Prefrontal cortex activation while walking did not change but gait speed improved after a randomized physical therapy intervention.

BACKGROUND: Higher prefrontal cortex (PFC) activation while walking may indicate reduced gait automaticity. AIM: We examine whether PFC activation during walking improves after training in older adults at risk for mobility disability. METHODS: Forty-two adults aged ≥ 65 participated in a randomized clinical trial (NCT026637780) of a 12-week timing and coordination physical therapy intervention to improve walking (n = 20 intervention, n = 22 active control). PFC activation was measured by functional near-infrared spectroscopy (fNIRS) during four walking tasks over 15 m, each repeated 4 times: even surface walking, uneven surface walking, even dual-task, uneven dual-task; dual-task was reciting every other letter of the alphabet while walking. Gait speed and rate of correct letter generation were recorded. Linear mixed models tested between arm differences in change of fNIRS, gait speed, and letter generation from baseline to follow-up (12-week, 24-week, and 36-week). RESULTS: Intervention arms were similar in mean age (74.3 vs. 77.0) and baseline gait speed (0.96 vs. 0.93 m/s). Of 24 comparisons of between arm differences in the fNIRS signals, only two were significant which were not supported by differences at other follow-up times or on other tasks. Gait speed, particularly during dual-task conditions, and correct letter generation did improve post-intervention but improvements did not differ by arm. DISCUSSION AND CONCLUSIONS: After training, PFC activation during walking generally did not improve and did not differ by intervention arm. Improvements in gait speed without increased PFC activation may point toward more efficient neural control of walking.

Fear of falling in community-dwelling older adults: What their gait acceleration pattern reveals.

BACKGROUND: Fear of Falling (FOF) is common among community-dwelling older adults and is associated with increased fall-risk, reduced activity, and gait modifications. OBJECTIVE: In this cross-sectional study, we examined the relationships between FOF and gait quality. METHODS: Older adults (N=232; age 77±6; 65 % females) reported FOF by a single yes/no question. Gait quality was quantified as (1) harmonic ratio (smoothness) and other time-frequency spatiotemporal variables from triaxial accelerometry (Vertical-V, Mediolateral-ML, Anterior-Posterior -AP) during six-minute walk; (2) gait speed, step-time CoV (variability), and walk-ratio (step-length/cadence) on a 4-m instrumented walkway. Mann Whitney U-tests and Random forest classifier compared gait between those with and without FOF. Selected gait variables were used to build Support Vector Machine (SVM) classifier and performance was evaluated using AUC-ROC. RESULTS: Individuals with FOF had slower gait speed (103.66 ± 17.09 vs. 110.07 ± 14.83 cm/s), greater step time CoV (4.17 ± 1.66 vs. 3.72 ± 1.24 %), smaller walk-ratio (0.53 ± 0.08 vs. 0.56 ± 0.07 cm/steps/minute), smaller standard deviation V (0.15 ± 0.06 vs. 0.18 ± 0.09 m/s2), and smaller harmonic-ratio V (2.14 ± 0.73 vs. 2.38 ± 0.58), all p<.01. Linear SVM yielded an AUC-ROC of 67 % on test dataset, coefficient values being gait speed (-0.19), standard deviation V (-0.23), walk-ratio (-0.36), and smoothness V (-0.38) describing associations with presence of FOF. CONCLUSION: Older adults with FOF have reduced gait speed, acceleration adaptability, walk-ratio, and smoothness. Disrupted gait patterns during fear of falling could provide insights into psychosocial distress in older adults. Longitudinal studies are warranted.

Association of Gait Quality With Daily-Life Mobility: An Actigraphy and Global Positioning System Based Analysis in Older Adults.

