and minimal cybersickness (0-3/64). Conclusion: Findings collected in the early development phase of the VR intervention will allow addressing favorable/unfavorable factors and incorporating desired optimal features, prior to conducting effectiveness and implementation studies. IMPLICATIONS FOR REHABILITATION: This study presents the development process of a new virtual reality (VR) intervention for community walking and participation in stroke survivors. Results from the focus group and hands-on pilot trial suggest that the VR intervention is feasible and accepted by clinicians and stroke survivors. Addressing favorable/unfavorable factors and incorporating features desired by clinicians in the development of the VR tool should promote its eventual implementation in clinical setting. [ABSTRACT FROM AUTHOR]

Lower-limb movements and muscle-activity patterns were assessed from seven normal and seven ambulatory subjects with incomplete spinal-cord injury (SCI) during level and uphill treadmill walking (5, 10 and 15°). Increasing the treadmill grade from 0° to 15° induced an increasingly flexed posture of the hip, knee and ankle during initial contact in all normal subjects, resulting in a larger excursion throughout stance. This adaptation process actually began in mid-swing with a graded increase in hip flexion and ankle dorsiflexion as well as a gradual decrease in knee extension. In SCI subjects, a similar trend was found at the hip joint for both swing and stance phases, whereas the knee angle showed very limited changes and the ankle angle showed large variations with grade throughout the walking cycle. A distinct coordination pattern between the hip and knee was observed in normal subjects, but not in SCI subjects during level walking. The same coordination pattern was preserved in all normal subjects and in five of seven SCI subjects during uphill walking. The duration of electromyographic (EMG) activity of thigh muscles was progressively increased during uphill walking, whereas no significant changes occurred in leg muscles. In SCI subjects, EMG durations of both thigh and leg muscles, which were already active throughout stance during level walking, were not significantly affected by uphill walking. The peak amplitude of EMG activity of the vastus lateralis, medial hamstrings, soleus, medial gastrocnemius and tibialis anterior was progressively increased during uphill walking in normal subjects. In SCI subjects, the peak amplitude of EMG activity of the medial hamstrings was adapted in a similar fashion, whereas the vastus lateralis, soleus and medial gastrocnemius showed very limited adaptation during uphill walking. We conclude that SCI subjects can adapt to uphill treadmill walking within certain limits, but they use different strategies to adapt to the changing locomotor demands. [ABSTRACT FROM AUTHOR]

Background: Augmenting auditory feedback through an error-augmentation paradigm could facilitate the perception and correction of gait asymmetry in stroke survivors, but how such a paradigm should be tailored to individual asymmetry profiles remains unclear. Before implementing the paradigm in rehabilitation, we need to investigate the instantaneous effects of distorted footstep sound feedback on gait symmetry in healthy young adults. Methods: Participants (n = 12) walked on a self-paced treadmill while listening to their footstep sounds, which were distorted unilaterally according to five conditions presented randomly: small delay; small advance; large delay; large advance; or unmodified (control). The primary outcomes were swing time ratio (SWR) and step length ratio (SLR). Secondary outcomes included walking speed, bilateral swing time, step length, and maximum toe height, as well as hip, knee, and ankle angle excursions. Results: SWR (p < 0.001) but not SLR (p ≥ 0.05) was increased in all distorted feedback conditions compared to the control condition. Increased swing time on the perturbed side ipsilateral to feedback distortion was observed in the advanced conditions (p < 0.001), while swing time increased bilaterally in the delayed conditions (p < 0.001) but to a larger extent on the unperturbed side contralateral to feedback distortion. Increases in swing time were accompanied by larger maximum toe height as well as larger hip and knee joint excursions (p < 0.05 to p < 0.001). No differences in any outcomes were observed between small and large feedback distortion magnitudes. Conclusions: Distorted footstep sound feedback successfully elicits adaptation in temporal gait symmetry (SWR), with distinct modulation patterns for advanced vs. delayed footstep sounds. Spatial symmetry (SLR) remains unaltered, likely because auditory feedback primarily conveys temporal information. This research lays the groundwork to implement personalized augmented auditory feedback in neurorehabilitation. [ABSTRACT FROM AUTHOR]

