Impact of context specificity on response to the shortened WOMAC function scale in patients undergoing total knee arthroplasty.

OBJECTIVE: To determine, in patients undergoing total knee arthroplasty (TKA), whether increasing context specificity of selected items of the shortened version of the Western Ontario and McMaster Universities Osteoarthritis Index function (WOMAC-F) scale (ShortMAC-F) (i) enhanced the convergent validity of the ShortMAC-F with performance-based mobility measures and (ii) impacted on mean scale score, structural validity, reliability, and interpretability. DESIGN: Secondary analysis of randomized clinical trial data. SETTING AND PARTICIPANTS: Patients undergoing TKA (n=114). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The ShortMAC-F was modified by specifying the "ascending stairs" and "rising from sitting" items to enquire about difficulty in performing the tasks without reliance on compensatory strategies, while the modified "level walking" item enquired about difficulty in walking 400 meters. Before and 12 weeks after TKA, patients completed the WOMAC-F, modified ShortMAC-F, knee pain scale, sit-to-stand test, fast gait speed test, and stair-climb test. Interpretability was evaluated by calculating anchor-based substantial clinical benefit (SCB) estimates. RESULTS: The modified ShortMAC-F correlated significantly more strongly than ShortMAC-F or WOMAC-F with pooled performance measures (differences in correlation values, 0.12-0.14). Increasing item context specificity of the ShortMAC-F did not influence its psychometric properties of unidimensionality (comparative fit and Tucker-Lewis indices >0.95; root mean square error of approximation, 0.05-0.08), reliability (Cronbach alpha, 0.75-0.83), correlation with pain intensity (correlation values, 0.48-0.52), and SCB estimates (16 percentage points); however, it resulted in lower mean score (4.5-4.8 points lower). CONCLUSIONS: The modified ShortMAC-F showed sufficient measurement properties for clinical application, and it seemed more adept than WOMAC-F at correlating with performance-based measures in TKA.

Modifying the Mobility Scale for Acute Stroke (MSAS) for All Stroke Phases (MSAllS): Measurement Properties and Clinical Application.

OBJECTIVE: To develop and examine the measurement properties and interpretability of the Mobility Scale for "All" Stroke Phases (MSAllS) as a potential single outcome measure to capture improvements in physical function throughout the stroke continuum. DESIGN: Retrospective cross-sectional study. SETTING: Inpatient rehabilitation unit. PARTICIPANTS: People after stroke at discharge from rehabilitation (N=309). INTERVENTION: Not applicable. MAIN OUTCOME MEASURE(S): We developed MSAllS by extending the highest MSAS level (walk 10 m independently) with 4 gait speed levels. To establish a clinical anchor, we extracted a 4-level discharge outcome. To assess the distributional properties and internal consistency of MSAllS, we evaluated its ceiling effects and calculated the Cronbach alpha, respectively. To assess structural validity, we performed a confirmatory factor analysis. To assess (i) its convergent validity with the FIM and (ii) its predictive validity with the clinical anchor, we used Spearman's rank correlations. To evaluate the clinical interpretability of MSAllS, we used an item-response theory-based method to estimate MSAllS thresholds associated with the clinical anchor. RESULTS: The MSAllS had lower ceiling effects compared with MSAS (0% vs 25%). Internal consistency of MSAllS was excellent (α=0.94). Structural validity of MSAllS demonstrated a good fit (Comparative Fit Index=0.95; Tucker-Lewis Index=0.92; Root Means Square Error of Approximation=0.17). MSAllS demonstrated a moderate correlation (rho=0.66) with FIM score and with the clinical anchor (rho=0.75). MSAllS thresholds for increasing levels of the clinical anchor were 22 (20.8 to 23.6) - at least moderate assistance with walking/transfers, 28 (27.5 to 29.4) - at most supervision with walking, and 33 (32.5 to 33.4) - able to walk unassisted. CONCLUSION: The MSAllS showed adequate measurement properties and clinical interpretability. MSAllS has the potential to be a single universal measure to evaluate physical function after stroke but further evaluation of clinical interpretability is required.

Cost and outcomes of Hospital-based Usual cAre versus Tele-monitor self-directed Rehabilitation (HUATR) in patients with total knee arthroplasty: A randomized, controlled, non-inferiority trial.