OBJECTIVE: Walking is a key component of daily-life mobility. We examined associations between laboratory-measured gait quality and daily-life mobility through Actigraphy and Global Positioning System (GPS). We also assessed the relationship between two modalities of daily-life mobility i.e., Actigraphy and GPS. METHODS: In community-dwelling older adults (N = 121, age = 77±5 years, 70% female, 90% white), we obtained gait quality from a 4-m instrumented walkway (gait speed, walk-ratio, variability) and accelerometry during 6-Minute Walk (adaptability, similarity, smoothness, power, and regularity). Physical activity measures of step-count and intensity were captured from an Actigraph. Time out-of-home, vehicular time, activity-space, and circularity were quantified using GPS. Partial Spearman correlations between laboratory gait quality and daily-life mobility were calculated. Linear regression was used to model step-count as a function of gait quality. ANCOVA and Tukey analysis compared GPS measures across activity groups [high, medium, low] based on step-count. Age, BMI, and sex were used as covariates. RESULTS: Greater gait speed, adaptability, smoothness, power, and lower regularity were associated with higher step-counts (0.20<|ρp| < 0.26, p < .05). Age(ß = -0.37), BMI(ß = -0.30), speed(ß = 0.14), adaptability(ß = 0.20), and power(ß = 0.18), explained 41.2% variance in step-count. Gait characteristics were not related to GPS measures. Participants with high (>4800 steps) compared to low activity (steps<3100) spent more time out-of-home (23 vs 15%), more vehicular travel (66 vs 38 minutes), and larger activity-space (5.18 vs 1.88 km2), all p < .05. CONCLUSIONS: Gait quality beyond speed contributes to physical activity. Physical activity and GPS-derived measures capture distinct aspects of daily-life mobility. Wearable-derived measures should be considered in gait and mobility-related interventions.

Uneven surface and cognitive dual-task independently affect gait quality in older adults.

BACKGROUND: Real-world mobility involves walking in challenging conditions. Assessing gait during simultaneous physical and cognitive challenges provides insights on cognitive health. RESEARCH QUESTION: How does uneven surface, cognitive task, and their combination affect gait quality and does this gait performance relate to cognitive functioning? METHODS: Community-dwelling older adults (N = 104, age=75 ± 6 years, 60 % females) performed dual-task walking paradigms (even and uneven surface; with and without alphabeting cognitive task (ABC)) to mimic real-world demands. Gait quality measures [speed(m/s), rhythmicity(steps/minute), stride time variability (%), adaptability (m/s2), similarity, smoothness, power (Hz) and regularity] were calculated from an accelerometer worn on the lower back. Linear-mixed modelling and Tukey analysis were used to analyze independent effects of surface and cognitive task and their interaction on gait quality. Partial Spearman correlations compared gait quality with global cognition and executive function. RESULTS: No interaction effects between surface and cognitive task were found. Uneven surface reduced gait speed(m/s) (ß = -0.07). Adjusted for speed, uneven surface reduced gait smoothness (ß = -0.27) and increased regularity (ß = 0.09), Tukey p < .05, for even vs uneven and even-ABC vs uneven-ABC. Cognitive task reduced gait speed(m/s) (ß = -0.12). Adjusted for speed, cognitive task increased variability (ß = 7.60), reduced rhythmicity (ß = -6.68) and increased regularity (ß = 0.05), Tukey p < .05, for even vs even-ABC and uneven vs uneven-ABC. With demographics as covariates, gait speed was not associated with cognition. Gait quality [lower variability during even-ABC (ρp =-.31) and uneven-ABC (ρp =-.28); greater rhythmicity (ρp between.22 and.29) and greater signal-adaptability AP (ρp between.22 and.26) during all walking tasks] was associated with better global cognition. Gait adaptability during even (ρp =-0.21, p = 0.03) and uneven(ρp =-0.19, p = 0.04) walking was associated with executive function. SIGNIFICANCE: Surface and cognitive walking tasks independently affected gait quality. Our study with high-functioning older adults suggests that task-related changes in gait quality are related to subtle changes in cognitive functioning.

Effect of Timing and Coordination Training on Mobility and Physical Activity Among Community-Dwelling Older Adults: A Randomized Clinical Trial.