Background/Objectives: Acquired brain injury (ABI) is a major cause of global disability. Many ABI patients exhibit oculomotor dysfunctions that impact their daily life and rehabilitation outcomes. Current clinical tools for oculomotor function (OMF) assessment are limited in their usability. In this proof-of-principle study, we aimed to develop an efficient tool for OMF screening and to assess the feasibility, acceptability, and relevance in a small sample of ABI and control participants. Methods: We created the Rehabilitation Oculomotor Screening Evaluation (ROSE) by reviewing existing OMF assessments. ROSE was pilot-tested on ABI patients (n = 10) and age-matched controls (n = 10). Data regarding the characteristics of the assessment, such as the duration, level of participant comprehension, and participant experience were also collected. Results: ROSE takes <20 min ( x ¯ = 12.5), is easy to complete (agreement x ¯ = 4.6/5), and is well-accepted ( x ¯ = 4.8/5). Patients scored higher in all subtests and total score ( x ¯ = 34.8 for ABI vs. 8.9 for controls). Most subtests did not provoke any symptoms, especially for controls. There were no significant between-group differences in symptom provocation. This proof-of-principle study shows that ROSE is feasible, acceptable, and relevant for adult ABI patients. Conclusions: ROSE needs further evaluation for reliability testing and validation in larger samples and diverse neurological conditions. Establishing norms for various ages, sexes, and populations should be considered for the deployment of ROSE as an OMF clinical tool. [ABSTRACT FROM AUTHOR]

Background: Walking with a haptic tensile force applied to the hand in a virtual environment (VE) can induce adaptation effects in both chronic stroke and non-stroke individuals. These effects are reflected in spatiotemporal outcomes such as gait speed. However, the concurrent kinematic changes occurring in bilateral lower limb coordination have yet to be explored.Methods: Chronic stroke participants were stratified based on overground gait speed into lower functioning (LF < 0.8 m/s, N = 7) and higher functioning (HF ≥ 0.8 m/s, N = 7) subgroups. These subgroups and an age-matched control group (N = 14, CG) walked on a self-paced treadmill in a VE with either robot-generated haptic leash forces delivered to the hand and then released or with an instrumented cane. Walking in both leash (10 and 15 N) and cane conditions were compared to pre-force baseline values to evaluate changes in lower limb coordination outcomes.Results: All groups showed some kinematic changes in thigh, leg and foot segments when gait speed increased during force and post-force leash as well as cane walking. These changes were also reflected in intersegmental coordination and 3D phase diagrams, which illustrated increased intersegmental trajectory areas (p < 0.05) and angular velocity. These increases could also be observed when the paretic leg transitions from stance to swing phases while walking with the haptic leash. The Sobolev norm values accounted for both angular position and angular velocity, providing a single value for potentially quantifying bilateral (i.e. non-paretic vs paretic) coordination during walking. These values tended to increase (p < 0.05) proportionally for both limbs during force and post-force epochs as gait speed tended to increase.Conclusions: Individuals with chronic stroke who increased their gait speed when walking with tensile haptic forces and immediately after force removal, also displayed moderate concurrent changes in lower limb intersegmental coordination patterns in terms of angular displacement and velocity. Similar results were also seen with cane walking. Although symmetry was less affected, these findings appear favourable to the functional recovery of gait. Both the use of 3D phase diagrams and assigning Sobolev norm values are potentially effective for detecting and quantifying these coordination changes. [ABSTRACT FROM AUTHOR]