OBJECTIVE: To evaluate the clinical efficacy and cost-effectiveness of telemonitored self-directed rehabilitation (TR) compared with hospital-based rehabilitation (HBR) for patients with total knee arthroplasty (TKA). DESIGN: In this randomized, non-inferiority clinical trial, 114 patients with primary TKA who were able to walk independently preoperatively were randomized to receive HBR (n = 58) or TR (n = 56). HBR comprised at least five physical therapy sessions over 10 weeks. TR comprised a therapist-led onboarding session, followed by a 10-week unsupervised home-based exercise program, with asynchronous monitoring of rehabilitation outcomes using a telemonitoring system. The primary outcome was fast-paced gait speed at 12 weeks, with a non-inferiority margin of 0.10 m/s. For economic analysis, quality-adjusted-life-years (QALY) was the primary economic outcome (non-inferiority margin, 0.027 points). RESULTS: In Bayesian analyses, TR had >95% posterior probability of being non-inferior to HBR in gait speed (week-12 adjusted TR-HBR difference, 0.02 m/s; 95%CrI, -0.05 to 0.10 m/s; week-24 difference, 0.01 m/s; 95%CrI, -0.07 to 0.10 m/s) and QALY (0.006 points; 95%CrI, -0.006 to 0.018 points). When evaluated from a societal perspective, TR was associated with lower mean intervention cost (adjusted TR-HBR difference, -S$227; 95%CrI, -112 to -330) after 24 weeks, with 82% probability of being cost-effective compared with HBR at a willingness to pay of S$0/unit of effect for the QALYs. CONCLUSIONS: In patients with uncomplicated TKAs and relatively good preoperative physical function, home-based, self-directed TR was non-inferior to and more cost-effective than HBR over a 24-week follow-up period. TR should be considered for this patient subgroup.

Using item response theory to estimate interpretation threshold values for the Frailty Index in community dwelling older adults.

BACKGROUND: Although the frailty index (FI) is designed as a continuous measure of frailty, thresholds are often needed to guide its interpretation. This study aimed to introduce and demonstrate the utility of an item response theory (IRT) method in estimating FI interpretation thresholds in community-dwelling adults and to compare them with cutoffs estimated using the receiver operating characteristics (ROC) method. METHODS: A sample of 1,149 community-dwelling adults (mean[SD], 68[7] years) participated in this cross-sectional study. Participants completed a multi-domain geriatric screen from which the 40-item FI and 3 clinical anchors were computed - namely, (i)self-reported mobility limitations (SRML), (ii)"fair" or "poor" self-rated health (SRH), and (iii) restricted life-space mobility (RLSM). Participants were classified as having SRML-1 if they responded "Yes" to either of the 2 questions regarding walking and stair climbing difficulty and SRML-2 if they reported having walking and stair climbing difficulty. Participants with a Life Space Assessment score <60 points were classified as having RLSM. Threshold values for all anchor questions were estimated using the IRT method and ROC analysis with Youden criterion. RESULTS: The proportions of participants with SRML-1, SRML-2, Fair/Poor SRH, and RLSM were 21 %, 8 %, 22 %, and 9 %, respectively. The IRT-based thresholds for SRML-2 (0.26), fair/poor SRH (0.29), and RLSM (0.32) were significantly higher than those for SRML-1 (0.18). ROC-based FI cutoffs were significantly lower than IRT-based values for SRML-2, SRH, and RLSM (0.12 to 0.17), and they varied minimally and non-systematically across the anchors. CONCLUSIONS: The IRT method identifies biologically plausible FI thresholds that could meaningfully complement and contextualize existing thresholds for defining frailty.

Time course and correlates of psychological distress post spinal surgery: A longitudinal study.

Background: Psychological distress post lumbar spine surgery is associated with poorer outcomes. There is a scarcity of studies devoted to analyzing the risk factors associated with psychological distress in patients who have undergone lumbar fusion surgery. The purpose of this study was to (1) describe the time course and severity of psychological distress using the STarT Back Tool (SBT) and (2) determine the demographic and clinical predictors of SBT score post lumbar spine fusion surgery. Methods: This retrospective longitudinal study analyzed 227 subjects with 1- and 2-level lumbar fusion surgery who underwent standardized assessment preoperatively and at 4 and 12 weeks postoperatively. Preoperative variables collected were demographic, clinical, and psychological variables. Postoperative psychological distress was measured by self-reported SBT. Risk factors for SBT over time were identified using ordinal and mixed-effects modelling. Results: Although the trajectory of SBT levels declined postoperatively over time, at week-12, 20% of patients had moderate to high SBT. Postoperative SBT scores at week-4 time point was significantly greater than SBT scores at week-8 (OR = 2.7, 95% credible interval [CrI]; 1.8-3.9). Greater SBT scores at week-4 were strongly associated with greater SBT scores throughout 12 weeks of follow-up (OR = 7.3, [95% CrI; 1.2-31.4]). Greater postoperative SBT levels over time were associated with being male (OR = 2.2, 95% CrI; 1.0-3.9), greater preoperative back or leg pain intensity (OR = 2.2; 95% CrI: 1.0-4.4), greater preoperative leg weakness (OR = 4.2, 95% CrI: 1.7-7.5) and higher preoperative depression levels (OR = 4.8; 95% CrI: 1.6-10.4). Conclusion: Postoperative SBT levels declined nonlinearly over time. However, a sizable proportion of patients had moderate to high psychological distress at week-12 postsurgery. Greater preoperative back or leg pain intensity, leg weakness and depression levels, and male gender were risk factors of greater psychological distress postsurgery. Although requiring validation, our study has identified potential modifiable risk factors which may give an opportunity to provide early (preoperative) and targeted strategies to optimize postoperative psychosocial outcomes in patients undergoing lumbar fusion surgeries.