Importance: Standard exercise interventions targeting underlying physiologic system impairments have limited success in improving walking. Augmenting standard interventions with timing and coordination training, which incorporates the principles of motor learning and integrates multiple systems, may be more successful. Objective: To determine whether a standard strength and endurance program incorporating timing and coordination training (standard-plus) improves gait speed more than strength and endurance training alone. Design, Setting, and Participants: The Program to Improve Mobility in Aging (PRIMA) study was an assessor-blinded, randomized, 2-group intervention trial that included a 12-week intervention and 24-week follow-up period. The trial was conducted at a university research clinic from 2016 to 2020. Participants included 249 community-dwelling older adults (aged ≥65 years) with gait speed between 0.60 and 1.20 m/s. Statistical analysis was performed from December 2020 to March 2021. Interventions: Participants were randomized to standard strength and endurance (n = 125) or standard-plus, including timing and coordination training (n = 124), 50 to 60 minutes, twice a week for 12 weeks. Main Outcomes and Measures: Primary outcome of gait speed and secondary outcomes representing components of the intervention (leg strength and power, 6-minute walk test, chair sit-and-reach test, and figure of 8 walk test) and activity and participation (Late Life Function and Disability Instrument and daily physical activity measured by accelerometry) were measured at 12, 24, and 36 weeks. Results: Among 249 randomized participants, 163 (65.5%) were female, 22 (8.8%) were Black, 219 (88.0%) were White; mean (SD) age was 77.4 (6.6) years; mean (SD) gait speed was 1.07 (0.16) m/s; and 244 (98.0%) completed the intervention. The 2 groups did not have significantly different improvements in gait speed or secondary outcomes representing the components of the intervention at any time point. For gait speed, individuals in the standard-plus group had a mean (SD) improvement of 0.079 (0.135) m/s over 12 weeks, 0.065 m/s (0.141) over 24 weeks, and 0.059 (0.150) m/s over 36 weeks; individuals in the standard group improved gait speed by 0.081 (0.124) m/s over 12 weeks, 0.051 (0.129) m/s over 24 weeks, and 0.065 (0.148) m/s over 36 weeks. Conclusions and Relevance: This randomized clinical trial found no difference in gait speed change between the standard and standard-plus intervention groups, and both groups showed sustained improvements in mobility 24 weeks after the intervention. Trial Registration: ClinicalTrials.gov Identifier: NCT02663778.

Academy of Geriatric Physical Therapy Research Agenda: Rationale for the Development and the Intent for Use.

The rationale for the development and the intent for use of a research agenda for the Academy of Geriatric Physical Therapy is described. The reasons for the research agenda for geriatric physical therapy are (1) to have a broad representation of the research conducted by physical therapist(s) working with older adults, (2) to provide guidance and assistance to emerging investigators to aid the trajectory of a research career, and (3) as a document to engage potential funding agencies, foundations, and individuals in support of physical therapist-conducted research. The design was based on the Research Agenda for Physical Therapy (APTA document), formatted to be consistent with the World Health Organization International Classification of Functioning, Disability and Health, priority ratings for the research statements, and specific examples of research questions for each category of the Research Agenda. The Academy of Geriatric Physical Therapy Research Agenda generated to be a living document, with revisions to research questions and priority ratings expected in the future to enable the agenda to adapt to changes in science, practice, workforce, education, and health policy.

Facilitators and barriers to real-life mobility in community-dwelling older adults: a narrative review of accelerometry- and global positioning system-based studies.

Real-life mobility, also called "enacted" mobility, characterizes an individual's activity and participation in the community. Real-life mobility may be facilitated or hindered by a variety of factors, such as physical abilities, cognitive function, psychosocial aspects, and external environment characteristics. Advances in technology have allowed for objective quantification of real-life mobility using wearable sensors, specifically, accelerometry and global positioning systems (GPSs). In this review article, first, we summarize the common mobility measures extracted from accelerometry and GPS. Second, we summarize studies assessing the associations of facilitators and barriers influencing mobility of community-dwelling older adults with mobility measures from sensor technology. We found the most used accelerometry measures focus on the duration and intensity of activity in daily life. Gait quality measures, e.g., cadence, variability, and symmetry, are not usually included. GPS has been used to investigate mobility behavior, such as spatial and temporal measures of path traveled, location nodes traversed, and mode of transportation. Factors of note that facilitate/hinder community mobility were cognition and psychosocial influences. Fewer studies have included the influence of external environments, such as sidewalk quality, and socio-economic status in defining enacted mobility. Increasing our understanding of the facilitators and barriers to enacted mobility can inform wearable technology-enabled interventions targeted at delaying mobility-related disability and improving participation of older adults in the community.

Mobility of Older Adults: Gait Quality Measures Are Associated With Life-Space Assessment Scores.

