How to measure balance in clinical practice. A systematic review of the psychometrics and clinical utility of measures of balance activity for neurological conditions

Assessing standing balance with MOTI: a validation study

OBJECTIVES

This study aimed to determine the validity and reliability of a new device called MOTI for measuring balance by comparing its performance that with of the gold-standard force platform.

METHODS

The study involved collecting data from both devices in dual- and single-leg standing positions with eyes open and closed and using statistical measures to compare their performance.

RESULTS

The results showed that MOTI can accurately measure balance during dual-leg standing tasks but has poor to moderate performance during single-leg standing tasks. However, it could detect small changes in postural sway caused by a reduced base of support and/or visual feedback. The study also found that the test-retest reliability was poor to moderate for both devices.

CONCLUSIONS

These findings suggest that MOTI has potential as a reliable tool for measuring balance during certain tasks, but further research is needed to improve its performance during single-leg standing. This study provides valuable insights into the validity and reliability of MOTI for measuring balance and highlights the need for further investigation.

Balance function in critical illness survivors and evaluation of psychometric properties of the Mini-BESTest

Critical illness survivors commonly face impairments, such as intensive care unit-acquired weakness (ICUAW) which is characterized by muscle weakness and sensory deficits. Despite these symptoms indicating potential balance deficits, systematic investigations and validated assessments are lacking. Therefore, we aimed to assess balance function using the Mini-BESTest, evaluate its psychometric properties, and identify associated variables. Balance was assessed post-ICU discharge (V1) and at discharge from inpatient neurorehabilitation (V2) in patients with ≥ 5 days of invasive ventilation. Mini-BESTest measurement characteristics were evaluated in an ambulatory subgroup. A multiple linear regression was conducted. The prospective cohort study comprised 250 patients (34% female, 62 ± 14 years, median ICU stay 55 days). Median Mini-BESTest scores improved significantly from V1 (5 (IQR 0-15)) to V2 (18.5 (10-23)) with a large effect size. Excellent inter-rater and test-retest reliabilities of the Mini-BESTest were observed (ICC = 0.981/0.950). Validity was demonstrated by a very high correlation with the Berg Balance Scale (ρ = 0.90). No floor or ceiling effects were detected. Muscle strength, cognitive function, cerebral disease, critical illness polyneuropathy/myopathy, and depression were significantly associated with balance. Despite significant improvements during the rehabilitation period, balance disorders were prevalent in critical illness survivors. Ongoing therapy is recommended. Due to its excellent psychometric properties, the Mini-BESTest is suitable for use in critical illness survivors.Registration: The study was registered at the German Clinical Trials Register (DRKS00021753, date of registration: 2020-09-03).

Neurocognitive change over the course of a multiday external lumbar drain trial in patients with suspected normal pressure hydrocephalus

Objective: To characterize neurocognitive response to cerebrospinal fluid (CSF) diversion during a multiday external lumbar drainage (ELD) trial in patients with suspected normal pressure hydrocephalus (NPH). Methods: Inpatients (N = 70) undergoing an ELD trial as part of NPH evaluation participated. Cognition and balance were assessed using standardized measures before and after a three-day ELD trial. Cognitive change pre- to post-ELD trial was assessed in relation to change in balance, baseline neuroimaging findings, NPH symptoms, demographics, and other disease-relevant clinical parameters. Results: Multiday ELD resulted in significant cognitive improvement (particularly on measures of memory and language). This improvement was independent of demographics, test-retest interval, number of medical and psychiatric comorbidities, NPH symptom duration, estimated premorbid intelligence, baseline level of cognitive impairment, cerebrovascular disease burden, degree of ventriculomegaly, or other NPH-related morphological brain alterations. Balance scores evidenced a greater magnitude of improvement than cognitive scores and were weakly, but positively correlated with cognitive change scores. Conclusions: Findings suggest that cognitive improvement associated with a multiday ELD trial can be sufficiently captured with bedside neurocognitive testing. These findings support the utility of neuropsychological consultation, along with balance assessment, in informing clinical decision-making regarding responsiveness to temporary CSF diversion for patients undergoing elective NPH evaluation. Implications for the understanding of neuroanatomical and cognitive underpinnings of NPH are discussed.

Effects of physical exercise interventions on balance, postural stability and general mobility in Parkinson's disease: a network meta-analysis

OBJECTIVE

To assess which type of physical exercise intervention has the most beneficial effects on balance, postural stability and general mobility in patients with Parkinson's disease. These parameters were assessed using the Activities-specific Balance Confidence (ABC) scale, Berg Balance Scale (BBS), Mini-Balance Evaluation Systems Test (MiniBESTest) and Timed Up and Go Test (TUG).

DESIGN

Network meta-analysis.

METHODS

The PubMed, Cochrane Central Register of Controlled Trials, and Web of Science databases were searched up to August 2022 to identify randomized controlled trials on the effects of physical exercise interventions on balance, postural stability, and general mobility. The network meta-analysis included pairwise and indirect comparisons of results on the ABC scale, BBS, MiniBESTest, and TUG across 8 categories of physical exercise.

RESULTS

Eighty-six studies with a total of 4,693 patients were included. For the ABC scale, the indirect comparison showed that the highest effect size was observed for balance vs sensorimotor training without including endurance interventions (0.62; 95% confidence interval (95% CI) 0.06, 1.17). The highest effect sizes for BBS were observed for alternative exercises (1.21; 95% CI 0.62, 1.81), body-weight supported (BWS) interventions (1.31; 95% CI 0.57, 2.05), dance (1.18; 95% CI 0.33, 2.03) and sensorimotor training, including endurance interventions (1.10; 95% CI 0.46, 1.75) vs control groups. Indirect comparisons showed that the highest effect size for the MiniBESTest were observed for balance (0.75; 95% CI 0.46, 1.04) and resistance (0.58; 95% CI 0.10, 1.07) vs control groups. For the TUG, comparisons showed a significant effect size for alternative exercises (-0.54; 95% CI -0.82, -0.26), balance (-0.42; 95% CI -0.75, -0.08), resistance (-0.60; 95% CI -0.89, -0.31), and sensorimotor training including endurance interventions (-0.61; 95% CI -0.95, -0.27) vs control comparisons.

CONCLUSION

Balance interventions improve balance, postural stability, and general mobility in people with Parkinson's disease. Moreover, alternative exercises, dance, BWS interventions, resistance, and sensorimotor training, including and not including endurance interventions, are also effective.

Balancing Act: Acute and Contextual Vestibular Sensations of Cranial Electrotherapy Stimulation Using Survey and Sensor Outcomes in a Non-Clinical Sample

Cranial electrotherapy stimulation (CES) delivers low-intensity electrical currents to the brain to treat anxiety, depression, and pain. Though CES is considered safe and cost-effective, little is known about side effects emerging across different contexts. Our objective was to investigate how varying physical and cognitive demands impact the frequency and intensity of CES vestibular sensations in a sample of healthy young adults. We used a 2 (stimulation: sham, active) × 2 (physical demand: static sway, dynamic sit-to-stand) × 2 (cognitive demand: single-task remain silent, dual-task count backward) repeated measures design. Vestibular sensations were measured with surveys and wearable sensors capturing balance changes. Active stimulation did not influence reported vestibular sensations. Instead, high physical demand predicted more sensation reports. High cognitive demand, but not active stimulation, predicted postural sway unsteadiness. Significant effects of active stimulation on balance were observed only during the dynamic sit-to-stand transitions. In summary, CES induces vestibular sensations only for a specific outcome under certain circumstances. Our findings imply that consumers can safely maximize the benefits of CES while ensuring they are taking steps to minimize any potential side effects by considering their context and circumstances.

The minimal important difference for the Postural Assessment Scale for Stroke Patients in the subacute stage

BACKGROUND

The minimal important difference (MID) of the Postural Assessment Scale for Stroke Patients (PASS) remains unknown, limiting the interpretation of change scores.

OBJECTIVES

To estimate the MID of the PASS in patients with subacute stroke.

METHODS

Data at admission and discharge for 240 participants were retrieved from a longitudinal study. The "mobility" item of the Barthel Index was used as the anchor for indicating the improvement of posture control. Receiver operating characteristic (ROC) method was used to estimate the anchor-based MID of the PASS.

RESULTS

The ROC method identified a MID of 3.0 points, with a sensitivity of 81.0 % and a specificity of 75.6 %.

CONCLUSION

The MID of the PASS was 3.0 points, indicating that if a patient achieves an improvement of 3.0 or more points on the PASS, they have a clinically important improvement in posture control. Our results can help in interpreting change scores and aid in understanding the clinical values of treatment outcomes.

Comparison of different methods used in balance evaluation in children with diparetic cerebral palsy

PURPOSE

In this study, we aimed to investigate the validity and reliability of Single Leg Stance (SLS), Tandem Stance (TS) and Pediatric Reach Tests (PRT) in children with Cerebral Palsy (CP).

METHODS

Fifty-three children (31 boys, 22 girls, age:3-15 years, Gross Motor Function Classification System (GMFCS) Level I- II with diparetic CP were included the study. SLS, TS, PRT test used for balance evaluations. SLS test was made by standing on dominant (D) and non-dominant (ND) extremity both eyes opened (EO) and closed (EC).