Validity and reliability of a new clinician-rated tool for freezing of gait severity.

PURPOSE: The Freezing of Gait Severity Tool (FOG Tool) was developed because of limitations in existing assessments. This cross-sectional study investigated its validity and reliability. METHODS: People with Parkinson's disease (PD) were recruited consecutively from clinics. Those who could not walk eight-metres independently (with or without an assistive device), comprehend instructions, or with co-morbidities affecting walking were excluded. Participants completed a set of assessments including the FOG Tool, Timed Up and Go (TUG), and Freezing of Gait Questionnaire. The FOG Tool was repeated and those reporting no medication state change evaluated for test-retest reliability. Validity and reliability were investigated through Spearman's correlations and ICC (two-way, random). McNemar's test was applied to compare the FOG Tool and TUG on the proportion of people with freezing. RESULTS: Thirty-nine participants were recruited [79.5%(n = 31) male; Median(IQR): age-73.0(9.0) years; disease duration-4.0(5.8) years]. Fifteen (38.5%) contributed to test-retest reliability analyses. The FOG Tool demonstrated strongest associations with the Freezing of Gait Questionnaire (ρ = 0.67, 95%CI 0.43-0.83). Test-retest reliability was excellent (ICC = 0.96, 95%CI 0.88-0.99). The FOG Tool had 6.2 times the odds (95%CI 2.4-20.4, p < 0.001) of triggering freezing compared to the TUG. CONCLUSIONS: The FOG Tool appeared adequately valid and reliable in this small sample of people with PD. It was more successful in triggering freezing than the TUG.Implications for RehabilitationThe Freezing of Gait Severity Tool's assessment course is more effective than the commonly-used Timed Up and Go's assessment course for eliciting freezing of gait for clinical evaluation in people with Parkinson's disease.The Freezing of Gait Severity Tool can be considered for scoring freezing of gait severity in people with Parkinson's disease in the clinical setting.

Reliability and variability of physiotherapists scoring freezing of gait through video analysis.

BACKGROUND: The "gold standard" marker for freezing of gait severity is percentage of time spent with freezing observed through video analysis. OBJECTIVE: This study examined inter- and intra-rater reliability and variability of physiotherapists rating freezing of gait severity through video analysis and explored the effects of experience. METHODS: Thirty physiotherapists rated 14 videos of Timed Up and Go performance by people with Parkinson's and gait freezing. Ten videos were unique, while four were repeated. Freezing frequency, total duration, and percentage of time spent with freezing were computed. Reliability and variability were estimated using ICC (2,1) and mean absolute differences. Between-group differences were calculated with the one-way ANOVA. RESULTS: Inter- and intra-rater reliability ranged from moderate to good (ICC: inter-rater frequency = 0.63, duration = 0.78, percentage = 0.50; intra-rater frequency = 0.84, duration = 0.89, percentage = 0.50). Variability for freezing frequency was two episodes. Inter- and intra-rater variability for total freezing duration was 18.8 and 12.3 seconds, respectively. For percentage of time spent with freezing, this was 15.2% and 13.5%. Physiotherapy experience had no effect. CONCLUSION: Physiotherapists demonstrated sufficient reliability, but variability was large enough to cause changes in severity classifications on existing rating scales. Percentage of time spent with freezing was the least reliable marker, supporting the use of freezing frequency or total duration instead.

Scoring festination and gait freezing in people with Parkinson's: The freezing of gait severity tool-revised.

