Ying-Chih Wang

Assessing dexterity function: A comparison of two alternatives for the NIH toolbox

STUDY DESIGN Clinical measurement. INTRODUCTION Manual dexterity is an important aspect of motor function across the age span. PURPOSE OF THE STUDY To identify a single measure of manual dexterity for inclusion in the National Institutes of Health (NIH) Toolbox Assessment of Neurological and Behavioral Function. METHODS A total of 340 subjects participated in our study. Two alternatives, Rolyan® 9-Hole Peg Test (9-HPT) and Grooved Pegboard test, were compared by assessing their score range across age groups (3-85 yr) and their test-retest reliability, concurrent, and known groups validity. RESULTS The 9-HPT was a simple, efficient, and low-cost measure of manual dexterity appropriate for administration across the age range. Test-retest reliability coefficients were 0.95 and 0.92 for right and left hands, respectively. The 9-HPT correlated with Bruininks-Oseretsky Test (BOT) of Motor Proficiency, dexterity subscale, at -0.87 to -0.89 and with Purdue Pegboard at -0.74 to -0.75. The Grooved Pegboard had good test-retest reliability (0.91 and 0.85 for right and left hands, respectively). The Grooved Pegboard correlated with BOT at -0.50 to -0.63 and with Purdue Pegboard at -0.73 to -0.78. However, the Grooved Pegboard required longer administration time and was challenging for the youngest children and oldest adults. CONCLUSIONS Based on its feasibility and measurement properties, the 9-HPT was recommended for inclusion in the motor battery of the NIH Toolbox. LEVEL OF EVIDENCE NA.

Grip and knee extension muscle strength reflect a common construct among adults.

Introduction: Both grip and knee extension strength are often used to characterize overall limb muscle strength. We sought to determine if the measures actually reflect a common construct. Methods: The isometric grip and knee extension strength of 164 healthy men and women (range, 18–85 years) were measured bilaterally using standard procedures. Pearson correlations (r), Cronbach alpha, principal components analysis, and multiple regression/correlation were used to investigate the dimensionality of the measures. Results: Left and right grip forces and knee extension torques were highly correlated, internally consistent, and loaded on a single component. Gender and age explained the variance in both measures, but height added to the explanation of grip strength, whereas weight added to the explanation of knee extension strength. Conclusions: Among healthy adults, grip and knee extension strength reflect a common underlying construct. The measures, however, are affected differently by height and weight. Muscle Nerve 46: 555–558, 2012

Computerized adaptive test for patients with knee impairments produced valid and responsive measures of function

OBJECTIVE Assess practicality of using a computerized adaptive test (CAT) in routine clinical practice, perform a psychometric evaluation of content range coverage and test precision, and assess known group construct validity, sensitivity to change and responsiveness of knee CAT functional status (FS) measures. STUDY DESIGN AND SETTING Secondary analysis of retrospective intake and discharge rehabilitation FS data collected in a prospective cohort study. Data represented a convenience sample of 21,896 patients with knee impairments receiving outpatient physical therapy in 291 clinics in 30 U.S. states (2005-2007). RESULTS The CAT used an average of seven items to produce precise estimates of FS that adequately covered the content range with negligible floor and ceiling effects. Test information functions and standard errors supported FS measure precision. FS measures discriminated patients by age, symptom acuity, surgical history, condition complexity, and prior exercise history in clinically logical ways. Seventy-two percent of patients obtained discharge FS measures > or = minimal detectable change (95% confidence interval). Change of 9 FS units (0-100 scale) represented minimal clinically important improvement, which 67% of patients obtained. CONCLUSION The knee CAT was efficient and produced precise, valid, and responsive measures of FS for patients receiving therapy for knee impairments and functioned well in routine clinical application.