RESULTS

The mean age of childrens were 7.88±3.43 years. The Cronbach's - coefficients of all tests used to evaluate the internal consistency were found to excellent to acceptable level. SLS-D with EO/ EC, SLS-ND with EO/ EC and TS with EO had strong correlation, TS with EC and PRT-Forward moderate correlation, PRT-Right and eft low correlation with GMFCS. All tests except PRT-Right and PRT-Left were discriminate balance ability between GMFCS level I and level II (AUC>0.800).

CONCLUSION

In this study, we used SLS, TS, PRT for balance evaluations and we investigated reliability and validity (construct and predictive) of each balance tests in childeren with diparetic CP. All tests were sensitive in distinguishing between GMFCS levels I and II, except PRT-Right and PRT-Left. As a result of the study, it was determined that the tests were valid and reliable, suggesting that physiotherapists will provide clinical advantage in order to quickly learn about the balance of children with CP.

Clinimetric evaluation of five clinically feasible measures of the leg extensor muscle strength in neurological rehabilitation settings

A gold-standard clinical measure of leg muscle strength has not been established. Therefore, the aim of this study was to evaluate clinimetric properties of five clinically feasible measures of lower-limb extensor muscle strength in neurological rehabilitation settings. This was a cross-sectional observational study of 36 participants with leg weakness as a result of a neurological condition/injury. Participants were recruited across a range of walking abilities, from non- to independently ambulant. Each was assessed using each of the following five measures: manual muscle test (MMT), hand-held dynamometry (HHD), seated single leg press one repetition maximum (1RM), functional sit-to-stand (STS) test and seated single leg press measured with a load cell. Each clinical measure was evaluated for its discriminative ability, floor/ceiling effects, test-retest reliability and clinical utility. The load cell and HHD were the most discriminative of the tests and were also resistant to floor/ceiling effects; however, the load cell was superior to the HHD when compared for its clinical utility. The MMT/STS tests received perfect scores for clinical utility, although similar to the 1RM test, they were susceptible to floor and ceiling effects. The load cell leg press test was the only measure of lower limb strength to satisfy all four clinimetric properties. Implications for clinical practice include, firstly, that strength tests available to clinicians vary in their clinimetric properties. Secondly, the functional status of the person will determine selection of the best clinical strength test. And lastly, load cell device technology should be considered for clinical strength assessments.

The Functional Balance Ability Measure: A Measure of Balance Across the Spectrum of Functional Mobility in Persons Post-Stroke

Objective

To determine whether the measurement properties of an instrument that combines items from the Berg Balance Scale (BBS) and the Functional Gait Assessment (FGA) called the Functional Balance Ability Measure (FBAM) supports measuring balance across the functional mobility spectrum.

Design

Retrospective cohort.

Setting

Item-level data were from an archival research database.

Participants

Ambulatory individuals (N=93, BBS=50 [29-56], FGA=16 [0-30], Fugl-Meyer Assessment of Lower Extremities=27 [14-34], self-selected walking speed=0.4±0.2 m/s, mean age ± SD, 61.7±11.3y; 30.1% female) with chronic stroke (≥6 months).

Interventions

Not applicable.

Main Outcome Measures

Unidimensionality was evaluated with a principal components analysis (PCA) of residuals. FBAM rating-scale characteristics, item hierarchy, item and person fit, and person separation were investigated using the Andrich Rating Scale Model.

Results

PCA findings indicate the FBAM is sufficiently unidimensional. Rating scale structure was appropriate without modifying the original BBS and FGA scoring systems. Item hierarchy aligned with clinical and theoretical predictions (hardest item: FGA-gait with narrow base of support, easiest item: BBS-sitting unsupported). One item (BBS-standing on 1 foot) misfit, however, removal marginally affected person measures and model statistics. The FBAM demonstrated high person reliability (0.9) and 6 people (∼6%) misfit the expected response pattern. The FBAM separated participants into 4 statistically distinct strata, without a floor or ceiling effect.

Conclusions

The FBAM is a unidimensional measure for balance ability across a continuum of functional tasks. Rating-scale characteristics, item hierarchy, item and person fit, and person separation support the FBAM's measurement properties in persons with chronic stroke. Future work should investigate measurement with fewer items and whether the FBAM addresses barriers to adoption of standardized balance measures in clinical practice.

Feasibility, criterion and construct convergent validity of the 2-minute walk test and the 10-meter walk test in an oncological context

Objective

To examine the feasibility, the criterion, and the construct convergent validity of the 2-Minute Walk Test (2MWT) and the 10-Meter Walk Test (10MeWT) against the 6-Minute Walk Test (6MWT) to assess walking capacity in people with cancer. The criterion concurrent validity of a self-test version of the 10MeWT (10MeWTself-test) was also evaluated against the 10MeWT.

Methods

Fifty-six people with cancer performed the 2MWT, the 10MeWT at comfortable and fast speeds, the 6MWT, and the 10MeWTself-test. The feasibility of the tests was assessed using safety, adverse events, space requirements, time taken to administer and interpret the tool, equipment or training required, cost, and portability as criteria. Validity was assessed using Pearson correlation coefficients and Bland Altman plots.

Results

The 2MWT, 6MWT, 10MeWT, and 10MeWTself-test were feasible for people with cancer. The 2MWT and the 10MeWT results were moderately to strongly correlated with the 6MWT results (0.61 < r < 0.84, p < 0.001). The 10MeWTself-test results were strongly correlated with the 10MeWT results at comfortable and fast speeds (r = 0.99, p < 0.001).

Conclusions

The 2MWT, 10MeWT, and 10MeWTself-test are simple, rapid, and feasible tests for use in people with cancer. The strong correlation between the 2MWT and 6MWT results indicates that the 2MWT can be used as an alternative walking capacity assessment tool. The 10MeWT results moderately correlated with those of the other two tests, suggesting that it partially measures the same construct of walking capacity in walking-independent outpatients with cancer. The 10MeWTself-test showed promising results but needs further investigations in ecological settings.

Clinical Static Balance Assessment: A Narrative Review of Traditional and IMU-Based Posturography in Older Adults and Individuals with Incomplete Spinal Cord Injury

Maintaining a stable upright posture is essential for performing activities of daily living, and impaired standing balance may impact an individual's quality of life. Therefore, accurate and sensitive methods for assessing static balance are crucial for identifying balance impairments, understanding the underlying mechanisms of the balance deficiencies, and developing targeted interventions to improve standing balance and prevent falls. This review paper first explores the methods to quantify standing balance. Then, it reviews traditional posturography and recent advancements in using wearable inertial measurement units (IMUs) to assess static balance in two populations: older adults and those with incomplete spinal cord injury (iSCI). The inclusion of these two groups is supported by their large representation among individuals with balance impairments. Also, each group exhibits distinct aspects in balance assessment due to diverse underlying causes associated with aging and neurological impairment. Given the high vulnerability of both demographics to balance impairments and falls, the significance of targeted interventions to improve standing balance and mitigate fall risk becomes apparent. Overall, this review highlights the importance of static balance assessment and the potential of emerging methods and technologies to improve our understanding of postural control in different populations.

Technology-based balance performance assessment can eliminate floor and ceiling effects

Many clinical measurement tools for balance have ceiling effects. Technology-based assessments using virtual reality systems such as the Computer-Assisted Rehabilitation Environment (CAREN) may provide a way to develop objective, quantitative measures that scale from low to high levels of difficulty. Our objective was to: (1) develop a performance assessment tool (PAT) for the CAREN; (2) quantify the reliability of the tool; (3) validate the scores against clinical balance measures; and (4) compare the scores from a population with balance impairments to those from able-bodied individuals in a cross-sectional validation study. Three games were developed on the CAREN and tested on 49 participants (36 able-bodied and 13 with impaired mobility). For each module, the corresponding measures were transformed into scores using a series of functions such that ceiling and flooring effects would be minimized. The results showed an association between scores and age, an overlap in scores from impaired high-performance individuals and able-bodied low performance individuals, and a correlation of PAT scores with other clinical tests. Several of the limitations of current clinical tools, including floor and ceiling effects, were overcome by the PAT, suggesting that the PAT can be used to monitor the effect of rehabilitation and training.

The Influence of Anthropometric Variables and Filtering Frequency on Center of Pressure Data

Good postural control is considered to be a key component of an active lifestyle, and numerous studies have investigated the Center of Pressure (CoP) as a way of identifying motor deficits. However, the optimal frequency range for assessing CoP variables and the effect of filtering on the relationships between anthropometric variables and CoP are unclear. The aim of this work is to show the relationship between anthropometric variables and different ways of filtering the CoP data. CoP was measured in 221 healthy volunteers using a KISTLER force plate in four different test conditions, both mono and bipedal. The results show no significant changes in the existing correlations of the anthropometric variable values over different filter frequencies between 10 Hz and 13 Hz. Therefore, the findings with regard to anthropometric influences on CoP, with a reasonable but less than ideal filtering of the data, can be applied to other study settings.