Background: Developing rehabilitation strategies to improve functional walking and postural control in patients is a priority for rehabilitation clinicians and researchers alike. One possible strategy is the use of sensory modalities to elicit adaptive locomotor gait patterns. This study aimed to explore to what extent haptic inputs, in the form of forward-leading tensile forces delivered to the hand, compared to no force, may lead to adaptation and post-adaptation effects on gait parameters, during and after the haptic exposure, respectively.Methods: Thirteen healthy young individuals were recruited for this study. We developed an innovative system combining virtual reality and haptic tensile forces in the direction of locomotion to simulate walking with a dog. A robotic arm generated forces via an adapted leash to the participant's hand while they walked on a self-paced treadmill immersed in a virtual environment with scene progression synchronized to the treadmill.Results: All participants showed significant increases in instantaneous gait velocity and stride length, with accompanying decreases in double-limb support time (p < 0.05) when walking with a haptic tensile force of either 10 or 20 N, relative to pre-force epoch levels, indicating an adaptation effect. When the 10 or 20 N force was removed, gait measures generally remained changed relative to baseline pre-force levels (p < 0.05), providing evidence of a post-adaptation effect.Conclusions: Changes in spatiotemporal outcomes provide evidence that both adaptation and post-adaptation effects were present in response to the application and removal of a haptic force. Future studies will investigate whether similar changes in elderly and post-stroke populations can be actualized during steady-state walking. [ABSTRACT FROM AUTHOR]

Background: Reading text messages is associated with accidents while walking in community places.Research Question: To what extent does reading text messages at different stages of obstacle circumvention affect avoidance strategies while walking in young vs. older adults?Methods: Sixteen healthy young and 14 older adults were assessed while walking and viewing a virtual environment (VE) simulating a subway station with three virtual pedestrians positioned 7.5 m away from the participant in the centre (0°), left and right (±40°). As participants advanced 0.5 m towards a target in the far space, a virtual pedestrian randomly approached them. Text messages were delivered at onset of pedestrian movement (0.5 m; early message) or during obstacle circumvention (2.5 m; late message). A Vicon motion capture system captured trajectory displacement while walking.Results: In both age groups, accuracy of message report (AMR) was reduced for early compared to late messages (p < 0.001), although older adults showed larger deterioration (p < 0.001) compared to younger participants. Locomotor outcomes (obstacle clearance, onset time of avoidance and walking speed) showed no differences between young and older participants (p > 0.05). Early messages led to slower walking speed (p < 0.001) and more frequent collisions compared to late messages and the no-message condition. Late messages yielded faster walking speed (p < 0.001) and onset time of avoidance (p < 0.02) compared to the other conditions.Significance: Results indicate that the stage of an avoidance strategy at which text messages are received impacts on pedestrian circumvention, with early messages posing a greater challenge to collision avoidance. In older adults, the reduced AMR suggests larger dual-task interference and prioritization of the walking task. The lack of further walking speed reduction in older vs. young adults may put them at greater risk of collisions in crowded, unpredictable community environments. [ABSTRACT FROM AUTHOR]

Background: Visual vertigo (VV) is a common symptom in people with persistent postural–perceptual dizziness (PPPD). Few subjective scales are validated for assessing the intensity of VV, yet these scales are limited by recall bias, as they require individuals to rate their symptoms from memory. The computer-Visual Vertigo Analogue Scale (c-VVAS) was developed by adapting five scenarios from the original paper-VVAS (p-VVAS) into 30 s video clips. The aim of this pilot study was to develop and test a computerized video-based tool for the assessment of visual vertigo in people with PPPD. Methods: PPPD participants (n = 8) and age- and sex-matched controls (n = 8) completed the traditional p-VVAS and the c-VVAS. A questionnaire about their experiences using the c-VVAS was completed by all participants. Results: There was a significant difference between the c-VVAS scores from the PPPD and the control group (Mann–Whitney, p < 0.05). The correlation between the total c-VVAS scores and the total c-VVAS scores was not significant (r = 0.668, p = 0.07). The study showed a high acceptance rate of the c-VVAS by participants (mean = 91.74%). Conclusion: This pilot study found that the c-VVAS can distinguish PPPD subjects from healthy controls and that it was well-received by all participants. [ABSTRACT FROM AUTHOR]