BACKGROUND: The relation of gait quality to real-life mobility among older adults is poorly understood. This study examined the association between gait quality, consisting of step variability, smoothness, regularity, symmetry, and gait speed, and the Life-Space Assessment (LSA). METHOD: In community-dwelling older adults (N = 232, age 77.5 ± 6.6, 65% females), gait quality was derived from (i) an instrumented walkway: gait speed, variability, and walk ratio and (ii) accelerometer: signal variability, smoothness, regularity, symmetry, and time-frequency spatiotemporal variables during 6-minute walk. In addition to collecting LSA scores, cognitive functioning, walking confidence, and falls were recorded. Spearman correlations (speed as covariate) and random forest regression were used to assess associations between gait quality and LSA, and Gaussian mixture modeling (GMM) was used to cluster participants. RESULTS: Spearman correlations of ρ p = .11 (signal amplitude variability mediolateral [ML] axis), ρ p = .15 and ρ p = -.13 (symmetry anterior-posterior-vertical [AP-V] and ML-AP axes, respectively), ρ p = .16 (power V), and ρ = .26 (speed), all p <.05 and marginally related, ρ p = -.12 (regularity V), ρ p = .11 (smoothness AP), and ρ p = -.11 (step-time variability), all p <.1, were obtained. The cross-validated random forest model indicated good-fit LSA prediction error of 17.77; gait and cognition were greater contributors than age and gender. GMM indicated 2 clusters. Group 1 (n = 189) had better gait quality than group 2 (n = 43): greater smoothness AP (2.94 ± 0.75 vs 2.30 ± 0.71); greater similarity AP-V (.58 ± .13 vs .40 ± .19); lower regularity V (0.83 ± 0.08 vs 0.87 ± 0.10); greater power V (1.86 ± 0.18 vs 0.97 ± 1.84); greater speed (1.09 ± 0.16 vs 1.00 ± 0.16 m/s); lower step-time coefficient of variation (3.70 ± 1.09 vs 5.09 ± 2.37), and better LSA (76 ± 18 vs 67 ± 18), padjusted < .004. CONCLUSIONS: Gait quality measures taken in the clinic are associated with real-life mobility in the community.

Acceleration Gait Measures as Proxies for Motor Skill of Walking: A Narrative Review.

In adults 65 years or older, falls or other neuromotor dysfunctions are often framed as walking-related declines in motor skill; the frequent occurrence of such decline in walking-related motor skill motivates the need for an improved understanding of the motor skill of walking. Simple gait measurements, such as speed, do not provide adequate information about the quality of the body motion's translation during walking. Gait measures from accelerometers can enrich measurements of walking and motor performance. This review article will categorize the aspects of the motor skill of walking and review how trunk-acceleration gait measures during walking can be mapped to motor skill aspects, satisfying a clinical need to understand how well accelerometer measures assess gait. We will clarify how to leverage more complicated acceleration measures to make accurate motor skill decline predictions, thus furthering fall research in older adults.

Potential long-term impact of "On The Move" group-exercise program on falls and healthcare utilization in older adults: an exploratory analysis of a randomized controlled trial.

BACKGROUND: Wellness program participation may reduce the risk of falling, emergency department-use, and hospitalization among older adults. "On the Move" (OTM), a community-based group exercise program focused on the timing and coordination of walking, improved mobility in older adults, but its impact on falls, emergency department-use, and hospitalizations remains unclear. The aim of this preliminary study was to investigate the potential long-term effects that OTM may have on downstream, tertiary outcomes. METHODS: We conducted a secondary analysis of a cluster-randomized, single-blind intervention trial, which compared two community-based, group exercise programs: OTM and a seated exercise program on strength, endurance, and flexibility (i.e. 'usual-care'). Program classes met for 50 min/session, 2 sessions/week, for 12 weeks. Older adults (≥65 years), with the ability to ambulate independently at ≥0.60 m/s were recruited. Self-reported incidence of falls, emergency department visitation, and hospitalization were assessed using automated monthly phone calls for the year following intervention completion. Participants with ≥1 completed phone call were included in the analyses. Incidence rate ratios (IRRs) and 95% confidence intervals (CIs) were calculated (reference = usual-care). RESULTS: Participants (n = 248) were similar on baseline characteristics and number of monthly phone calls completed. Participants in the seated exercise program attended an average of 2.9 more classes (p = .017). Of note, all results were not statistically significant (i.e. 95% CI overlapped a null value of 1.0). However, point estimates suggest OTM participation resulted in a decreased incidence rate of hospitalization compared to usual-care (IRR = 0.88; 95% CI = 0.59-1.32), and the estimates strengthened when controlling for between-group differences in attendance (adjusted IRR = 0.82; 95% CI = 0.56-1.21). Falls and emergency department visit incidence rates were initially greater for OTM participants, but decreased after controlling for attendance (adjusted IRR = 1.08; 95% CI = 0.72-1.62 and adjusted IRR = 0.96; 95% CI = 0.55-1.66, respectively). CONCLUSION: Compared to a community-based seated group exercise program, participation in OTM may result in a reduced risk of hospitalization. When OTM is adhered to, the risk for falling and hospitalizations are attenuated. However, definitive conclusions cannot be made. Nevertheless, it appears that a larger randomized trial, designed to specifically evaluate the impact of OTM on these downstream health outcomes is warranted. TRIAL REGISTRATION: Clinical trials.gov (NCT01986647; prospectively registered on November 18, 2013).