The effect of telerehabilitation on balance in stroke patients: is it more effective than the traditional rehabilitation model? A meta-analysis of randomized controlled trials published during the COVID-19 pandemic

Objective

Telerehabilitation and telemedicine have gradually gained popularity. In 2019, the outbreak of COVID-19 started in Wuhan and then spread across the world. To date, most countries have opted to coexist with the virus. However, patients, especially those who have suffered a stroke, should take measures to avoid being infected with any disease as much as possible since any infectious disease can lead to adverse events for them. Telerehabilitation can be beneficial to stroke patients as they are less likely to be infected by the virus. In recent years, several studies on telerehabilitation have been conducted globally. This meta-analysis aimed to investigate the effects of telerehabilitation on the balance ability of stroke patients, compare the efficacy of conventional rehabilitation with telerehabilitation, explore the characteristics of telerehabilitation and conventional rehabilitation, and provide recommendations for rehabilitation programs in the context of the global pandemic.

Methods

We searched Pubmed, Embase, the Web of Science, and The Cochrane Library databases from 1 January 2020 to 31 December 2022 for randomized controlled trials published in English that evaluated the improvement of balance function in stroke patients after telerehabilitation and compared the differences between telerehabilitation (TR) and conventional rehabilitation (CR). The random-effects model was utilized to calculate mean differences (MDs) with 95% confidence intervals (CIs) to estimate intervention effects. Statistical heterogeneity was assessed according to the I² values. The risk of bias was measured using the Cochrane risk-of-bias assessment tool.

Results

We included nine studies in the system evaluation, all of which were included in the pooled analysis. All outcomes in the experimental and control groups improved over time. The comparison between groups concluded that people who received the telerehabilitation intervention had a significant improvement in the Berg Balance Scale (MD = 2.80; 95% CI 0.61, 4.98, P < 0.05, I2 = 51.90%) and the Fugl-Meyer Assessment (MD = 8.12; 95% CI 6.35, 9.88, P < 0.05, I2 = 0) compared to controls. The Timed Up and Go test (MD = -4.59; 95% CI -5.93, -.25, P < 0.05, I² = 0) and Tinetti Performance-Oriented Mobility Assessment-Balance (MD = 2.50; 95% CI 0.39, 4.61, P < 0.05) scored better in the control group than in the experimental group. There were no significant differences in other outcomes between the two groups.

Conclusion

Studies on changes in medical conditions during the COVID-19 pandemic also demonstrated that, for stroke patients, telerehabilitation achieves similar effects as the conventional rehabilitation model and can act as a continuation of the conventional rehabilitation model. Owing to the different equipment and intervention programs of telerehabilitation, its curative effect on the static balance and reactive balance of stroke patients may be different. Currently, telerehabilitation may be more conducive to the rehabilitation of patients' static balance abilities, while conventional rehabilitation is more effective for the rehabilitation of patients' reactive balance. Therefore, further studies are needed for investigating the difference in efficacy between varied devices and telerehabilitation programs. Further research is needed on static and reactive balance. In addition, such research should have a large body of literature and a large sample size to support more definitive findings based on the context of the COVID-19 pandemic.

Systematic review registration

CRD42023389456.

EMG-EMG coherence during voluntary control of human standing tasks: a systematic scoping review

Background

Intra- or inter-muscular (EMG-EMG) coherence is a simple and non-invasive method for estimating central nervous system control during human standing tasks. Although this research area has developed, no systematic literature review has been conducted.

Objectives

We aimed to map the current literature on EMG-EMG coherence during various standing tasks to identify the research gaps and summarize previous studies comparing EMG-EMG coherence between healthy young and elderly adults.

Methods

Electronic databases (PubMed, Cochrane Library, and CINAHL) were searched for articles published from inception to December 2021. We incorporated studies that analyzed EMG-EMG coherence of the postural muscles in various standing tasks.

Results

Finally, 25 articles fulfilled the inclusion criteria and involved 509 participants. Most participants were healthy young adults, while only one study included participants with medical conditions. There was some evidence that EMG-EMG coherence could identify differences in standing control between healthy young and elderly adults, although the methodology was highly heterogeneous.

Conclusion

The present review indicates that EMG-EMG coherence may help elucidate changes in standing control with age. In future studies, this method should be used in participants with central nervous system disorders to understand better the characteristics of standing balance disabilities.

Exposure to volatile hydrocarbons and neurologic function among oil spill workers up to 6 years after the Deepwater Horizon disaster

BACKGROUND

During the 2010 Deepwater Horizon (DWH) disaster, oil spill response and cleanup (OSRC) workers were exposed to toxic volatile components of crude oil. Few studies have examined exposure to individual volatile hydrocarbon chemicals below occupational exposure limits in relation to neurologic function among OSRC workers.

OBJECTIVES

To investigate the association of several spill-related chemicals (benzene, toluene, ethylbenzene, xylene, n-hexane, i.e., BTEX-H) and total petroleum hydrocarbons (THC) with neurologic function among DWH spill workers enrolled in the Gulf Long-term Follow-up Study.

METHODS

Cumulative exposure to THC and BTEX-H across the oil spill cleanup period were estimated using a job-exposure matrix that linked air measurement data to detailed self-reported DWH OSRC work histories. We ascertained quantitative neurologic function data via a comprehensive test battery at a clinical examination that occurred 4-6 years after the DWH disaster. We used multivariable linear regression and modified Poisson regression to evaluate relationships of exposures (quartiles (Q)) with 4 neurologic function measures. We examined modification of the associations by age at enrollment (<50 vs. ≥50 years).

RESULTS

We did not find evidence of adverse neurologic effects from crude oil exposures among the overall study population. However, among workers ≥50 years of age, several individual chemical exposures were associated with poorer vibrotactile acuity of the great toe, with statistically significant effects observed in Q3 or Q4 of exposures (range of log mean difference in Q4 across exposures: 0.13-0.26 μm). We also observed suggestive adverse associations among those ≥ age 50 years for tests of postural stability and single-leg stance, although most effect estimates did not reach thresholds of statistical significance (p < 0.05).

CONCLUSIONS

Higher exposures to volatile components of crude oil were associated with modest deficits in neurologic function among OSRC workers who were age 50 years or older at study enrollment.

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.

Measurement of Mobility and Physical Function in Patients Hospitalized With Hip Fracture: A Systematic Review of Instruments and Their Measurement Properties

OBJECTIVE

Hip fractures are common and significantly impact mobility and physical function. Measurement of patient progress post hip fracture in the acute hospital setting is important to monitor early recovery and outcomes. The objective of this systematic review was to assess the measurement properties (reliability, validity, responsiveness), interpretability, and clinical utility of instruments used to measure mobility and physical function in patients with hip fracture in the acute hospital setting.

METHODS

Three databases (MEDLINE, Embase, and CINAHL) were searched. Studies reporting direct clinician assessment instruments to measure mobility or physical function in patients with hip fracture were included. Data were extracted by 2 reviewers, and the quality of each study was determined using the COnsensus-based Standards for the selection of health Measurement INstruments risk of bias checklist.

RESULTS

Sixty-eight studies were included with 19 measurement instruments identified. The most frequently used instruments were the Timed "Up & Go" Test (TUG) (19 studies), Barthel Index (BI) (18 studies), Cumulated Ambulation Score (CAS) (18 studies), and Functional Independence Measure (FIM) (14 studies). All 4 of these instruments demonstrated good predictive validity (clinical outcomes and mortality) and responsiveness over time (effect sizes 0.63-2.79). The BI and CAS also had good reliability (intraclass correlation coefficient [ICC] >0.70). Floor effects were demonstrated for the TUG, CAS, and FIM (16%-60% of patients). The TUG, CAS, and BI all had good clinical utility.

CONCLUSION

Depending on the context (use by treating clinicians, research, benchmarking), 1 or a combination of the BI, CAS, and TUG provide robust measurement of mobility and physical function for patients with hip fracture in the acute hospital setting.

IMPACT

This study identified 3 instruments suitable for measuring mobility and physical function in hospitalized patients following hip fracture. This provides clinicians with tools to measure patient progress and benchmark across sites to improve patient outcomes.

Is telehealth an effective and feasible option for improving falls-related outcomes in community-dwelling adults with neurological conditions? A systematic review and meta-analysis

OBJECTIVE

To determine the effectiveness of telehealth interventions in reducing community falls risk or rates compared to equivalent in-person interventions in adults with neurological conditions.

DATA SOURCES

Eight electronic databases, trial registries and search engines were searched for the concepts 'falls', 'neurological conditions', and 'telehealth', limited to English language, from inception until August 2022.

REVIEW METHODS

Search for original research where the intervention was delivered via synchronous videoconferencing with the aim of reducing falls and falls-related outcomes. Screening and risk of bias assessment were completed by two independent researchers. Outcome data included falls rates, falls-related outcomes, safety, feasibility, and acceptability. Risk of bias was assessed using the ROB-2 and ROBINS-I tools. Quality of evidence was rated with the grading of recommendations, assessment, development and evaluation (GRADE) approach.

RESULTS

Seventeen studies with 581 participants were included; six were randomised controlled trials. Risk of bias ranged from low to high. Only one study (n = 76) reported falls and did not find differences between telehealth and in-person physiotherapy. There was low-quality evidence that telehealth interventions improve balance outcomes more than face-to-face interventions (pooled between-group mean difference 2.48 Berg Balance Scale units, 95%CI 0.77 to 4.20). Fear of falling was not different between intervention delivery modes.