BACKGROUND AND PURPOSE: To improve existing clinical assessments for freezing of gait (FOG) severity, a new clinician-rated tool which integrates the varied types of freezing (FOG Severity Tool-Revised) was developed. This cross-sectional study investigated its validity and reliability. METHODS: People with Parkinson's disease who were able to independently ambulate eight-metres and understand study instructions were consecutively recruited from outpatient clinics of a tertiary hospital. Those with co-morbidities severely affecting gait were excluded. Participants were assessed with the FOG Severity Tool-Revised, three functional performance tests, the FOG Questionnaire, and outcomes measuring anxiety, cognition, and disability. The FOG Severity Tool-Revised was repeated for test-retest reliability. Exploratory factor analysis and Cronbach's alpha were computed for structural validity and internal consistency. Reliability and measurement error were estimated with ICC (two-way, random), standard error of measurement, and smallest detectable change (SDC95 ). Criterion-related and construct validity were calculated with Spearman's correlations. RESULTS: Thirty-nine participants were enrolled [79.5% (n = 31) male; Median (IQR): age-73.0 (9.0) years; disease duration-4.0 (5.8) years], with fifteen (38.5%) who reported no medication state change contributing a second assessment for reliability estimation. The FOG Severity Tool-Revised demonstrated sufficient structural validity and internal consistency (α = 0.89-0.93), and adequate criterion-related validity compared to the FOG Questionnaire (ρ = 0.73, 95% CI 0.54-0.85). Test-retest reliability (ICC = 0.96, 95%CI 0.86-0.99) and random measurement error (%SDC95  = 10.4%) was acceptable in this limited sample. DISCUSSION AND CONCLUSIONS: The FOG Severity Tool-Revised appeared valid in this initial sample of people with Parkinson's. While its psychometric properties remain to be confirmed in a larger sample, it may be considered for use in the clinical setting.

Estimating cutpoints of gait speed and sit-to-stand test values for self-reported mobility limitations in a cohort of community-dwelling older adults from Singapore: comparing receiver operating characteristic (ROC) analysis with adjusted predictive modelling.

OBJECTIVES: Clinical interpretability of the gait speed and 5-times sit-to-stand (5-STS) tests is commonly established by comparing older adults with and without self-reported mobility limitations (SRML) on gait speed and 5-STS performance, and estimating clinical cutpoints for SRML using the receiver operating characteristics (ROC) method. Accumulating evidence, however, suggests that the adjusted predictive modeling (APM) method may be more appropriate to estimate these interpretational cutpoints. Thus, we aimed to compare, in community-dwelling older adults, gait speed and 5-STS cutpoints estimated using the ROC and APM methods. DESIGN: Cross-sectional study. SETTING AND PARTICIPANTS: This study analyzed data from 955 community-dwelling independently walking older adults (73%women) aged ≥60 years (mean, 68; range, 60-88). METHODS: Participants completed the 10-metre gait speed and 5-STS tests. Participants were classified as having SRML if they responded "Yes" to either of the 2 questions regarding walking and stair climbing difficulty. Cutpoints for SRML and its component questions were estimated using ROC analysis with Youden criterion and the APM method. RESULTS: The proportions of participants with self-reported walking difficulty, self-reported stair climbing difficulty, and SRML were 10%, 19%, and 22%, respectively. Gait speed and 5-STS time were moderately correlated with each other (r=-0.56) and with the self-reported measures (absolute r-values, 0.39-0.44). ROC-based gait speed cutpoints were 0.14 to 0.16 m/s greater than APM-based cutpoints (P < 0.05) whilst ROC-based 5-STS time cutpoints were 0.8 to 3.3 s lower than APM-based cutpoints (P < 0.05 for walking difficulty). Compared with ROC-based cutpoints, APM-based cutptoints were more precise and they varied monotonically with self-reported walking difficulty, self-reported stair climbing difficulty, and SRML. CONCLUSIONS AND IMPLICATIONS: In a sample of 955 older adults, our findings of precise and biologically plausible gait speed and 5-STS cutpoints for SRML estimated using the APM method indicate that this promising method could potentially complement or even replace traditional ROC methods.

Associations of height, weight, and body mass index with handgrip strength: A Bayesian comparison in older adults.

BACKGROUND & AIMS: Handgrip strength is commonly normalized or stratified by body size to define subgroup-specific cut-points and reference limits values. However, it remains unclear which anthropometric variable is most strongly associated with handgrip strength. We aimed to, in older adults with no self-reported mobility limitations, determine whether height, weight, and body mass index (BMI) were meaningfully associated with handgrip strength. METHODS: This cross-sectional study included community-dwelling ambulant participants, and we identified 775 older adults who reported no difficulty walking 100 m, climbing stairs, and rising from the chair. Handgrip strength was measured with a digital dynamometer. Bayesian linear regression was used to estimate the probabilities that the positive associations of height, weight, and BMI with handgrip strength exceeded 0 kg (the null value) and 2.5 kg (the clinically meaningful threshold value). RESULTS: Mean handgrip strength was 22.1 kg (SD, 4) for women and 32.9 kg (SD, 6) for men. Body height, weight, and BMI had >99.9% probabilities of a positive association with handgrip strength; however, the associations of per interquartile increase in body weight and BMI with handgrip strength had low probabilities (<5%) of exceeding the clinically meaningful threshold of 2.5 kg. In contrast, body height had the highest probability (99.6%) of a clinically meaningful association with handgrip strength: adjusting for age and gender, handgrip strength was 3.2 kg (95% CrI, 2.7 to 3.8) greater in older adults 1.61 m tall than in older adults 1.51 m tall. CONCLUSIONS: In a large sample of mobile-intact older adults, handgrip strength differed meaningfully by body height. Although requiring validation, our findings suggest that future efforts should be directed at normalizing handgrip strength by body height to better define subgroup-specific handgrip weakness. A web-based application (https://sghpt.shinyapps.io/ippts/) was created to allow interactive exploration of predicted values and reference limits of age-, gender-, and height-subgroups.