The seventh edition of the Canadian Stroke Best Practice Recommendations for Rehabilitation and Recovery following Stroke includes a new section devoted to the provision of virtual stroke rehabilitation. This consensus statement uses Grading of Recommendations, Assessment, Development and Evaluations methodology and Appraisal of Guidelines for Research & Evaluation II principles. A literature search was conducted using PubMed, Embase, and Cochrane databases. An expert writing group reviewed all evidence and developed recommendations, as well as consensus-based clinical considerations where evidence was insufficient for a recommendation. All recommendations underwent internal and external review. These recommendations apply to hospital, ambulatory care, and community-based settings where virtual stroke rehabilitation is provided. This guidance is relevant to health professionals, people living with stroke, healthcare administrators, and funders. Recommendations address issues of access, eligibility, consent and privacy, technology and planning, training and competency (for healthcare providers, patients and their families), assessment, service delivery, and evaluation. Virtual stroke rehabilitation has been shown to safely and effectively increase access to rehabilitation therapies and care providers, and uptake of these recommendations should be a priority in rehabilitation settings. They are key drivers of access to high-quality evidence-based stroke care regardless of geographical location and personal circumstances in Canada. [ABSTRACT FROM AUTHOR]

Circumvention around an obstacle entails a dynamic interaction with the obstacle to maintain a safe clearance. We used a novel mathematical interpolation method based on the modified Shepard’s method of Inverse Distance Weighting to compute dynamic clearance that reflected this interaction as well as minimal clearance. This proof-of-principle study included seven young healthy, four post-stroke and four healthy age-matched individuals. A virtual environment designed to assess obstacle circumvention was used to administer a locomotor (walking) and a perceptuo-motor (navigation with a joystick) task. In both tasks, participants were asked to navigate towards a target while avoiding collision with a moving obstacle that approached from either head-on, or 30° left or right. Among young individuals, dynamic clearance did not differ significantly between obstacle approach directions in both tasks. Post-stroke individuals maintained larger and smaller dynamic clearance during the locomotor and the perceptuo-motor task respectively as compared to age-matched controls. Dynamic clearance was larger than minimal distance from the obstacle irrespective of the group, task and obstacle approach direction. Also, in contrast to minimal distance, dynamic clearance can respond differently to different avoidance behaviors. Such a measure can be beneficial in contrasting obstacle avoidance behaviors in different populations with mobility problems. [ABSTRACT FROM AUTHOR]

Rationale: Cardiovascular exercise is an effective method to improve cardiovascular health outcomes, but also promote neuroplasticity during stroke recovery. Moderate-intensity continuous cardiovascular training (MICT) is an integral part of stroke rehabilitation, yet it may remain a challenge to exercise at sufficiently high intensities to produce beneficial adaptations to neuroplasticity. High-intensity interval training (HIIT) could provide a viable alternative to achieve higher intensities of exercise by using shorter bouts of intense exercise interspersed with periods of recovery.Methods and Design: This is a two-arm, parallel-group multi-site RCT conducted at the Jewish Rehabilitation Hospital (Laval, Québec, Canada) and McMaster University (Hamilton, Ontario, Canada). Eighty participants with chronic stroke will be recruited at both sites and will be randomly allocated into a HIIT or MICT individualized exercise program on a recumbent stepper, 3 days per week for 12 weeks. Outcomes will be assessed at baseline, at 12 weeks post-intervention, and at an 8-week follow-up.Outcomes: The primary outcome is corticospinal excitability, a neuroplasticity marker in brain motor networks, assessed with transcranial magnetic stimulation (TMS). We will also examine additional markers of neuroplasticity, measures of cardiovascular health, motor function, and psychosocial responses to training.Discussion: This trial will contribute novel insights into the effectiveness of HIIT to promote neuroplasticity in individuals with chronic stroke.Trial Registration: ClinicalTrials.gov NCT03614585 . Registered on 3 August 2018. [ABSTRACT FROM AUTHOR]