CONCLUSION

Findings suggest that telehealth delivered falls prevention interventions are safe, feasible and acceptable in community-dwelling adults with neurological conditions, however, data related to effectiveness in reducing falls is limited. Low-quality evidence suggests that telehealth may deliver similar or better outcomes for standing balance in this population.PROSPERO Registration: (CRD42021240167).

The Use of Portable Devices for the Instrumental Assessment of Balance in Patients with Chronic Stroke: A Systematic Review

BACKGROUND

Improving balance remains a challenge in stroke rehabilitation. The technological development has allowed the design of more accessible and user-friendly systems for assessing postural control.

OBJECTIVES

The aim of this review was to analyze portable devices for the instrumental assessment of balance in patients with chronic stroke.

METHODS

PRISMA guidelines were used to carry out the systematic review. The literature search was restricted to articles written in English or Spanish published from 2013 to December 2022 in Pubmed, Web of Science, Scopus, PEDro, and CINAHL. Of the 309 search results, 229 unique references were reviewed after duplicates were removed. The PEDro scale was applied to evaluate the methodological quality of the included papers, and the degree of evidence and level of recommendation were determined through the Oxford Centre for Evidence-Based Medicine.

RESULTS

A total of seven articles reporting on five different balance testing devices were included in this systematic review; they regarded BIORescue, a smartphone application, and the Biodex-BioSway Balance System for the evaluation of standing balance, and SwayStar Balance and Xsens ForceShoes™ for the evaluation of dynamic balance during walking.

CONCLUSIONS

The use of portable devices that assess balance in adult patients with chronic stroke is scarce.

Construct Validity of the Revised High-Level Mobility Assessment Tool for Children Who Are Developing Typically

OBJECTIVE

The aim of this project was to evaluate the construct validity of the high-level mobility assessment tool (HiMAT) for children who are developing typically with no underlying condition that may affect mobility.

METHODS

The HiMAT is a revised 8-item measure of high-level mobility. Rasch analysis was used to assess fit to the Rasch model indicating unidimensionality, person separation index local dependency, targeting of items, and differential item functioning.

RESULTS

Children with typical development aged 5 to 12 years (n = 1091; 554 girls and 537 boys) were recruited from 8 schools. The mean HiMAT score was 22.4/32 (range, 8-32). Data fit the Rasch model, indicating that the HiMAT was a unidimensional scale assessing a single construct (high-level mobility). The person separation index was .86, indicating good reliability. The skip item exhibited differential item functioning by sex. Although items were well targeted, the fit residual mean for persons was 2.40, indicating most found the tasks easy to complete. Unlike in adult populations, 2 items (walk and walk over obstacle) exhibited local dependency >0.2.

CONCLUSION

The HiMAT is a unidimensional targeted performance measure of high-level mobility for children with typical development aged 5 to 12 years. Further examination of the relationship between the test items "walk" and "walk over an obstacle" may be required to ensure that scores on these items are truly independent of one another.

Effect of home-based virtual reality training and telerehabilitation on balance in individuals with Parkinson disease, multiple sclerosis, and stroke: a systematic review and meta-analysis

OBJECTIVE

In the last decade, there is a growing interest in the use of virtual reality for rehabilitation in clinical and home settings. The aim of this systematic review is to do a summary of the current evidence on the effect of home-based virtual reality training and telerehabilitation on postural balance in individuals with central neurological disorders.

METHODS

Literature was searched in PubMed, Web of Science, PEDro, ScienceDirect, and MEDLINE. Randomized controlled trials (RCTs) evaluating the effect of home-based virtual reality (VR) training and telerehabilitation (TR) on postural balance in patients with Parkinson's disease, Multiple sclerosis or stroke. Studies were imported to EndNote and Excel to perform two screening phases by four reviewers. Risk of bias was assessed using PEDro scale and Cochrane assessment tool for risk of bias. Synthesis of the data on comparative outcomes was performed using RevMan software.

RESULTS

Seven RCTs were included, with all three pathologies represented. VR and TR consisted of a training device (e.g., Nintendo Wii or Xbox 360) and a monitoring device (e.g., Skype or Microsoft Kinect). Five studies used the Berg Balance Scale (BBS) for measuring postural balance. Across studies, there was an improvement in BBS scores over time in both experimental and control groups, and the effect remained at follow-up for both groups. However, there was no significant difference between  groups post-intervention (MD = 0.74, p = 0.45).

CONCLUSION

Home-based VR and TR can be used as prolongation to conventional therapy.

Association between endurance of the trunk extensor muscles and balance performance in community-dwelling older adults: a cross-sectional analysis

Background/Aims

Previous research has disregarded the performance of the extensor muscle group of the trunk in balance control. The main purpose of this exploratory study was to assess the association between balance performance and endurance of the trunk extensor muscles in older adults, considering possible co-factors such as age and body mass index.

Methods

A correlational and predictive cross-sectional study was conducted with 61 community dwelling older adults (women n=45) with a mean age of 71 years (± standard deviation 6 years), and a mean body mass index of 28.1 kg/m2 (± standard deviation ± 4.7 kg/m2). The Berg Balance Scale was used to assess balance performance and Trunk Extensor Endurance Test to assess muscle endurance. Spearman's correlation coefficients (ρ) and single and multiple regression analyses were performed. Statistical significance was set at 0.05.

Results

The largest correlations were found between the Berg Balance Scale score and Trunk Extensor Endurance Test (ρ=0.41, P=0.001) and body mass index (ρ=−0.36, P=0.005). Muscle endurance alone predicted ~10% of the Berg Balance Scale score (R2=0.10, P=0.015). When combined with body mass index, it accounted for ~19% (R2=0.19, P=0.002). Adding the remaining variable (age) to the previous model increased the prediction by ~3% (R2=0.22, P=0.002).

Conclusions

Muscle endurance and body mass index significantly predicted (~19%) balance performance in older adults. Because these are modifiable factors, they should be routinely included in the screening of balance performance in older adults and addressed accordingly in preventive or rehabilitation programmes.

Anthropometric, Psychosocial, Physiological, and Postural Observances During Ramadan in Men With Chronic Obstructive Pulmonary Disease

This study aimed to carry out a Ramadan observance (RO) on anthropometric, psychosocial, physiological, and postural characteristics of patients with chronic obstructive pulmonary disease (COPD). Twenty COPD patients were evaluated. Tests performed 1 week before Ramadan (C), and during the second (R-2) and the fourth weeks of Ramadan (R-4) included standard anthropometry, spirometry, a quality of life questionnaire (VQ11), a 6-minute walking test (6MWT), measurement of maximal voluntary contraction force of the quadriceps (MVC), Timed Get Up and Go (TUG), Berg Balance Scale (BBS), and Unipedal Stance (UST). During R-2, there were significant decreases in forced vital capacity and forced expiratory volumes, 6MWT distance, MVC, BBS, and UST, with significant increases in TUG and significant changes in VQ11. During R-4, there was some recovery, but all variables remained significantly different from initial control data. To conclude, RO adversely affects pulmonary function, exercise performance, postural balance, and quality of life in COPD, with some recovery by the R-4. Although a number of functional consequences remain to be elucidated, functional losses were insufficient to limit daily living in our sample, but further studies are recommended in those with more severe COPD, paying particular attention to postural disturbances and a possible increase in the risk of falls.

Feasible and clinical relevant outcome measures for adults with mitochondrial disease

There is no consensus on clinical outcome measures that reflect function, activities and participation which are suitable for adults with mitochondrial diseases (MD). The aim of this study was to determine feasible and clinically relevant outcome measures for patients with MD . In 156 adult patients with MD, endurance, balance, strength and mobility tests were evaluated. All tests showed a negative deviation to healthy reference values. Balance tests were feasible and significantly correlated with clinical severity. The Åstrand cycle test was not feasible in 55%, whereas the feasibility of the 6 min walking test is unclear in patients with MD.

Best Quantitative Tools for Assessing Static and Dynamic Standing Balance after Stroke: A Systematic Review

Purpose: Our objective was to examine the psychometric qualities (reliability and validity) and clinical utility of quantitative tools in measuring the static and dynamic standing balance of individuals after stroke. Method: We searched four databases (PubMed/MEDLINE, PEDro, Embase, and CINAHL) for studies published from January 2018 through September 2019 and included those that assessed the psychometric properties of standing balance tests with an adult stroke population. We evaluated the quality of the studies using the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) checklist and assessed each test on a utility assessment scale. Results: A total of 22 studies met the inclusion criteria, and 18 quantitative tools for assessing static or dynamic standing balance of individuals with stroke were analyzed. Findings support good or excellent reliability for all tests, whereas correlations for validity ranged from weak to strong. Study quality was variable. Dynamic balance tests had better clinical utility scores than static ones. Five tests had complete psychometric analyses: quiet standing on a force platform, five-step test, sideways step, step length, and turn tests.

Reliability, Validity, Clinical Utility, and Responsiveness of Measures for Assessing Mobility and Physical Function in Patients With Traumatic Injury in the Acute Care Hospital Setting: A Prospective Study

OBJECTIVE

The longer-term impact of injury is increasingly recognized, but the early phases of recovery are less well understood. The best tools to measure early recovery of mobility and physical function following traumatic injury are unclear. The purpose of this study was to assess the clinical utility, validity, reliability, and responsiveness of 4 mobility and physical function measures in patients following traumatic injury.