Development and validation of a physical frailty phenotype index-based model to estimate the frailty index.

BACKGROUND: The conventional count-based physical frailty phenotype (PFP) dichotomizes its criterion predictors-an approach that creates information loss and depends on the availability of population-derived cut-points. This study proposes an alternative approach to computing the PFP by developing and validating a model that uses PFP components to predict the frailty index (FI) in community-dwelling older adults, without the need for predictor dichotomization. METHODS: A sample of 998 community-dwelling older adults (mean [SD], 68 [7] years) participated in this prospective cohort study. Participants completed a multi-domain geriatric screen and a physical fitness assessment from which the count-based PFP and the 36-item FI were computed. One-year prospective falls and hospitalization rates were also measured. Bayesian beta regression analysis, allowing for nonlinear effects of the non-dichotomized PFP criterion predictors, was used to develop a model for FI ("model-based PFP"). Approximate leave-one-out (LOO) cross-validation was used to examine model overfitting. RESULTS: The model-based PFP showed good calibration with the FI, and it had better out-of-sample predictive performance than the count-based PFP (LOO-R2, 0.35 vs 0.22). In clinical terms, the improvement in prediction (i) translated to improved classification agreement with the FI (Cohen's kw, 0.47 vs 0.36) and (ii) resulted primarily in a 23% (95%CI, 18-28%) net increase in FI-defined "prefrail/frail" participants correctly classified. The model-based PFP showed stronger prognostic performance for predicting falls and hospitalization than did the count-based PFP. CONCLUSION: The developed model-based PFP predicted FI and clinical outcomes more strongly than did the count-based PFP in community-dwelling older adults. By not requiring predictor cut-points, the model-based PFP potentially facilitates usage and feasibility. Future validation studies should aim to obtain clear evidence on the benefits of this approach.

Discordance Between Self-Reported and Performance-Based Physical Function in Patients Who Have Knee Osteoarthritis: Associations With Pain Intensity and Negative Affect.

BACKGROUND: Although self-reported measures of physical disability are strong indication criterion for total knee arthroplasty (TKA) in painful knee osteoarthritis (OA), some patients may report greater-than-observed disability. Contributing factors to this discordance are relatively unexplored. We aimed to examine whether pain and negative affect, including anxiety and depression, were associated with the discordance of self-reported measures with performance-based measures (PPM) of physical function. METHODS: We used cross-sectional data (n = 212) from two randomized rehabilitation trials in knee OA. All patients were assessed for knee pain intensity and symptoms of anxiety and depression. Self-reported function was assessed by the Western Ontario and McMaster Universities Arthritis Index (WOMAC) physical-function subscale. Objective performance-based measures (PPMs) of physical function were assessed by timed gait and stair tests. Continuous discordance scores were quantified by the difference in percentiles between WOMAC and PPMs (WOMAC-PPM), where a positive discordance, WOMAC-PPM >0, implied greater perceived than observed disability. RESULTS: Around 1 in 4 patients had >20 percentile units in WOMAC-PPM discordance. In Bayesian regression analyses, knee pain intensity had >99% posterior probability of positive associations with WOMAC-PPM discordance. Among patients awaiting TKA, anxiety intensity had approximately 99% probability of positive associations with discordance, and these associations had >65% probability of exceeding 10 percentile units. In contrast, depression had low (79% to 88%) probability of any association with discordance. CONCLUSION: In patients who have knee OA, a sizable proportion reported substantially greater physical disability than actually observed. Pain and anxiety intensity, but not depression, were meaningful predictors of this discordance. If validated, our findings may help in refining patient selection criteria for TKA.

Clinical Interpretability of Quadriceps Strength and Gait Speed Performance in Total Knee Arthroplasty: A Longitudinal Study.