Development and Validation of Person-Centered Cut-Points for the Figure-of-8-Walk Test of Mobility in Community-Dwelling Older Adults.

BACKGROUND: The Figure-of-8-Walk test (F8WT) is a performance measure of the motor skill of walking. Unlike walking speed over a straight path, it captures curved path walking, which is essential to real-world activity, but meaningful cut-points have yet to be developed for the F8WT. METHODS: A secondary analysis of 421 community-dwelling older adults (mean age 80.7 ± 7.8), who participated in a community-based exercise clinical trial, was performed. Area under receiver operating characteristic curves (AUROCC) were calculated using baseline data, with F8WT performance discriminating different self-reported global mobility and balance dichotomies. Cut-points for the F8WT were chosen to optimize sensitivity and specificity. For validation, F8WT cut-points were applied to postintervention F8WT data. Participants were called monthly for 12 months after intervention completion to record self-reported incident falls, emergency department visits, and hospitalizations; risks of the outcomes were compared between those who performed well and poorly on the F8WT. RESULTS: F8WT performance times of ≤9.09 seconds and ≤9.27 seconds can discriminate those with excellent (sensitivity = 0.647; specificity = 0.654) and excellent/very good global mobility (sensitivity = 0.649; specificity = 0.648), respectively. A total number of steps ≤17 on the F8WT can discriminate those with excellent/very good/good global balance (sensitivity = 0.646; specificity = 0.608). Compared to those who performed poorly, those who performed well had a lower incidence of negative outcomes: F8WT time ≤9.09 seconds = 46%-59% lower; F8WT time ≤9.27 seconds = 46%-56% lower; F8WT steps ≤17 = 44%-50% lower. CONCLUSIONS: Clinicians may consider these preliminary cut-points to aid in their clinical decision making, but further study is needed for definitive recommendations.

Assessing gait efficacy in older adults: An analysis using item response theory.

BACKGROUND: Assessing confidence in walking in older adults is important, as mobility is a critical aspect of independence and function, and self-report provides complementary information to performance-based measures. The modified Gait Efficacy Scale (mGES) is a self-report measure used to examine confidence in walking. RESEARCH QUESTION: What are the psychometric properties of the mGES at the item level? Are there opportunities for improvement? METHODS: We performed a secondary analysis of baseline data from a cluster randomized trial of 424 community-dwelling older adults and reliability data from 123 participants. We fitted a graded response model to dissect the mGES to the item and individual response level and examined opportunities to improve and possible shorten the mGES. We examined psychometric characteristics such as internal consistency, test-retest reliability and construct validity with respect to other relevant measures. RESULTS: Mobility tasks such as navigating stairs and curbs with separate items for going up and down largely provide the same information on confidence, with downward direction providing slightly more. It may be reasonable to consider removal of walking 1/2 mile, stepping down and/or stair tasks with railings items due to little or duplicate information contributed compared to other items. The shortened scales proposed by removing the above items had similar psychometric properties to mGES. SIGNIFICANCE: The mGES has good psychometric properties, but can be potentially shortened to substantially reduce responder burden. The upward direction curb and stairs items can be removed to result in a 7-item scale with virtually no loss of desirable psychometrics. An alternative 3-item version, level surface walking, stepping down curb and climbing up stairs without a railing items, entails only a minimal loss in psychometric properties.

Intraclass Correlation Coefficients for Planning Cluster Randomized Trials in Community-Dwelling Older Adults.