METHODS

In this cohort, measurement-focused study (n = 100), the modified Iowa Level of Assistance Score, Acute Care Index of Function, Activity Measure for Post-Acute Care "6 Clicks" short forms, and Functional Independence Measure were completed during first and last physical therapy sessions. Clinical utility and floor and ceiling effects were documented. Known-groups validity (early vs late in admission and by discharge destination), predictive validity (using 6-month postinjury outcomes data), and responsiveness were established. Interrater reliability was assessed in 30 patients with stable mobility and function.

RESULTS

Participants had a median age of 52 years (interquartile range = 33-68 years), and 68% were male. The modified Iowa Level of Assistance Score, Acute Care Index of Function, and "6 Clicks" short forms were quick to administer (an extra median time of 30 seconds-1 minute), but the Functional Independence Measure took much longer (extra median time of 5 minutes). At the last physical therapy session, ceiling effects were present for all measures except the Functional Independence Measure (18%-33% of participants). All had strong known-groups validity (early vs late in admission and by discharge destination). All were responsive (effect sizes >1.0) and had excellent interrater reliability (intraclass correlation coefficients = 0.79-0.94).

CONCLUSION

All 4 measures were reliable, valid, and responsive; however, their clinical utility varied, and ceiling effects were common at physical therapy discharge.

IMPACT

This study is an important step toward evidence-based measurement in acute trauma physical therapy care. It provides critical information to guide assessment of mobility and physical function in acute trauma physical therapy, which may facilitate benchmarking across different hospitals and trauma centers and further progress the science and practice of physical therapy following traumatic injury.

Die deutsche Version des Brunel Balance Assessments zur Erfassung der Gleichgewichtsfähigkeit bei Menschen nach einem Schlaganfall: kulturelle Adaptation und erste psychometrische Evaluation

Hintergrund Das Brunel Balance Assessments (BBA) ist ein klinisches Messinstrument zur Erfassung der Gleichgewichtsfähigkeit von Menschen nach Schlaganfall. Die englischsprachige Originalversion des Assessments weist gute Gütekriterien auf.

Ziel Übersetzung und kulturelle Adaptation des BBA für den deutschsprachigen Raum sowie erste Einschätzung der Praktikabilität und Konstruktvalidität.

Methode Das BBA wurde konform einer etablierten Leitlinie ins Deutsche übersetzt. Als Teil dieses Prozesses wurde eine präfinale deutsche Version des Assessments über einen Zeitraum von 10 Wochen in einem ambulanten Rehabilitationszentrum von Physiotherapeut*innen klinisch angewendet. Die anschließende Überarbeitung des Assessments basierte auf den Erfahrungen der Anwender*innen. Eine erste Analyse der Konstruktvalidität folgte dem Ansatz des Hypothesentestens. Es wurde angenommen, dass das BBA stark mit Testwerten anderer Assessments des funktionellen Gleichgewichts und der Gehfähigkeit korreliert. Als Indikator der Praktikabilität wurde die Durchführungszeit des BBA erfasst.

Ergebnisse Die präfinale deutsche Version wurde von 10 Therapeut*innen mit 25 Patient*innen nach Schlaganfall klinisch angewendet. Durch geringfügige Anpassungen wurde eine finale deutsche Version des BBA erstellt. BBA-Testwerte korrelierten moderat mit Testwerten des TUG und Testwerten der FAC. Die durchschnittliche Durchführungszeit des BBA betrug 17 ± 4 Minuten.

Schlussfolgerung Das BBA wurde übersetzt, kulturell für den deutschsprachigen Raum adaptiert und steht nun für die klinische Anwendung zur Verfügung. Vorläufige Analysen weisen auf eine moderate Konstruktvalidität bei Patient*innen nach einem Schlaganfall im ambulanten Setting hin. Eine ausführliche Überprüfung der Gütekriterien steht aus.

Trunk Impairment as a Predictor of Activities of Daily Living in Acute Stroke

Background and purpose: Trunk function plays a key role in performing activities of daily living (ADL) including locomotion and sitting. Sitting and ADL should be performed as early as possible especially during the acute phase of stroke rehabilitation. Therefore, this study aimed to assess trunk function among patients with acute stroke using the Trunk Impairment Scale (TIS) and to predict its functional outcomes.

Methods: Overall, 67 patients with acute stroke (i.e., within 2 days of occurrence of the stroke) were included. The following clinical assessment items were obtained within 48 h after stroke onset and on the day before discharge from the hospital. Trunk function was examined using TIS and Trunk Control Test (TCT). The motor function of the upper and lower extremities was assessed using the stroke impairment assessment set motor (SIAS-M) score, and ADL was assessed using functional independence measure motor (FIM-M) items.

Results: Multiple regression analysis was performed using the stepwise regression method, using the total FIM-M score following discharge as the dependent variable and age, TIS, TCT, SIAS-M, and FIM-M within 48 h after stroke onset as the independent variables. Age, TIS, and FIM-M within 48 h after stroke onset were selected as the input variables and showed a high-adjusted determination coefficient (R² = 0.79; P < 0.001).

Conclusion: TIS is a reliable method for evaluating trunk control function and is an early predictor of ADL among patients with acute stroke.

Diagnostic tests to assess balance in patients with spinal cord injury: a systematic review of their validity and reliability

Background

Sophisticated biomechanical instruments can assess balance in patients with spinal cord injury (SCI) with accuracy and precision; however, they are costly and time consuming to use. Clinical diagnostic tests to assess balance in patients with SCI are less costly and easier to use, but there is limited literature available regarding their reliability and validity.

Objectives

To review systematically articles reporting the validity and reliability of diagnostic tests used to assess balance function in patients with SCI.

Methods

We searched for articles in the English language from the earliest record to December 15, 2020, which reported validity or reliability of any clinical instrument or diagnostic test used to assess balance in patients with SCI. Articles assessing balance in paraplegic patients with causes other than SCI were excluded. Databases included MEDLINE, AMED, EMBASE, HMIC, PsycINFO, CINAHL, Scopus, and Google Scholar. The COSMIN Risk of Bias checklist was used to assess the studies included and PRISMA-DTA guidelines were applied.

Results

We included 16 articles that assessed the validity or reliability of 10 diagnostic tests. The Functional Reach Test (FRT), Berg Balance Scale (BBS), and Mini-Balance Evaluation Systems Test (Mini-BESTest) were assessed by more than 1 study, while the remaining 7 diagnostic tests including the Function in Sitting Test, T-Shirt Test, Motor Assessment Scale item 3, Sitting Balance Score, 5 Times Sit-to-Stand Test, Tinetti scale, and Sitting Balance Measure were assessed by 1 study each. The FRT has good-to-excellent test-retest reliability, excellent inter-rater reliability, and good construct, concurrent, and convergent validity. The BBS has excellent inter-rater and intra-rater reliability, high internal consistency, and good concurrent and construct validity. The Mini-BESTest has excellent test-retest reliability, excellent inter-rater reliability, high internal consistency, and good concurrent, convergent, and construct validity.

Conclusions

The FRT, BBS, and Mini-BESTest appear to be valid and reliable clinical instruments to assess balance function in patients with SCI.

Evaluation of balance in patients with chronic obstructive pulmonary disease with practical tests

INTRODUCTION

Patients with chronic obstructive pulmonary disease (COPD) have impaired balance and hence fall more frequently. Easy application of balance evaluation tests can prevent the loss of time in the outpatient clinic for patients with COPD. In this study, we aimed to compare the efficacy of Berg Balance Scale (BBS), a time-consuming but a widely used test, with other easy-to-perform tests such as the Single Leg Stance (SLS), Five Repetition Sit to Stand (5STS), Four Step Square (FSST), and Timed Up and Go (TUG) tests.

METHODS

A total of 71 patients with COPD and 70 control subjects with matching demographic characteristics were included in the study. All patients undertook pulmonary function tests and their scores of 6-min walk-test (6MWT), modified Medical Research Council (mMRC) dyspnoea scale, COPD assessment questionnaire (CAT) and body mass index (B) were recorded. In addition, the severity of airway obstruction (O), the dyspnoea severity (D) and exercise capacity (E) (BODE) index scores were measured. All patients with COPD were classified into four groups, A to D, based on the GOLD 2017 criteria. All subjects undertook the BBS, SLS, 5STS, FSST and TUG tests.

RESULTS

Balance tests revealed increased balance impairment in patients with COPD in comparison with the control subjects (P < .05). The BBS, SLS, FSST and TUG examinations suggested that balance impairment was frequent in Groups C and D patients with COPD (P < .05). FSST and TUG had the highest correlation with BBS (r = -.812 and -.842 and P < .001 and <.001, respectively). The results of FSST and TUG were the closest to those of BBS test.

CONCLUSIONS

FSST and TUG tests can be applied for the assessment of bodily balance status among patients with COPD in outpatient clinics.

Characterization of standing balance after incomplete spinal cord injury: Alteration in integration of sensory information in ambulatory individuals

BACKGROUND

Up to one-third of individuals with a recent spinal cord injury (SCI) and most of the individuals with an incomplete lesion are able to regain partial balance and walking ability after the first-year post-injury. However, most individuals experience injurious falls while standing and frequent losses of balance post-rehabilitation, which can result in physical injuries and a fear of falling.

