Courtney D. Hall

The impact of aerobic activity on cognitive function in older adults: A new synthesis based on the concept of executive control

Numerous reaction time studies have suggested that age-related declines in cognitive function might be ameliorated by lifestyles involving aerobic activity or by interventionist programmes of aerobic exercise. These studies are far from conclusive, however, reflecting a failure to factor out cognitive from sensory and motor processes. Following a critical review of the literature, we report on recent developments that differentiate cognitive processes involving executive vs non-executive control, the former being associated with frontal lobe function. Three key studies suggest that aerobic exercise primarily improves executive control.

Prediction of Fall Risk Reduction as Measured by Dynamic Gait Index in Individuals with Unilateral Vestibular Hypofunction

Objective: To determine the effect of vestibular rehabilitation on reduction of fall risk in individuals with unilateral vestibular hypofunction and to identify those factors that predict fall risk reduction. Study Design: Retrospective chart review. Setting: Tertiary referral center. Patients: Forty-seven patients with unilateral vestibular hypofunction, aged 28 to 86 years, who were at risk for falls on initial assessment. Intervention: All patients underwent vestibular rehabilitation including adaptation exercises, designed to improve gaze stability, and gait and balance exercises. Main Outcome Measures: Fall risk (Dynamic Gait Index), visual acuity during head movements (Dynamic Visual Acuity), and subjective complaints were measured initially, at 2-week intervals, and at completion of physical therapy. Results: As a group, the patients had significantly reduced risk for falls (p < 0.001) after rehabilitation. Time from onset of symptoms did not affect the efficacy of vestibular rehabilitation. Both older (≥ 65 yr) and younger (< 65 yr) adults showed significant reductions in fall risk with vestibular rehabilitation (p < 0.001). However, a significantly greater proportion (χ2 = 0.016) of older adults remained at risk for falls at discharge compared with young adults (45% versus 11%). Initial Dynamic Gait Index and Dynamic Visual Acuity scores predicted fall risk reduction in patients with unilateral vestibular hypofunction. A model was developed using initial Dynamic Gait Index and Dynamic Visual Acuity scores to predict fall risk reduction. Conclusions: Vestibular rehabilitation is effective in significantly reducing fall risk in individuals with unilateral vestibular deficit. The model predicts fall risk reduction with good sensitivity (77%) and specificity (90%).

Cognitive and Motor Mechanisms Underlying Older Adults' Ability to Divide Attention While Walking

Background An impaired ability to allocate attention to gait during dual-task situations is a powerful predictor of falls. Objective The primary purpose of this study was to examine the relative contributions of participant characteristics and motor and cognitive factors to the ability to walk while performing cognitive tasks. The impact of cognitive task complexity on walking also was examined. Design A cross-sectional, exploratory study design was used. Methods Seventy-seven community-dwelling older adults with a mean (SD) age of 75.5 (5.8) years completed comprehensive testing. Participant characteristics were assessed via questionnaires. The motor test battery included measures of strength (force-generating capacity), gait speed, and static and dynamic balance. The cognitive abilities test battery assessed psychomotor and perceptual speed, recall and working memory, verbal and spatial ability, and attention (sustained, selective, and divided). Time to walk while performing 4 cognitive tasks was measured. In addition, dual-task costs (DTCs) were calculated. Multiple hierarchical regressions explored walking under dual-task conditions. Results The ability to walk and perform a simple cognitive task was explained by participant characteristics and motor factors alone, whereas walking and performing a complex cognitive task was explained by cognitive factors in addition to participant and motor factors. Regardless of the cognitive task, participants walked slower under dual-task conditions than under single-task conditions. Increased cognitive task complexity resulted in greater slowing of gait: gait DTCs were least for the simplest conditions and greatest for the complex conditions. Limitations Walking performance was characterized by a single parameter (time), whereas other spatiotemporal parameters have been related to dual-task performance. However, this type of measurement (timed performance) will be easy to implement in the clinic. Conclusions Two factors—participant characteristics and motor abilities—explained the majority of variance of walking under dual-task conditions; however, cognitive abilities also contributed significantly to the regression models. Rehabilitation focused on improving underlying balance and gait deficits, as well as specific cognitive impairments, may significantly improve walking under dual-task conditions.

Reliability of clinical measures used to assess patients with peripheral vestibular disorders.