Abstract: Modulation of lower limb somatosensory information by tendon or plantar vibration produces directionally specific, vibration-induced falling reactions that depend on the tendon or the region of the sole that is vibrated. This study characterized the effects of different patterns of plantar cutaneo-muscular vibration and bilateral Achilles tendon vibration (ATV) on the postural strategies observed during quiet and perturbed stance. Twelve healthy young participants stood barefooted, with their vision blocked, on two sets of plantar vibrators placed on two AMTI force plates embedded in a moveable support surface. Two other vibrators were positioned over the Achilles tendons. Participants were randomly exposed to different patterns of plantar cutaneo-muscular and ATV. Tilts of the support surface in the toes-up (TU) and toes-down (TD) directions were given 5–8s after the beginning of vibration. Body kinematics in 3D and ground reaction forces were recorded. Bilateral ATV applied with or without rearfoot vibration (RFV) during quiet stance resulted in a whole-body backward leaning accompanied by an increase in trunk extension and hip and knee flexion. RFV alone produced a forward whole-body tilt with increased flexion in trunk, hip, and ankle. When stance was perturbed by TU tilts, the center of mass (CoM) and center of pressure (CoP) displacements were larger in the presence of RFV or ATV and associated with increased peak trunk flexion. TD tilts with or without ATV resulted in no significant difference in CoM and CoP displacements, while larger trunk extension and smaller distal angular displacements were observed during ATV. RFV altered the magnitude of the balance reactions, as observed by an increase in CoP displacements and variable response in trunk displacement. Significant interactions between ATV and RFV were obtained for the peak angular excursions for both directions of perturbations, where ATV either enhanced (for TU tilts) or attenuated (for TD tilts) the influence of RFV. Manipulating somatosensory information from the plantar cutaneo-muscular and muscle spindle Ia afferents thus results in altered and widespread postural responses, as shown by profound changes in body kinematics and CoM and CoP displacements. This suggests that the CNS uses plantar cutaneo-muscular and ankle spindle afferent inputs to build an appropriate reference of verticality that influences the control of equilibrium during quiet and perturbed stance. [Copyright &y& Elsevier]

Abstract: It is not known how the flexible protective zone maintained around oneself during locomotion (personal space or PS; see [Gérin-Lajoie M, Richards CL, McFadyen BJ. The negotiation of stationary and moving obstructions during walking: anticipatory locomotor adaptations and preservation of personal space. Motor Control 2005;9:242–69]) is modulated with walking speed, whether both sides of the PS are symmetrical, and whether the circumvention of physical and virtual obstructions elicit the same use of such PS. Personal space was measured in ten adults as they circumvented a cylindrical obstacle that was stationary within their path. Both left and right passes were performed at natural self-selected, slow and fast walking speeds. The same circumvention task was also performed at natural speeds in an immersive virtual environment (VE) replicating the same obstruction scenario. The shape and size of PS were maintained across walking speeds, and a smaller PS was generally observed on the dominant side. The general shape and lateral bias of the PS were preserved in the VE while its size was slightly increased. The systematic behavior across walking speeds and types of environment and the lateral bias suggest that PS is used to control navigation. This study deepens our understanding of normal adaptive walking behavior and has implications for the development of better tools for the assessment and retraining of locomotor capacity in different populations, from people with walking deficits to elite athletes. Since the PS behavior was shown to be robust in the VE used for this study, the virtual reality technology is proposed as a promising platform for the development of such assessment and retraining applications. [Copyright &y& Elsevier]

Abstract: Objective: Altering proprioceptive information in the lower limbs by vibration produces direction-specific falling and postural instability, which can persist after vibration stops. The objectives of this study were to describe the changes in trunk and lower limbs postural orientation and muscles activities during and after the end of bilateral Achilles tendon vibration (TV). Methods: Twelve healthy young subjects were exposed to 30s periods of TV while blindfolded. Whole-body kinematics, kinetics and EMG of eight lower limb and trunk muscles were recorded prior, during and 5 or 25s after TV. Results: TV during quiet standing produced a whole-body backward shift characterized by greater extension in the trunk and lower limbs. Five seconds after TV, two trends of recovery could be observed, either an overcorrection or undercorrection of the initial position. Conclusions: A continuum of postural orientations are adopted during and after vibration and the movements are not restricted to the ankle joints, despite the local nature of the proprioceptive stimulation. Significance: The widespread influence of vibration as a proprioceptive stimulation when assessing its effects on posture and balance needs to be considered. Further studies should include whole-body analyses to document more thoroughly the postural strategies for balance maintenance during vibration. [Copyright &y& Elsevier]