Motor Unit Number Reductions in Paretic Muscles of Stroke Survivors

The objective of this study is to assess whether there is evidence of spinal motoneuron loss in paretic muscles of stroke survivors, using an index measurement called motor unit number index (MUNIX). MUNIX, a recently developed novel neurophysiological technique, provides an index proportional to the number of motor units in a muscle, but not necessarily an accurate absolute count. The MUNIX technique was applied to the first dorsal interosseous (FDI) muscle bilaterally in nine stroke subjects. The area and power of the maximum M-wave and the interference pattern electromyogram (EMG) at different contraction levels were used to calculate the MUNIX. A motor unit size index (MUSizelndex) was also calculated using maximum M-wave recording and the MUNIX values. We observed a significant decrease in both maximum M-wave amplitude and MUNIX values in the paretic FDI muscles, as compared with the contralateral muscles. Across all subjects, the maximum M-wave amplitude was 6.4 ± 2.3 mV for the paretic muscles and 9.7 ± 2.0 mV for the contralateral muscles (p <; 0.001). These measurements, in combination with voluntary EMG recordings, resulted in the MUNIX value of 109 ± 53 for the paretic muscles, much lower than the MUNIX value of 153 ± 38 for the contralateral muscles (p <; 0.01). No significant difference was found in MUSizelndex values between the paretic and contralateral muscles. However, the range of MUSizelndex values was slightly wider for paretic muscles (48.8-93.3 μV) than the contralateral muscles (51.7-84.4 μV). The findings from the index measurements provide further evidence of spinal motoneuron loss after a hemispheric brain lesion.

Screening for Elevated Levels of Fear-Avoidance Beliefs Regarding Work or Physical Activities in People Receiving Outpatient Therapy

Background: Screening people for elevated levels of fear-avoidance beliefs is uncommon, but elevated levels of fear could worsen outcomes. Developing short screening tools might reduce the data collection burden and facilitate screening, which could prompt further testing or management strategy modifications to improve outcomes. Objective: The purpose of this study was to develop efficient yet accurate screening methods for identifying elevated levels of fear-avoidance beliefs regarding work or physical activities in people receiving outpatient rehabilitation. Design: A secondary analysis of data collected prospectively from people with a variety of common neuromusculoskeletal diagnoses was conducted. Methods: Intake Fear-Avoidance Beliefs Questionnaire (FABQ) data were collected from 17,804 people who had common neuromusculoskeletal conditions and were receiving outpatient rehabilitation in 121 clinics in 26 states (in the United States). Item response theory (IRT) methods were used to analyze the FABQ data, with particular emphasis on differential item functioning among clinically logical groups of subjects, and to identify screening items. The accuracy of screening items for identifying subjects with elevated levels of fear was assessed with receiver operating characteristic analyses. Results: Three items for fear of physical activities and 10 items for fear of work activities represented unidimensional scales with adequate IRT model fit. Differential item functioning was negligible for variables known to affect functional status outcomes: sex, age, symptom acuity, surgical history, pain intensity, condition severity, and impairment. Items that provided maximum information at the median for the FABQ scales were selected as screening items to dichotomize subjects by high versus low levels of fear. The accuracy of the screening items was supported for both scales. Limitations: This study represents a retrospective analysis, which should be replicated using prospective designs. Future prospective studies should assess the reliability and validity of using one FABQ item to screen people for high levels of fear-avoidance beliefs. Conclusions: The lack of differential item functioning in the FABQ scales in the sample tested in this study suggested that FABQ screening could be useful in routine clinical practice and allowed the development of single-item screening for fear-avoidance beliefs that accurately identified subjects with elevated levels of fear. Because screening was accurate and efficient, single IRT-based FABQ screening items are recommended to facilitate improved evaluation and care of heterogeneous populations of people receiving outpatient rehabilitation.

Important factors influencing the return to work after stroke.