Objectives: With the emerging trends, more cluster randomized trials will be conducted in older adults, where facilities are randomized rather than individuals. Similarity of individuals from a facility (intraclass correlation coefficient/ICC) plays a critical role, but not readily available. We document ICCs for measures commonly used in community-dwelling older adults and discuss implications. Method: Secondary analysis of a range of baseline measures from the On the Move cluster randomized trial, whose ICCs were computed using a linear mixed model. Results: Self-reported disability measures related to facility characteristics and sense of community had the greatest ICCs (>0.10), while mobility performance measures had 0.05 to 0.10, and cognitive measure 0.11. Discussion: The ICCs for measures commonly used in older adults are of a sufficient magnitude to have a substantial impact on planned sample size of a study and credibility of results, and should be taken into consideration in study planning and data analysis.

Program to improve mobility in aging (PRIMA) study: Methods and rationale of a task-oriented motor learning exercise program.

Walking difficulty is a common and costly problem in older adults. A potentially important yet unaddressed strategy to enhance walking ability through exercise intervention is to add a timing and coordination component in gait training (i.e. task specific timing and coordination exercise intervention) to the usual strength, endurance, and flexibility training. We describe the methods and rationale of a randomized single-blind, physical therapist supervised, exercise intervention trial to compare the effects of a standard strength, endurance, and flexibility program to a standard plus timing and coordination program in community-dwelling older adults walking slower than the desired gait speed of 1.2 m/s. Exercise sessions are twice weekly for 12 weeks. Participants are assessed at baseline, 12 weeks (post intervention), 24 weeks and 36 weeks. The primary outcome is gait speed, secondary outcomes represent components of the interventions (strength, endurance, flexibility, timing and coordination), and tertiary outcomes are measure of activity and participation (Late Life Function and Disability Instrument and physical activity). The findings of this trial will (1) establish if a standard-plus task specific timing and coordination program is superior to a standard strength and endurance program in improving mobility, activity and participation and (2) determine if the improvements are sustained over time. The information derived from this project will provide valuable insight into the prevention and management of walking difficulty, which is so common in older Americans.

Effect of Community-Based Group Exercise Interventions on Standing Balance and Strength in Independent Living Older Adults.

BACKGROUND AND PURPOSE: Many interventions to improve mobility in older adults often include exercises to address underlying impairments such as strength deficits. Task-oriented exercise interventions that focus more on walking and stepping tasks that may be encountered in the community have been considered for improving mobility in older adults. The main purpose was to examine the effect of task-oriented and impairment-based group exercise interventions on standing balance and lower extremity muscle strength. METHODS: This is an ancillary study to a cluster-randomized clinical trial. Participants included 107 older adults. Participants were randomized by facility to 1 of 2 different interventions, or a waitlist control group. The On the Move (OTM) task-oriented intervention consisted of warm-up, timing and coordination (stepping and walking patterns), strengthening, and stretching exercises. The standard of care impairment-based exercise intervention (STD) consisted of warm-up, strength, endurance, and stretching exercises. Postural sway and balance measures were recorded before and after the 12-week interventions. An accelerometer was used to collect postural sway for 6 different standing balance conditions. A portable load cell was used to assess lower extremity muscle strength for 3 muscle groups. RESULTS AND DISCUSSION: The OTM group had a significant reduction in sway acceleration during most of the balance conditions over the 12-week period, whereas the STD had smaller, nonsignificant reductions. Both exercise interventions had a significant reduction in sway compared with the waitlist control group in at least 1 balance condition. The OTM and STD groups had significant increases in hip abduction strength during the intervention and the STD group also had an increase in knee extension strength. The waitlist group had a significant reduction in strength in all muscle groups during the 12-week period. Strength changes in both exercise groups were significantly different from the waitlist group but not from each other. CONCLUSION: Both exercise intervention groups had an improvement in standing balance and lower extremity strength when compared with a waitlist group that did not receive exercise. Although the exercise groups did not significantly differ from each other, the OTM exercise group showed a trend toward improvement in static standing balance conditions.

Phonation Demonstrates Goal Dependence Under Unique Vocal Intensity and Aerobic Workload Conditions.