RESEARCH QUESTION

Control of balance during quiet standing depends on the integration of sensory information. Since SCI causes sensory and motor impairments, understanding the underlying mechanisms of how postural control is regulated is of significant importance for targeted and guided rehabilitation post-SCI.

METHODS

We characterized the impact of a variety of challenging conditions on the standing balance for eight participants with incomplete SCI with walking ability compared to twelve age-matched able-bodied individuals using a waist-mounted inertial measurement unit (IMU). We compared balance biomarkers derived from IMUs' readouts under conditions that challenged balance by affecting somatosensory (i.e., standing on hard vs. foam surfaces) and visual (i.e., eyes open vs. closed) inputs. We performed a three-way ANOVA or a Kruskal-Wallis test to characterize changes in postural control post-SCI based on reliance on somatosensory and visual information using balance biomarkers.

RESULTS

We observed a reduced stability performance, an increased control demand, and a less effective active correction post-SCI in all standing conditions. Due to impaired somatosensory feedback, individuals with incomplete SCI showed a higher and lower reliance on visual and somatosensory information, respectively, for maintaining balance (p < 0.05).

SIGNIFICANCE

Using a single waist-mounted IMU, the proposed method could characterize standing balance in individuals with incomplete SCI compared to able-bodied participants. Having high clinical utility and sufficient resolution with discriminatory ability, our method could be used in the future to objectively evaluate the effectiveness of rehabilitative interventions on the balance performance of individuals with SCI.

Functional Gait Assessment scale in the rehabilitation of patients after vestibular tumor surgery in an acute hospital

BACKGROUND

Patients in the acute phase of rehabilitation after vestibular tumor surgery are dysfunctional in basic daily activities. Balance, gait impairments, and falls are prevalent with vestibular loss.

AIM

To determine the degree of balance disorders after vestibular tumor surgery, the susceptibility to falls and to assess motor tasks using the Functional Gait Assessment (FGA) scale for functional gait, as part of the vestibular rehabilitation program during hospital stay.

METHODS

Patients who achieved a score higher than 25 points on the Mini-Mental State Examination and higher than 8 points on the Barthel index were included in the study. They were evaluated with the Berg Balance Scale the second day after surgery, during their hospital stay, at discharge, and three months after surgery. Throughout their hospitalization, patients took part in the vestibular rehabilitation program, focusing on multiple motor tasks included in the FGA.

RESULTS

All patients progressed clinically and statistically significant differences in functional activities of daily living were observed during hospitalization, before discharge to the home environment (median = 11; P = 0.0059) and three months after vestibular tumor surgery (median = 8; P = 0.0058). After discharge from hospital, four patients were at risk of falls, and two patients were at risk at three months.

CONCLUSION

Our study showed a positive effect of the use of FGA tasks as part of a rehabilitation program on functional activities of daily living in patients after vestibular tumor surgery. Nevertheless, we suggest further research to include a larger sample and a control group to overcome the deficiencies of our study.

Cross-cultural adaption and validation of the German version of the Mini-BESTest in individuals after stroke: an observational study

Background

Postural control is a very important function in everyday life. However, assessing postural control with commonly used measurement instruments (MIs) is limited due to deficits in their psychometric properties. The Mini-Balance Evaluation Systems Test (Mini-BESTest) is a comprehensive and multidimensional MI for assessing postural control in persons with limited balance function, such as individuals after stroke. Despite the increasing use of the Mini-BESTest worldwide, no German version is available.

Research question

Is the German version of the Mini-BESTest (GVMBT) comprehensible and valid for measuring postural control in individuals after stroke?

Methods

The Mini-BESTest was translated and cross-culturally adapted, following established guidelines. It was pilot-tested with ten participants. This observational measurement and validation study was conducted at one point and included 50 participants with subacute and chronic stroke (mean age: 64.58 ± 13.34 years/ 34 men/ 16 women). Convergent validity was investigated using 1) the Berg Balance Scale (BBS) and 2) the Timed “Up & Go” (TUG). The MIs were evaluated for normal distribution with the calculation of skewness, kurtosis and Q-Q-Plots. Spearman correlation coefficients and Bland Altman analysis were used to examine the relationship between the MIs. The internal consistency was assessed using Cronbach’s alpha.

Results

Comprehension of the GVMBT was confirmed. The GVMBT correlated significantly with the BBS (r_s = 0.93) and the TUG (r_s = − 0.85). Bland Altman analysis revealed low absolute differences. The GVMBT demonstrated no significant floor or ceiling effects and showed excellent internal consistency (Cronbach’s α = 0.90).

Significance

The GVMBT has excellent validity and internal consistency. Due to this and its specific subcategories, the GVMBT is recommended for the use in research and clinical practice. Further psychometric properties should be evaluated.

A self-management programme to reduce falls and improve safe mobility in people with secondary progressive MS: the BRiMS feasibility RCT

BACKGROUND

Balance, mobility impairments and falls are common problems for people with multiple sclerosis (MS). Our ongoing research has led to the development of Balance Right in MS (BRiMS), a 13-week home- and group-based exercise and education programme intended to improve balance and encourage safer mobility.

OBJECTIVE

This feasibility trial aimed to obtain the necessary data and operational experience to finalise the planning of a future definitive multicentre randomised controlled trial.

DESIGN

Randomised controlled feasibility trial. Participants were block randomised 1 : 1. Researcher-blinded assessments were scheduled at baseline and at 15 and 27 weeks post randomisation. As is appropriate in a feasibility trial, statistical analyses were descriptive rather than involving formal/inferential comparisons. The qualitative elements utilised template analysis as the chosen analytical framework.

SETTING

Four sites across the UK.

PARTICIPANTS

Eligibility criteria included having a diagnosis of secondary progressive MS, an Expanded Disability Status Scale (EDSS) score of between ≥ 4.0 and ≤ 7.0 points and a self-report of two or more falls in the preceding 6 months.

INTERVENTIONS

Intervention - manualised 13-week education and exercise programme (BRiMS) plus usual care. Comparator - usual care alone.

MAIN OUTCOME MEASURES

Trial feasibility, proposed outcomes for the definitive trial (including impact of MS, mobility, quality of life and falls), feasibility of the BRiMS programme (via process evaluation) and economic data.

RESULTS

A total of 56 participants (mean age 59.7 years, standard deviation 9.7 years; 66% female; median EDSS score of 6.0 points, interquartile range 6.0-6.5 points) were recruited in 5 months; 30 were block randomised to the intervention group. The demographic and clinical data were broadly comparable at baseline; however, the intervention group scored worse on the majority of baseline outcome measures. Eleven participants (19.6%) withdrew or were lost to follow-up. Worsening of MS-related symptoms unrelated to the trial was the most common reason (n = 5) for withdrawal. Potential primary and secondary outcomes and economic data had completion rates of > 98% for all those assessed. However, the overall return rate for the patient-reported falls diary was 62%. After adjusting for baseline score, the differences between the groups (intervention compared with usual care) at week 27 for the potential primary outcomes were MS Walking Scale (12-item) version 2 -7.7 [95% confidence interval (CI) -17.2 to 1.8], MS Impact Scale (29-item) version 2 (MSIS-29vs2) physical 0.6 (95% CI -7.8 to 9) and MSIS-29vs2 psychological -0.4 (95% CI -9.9 to 9) (negative score indicates improvement). After the removal of one outlier, a total of 715 falls were self-reported over the 27-week trial period, with substantial variation between individuals (range 0-93 falls). Of these 715 falls, 101 (14%) were reported as injurious. Qualitative feedback indicated that trial processes and participant burden were acceptable, and participants highlighted physical and behavioural changes that they perceived to result from undertaking BRiMS. Engagement varied, influenced by a range of condition- and context-related factors. Suggestions to improve the utility and accessibility of BRiMS were highlighted.

CONCLUSIONS

The results suggest that the trial procedures are feasible and acceptable, and retention, programme engagement and outcome completion rates were sufficient to satisfy the a priori progression criteria. Challenges were experienced in some areas of data collection, such as completion of daily diaries.

FUTURE WORK

Further development of BRiMS is required to address logistical issues and enhance user-satisfaction and adherence. Following this, a definitive trial to assess the clinical effectiveness and cost-effectiveness of the BRiMS intervention is warranted.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN13587999.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 23, No. 27. See the NIHR Journals Library website for further project information.

Consensus-Based Core Set of Outcome Measures for Clinical Motor Rehabilitation After Stroke-A Delphi Study

Introduction: Outcome measures are key to tailor rehabilitation goals to the stroke patient's individual needs and to monitor poststroke recovery. The large number of available outcome measures leads to high variability in clinical use. Currently, an internationally agreed core set of motor outcome measures for clinical application is lacking. Therefore, the goal was to develop such a set to serve as a quality standard in clinical motor rehabilitation poststroke.

Methods: Outcome measures for the upper and lower extremities, and activities of daily living (ADL)/stroke-specific outcomes were identified and presented to stroke rehabilitation experts in an electronic Delphi study. In round 1, clinical feasibility and relevance of the outcome measures were rated on a 7-point Likert scale. In round 2, those rated at least as “relevant” and “feasible” were ranked within the body functions, activities, and participation domains of the International Classification of Functioning, Disability, and Health (ICF). Furthermore, measurement time points poststroke were indicated. In round 3, answers were reviewed in reference to overall results to reach final consensus.