OBJECTIVE: After a total knee arthroplasty, physical assessments of quadriceps strength and gait speed performance are often undertaken during rehabilitation. Our study aimed to improve their clinical interpretability by examining trajectory curves across levels of self-reported walking and stair climbing function. DESIGN: A sample of 2624 patients with primary total knee arthroplasty participated in this retrospective longitudinal study. Monthly, for 4 mos after surgery, quadriceps strength and gait speed were quantified. At the month-6 time point, self-reported walking and stair climbing function was measured. RESULTS: All physical measures improved nonlinearly over time. In mixed-effects models, greater quadriceps strength and gait speed over time were associated with higher month-6 self-reported walking and stair climbing function ( P < 0.001). Steeper gains in quadriceps strength and gait speed were associated with higher levels of walking and stair-climbing function (interaction P < 0.001). Among female patients who had great difficulty with stair ascent and ambulation, quadriceps strength trajectory curves plateaued after 8 wks after total knee arthroplasty. CONCLUSIONS: By stratifying trajectory curves across clinically interpretable functional levels, our findings potentially provide patients and clinicians a means to better interpret the continuous-scaled quadriceps strength and gait speed values. This information may be valuable when engaging patients in shared decision making and expectation setting. TO CLAIM CME CREDITS: Complete the self-assessment activity and evaluation online at http://www.physiatry.org/JournalCME. CME OBJECTIVES: Upon completion of this article, the reader should be able to: (1) Understand how self-reported walking and stair climbing abilities improved from baseline before total knee arthroplasty (total knee arthroplasty) to 6 mos postoperatively; (2) Describe the time course of the 2 performance-based measures of quadriceps strength and walking speed after a total knee arthroplasty; and (3) Relate the trajectories of post-total knee arthroplasty quadriceps strength and walking speed measurements across distinct levels of self-reported walking and stair climbing function. LEVEL: Advanced. ACCREDITATION: The Association of Academic Physiatrists is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.The Association of Academic Physiatrists designates this Journal-based CME activity for a maximum of 1.0 AMA PRA Category 1 Credit(s) ™. Physicians should only claim credit commensurate with the extent of their participation in the activity.

Quiet standing postural control variables in subacute stroke: associations with gait and balance, falls prediction and responsiveness.

PURPOSE: To examine the construct validity, predictive validity and responsiveness of standing centre of pressure variables in subacute stroke. MATERIALS AND METHODS: Seventy-nine ambulatory individuals were assessed before inpatient rehabilitation discharge and three months later. Measures were: gait speed (6-metre walk), dynamic balance (step test), and quiet standing (Wii Balance Board). Centre of pressure speed, amplitude, standard deviation, root mean square, wavelet decomposition, and detrended fluctuation analysis were examined. Falls data were collected over a 12-month period post-discharge. RESULTS: Moderate strength correlations (r = -0.505 to -0.548) with gait speed and step test scores were shown for 3/26 centre of pressure variables (mediolateral speed, low and moderate frequency wavelet). Twenty-two participants fell and the prediction was significant for gait speed and step test (IQR-odds ratio (OR) = 4.00 & 3.21) and 3/26 centre of pressure variables (mediolateral low-frequency wavelet: IQR-OR = 2.71; mediolateral detrended fluctuation analysis: IQR-OR = 3.06; anteroposterior detrended fluctuation analysis: IQR-OR = 2.71). Significant changes over time occurred for gait speed and step test scores and 20/26 centre of pressure variables. CONCLUSIONS: Standing centre of pressure variables have limited validity to reflect dynamic balance and falls risk after stroke. Frequency and complexity measures warrant further exploration.Implications for rehabilitationOur findings indicate that quiet standing centre of pressure variables have limited validity to reflect dynamic balance tasks and predict falls after stroke.The mediolateral and higher frequency variables may be more strongly recommended than the commonly used total centre of pressure speed measure.Measures of signal frequency and complexity may provide insight into postural control mechanisms and how these change over time following stroke.

The neglected barrier to medication use: a systematic review of difficulties associated with opening medication packaging.

Difficulty opening medication packaging can have serious consequences that can lead to patient harm via medication mismanagement or poor adherence. However, the quality of literature pertaining to these issues has yet to be collated and critiqued. This systematic review examined cross-sectional studies that objectively examined the ability of participants to open different medication packaging. Of the 8,692 studies identified, 12 met the inclusion criteria, all of which were direct observational studies given that prior research has identified a mismatch between self-report and actual ability. Scoring via the Appraisal Tool for Cross Sectional Studies revealed that the methodological quality of included studies was typically low. Study samples mostly consisted of older adults. All studies reported a non-negligible proportion of participants unable to open packaging, with the most difficulty associated with child-resistant containers. Several studies examined associations; however, no factor was consistently found to be significantly associated with the ability to open packaging. Despite these studies spanning >40 years, the packaging types examined remained largely the same. This suggests that, despite decades of research demonstrating that packaging is problematic, there has been a stagnation in medication packaging development. Whether this is attributed to a paucity of high-quality research, and therefore a lack of strong evidence that change is needed, is unclear. Future research should strive for better methodological quality, with generalisable cohorts assessed via observation in their home. If the problems identified in prior research persist, this may provide the impetus for change that is overdue in the medication packaging industry.