Abstract: The head, containing the gravity sensors (vestibular system) and the visual system, must be stabilized in space to provide a steady reference. During walking, the head also needs to be free to move to allow scanning of surrounding objects and steering of locomotion. With aging, deteriorations in motor and sensory systems and their integration are commonly observed. Nevertheless, the strategies used by elderly subjects to complete challenging tasks that require precise sensorimotor integration, such as turning the head rapidly during gait, is not known. The objective of this study was to determine the effects of aging on the movement coordination of the head, trunk and pelvis when executing a rapid head motion in response to a visual signal. Elderly and young subjects turned their head rapidly (up, down, left, right or none) in response to a visual signal, during standing and walking. The 3-D positions of head, trunk and pelvis were recorded and analyzed. All subjects, young and old, successfully performed the task during both standing and walking without any loss of balance. Postural stability was maintained as large head motions were accompanied by relatively small trunk and pelvis movements. Horizontal plane movements associated with right and left head turns were significantly larger than sagittal plane movements associated with head up and down motions. Head motions were significantly slower and smaller in elderly subjects, and resulted in disrupted horizontal plane trunk–pelvis coordination during walking. We conclude that head, trunk and pelvis movements are coordinated in a task-dependent manner such that their movement amplitudes induced by rapid voluntary head motions are larger in walking than in standing. This task-dependent movement coordination is affected by aging. [Copyright &y& Elsevier]

The sixth update of the Canadian Stroke Best Practice Recommendations: Rehabilitation, Recovery, and Reintegration following Stroke. Part one: Rehabilitation and Recovery Following Stroke is a comprehensive set of evidence-based guidelines addressing issues surrounding impairments, activity limitations, and participation restrictions following stroke. Rehabilitation is a critical component of recovery, essential for helping patients to regain lost skills, relearn tasks, and regain independence. Following a stroke, many people typically require rehabilitation for persisting deficits related to hemiparesis, upper-limb dysfunction, pain, impaired balance, swallowing, and vision, neglect, and limitations with mobility, activities of daily living, and communication. This module addresses interventions related to these issues as well as the structure in which they are provided, since rehabilitation can be provided on an inpatient, outpatient, or community basis. These guidelines also recognize that rehabilitation needs of people with stroke may change over time and therefore intermittent reassessment is important. Recommendations are appropriate for use by all healthcare providers and system planners who organize and provide care to patients following stroke across a broad range of settings. Unlike the previous set of recommendations, in which pediatric stroke was included, this set of recommendations includes primarily adult rehabilitation, recognizing many of these therapies may be applicable in children. Recommendations related to community reintegration, which were previously included within this rehabilitation module, can now be found in the companion module, Rehabilitation, Recovery, and Community Participation following Stroke. Part Two: Transitions and Community Participation Following Stroke. [ABSTRACT FROM AUTHOR]

Gait asymmetry, which is common after stroke, is typically characterized using spatiotemporal parameters of gait that do not consider the aspect of movement coordination. In this manuscript, we examined whether an avatar-based feedback provided as a single-session intervention to improve gait symmetry also improved inter-limb coordination among people with stroke and we examined the relationship between changes in coordination and step length symmetry. Twelve stroke participants walked on a self-paced treadmill with and without a self-avatar that replicated their locomotor movements in real time. Continuous relative phase and angular coefficient of correspondence calculated using bilateral sagittal hip movements were used to quantify temporal and spatial interlimb coordination, respectively. Spatial gait symmetry, previously shown to improve with the avatar feedback, was quantified using step length ratio between both limbs, with the largest value as numerator. Participants who improved their spatial symmetry during avatar exposure also improved their temporal coordination, while spatial coordination remained unchanged. Overall, improvements in spatial symmetry correlated positively with improvements in temporal coordination. The non-paretic hip and paretic ankle angle excursion in the sagittal plane also significantly increased during avatar exposure. Improvements in gait symmetry may be explained by changes in interlimb coordination. Current data and existing literature further suggest that such improvements are largely driven by adaptations in non-paretic leg movements, notably at the hip. By providing real-time information on walking movements not affordable in other ways, avatar-based feedback shows great potential to improve gait symmetry and interlimb coordination post-stroke. • Real-time avatar feedback improves post-stroke gait symmetry and coordination • Improvements in gait symmetry correlate with improvements in interlimb coordination • Observed improvements appear largely driven by adaptations on the non-paretic side [ABSTRACT FROM AUTHOR]