Purpose This study investigated whether metabolic respiratory requirements (treadmill workload) affected glottal valving in phonation, based on aerodynamic measures, when a sound pressure level (vocal SPL) is dictated as a target goal. Consistent with a theory of action, we hypothesized that adjustments in glottal valving as measured by laryngeal airway resistance would be dependent upon vocal SPL level, even as workload increased, and loud vocal SPL would interfere more with respiratory homeostasis than spontaneous vocal SPL. Method Thirty-two women enrolled who were ages 18-35 years. A repeated-measures design was used with random assignment of workload and vocal SPL conditions. Aerodynamic and acoustic data were collected during phonation, as were gas volume and concentration data. Analyses were performed with generalized estimating equations. Results Laryngeal airway resistance at a low workload significantly increased when vocal SPL changed from spontaneous to loud. At a loud vocal SPL, laryngeal airway resistance decreased when workload changed from rest to either low or high. Regarding the respiratory system response, minute ventilation increased at a loud vocal SPL when workload changed from rest to either low or high. End-tidal CO2 increased under low and high workloads relative to rest at loud and spontaneous vocal SPLs. Conclusions Mostly consistent with a theory of action, in which motor control is goal dependent (i.e., vocal SPL targets), speakers can achieve a loud vocal SPL despite increases in workload requirements. In contrast, laryngeal airway resistance stays relatively low when vocal SPL occurs spontaneously, suggesting glottal adjustments are made to improve gas exchange as metabolic respiratory requirements become prioritized. Metabolic respiratory requirements appear to be overcome by the overlay of motor control for voicing when a loud vocal SPL is targeted. The implication of goal-dependent phonation for clinicians is that real-world conditions (i.e., loud vocal SPL) matter in vocal testing and voice therapy.

An observational treatment-based gait pattern classification method for targeting interventions for older adult males with mobility problems: Validity based on movement control and biomechanical factors.

BACKGROUND: A reliable and valid observational gait assessment intended to guide clinical intervention for gait deficits in older adults has not been proposed. A quick gait classification method which tailors clinical management for different patterns of gait dysfunction may be useful for clinicians with limited access to apply computer-assisted gait analyses. RESEARCH QUESTION: This work aims to establish reliability and validity of the Treatment-Based Gait Pattern Classification (TBGPC) that can be used to quickly identify and classify mobility problems of older males, and possibly target interventions for specific gait deficits in clinical settings. METHOD: Videotapes of 116 older male veterans referred for mobility problems were analyzed in this cross-sectional study. The TBGPC defined by movement control (consistent, inconsistent) and postural biomechanical factors (usual, flexed, extended, crouched) was validated by comparing means of individual items of the Modified Gait Abnormality Rating Scale (GARS-M) across groups. RESULTS: Kappas for interrater reliability of the TBGPC movement control and biomechanical components were 0.59 and 0.75, respectively; for intrarater reliability, 0.82 and 0.72, respectively. Both movement control and biomechanical components were validated. All GARS-M items were different between older males with consistent and inconsistent gait. Within the consistent and inconsistent group, hip ROM was one of the most differentiating GARS-M item between older males with usual and flexed gait and flexed and crouched group. Total GARS-M score and guardedness were two differentiating factors between the usual and crouched group. SIGNIFICANCE: Gait patterns of older males were reliably recognized and validated by mean differences in abnormal characteristics of gait across patterns. The TBGPC may be useful to quickly identify and classify mobility problems of older males and to guide clinical intervention.

Spatiotemporal variability underlying skill in curved-path walking.

BACKGROUND: Daily life walking frequently involves curved paths. While mean gait characteristics and orientation of the body during curved path walking have been described, little has been reported about spatiotemporal variability during curved path walking and its relation to the motor skill of walking in older adults. RESEARCH QUESTION: Among community-dwelling older adults, is greater spatiotemporal variability during curved path walking related to better curved path walking ability? METHODS: Community dwelling older adults (n = 34) completed the Figure-of-8 Walk Test (F8W, a measure of curved path walking ability) and usual straight path walking on an instrumented walkway. Standard deviations for step length, stride width and step time (step length variability, SLV, stride width variability, SWV, step time variability, STV) during both conditions were determined, along with time and number of steps to complete F8W. Associations were examined with Pearson r correlation coefficients, regressions determined contributions of variability during curved path walking to F8W performance, and AUC analyses were used to determine the ability of variability during curved path walking to distinguish better vs poorer F8W performance. RESULTS: F8W time and steps were negatively associated with both SLV (r's = -0.37, p < 0.05) and SWV (r's = -0.67 to -0.82, p < 0.001). Both SLV and SWV independently contributed to F8W performance (SLV ßs = -0.26 to -0.29, p < 0.03; SWV ßs = -0.74 to -0.76, p < 0.001). The AUC of the ROC curve for SLV was 0.716, and for SWV was 0.765. SIGNIFICANCE: Greater spatial variability, particularly SWV, was associated with better motor skill of curved path walking. It is important for clinicians to understand the variables that contribute to successful performance of complex walking tasks as these can be targets for rehabilitation. The findings suggest that practice of adjustment of stride width and step length during walking are important.