Developing the Freezing of Gait Severity Tool: A Delphi consensus study to determine the content of a clinician-rated assessment for freezing of gait severity.

OBJECTIVES: There is no standardisation of tasks or measures for evaluation of freezing of gait severity in people with Parkinson's disease. This study aimed to develop a clinician-rated tool for freezing of gait severity (i.e. Freezing of Gait Severity Tool), through determining clinicians' ratings of the most important triggering circumstances to be examined and aspects of freezing of gait to be measured. DESIGN: A three-round, web-based Delphi study. PARTICIPANTS: Healthcare professionals, with at least five years' experience in managing freezing of gait in people with Parkinson. MAIN OUTCOME MEASURES: Round 1 required participants (n = 28) to rate items on a 5-point Likert scale, based on priority for inclusion in the Freezing of Gait Severity Tool. In Round 2, participants (n = 18) ranked the items based on priority for inclusion. In Round 3, participants (n = 18) confirmed or rejected the shortlisted items by judging their ability, on a binary scale, to screen for freezing of gait, detect changes in freezing severity, and discriminate between degrees of severity. RESULTS: Participants agreed with the triggering circumstances of turning hesitation, narrow space hesitation, start hesitation, cognitive dual-tasking, and open space hesitation should be assessed; and the aspects of gait freezing to be measured included freezing type, number of freezing episodes during a task, and average duration of freezing episodes. CONCLUSIONS: This study attained a consensus for the items to be included in a clinician-rated tool for freezing of gait severity. Future studies should investigate psychometric properties and clinical feasibility of the Freezing of Gait Severity Tool.

Sit-to-Stand Weight-Bearing Symmetry Performance in Total Knee Arthroplasty: Recovery Curves, Correlates, and Predictive Validity With Gait Speed.

OBJECTIVE: After total knee arthroplasty, the ability to weight bear symmetrically during the sit-to-stand task provides important information regarding altered movement patterns. Despite this, comprehensive recovery curves and validity data for sit-to-stand weight-bearing symmetry are lacking in the total knee arthroplasty population. Our study aimed to (1) develop recovery curves with reference ranges, (2) identify the correlates of standard and constrained sit-to-stand weight-bearing symmetry, and (3) evaluate their predictive validity with gait speed. DESIGN: We performed a retrospective longitudinal study of 706 patients with primary unilateral total knee arthroplasty. Monthly, for 4 mos after surgery, sit-to-stand weight-bearing symmetry, knee pain, knee range of motion, quadriceps strength, and gait speed were quantified. RESULTS: Standard and constrained sit-to-stand weight-bearing symmetry measures improved nonlinearly over time. Standard sit-to-stand weight-bearing symmetry was most strongly associated with bilateral quadriceps strength, whereas constrained sit-to-stand weight-bearing symmetry was most strongly associated with ipsilateral quadriceps strength. Knee range of motion and contralateral knee pain were additional correlates. Both standard sit-to-stand and constrained sit-to-stand weight-bearing symmetry were independently and nonlinearly associated with gait speed in multivariable models. CONCLUSIONS: Our study provided recovery curves and validity data to support routine clinical measurement of sit-to-stand weight-bearing symmetry in total knee arthroplasty. Our results also indicate that constrained sit-to-stand may promote greater use of the operated limb than standard sit-to-stand.

Screening accuracy of percentage predicted gait speed for prefrailty/frailty in community-dwelling older adults.

AIM: In order to account for the variability in gait speed due to demographic factors, an observed gait speed value can be compared with its predicted value based on age, sex, and body height (observed gait speed divided by predicted gait speed, termed "GS%predicted" henceforth). This study aimed to examine the screening accuracy of an optimal GS%predicted threshold for prefrailty/frailty. METHODS: This cross-sectional study included 998 community-dwelling ambulant participants aged >50 years (mean age = 68 years). Participants completed a multi-domain geriatric screen and a physical fitness assessment, from which the 10-m habitual gait speed, GS%predicted, Physical Frailty Phenotype (PFP) index, and 36-item Frailty Index (FI) were computed. RESULTS: Based on the FI, ~49% of participants had pre-frailty or frailty. The optimal threshold of GS%predicted (0.93) had greater screening accuracy than the 1.0 m/s fixed threshold for gait speed (AUC, 0.65 vs. 0.60; DeLong's P < 0.001). Replacing gait speed with GS%predicted in the PFP improved its overall discrimination (AUC, 0.70 vs. 0.67 of original PFP; DeLong's P < 0.001). CONCLUSIONS: Defining a "slow" gait speed by a GS%predicted value of <0.93 provided greater screening accuracy than the traditional 1.0 m/s threshold for gait speed. Our results also support the use of GS%predicted-derived PFP to identify older adults at risk of prefrailty/frailty. Geriatr Gerontol Int 2022; 22: 575-580.