Results: In total, 119 outcome measures were presented to 33 experts from 18 countries. The recommended core set includes the Fugl–Meyer Motor Assessment and Action Research Arm Test for the upper extremity section; the Fugl–Meyer Motor Assessment, 10-m Walk Test, Timed-Up-and-Go, and Berg Balance Scale for the lower extremity section; and the National Institutes of Health Stroke Scale, and Barthel Index or Functional Independence Measure for the ADL/stroke-specific section. The Stroke Impact Scale was recommended spanning all ICF domains. Recommended measurement time points are days 2 ± 1 and 7; weeks 2, 4, and 12; 6 months poststroke and every following 6th month.

Discussion and Conclusion: Agreement was found upon a set of nine outcome measures for application in clinical motor rehabilitation poststroke, with seven measurement time points following the stages of poststroke recovery. This core set was specifically developed for clinical practice and distinguishes itself from initiatives for stroke rehabilitation research. The next challenge is to implement this clinical core set across the full stroke care continuum with the aim to improve the transparency, comparability, and quality of stroke rehabilitation at a regional, national, and international level.

Evaluation of the psychometric properties and clinical applications of the Timed Up and Go test in Parkinson disease: a systematic review

To review and systematically summarize the psychometric and clinical properties (reliability, validity, responsiveness) of the Timed Up and Go test applied to persons diagnosed with Parkinson disease. A systematic review was performed by screening four scientific databases (MED-LINE, CINAHL, and PubMed). Independent reviewers selected and extracted data from articles that assessed the reliability, validity, sensitivity to change, and/or clinical properties of the Timed Up and Go test in persons with Parkinson disease. Twenty-four studies were selected. Nine analyzed reliability and yielded “good” to “moderate” scores. Seventeen used a range of different contrast tests to assess validity of the Timed Up and Go test and found “good” quality scores in those that assessed balance. Only two studies analyzed sensitivity to change and they reported “poor” quality scores. The use of Timed Up and Go in Parkinson disease patients presents good reliability and validity (when compared to tests that assess balance).

Using robotic mechanical perturbations for enhanced balance assessment

Balance impairment is critical for many patient groups such as those with neural and musculoskeletal disorders and also the elderly. Accurate and objective assessment of balance performance has led to the development of several indices based on the measurement of the center of pressure. In this study, a robotic device was designed and fabricated to provide controlled and repeatable mechanical perturbations to the standing platform of the user. The device uses servo-controlled actuators and two parallel mechanisms to provide independent rotations in mediolateral and anterior-posterior directions. The device also provides visual feedback of the center of pressure position to the user. Functional tests were run and showed that the device is able to provide an appropriate dynamics (time constant of 0.19 s and bandwidth of 0.85 Hz) for the two motions. The efficacy of the device on the balance assessment was then evaluated experimentally. Ten healthy subjects performed a balance task with and without perturbations and seven center of pressure indices were measured. It was shown that the sensitivity of the indices to the user's performance was statistically increased in all indices particularly in anterior/posterior direction when the mechanical perturbations were present.

Identifying Instruments to Assess Care Quality for Individuals With Custom Ankle Foot Orthoses: A Scoping Review

OBJECTIVES

We conducted 2 complementary scoping reviews to identify instruments that assess the experience and outcomes of custom ankle-foot orthosis (AFO) care in individuals with neurologic and traumatic conditions and to determine to what extent they might be psychometrically sound for AFO users. A stakeholder advisory committee considered to what extent the identified and psychometrically sound instruments might be feasible for use in developing quality measures for custom AFO users.

DATA SOURCES

Both scoping reviews were conducted using PubMed, the Cumulative Index to Nursing and Allied Health Literature, Embase, and Cochrane Systematic Reviews. The following were used for the first scoping review only: Cochrane Central Register of Controlled Trials and the Physiotherapy Evidence Database.

STUDY SELECTION

The initial scoping review yielded 79 articles with 82 instruments, 16 of which were used in 4 or more studies. The second scoping review yielded 57 articles reporting psychometric properties.

DATA EXTRACTION

Psychometric properties for populations who use AFOs were summarized for 15 of the 16 instruments. The advisory committee eliminated 2 insrtruments, noted overlap between 4 instruments in terms of the constructs measured, and suggested 6 potential contemporary substitutes.

DATA SYNTHESIS

Most instruments assessed activity (specifically mobility) and pertained to the National Quality Forum domain of "Health-Related Quality of Life." The 10-meter walk test, 6-minute walk test, Berg Balance Scale, Timed Up and Go, and Rivermead Mobility Index were reported to have adequate reliability and validity, and were considered feasible for administration in a clinical setting.

CONCLUSIONS

Complementary scoping reviews demonstrated that some instruments with reasonable psychometric properties are available that are feasible to use in developing quality measures for custom AFO care. However, experience of care instruments suitable for this population were not identified but are needed for a comprehensive evaluation of care quality for AFO users.

A systematic review of adults` sitting balance assessments in neurological and neuromuscular condition

Objectives:

To find out new assessment tools for sitting, in patients with neurological and neuromuscular conditions, to be recommended for rehabilitation practice locally in Saudi Arabia and internationally.

Methods:

Four databases were used: PubMed, Web of Science, Ovid Medline, and Cochrane. Inclusion criteria were articles published between the years 2009–2019; sitting, not standing or walking; assessment not intervention; published in English and studies on adults only. Exclusion criteria were any assessment that measures the standing/walking ability or has items for that, and studies that include pediatric or adolescent or both.

Results:

Ten articles met our criteria including 464 patients and divided into 3 main neurological conditions (stroke, SCI, and MS). One assessment (Function in Sitting Test) showed promising potential being implemented with both stroke and multiple sclerosis, Cronbach’s alpha, α were 0.91 and 0.98 indicating high internal consistency. It was used with SCI patients, however, no access was available to include this study in this review.

Conclusion:

This review indicates an extension of what was carried out by previous systematic reviews with neurological conditions. It seems that Function in Sitting Test is the most frequent assessment in this review with multiple neurological conditions (stroke, MS and SCI) with high internal consistency and high quality studies according to available data. However, this review showed that there is an absence of evidence for individuals with brain injury. Further work needs to be carried out to address such groups of patients to extend the choices that clinicians can use in rehabilitation sittings.

Reliability of a New Test of Balance Function in Healthy and Concussion Populations

Providing quantitative measures of balance and posture is a valuable aid in clinical assessment and in recent years several devices have been introduced that have demonstrated the accurate measure of balance via deviation of center of mass utilizing software algorithms and mobile devices. The purpose of this study was to assess the accuracy of EQ Balance against the Sway^TM Balance System (Sway), another balance device that is currently established as an accurate measure of balance, and to evaluate the test-retest reliability of EQ Balance. Seventy individuals presenting to a sports medicine and concussion clinic volunteered to participate in the assessment of balance utilizing Sway and EQ Balance simultaneously. The group included 25 males and 45 females (mean age: 37.8 ± 14.8, range: 13-65) with and without concussion or other neurological conditions (39 concussed vs. 31 non-neurologically injured, or healthy). Twenty-six of the concussed participants were balance-impaired. Participants performed five postures while holding the mobile device against their chest. Participants held a device holder that secured two devices: one iPhone 6 with EQ Balance and a second iPhone 6 with Sway Balance. The average balance score on all five stances was recorded as the "average balance score". Average balance scores were in statistical agreement between the two methods across the entire group, and for sub-groups according to the Deming regression (p < 0.01). The intra-class correlation (ICC) for the cohort was 0.87 (p < 0.001). Across the cohort, EQ Balance measured significantly worse balance scores in the balance-impaired group, comprised of participants with brain injury who failed a clinical balance screening test, compared to the group without clinically-determined balance impairment (this group includes healthy and some concussed patients). EQ Balance demonstrated safety, as it was considered safe to perform independently (i.e., without an observer) in those with impaired balance, and high test- retest reliability in the healthy and concussed patient population. Statistical agreement was established between the two measures of EQ Balance and Sway Balance for the average balance score across all five stances. The ICC analysis demonstrates strong consistency of the task output between test sessions. Given these results, EQ Balance demonstrates strength as a new balance assessment tool to accurately measure balance performance as part of a unique and novel gamified application in healthy and neurologically injured populations.

Effect of Kidney Transplant on Balance and Fall Risk

OBJECTIVES

Kidney transplant offers an improved quality of life and prolonged survival for patients with end-stage renal disease. This study aimed to compare balance and fall risk between kidney transplant recipients and healthy adults and to determine the relationship between biochemical parameters and fall risk and balance in kidney transplant recipients. As far as we know, this is the first study in the literature that evaluated whether balance changes occur in kidney transplant recipients using the Tetrax Interactive Balance System (Sunlight Medical Ltd., Ramat Gan, Israel).

MATERIALS AND METHODS

Our study included 131 kidney transplant recipients (80 male/53 female; mean age of 39 ± 12 y) and 158 healthy volunteers (86 male/69 female; mean age of 40 ± 15 y). Groups were statistically matched in age, male/female patients, and body mass index. Fall index percentages were calculated using the Tetrax posturography device. Risk of falling was compared between kidney transplant recipients and healthy participants. Kidney transplant recipients were divided into 3 groups based on risk of falling. Demographic and clinical characteristics of kidney transplant recipients were recorded, and statistical analyses were performed to analyze these parameters versus balance measurements.