Abstract: The amplified myeloma centrosome has been identified as a therapeutic target. The present study explored the expression and prognostic significance of the centrosome-associated protein PLK1 in myeloma and the effect of BI 2536, a potent and selective inhibitor of PLK1, on myeloma cells. High plasma cell expression of PLK1 protein in myeloma patient bone marrow biopsies is an independent adverse prognostic factor (HR=2.3, p =0.003 unadjusted; HR=1.9, p =0.03 in multivariable model). BI 2536 inhibits myeloma cell lines at nanomolar concentrations, and is therapeutic for xenografts in NOD/SCID mice. PLK1 inhibition is a potential new strategy for the treatment of multiple myeloma. [Copyright &y& Elsevier]

Abstract: Postural adjustments following mechanical perturbations have been studied in healthy seated humans. However, little is known on the minimal intensity that should be used to provoke a reaction. This knowledge could be essential to assess seated postural deficits in some pathological populations. The goal of the present study was to identify a low-intensity perturbation that could elicit postural reactions in healthy seated individuals. Six healthy participants sat on an adapted ergonomic chair fixed on a moveable support surface that was submitted to forward and backward translations. The head and trunk kinematics as well as the activity of sixteen neck and trunk muscles were recorded. The head, arm and trunk center of mass was computed using kinematics and standard anthropometric tables. We found that ramp displacements with an acceleration profile reaching a maximal value of 1.17m/s2 elicited reliable kinematic and electromyographic reactions across participants. Head and trunk segments initially responded opposite to the direction of translation, then reversed direction. Median peak-to-peak angular displacements in the neck, head and trunk, respectively, reached 3.6°, 7.0° and 7.1° for forward translations, and 4.0°, 8.2° and 7.0° for backward translations. For forward translations, neck and trunk flexor muscles were activated first, followed by the extensor muscles, whereas for backward translations, extensor muscles were activated first, followed by flexors. Although this perturbation is of low-intensity compared to those typically used previously to evoke postural reactions, this stimulus is sufficient to elicit a reliable response. We suggest that such a perturbation could be used to assess the physical condition of individuals with neck injuries. [Copyright &y& Elsevier]

Abstract: Previous studies have shown that individuals with WAD display decreased postural stability during standing and walking tasks. However, their ability to maintain seated upright posture has never been investigated. The objective of this study was to characterize kinematic and electromyographic postural stabilization patterns in individuals with chronic WAD and to compare these patterns with those in an able-bodied control group. Ten individuals with WAD and an age- and gender-matched group of healthy individuals were exposed to sudden forward and backward support surface translations while they were seated. Neck and trunk muscle activity and angular displacements as well as centers of mass (COMs) linear displacements at four levels of the head and trunk were computed. The displacement onset of the combined head, arms and trunk COM was significantly delayed in persons with WAD. However, their peak trunk angles were smaller and were reached sooner. In the WAD group, the activation onset of the lumbar erector spinae was less affected by perturbation direction and the sternocleidomastoid muscle, a neck flexor, showed a trend towards being activated later, compared to the healthy group. These results suggest that individuals with WAD may alter stretch reflex threshold and/or elicit a learned response for pain avoidance that may be direction-specific. Such findings highlight the importance of assessing both spatial and temporal characteristics across different levels of the spinal musculoskeletal system to evaluate multidirectional postural responses in WAD individuals. [Copyright &y& Elsevier]

Résumé non transmis [ABSTRACT FROM AUTHOR]