Reference Ranges for Gait Speed and Sit-to-Stand Performance in a Cohort of Mobility-Intact Community-Dwelling Older Adults From Singapore.

OBJECTIVES: Slow gait speed and sit-to-stand performance are associated with adverse clinical outcomes in older adults. Identifying older adults with functional performance "below norms" is the first step toward prevention. We aimed to (1) examine the associations of age, body height, and gender with gait speed and sit-to-stand performance and (2) develop subgroup-specific reference ranges in older adults with no self-reported mobility limitations. DESIGN: Cross-sectional study. SETTING AND PARTICIPANTS: This study analyzed data from 775 community-dwelling older adults who reported no difficulty walking 100 m, climbing stairs, and rising from the chair. METHODS: Gait speed and sit-to-stand performance were measured by the 10-m gait speed test and 5-times sit-to-stand test, respectively. Bayesian linear regression was used to derive 95% reference ranges for gait speed and sit-to-stand performance, defined by different levels of age, body height, and gender. RESULTS: Overall, 95% reference range was 0.89-1.79 m/s for habitual gait speed and 7.4-27.9 stands/30 s for sit-to-stand pace. Age had the highest posterior probability (>99%) of a meaningful association with both functional outcomes. Additionally, height was strongly associated with gait speed: a 10-cm increase in height was associated with 0.07 m/s (95% credible interval, 0.05-0.10) faster gait speed. For sit-to-stand test, the lower 95% reference range limits tended to be similar across gender and gender-specific height subgroups, owing to the associations of faster sit-to-stand pace with shorter height and male gender. Because extensive tables of reference ranges are impractical, a web-based application (https://sghpt.shinyapps.io/ippts/) is created to provide subgroup-specific reference ranges. CONCLUSIONS AND IMPLICATIONS: In a large sample of mobile-intact older adults, reference ranges for gait speed and sit-to-stand performance differed meaningfully by age. Furthermore, gait speed was stature dependent. Although requiring validation, our findings may be used to define subgroup-specific "below-range" values and to complement existing universal clinical cut points for gait speed and sit-to-stand performance.

Factors Associated with Pain Intensity and Walking Disability After Lumbar Fusion: A Longitudinal Study.

STUDY DESIGN: Retrospective longitudinal study. OBJECTIVE: To identify the preoperative factors associated with postoperative lumbar fusion recovery in back or leg pain, self-reported walking time, and gait speed over a 6-month period. SUMMARY OF BACKGROUND DATA: The demand for lumbar fusion surgeries has significantly increased over the years. Yet, some patients report persistent postsurgical pain and poor functional outcomes. Unfortunately, the associated risk factors are not well understood. METHODS: The study analyzed 232 subjects with mono- or bisegmental lumbar fusion surgery who underwent standardized assessment preoperatively and at 4, 12, and 24weeks postoperatively. Preoperative variables collected were demographic, clinical, and psychological variables. Back or leg pain was measured by the Numeric Pain Rating Scale. Walking disability was measured by self-reported walking time and performance-based fast gait speed. Risk factors of pain and walking disability over time were identified using ordinal and linear mixed-effects modeling. RESULTS: At 6 months post-surgery, 17% of patients reported having moderate or severe back/leg pain and 24% were unable to walk longer than 30 minutes. Greater preoperative self-reported leg weakness frequency and body-mass-index (BMI) were strongly associated with greater pain and walking disability. Additionally, greater preoperative depression symptoms were associated with greater back/leg pain (adjusted odds ratio = 4.0) and shorter walking time (adjusted odds ratio = 2.7)-but not with slower gait speed (difference = 0.01 m/s). Old age and female gender were strongly associated with gait speed but not with self-reported walking time. CONCLUSION: A sizable proportion of patients had poor pain and walking outcomes even at 6 months post-surgery. Preoperative leg weakness and BMI were consistent risk factors and patients with greater depression symptoms may have poorer self-reported outcomes. Although requiring validation, our study has identified potentially modifiable risk factors which may give clinicians an opportunity to provide early (preoperative) and targeted intervention strategies to optimize postoperative outcomes.Level of Evidence: NA.