Aging Delays Completion of Head Rotation Cycles in Continuous Gaze Stabilization Exercises despite Putative Healthy Vestibular Function.

INTRODUCTION: Aging is associated with loss of balance, with falls being one of the leading causes of death among the elderly in the USA. Gaze stabilization exercises (GSE) improve balance control in vestibular populations and could be useful to prevent falls in healthy individuals. However, the extent to which aging affects head kinematics in GSE is unknown. METHODS: Forty-eight younger (n = 25, 24 ± 6 years, 60% female) and older (n = 23, 66 ± 5 years, 56% female) adults completed six 30-s GSE. Participants were asked to maintain gaze fixation on a stationary target while continuously performing head movements in pitch (e.g., vertical) and yaw (e.g., horizontal) directions. The visual target was placed on the wall 1 m or 2 m away or handheld at arm's length. Head kinematics were recorded with an inertial measurement unit placed on the back of the participants' head. RESULTS: Older adults took significantly more time (e.g., delay) to complete cycles of head rotation in both pitch and yaw compared to younger participants across all GSE. Such delay was further increased during yaw head rotation while fixating gaze of the 1 m target. The average peak velocity (APV) and average angular displacement (AAD), however, were equivalent between groups in all GSE. CONCLUSION: Aging leads to the maintenance of head rotation APV and AAD at the expense of delayed cycles of head rotation, suggesting an age-dependent prioritization strategy (e.g., adapt duration first, range second) during continuous head movements. The distance of the visual target and head movement direction influenced elderly performance and should be considered when prescribing GSE to older populations.

Balance Interventions to Improve Upright Balance Control and Balance Confidence in People With Motor-Incomplete Spinal Cord Injury or Disease: A Systematic Review and Meta-analysis.

OBJECTIVES: To assist with clinical decision making, evidence syntheses are needed to demonstrate the efficacy of available interventions and examine the intervention components and dosage parameters. This systematic review and meta-analysis described the efficacy, components and dosage of interventions targeting upright balance control, balance confidence, and/or falls in adults with motor-incomplete spinal cord injury/disease (SCI/D). DATA SOURCES: A search strategy following the population, intervention, control, outcome framework was developed. Six databases were searched: APA PsychInfo, Cumulative Index to Nursing and Allied Health Literature, Embase, Emcare Nursing, Web of Science CC, and Medline. STUDY SELECTION: Title, abstract, and full-text screening were conducted by 2 researchers independently. Inclusion criteria included the following: (1) adults with chronic, motor-incomplete SCI/D; (2) physical intervention targeting upright postural control; and (3) clinical and/or biomechanical measures of upright balance control and/or balance confidence and/or documentation of falls. DATA EXTRACTION: Participant characteristics, balance intervention details, adverse events, and study results were extracted. The Downs and Black Checklist was used to assess methodological quality. Meta-analyses on pre-post intervention outcomes and a meta-regression of dosage were completed. Grading of Recommendations, Assessment, Development, and Evaluations approach was used to evaluate the quality of the evidence. DATA SYNTHESIS: The search returned 1664 unique studies; 26 were included. Methodological quality was moderate to good. Participants were 500 individuals with SCI/D, aged 18-74 years (males: females = 2.4:1). Minor adverse events were reported in 8 studies (eg, muscle soreness and fatigue). Walking interventions and upright balance training with visual feedback had clinically meaningful and significant pooled effects on improving standing balance control. Only walking interventions had a significant pooled effect on improving balance confidence. There were no significant findings on dosage response. Few studies evaluated the effects of balance interventions on the occurrence of falls. CONCLUSIONS: Walking interventions and upright balance training with visual feedback had greater effects on upright balance control than conventional physiotherapy; however, the quality of the evidence was very low.

Exoskeleton-based exercises for overground gait and balance rehabilitation in spinal cord injury: a systematic review of dose and dosage parameters.

BACKGROUND: Exoskeletons are increasingly applied during overground gait and balance rehabilitation following neurological impairment, although optimal parameters for specific indications are yet to be established. OBJECTIVE: This systematic review aimed to identify dose and dosage of exoskeleton-based therapy protocols for overground locomotor training in spinal cord injury/disease. METHODS: A systematic review was conducted in accordance with the Preferred Reporting Items Systematic Reviews and Meta-Analyses guidelines. A literature search was performed using the CINAHL Complete, Embase, Emcare Nursing, Medline ALL, and Web of Science databases. Studies in adults with subacute and/or chronic spinal cord injury/disease were included if they reported (1) dose (e.g., single session duration and total number of sessions) and dosage (e.g., frequency of sessions/week and total duration of intervention) parameters, and (2) at least one gait and/or balance outcome measure. RESULTS: Of 2,108 studies identified, after removing duplicates and filtering for inclusion, 19 were selected and dose, dosage and efficacy were abstracted. Data revealed a great heterogeneity in dose, dosage, and indications, with overall recommendation of 60-min sessions delivered 3 times a week, for 9 weeks in 27 sessions. Specific protocols were also identified for functional restoration (60-min, 3 times a week, for 8 weeks/24 sessions) and cardiorespiratory rehabilitation (60-min, 3 times a week, for 12 weeks/36 sessions). CONCLUSION: This review provides evidence-based best practice recommendations for overground exoskeleton training among individuals with spinal cord injury/disease based on individual therapeutic goals - functional restoration or cardiorespiratory rehabilitation. There is a need for structured exoskeleton clinical translation studies based on standardized methods and common therapeutic outcomes.

Head movement kinematics are differentially altered for extended versus short duration gait exercises in individuals with vestibular loss.

Head kinematics are altered in individuals with vestibular schwannoma (VS) during short duration gait tasks [i.e., Functional Gait Assessment (FGA)], both before and after surgery, yet whether these differences extend to longer duration gait exercises is currently unknown. Here we examined the effects of vestibular loss and subsequent compensation on head kinematics in individuals with VS during gait exercises of relatively extended versus short duration (< 10 versus 30 s), compared to age-matched controls. Six-dimensional head movements were recorded during extended and short duration gait exercises before and then 6 weeks after sectioning of the involved vestibular nerve (vestibular neurectomy). Standard functional, physiological, and subjective clinical assessments were also performed at each time point. Kinematics were differentially altered in individuals with vestibular loss at both time points during extended versus short duration exercises. Range of motion was significantly reduced in extended tasks. In contrast, movement variability predominately differed for the short duration exercises. Overall, our results indicate that quantifying head kinematics during longer duration gait tasks can provide novel information about how VS individuals compensate for vestibular loss, and suggest that measurements of range of motion versus variability can provide information regarding the different strategies deployed to maintain functional locomotion.