Purpose The purposes of this research were to (1) determine test-retest reliability of clinical measures of self reported disability and subjective complaints, gait, and fall risk; and (2) establish normal variability for each of these measures based on test-retest variability in people with peripheral vestibular disorders. Methods Sixteen patients with confirmed peripheral vestibular disorders performed 2 trials of each of the measures within a single physical therapy session. The measures included rating of disability, percent of day affected by dizziness, head movement induced dizziness, preferred gait speed, gait deviations, and Dynamic Gait Index. In order to assess test-retest reliability of the measures intraclass correlation coefficients (ICC) were calculated. Results All measurement tools demonstrated excellent reliability (ICC 3,1 = 0.86–1.00) except for head movement induced dizziness (ICC 3,1 = 0.48). For each measure we report normal variability as tested within a single session. Discussion Clinical measures commonly used in the assessment of vestibular patients were found to have excellent test-retest reliability, except for the subjective measure of head movement-induced dizziness. Conclusion Incorporation of valid and reliable assessments in clinical practice is critical in order to demonstrate the effectiveness of therapeutic intervention.

Vestibular Rehabilitation for Peripheral Vestibular Hypofunction: An Evidence-Based Clinical Practice Guideline: FROM THE AMERICAN PHYSICAL THERAPY ASSOCIATION NEUROLOGY SECTION.

Background: Uncompensated vestibular hypofunction results in postural instability, visual blurring with head movement, and subjective complaints of dizziness and/or imbalance. We sought to answer the question, “Is vestibular exercise effective at enhancing recovery of function in people with peripheral (unilateral or bilateral) vestibular hypofunction?” Methods: A systematic review of the literature was performed in 5 databases published after 1985 and 5 additional sources for relevant publications were searched. Article types included meta-analyses, systematic reviews, randomized controlled trials, cohort studies, case control series, and case series for human subjects, published in English. One hundred thirty-five articles were identified as relevant to this clinical practice guideline. Results/Discussion: Based on strong evidence and a preponderance of benefit over harm, clinicians should offer vestibular rehabilitation to persons with unilateral and bilateral vestibular hypofunction with impairments and functional limitations related to the vestibular deficit. Based on strong evidence and a preponderance of harm over benefit, clinicians should not include voluntary saccadic or smooth-pursuit eye movements in isolation (ie, without head movement) as specific exercises for gaze stability. Based on moderate evidence, clinicians may offer specific exercise techniques to target identified impairments or functional limitations. Based on moderate evidence and in consideration of patient preference, clinicians may provide supervised vestibular rehabilitation. Based on expert opinion extrapolated from the evidence, clinicians may prescribe a minimum of 3 times per day for the performance of gaze stability exercises as 1 component of a home exercise program. Based on expert opinion extrapolated from the evidence (range of supervised visits: 2-38 weeks, mean = 10 weeks), clinicians may consider providing adequate supervised vestibular rehabilitation sessions for the patient to understand the goals of the program and how to manage and progress themselves independently. As a general guide, persons without significant comorbidities that affect mobility and with acute or subacute unilateral vestibular hypofunction may need once a week supervised sessions for 2 to 3 weeks; persons with chronic unilateral vestibular hypofunction may need once a week sessions for 4 to 6 weeks; and persons with bilateral vestibular hypofunction may need once a week sessions for 8 to 12 weeks. In addition to supervised sessions, patients are provided a daily home exercise program. Disclaimer: These recommendations are intended as a guide for physical therapists and clinicians to optimize rehabilitation outcomes for persons with peripheral vestibular hypofunction undergoing vestibular rehabilitation. Video Abstract available for more insights from the author (see Video, Supplemental Digital Content 1, http://links.lww.com/JNPT/A124).

Efficacy of gaze stability exercises in older adults with dizziness.

Background and Purpose: The purpose of this study was to determine whether the addition of gaze stability exercises to balance rehabilitation would lead to greater improvements of symptoms and postural stability in older adults with normal vestibular function who reported dizziness. Methods: Participants who were referred to outpatient physical therapy for dizziness were randomly assigned to the gaze stabilization (GS) group (n = 20) or control (CON) group (n = 19). Dizziness was defined as symptoms of unsteadiness, spinning, a sense of movement, or lightheadedness. Participants were evaluated at baseline and discharge on symptoms, balance confidence, visual acuity during head movement, balance, and gait measures. The GS group performed vestibular adaptation and substitution exercises designed to improve gaze stability, and the CON group performed placebo eye exercises designed to be vestibular neutral. In addition, both groups performed balance and gait exercises. Results: There were no baseline differences (P > .05) between the GS and CON groups in age, sex, affect, physical activity level, or any outcome measures. Both groups improved significantly in all outcome measures with the exception of perceived disequilibrium. However, there was a significant interaction for fall risk as measured by Dynamic Gait Index (P = .026) such that the GS group demonstrated a significantly greater reduction in fall risk compared with the CON group (90% of the GS group demonstrated a clinically significant improvement in fall risk versus 50% of the CON group). Discussion and Conclusions: This study provides evidence that in older adults with symptoms of dizziness and no documented vestibular deficits, the addition of vestibular-specific gaze stability exercises to standard balance rehabilitation results in greater reduction in fall risk.