RESULTS

Risk of falling was not significantly different between groups according to Tetrax measurements (32.4 ± 23.4 vs 31.6 ± 21.7; P = .08). Serum creatinine levels were significantly higher in kidney transplant recipients with a higher risk of falling (1.17 ± 0.37 vs 1.63 ± 1.18 mg/dL; P = .01). The use of oral antidiabetic drugs was shown to increase the risk of falling (P = .02).

CONCLUSIONS

Although patients with end-stage renal disease are thought to have balance impairments, kidney transplant recipients in our study had balance control similar to that shown in the healthy population. Graft function in kidney transplant recipients is important for the balance system.

Robot-Assisted Stair Climbing Training on Postural Control and Sensory Integration Processes in Chronic Post-stroke Patients: A Randomized Controlled Clinical Trial

Background

Postural control disturbances are one of the important causes of disability in stroke patients affecting balance and mobility. The impairment of sensory input integration from visual, somatosensory and vestibular systems contributes to postural control disorders in post-stroke patients. Robot-assisted gait training may be considered a valuable tool in improving gait and postural control abnormalities.

Objective

The primary aim of the study was to compare the effects of robot-assisted stair climbing training against sensory integration balance training on static and dynamic balance in chronic stroke patients. The secondary aims were to compare the training effects on sensory integration processes and mobility.

Methods

This single-blind, randomized, controlled trial involved 32 chronic stroke outpatients with postural instability. The experimental group (EG, n = 16) received robot-assisted stair climbing training. The control group (n = 16) received sensory integration balance training. Training protocols lasted for 5 weeks (50 min/session, two sessions/week). Before, after, and at 1-month follow-up, a blinded rater evaluated patients using a comprehensive test battery. Primary outcome: Berg Balance Scale (BBS). Secondary outcomes:10-meter walking test, 6-min walking test, Dynamic gait index (DGI), stair climbing test (SCT) up and down, the Time Up and Go, and length of sway and sway area of the Center of Pressure (CoP) assessed using the stabilometric assessment.

Results

There was a non-significant main effect of group on primary and secondary outcomes. A significant Time × Group interaction was measured on 6-min walking test (p = 0.013) and on posturographic outcomes (p = 0.005). Post hoc within-group analysis showed only in the EG a significant reduction of sway area and the CoP length on compliant surface in the eyes-closed and dome conditions.

Conclusion

Postural control disorders in patients with chronic stroke may be ameliorated by robot-assisted stair climbing training and sensory integration balance training. The robot-assisted stair climbing training contributed to improving sensorimotor integration processes on compliant surfaces. Clinical trial registration (NCT03566901).

The Relations between Sitting Balance and Functional Recovery according to Characteristics of the Stroke Patients

We measured the difference of sitting pressure between the affected and unaffected sides (DSPAU) using sitting pressure measured with a force platform to identify sitting imbalance. The aim of this study is to investigate the relations between sitting balance and functional status or parameters according to characteristics stroke patients. We examine changes in DSPAU and functional assessment before and after a 3 week of rehabilitation in hemiplegic stroke patients (n = 73). These pre- and post-treatment data according to stroke characteristics, and correlations between the DSPAU and functional scales were analyzed. The DSPAU was greater in the non-ambulatory group compared to the ambulatory group, in patients who scored lower in the Medical Research Council (MRC) scores, and in patients whose the MRC scores for the lower limbs were lower than of the upper limbs. We observed that a decrease in the DSPAU was associated with an improvement in functional assessment parameters following rehabilitation. Further, changes in DSPAU were significantly correlated to the Modified Barthel Index. We observed that a decrease in DSPAU was associated with an improvement in functional parameters following rehabilitation. In conclusion, repeated measurements of sitting balance using DSPAU may be helpful to predict motor and functional recovery in stroke patient with hemiplegia.

Balance and fall risk in peritoneal dialysis patients

BACKGROUND

Vestibular, neurological and musculoskeletal functions are affected in patients with renal failure. These problems can in turn affect the balance system in peritoneal dialysis (PD) patients. Previously, postural balance changes were shown in hemodialysis patients. This is the first study that evaluates whether there are similar changes in patients with PD.

OBJECTIVE

This study aimed to compare balance and fall risk between patients undergoing PD treatment and healthy subjects, and aimed to determine the correlation between biochemical parameters and fall risk and balance assessments in PD patients.

METHODS

This controlled study included 58 patients receiving PD treatment (PD Group) and 75 healthy subjects (Control Group). The Berg Balance Scale (BBS) and Tetrax® Interactive Balance System were used for the comparison of balance between groups. For patients in the PD Group, duration of PD, blood pressure, Kt/Vurea (actual mass of urea removed via peritoneal dialysis), and serum biochemical parameters were recorded and correlation analysis was performed between these parameters and balance measurements.

RESULTS

There were no statistically significant differences between groups in terms of demographics or BBS scores (p> 0.05). The fall risk of patients in the PD Group was significantly higher than those in the Control Group (p< 0.0001) according to Tetrax measurements. Female gender, older age, higher BMI, and higher blood glucose levels were negatively correlated with balance parameters of PD patients (r> 0.3). There was no statistically significant correlation between duration of PD, blood pressure, and Kt/Vurea with balance parameters or fall risk.

CONCLUSIONS

Balance was impaired in patients undergoing PD in comparison to healthy subjects. Fall risk may be evaluated using the Tetrax® instead of BBS for this population. Serum glucose level, BMI and age appear to affect balance and fall risk. Therefore, optimization of body weight and normalization of serum glucose levels are important factors for improving balance. The duration of PD, blood pressure, and Kt/Vurea do not affect balance system.

Virtual reality in the rehabilitation of patients with stroke: an integrative review

ABSTRACT Objective: To describe the intervention protocols to using commercial video games as virtual reality (VR) in rehabilitation of patients with stroke. Methods: Integrative review using the descriptors “rehabilitation”, “virtual reality exposure therapy” and “videogames” in the LILACS and PUBMED databases. Articles published from 2011 to 2018 were selected. Results: We found 1,396 articles, 1,383 were excluded and 13 were selected. Most of the articles were randomized clinical trials published in 2014 or later. The sample size varied from 5–47 adults, or adults and elders, with chronic stroke. The Nintendo Wii® was the most used video game system. The intervention happened two or three times a week, each session lasting from 30 to 60 minutes, over 2–12 weeks. Balance, upper limb motor functions, quality of life and daily living activities were the most common evaluated outcomes. The Fugl-Meyer Assessment, Berg Balance Scale, Timed Up and Go test, Barthel Scale and SF-36 were the most common outcome measurement tools. Conclusions: The studies indicated improvement in dynamic balance, upper limb motor function and quality of life after rehabilitation using VR. The VR was more effective than conventional treatments for the outcome of dynamic balance. Two studies did not find any changes in static balance and daily living activities. Physical aspects and quality of life were the outcomes most evaluated by the researchers; as were the population with chronic strokes and protocols of long duration and low intensity. Few studies targeted immediate VR effects, performance in daily living activities and social participation.

Environmental Styrene Exposure and Sensory and Motor Function in Gulf Coast Residents

BACKGROUND

Although styrene is an established neurotoxicant at occupational exposure levels, its neurotoxicity has not been characterized in relation to general population exposures. Further, occupational research to date has focused on central nervous system impairment.

OBJECTIVE

We assessed styrene-associated differences in sensory and motor function among Gulf coast residents.

METHODS

We used 2011 National Air Toxics Assessment estimates of ambient styrene to determine exposure levels for 2,956 nondiabetic Gulf state residents enrolled in the Gulf Long-term Follow-up Study, and additionally measured blood styrene concentration in a subset of participants 1 to 2 y after enrollment ([Formula: see text]). Participants completed an enrollment telephone interview and a comprehensive test battery to assess sensory and motor function during a clinical follow-up exam 2 to 4 y later. Detailed covariate information was ascertained at enrollment via telephone interview. We used multivariate linear regression to estimate continuous differences in sensory and motor function, and log-binomial regression to estimate prevalence ratios for dichotomous outcomes. We estimated associations of both ambient and blood styrene exposures with sensory and motor function, independently for five unique tests.

RESULTS

Those participants in the highest 25% vs. lowest 75% of ambient exposure and those in the highest 10% vs. lowest 90% of blood styrene had slightly diminished visual contrast sensitivity. Mean vibrotactile thresholds were lower among those in the highest vs. lowest quartile of ambient styrene and the highest 10% vs. lowest 90% of blood styrene ([Formula: see text] log microns; 95% CI: [Formula: see text], [Formula: see text] and [Formula: see text] log microns; 95% CI: [Formula: see text], [Formula: see text], respectively). The highest vs. lowest quartile of ambient styrene was associated with significantly poorer postural stability, and (unexpectedly) with significantly greater grip strength.

DISCUSSION

We observed associations between higher styrene exposure and poorer visual, sensory, and vestibular function, though we did not detect associations with reduced voluntary motor system performance. Associations were more consistent for ambient exposures, but we also found notable associations with measured blood styrene. https://doi.org/10.1289/EHP3954.