Background: Limited evidence supports the effects of short-interval high-intensity interval training (HIIT) for improving cardiorespiratory fitness (V̇O 2 peak) after stroke. We aimed to compare the effects of 12 weeks of short-interval HIIT versus moderate-intensity continuous training (MICT) on V̇O 2 peak, cardiovascular risk factors, and mobility outcomes among individuals ≥6 months poststroke., Methods: This study was a multi-site, 12-week randomized controlled trial (NCT03614585) with an 8-week follow-up. Participants were randomized into 3 d/wk of HIIT (10×1 minute 80%-100% heart rate reserve interspersed with 1 minute 30% heart rate reserve [19 minutes]) or MICT (20-30 minutes 40%-60% heart rate reserve). Secondary outcomes of the trial, including V̇O 2 peak, cardiovascular risk factors (carotid-femoral pulse wave velocity, blood pressure, and waist-hip ratio), and mobility (6-minute walk test, 10 m gait speed), were reported. Linear mixed model analyses with a group×study time point interaction evaluated between-group differences., Results: Of the 305 potential participants, 82 consented (mean [SD] age 64.9 [9.3] years, 32 females [39%], 1.8 [1.2] years poststroke) and were randomized to HIIT (n=42, mean [SD] baseline V̇O 2 peak 17.3 [5.9] mL/kg·min) or MICT (n=40, mean [SD] baseline V̇O 2 peak 17.2 [6.0] mL/kg·min). Participants attended 82% of visits (n=2417/2952). No adverse events occurred during the study period. A significant group×study time point interaction was found (χ 2 =8.46; P =0.015) for V̇O 2 peak at 12 weeks (mean difference, 1.81 [95% CI, 0.58-3.04]; P =0.004) whereby the HIIT group had greater gains in V̇O 2 peak (∆3.52 mL/kg·min [95% CI, 2.47-4.57]; P <0.001) compared with the MICT group (∆1.71 mL/kg·min [95% CI, 0.55-2.86]; P =0.001). There was no between-group difference in V̇O 2 peak (mean difference, 1.08 [95% CI, -0.26 to 2.42]; P =0.11) at 8-week follow-up. No group×study time point interactions were found for cardiovascular risk factors or mobility outcomes., Conclusions: Short-interval HIIT may be an effective alternative to MICT for improving V̇O 2 peak at 12 weeks postintervention., Registration: URL: https://clinicaltrials.gov; Unique identifier: NCT03614585., Competing Interests: Dr Moncion and K.S. Noguchi are supported by an Ontario Graduate Scholarship. L. Rodrigues is supported by a Doctoral Scholarship from the Fonds Recherche Santé Québec. Dr Eng is supported by the Canada Research Chairs program. Dr Roig is supported by a Salary Award (Junior II) from Fonds de Recherche Santé Québec. This study is funded by an operating grant from the Canadian Institutes of Health Research (388320). Dr Tang reports grants from Canadian Institutes of Health Research; grants from Physiotherapy Foundation of Canada; and grants from Heart and Stroke Foundation of Canada.

Background: Rehabilitative treatments that promote neuroplasticity are believed to improve recovery after stroke. Animal studies have shown that cardiovascular exercise (CE) promotes neuroplasticity but the effects of this intervention on the human brain and its implications for the functional recovery of patients remain unclear. The use of biomarkers has enabled the assessment of cellular and molecular events that occur in the central nervous system after brain injury. Some of these biomarkers have proven to be particularly valuable for the diagnosis of severity, prognosis of recovery, as well as for measuring the neuroplastic response to different treatments after stroke., Objectives: To provide a critical analysis on the current evidence supporting the use of neurophysiological, neuroimaging, and blood biomarkers to assess the neuroplastic response to CE in individuals poststroke., Results: Most biomarkers used are responsive to the effects of acute and chronic CE interventions, but the response appears to be variable and is not consistently associated with functional improvements. Small sample sizes, methodological variability, incomplete information regarding patient's characteristics, inadequate standardization of training parameters, and lack of reporting of associations with functional outcomes preclude the quantification of the neuroplastic effects of CE poststroke using biomarkers., Conclusion: Consensus on the optimal biomarkers to monitor the neuroplastic response to CE is currently lacking. By addressing critical methodological issues, future studies could advance our understanding of the use of biomarkers to measure the impact of CE on neuroplasticity and functional recovery in patients with stroke., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.