Randomized Controlled Trial of Exercise to Improve Walking Energetics in Older Adults.

BACKGROUND AND OBJECTIVES: Mobility limitation is common and has been linked to high energetic requirements of daily activities, including walking. The study objective was to determine whether two separate forms of exercise could reduce the energy cost of walking and secondary outcomes related to activity and participation domains among older adults with mobility limitation. RESEARCH DESIGN AND METHODS: Community-dwelling older adults with self-reported mobility limitation (n = 72) were randomized to 12 weeks of twice-weekly, group-based, instructor-led timing and coordination, aerobic walking, or stretching and relaxation (active control) programs. The primary outcome was the energy cost of walking (mL O2/kg/m), assessed by a 5-minute treadmill walking test (0.8 m/s). Secondary outcomes were fatigability, physical activity, endurance, physical function, and life-space. Baseline-adjusted ANCOVAs were used to determine mean differences between exercise and control groups at 12 and 24 weeks. RESULTS: Exercise session attendance was high: 86% for timing and coordination, 81% for aerobic walking, and 90% for stretching and relaxation. At 12 weeks, timing and coordination reduced the mean energy cost of walking by 15% versus stretching and relaxation (p = .008). Among those with high baseline cost, timing and coordination reduced mean energy cost by 20% versus stretching and relaxation (p = .055). Reductions were sustained at 24 weeks. Aerobic walking had no effect on the energy cost of walking at 12 or 24 weeks. At 12 weeks, there was a trend toward faster gait speed (by 0.1 m/s) in timing and coordination versus stretching and relaxation (p = .074). Fatigability, physical activity, endurance, physical function, and life-space did not change with timing and coordination or aerobic walking versus stretching and relaxation at 12 or 24 weeks. DISCUSSION AND IMPLICATIONS: Twelve weeks of timing and coordination, but not aerobic walking, reduced the energy cost of walking among older adults with mobility limitation, particularly among those with high baseline energy cost; reductions in energy cost were sustained following training cessation. Timing and coordination also led to a trend toward faster gait speed.

Motor Control-based Group Exercise: Can It be Delivered as Effectively by Lay Leaders?

PURPOSE: On the Move (OTM), a motor control-based group exercise program for community-dwelling older adults, has produced greater gains in mobility than a standard group exercise program when delivered by research leaders. The purposes of this study were:1) to examine the effectiveness of OTM versus a standard program when delivered by lay leaders and 2) to compare the outcomes of OTM when delivered by research versus lay leaders. METHODS: Community-dwelling, medically stable older adults who could walk household distances participated. OTM consisted of warm-up, timing and coordination, strengthening, and stretching exercises. The seated standard program consisted of warm-up, aerobic, strengthening and stretching exercises. The primary outcome(s) of function and disability was the Late Life Function and Disability Instrument (LLFDI), and for walking ability were the Six Minute Walk Test and gait speed. RESULTS: 126 participants (mean age = 80.7±7.8 years, gait speed = 0.91 m/s) were randomized to OTM (n=49) or standard (n=77) programs. When taught by lay leaders, there were no significant between-intervention group differences in any of the outcomes (p>0.10). Comparing OTM outcomes between leaders, there was a statistical but not clinically meaningful difference in LLFDI disability (1.87±0.89, p=0.04) when taught by research versus lay leader, and moderate differences (p=0.06) in LLFDI overall function (1.89±1.02) and gait speed (0.05±0.03). Qualitative interview responses suggest that instructor-related concerns may have impacted program outcomes. CONCLUSION: When delivered by lay leaders OTM was not more effective than a standard program for improving function, disability, and mobility in older adults. Health promotion programs designed to improve mobility in community-dwelling older adults and based on a motor control theoretical background, may be best taught by rehabilitation professionals.