Effects of Tai Chi Intervention on Dual-Task Ability in Older Adults: A Pilot Study

OBJECTIVE To determine if a 12-week program of Tai Chi that has been shown to reduce falls incidence in older adults would improve the ability to allocate attention to balance under dual-task conditions. DESIGN Pre-/posttest experimental research design. SETTING Movement studies research laboratory. PARTICIPANTS Community dwelling older adults (N=15; range, 62-85y) participated in either Tai Chi training or health education classes (controls) for 12 weeks. INTERVENTIONS Participants in the Tai Chi group attended a twice-weekly, 1.5-hour class taught by an experienced instructor. The control group attended a biweekly, 1-hour class for lectures on health-related topics. MAIN OUTCOME MEASURES Two cognitive tasks (responding to auditory or visual stimulus as quickly as possible) were performed concurrently while maintaining static balance during the Sensory Organization Test (SOT) and while avoiding obstacles while walking. The percent change in performance relative to the single-task condition was calculated and defined as the dual-task cost. The dual-task cost was calculated for both the postural and cognitive measures. RESULTS There was no improvement in the performance of postural stability or cognitive task under dual-task conditions for the SOT for Tai Chi versus controls. There was no improvement in avoiding obstacles under dual-task conditions for Tai Chi versus controls. CONCLUSIONS Contrary to our hypothesis, the findings of this study did not support a benefit of Tai Chi on the ability to allocate attention to balance under dual-task conditions.

Age-related differences in Lower extremity power After support surface perturbations

OBJECTIVES: The purpose of this study was to examine a comprehensive measure relating to the ability to generate, absorb, and transfer mechanical energy introduced by a perturbation. It was hypothesized that this measure would reveal age‐related differences leading to different balance recovery responses (i.e., feet‐in‐place and compensatory step).

Dancing for Balance: Feasibility and Efficacy in Oldest-Old Adults With Visual Impairment

Background:Fall risk increases with age and visual impairment, yet the oldest-old adults (>85 years) are rarely studied. Partnered dance improves mobility, balance, and quality of life in older individuals with movement impairment. Objective:The aim of the study was to determine the feasibility and participant satisfaction of an adapted tango program amongst these oldest-old adults with visual impairment. Exploratory analyses were conducted to determine efficacy of the program in improving balance and gait. Methods:In a repeated-measures, one-group experimental design, 13 older adults (7 women; age: M = 86.9 years, SD = 5.9 years, range = 77–95 years) with visual impairment (best eye acuity: M = 0.63, SD = 0.6 logMAR) participated in an adapted tango program of twenty 1.5-hour lessons, within 11 weeks. Feasibility included evaluation of facility access, safety, volunteer assistant retention, and participant retention and satisfaction. Participants were evaluated for balance, lower body strength, and quality of life in two baseline observations, immediately after the program and 1 month later. Results:Twelve participants completed the program. The facility was adequate, no injuries were sustained, and participants and volunteers were retained throughout. Participants reported enjoyment and improvements in physical well-being. Exploratory measures of dynamic postural control (p < .001), lower body strength (p = .056), and general vision-related quality of life (p = .032) scores showed improvements following training. Discussion:These older individuals with visual impairment benefitted from 30 hours of tango instruction adapted for their capabilities.

Variables Associated With Outcome in Patients With Unilateral Vestibular Hypofunction

Background. Not all individuals with unilateral vestibular hypofunction (UVH) have fewer subjective complaints and improved function after vestibular rehabilitation. Objective. To identify factors and/or combinations of factors that are strongly associated with rehabilitation outcome in patients with UVH and that ultimately can be used to develop models to predict outcome. Methods. Data from 209 patients with UVH were analyzed. All patients participated in similar vestibular rehabilitation (5 weeks of home exercises and once-weekly clinic visits). Outcome measures included intensity of oscillopsia and dysequilibrium, balance confidence, perceived disability, percentage of time symptoms interfered with activities, gait speed, fall risk, and dynamic visual acuity (DVA). Bivariate correlation and regression analysis were used to determine relationships between baseline (pretherapy) measures and outcome at discharge. Results. No baseline measure of subjective complaints (eg, symptom intensity) predicted improvement of physical function (eg, gait speed). Similarly, no baseline measure of physical function predicted improvement of subjective complaints. Certain patient characteristics, such as gender and time from onset, were not related to any outcomes. Most comorbidities did not affect outcome; however, anxiety and/or depression were associated with lower balance confidence and higher percentage of time for which symptoms interfered with activities at discharge. Baseline DVA and gait speed were associated with DVA and gait speed at discharge, respectively. Dynamic gait index (DGI) at discharge was affected by age, baseline DGI, and history of falls. Conclusion. These results provide insight into recovery of patients with UVH. Therapists can use this information in the development of expectations for patient outcome and treatment priorities.