BACKGROUND As the field of rehabilitation shifts its focus towards improving functional capacity instead of managing disability, return to work (RTW) and return to the community emerge as key goals in a persons recovery from major disabling illness such as stroke. OBJECTIVE To compile important factors believed to influence RTW after a stroke. METHODS Based on a comprehensive literature review, we clustered similar factors and organized these factors based on the International Classification of Function, Disability and Health (ICF) framework: body functions or structure, activity participation, environmental factors and personal and psychosocial factors. RESULTS Overall, stroke severity, as assessed by the degree of residual disability such as weakness, neurological deficit or impairments (speech, cognition, apraxia, agnosia), has been shown to be the most consistent negative predictor of RTW. Many factors such as the number of working years remaining until retirement, depression, medical history, and occupation need to be taken into consideration for stroke survivors, as they can influence RTW decision making. Stroke survivors who are flexible and realistic in their vocational goal and emotionally accept their disability appear more likely to return to work. CONCLUSIONS There are many barriers to employment for stroke survivors ranging from physical and cognitive impairments to psychosocial and environmental factors.

Computerized adaptive test for patients with lumbar spine impairments produced valid and responsive measures of function.

Study Design. Outcomes instrument validation study. Objective. We evaluated administrative efficiency and psychometric adequacy of a computerized adaptive test (CAT) for patients with lumbar spine impairments seeking rehabilitation in outpatient therapy clinics. Summary of Background Data. CATs promise efficient outcomes data collection in clinical applications with little loss of measurement precision compared to paper and pencil surveys. The lumbar CAT has been developed and simulated and is currently used routinely in therapy clinics. The CAT has not been assessed for administrative efficiency, and the outcomes measures estimated using the CAT have not been assessed using prospective data collection for validity, sensitivity to change, or responsiveness. Methods. Data from 17,439 patients with lumbar spine impairments receiving outpatient rehabilitation in 377 clinics in 30 states (United States) were analyzed. We evaluated efficiency of routine CAT administration and assessed construct validity, sensitivity to change, and responsiveness of CAT measures of lumbar functional status (FS). Results. On average, patients took less than 2 minutes (standard deviation <1 minute) to answer 7 CAT items (standard deviation, 3), which produced precise estimates of FS that adequately covered the content range with negligible floor and ceiling effects. Patients who were older had more chronic symptoms, had more surgeries, had more comorbidities, and did not exercise before receiving rehabilitation reported worse discharge FS. A total of 66% of patients obtained statistically significant change (95% confidence interval minimal detectable change) at discharge. Change of 5 FS units (scale, 0–100) represented minimal clinically important improvement, which 70% of patients obtained. Minimal detectable change and minimal clinically important improvement were associated with intake FS. Conclusion. We concluded the lumbar CAT administration was efficient, and CAT FS measures were precise, valid, sensitive, and responsive, supporting lumbar CAT use in clinical and research applications.

Sit-to-stand test: Performance and determinants across the age-span.

Although the validity of the sit-to-stand (STS) test as a measure of lower limb strength has been questioned, it is widely used as such among older adults. The purposes of this study were: 1) to describe five-repetition STS test (FRSTST) performance (time) by adolescents and adults and 2) to determine the relationship of isometric knee extension strength (force and torque), age, gender, weight, and stature with that performance. Participants were 111 female and 70 male (14-85 years) community-dwelling enrollees in the NIH Toolbox Assessment of Neurological and Behavioral Function. The FRSTST was conducted using a standard armless chair. Knee extension force was measured using a belt-stabilized hand-held dynamometer; knee extension torque was measured using a Biodex dynamometer. The mean times for the FRSTST ranged from 6.0 sec (20-29 years) to 10.8 sec (80-85 years). For both the entire sample and a sub-sample of participants 50-85 years, knee extension strength (r = -0.388 to -0.634), age (r = 0.561 and 0.466), and gender (r = 0.182 and 0.276) were correlated significantly with FRSTST times. In all multiple regression models, knee extension strength provided the best explanation of FRSTST performance, but age contributed as well. Bodyweight and stature were less consistent in explaining FRSTST performance. Gender did not add to the explanation of FRSTST performance. Our findings suggest, therefore, that FRSTST time reflects lower limb strength, but that performance should be interpreted in light of age and other factors.

Adequacy of belt-stabilized testing of knee extension strength.

Bohannon, RW, Bubela, DJ, Wang, Y-C, Magasi, SR, and Gershon, RC. Adequacy of belt-stabilized testing of knee extension strength. J Strength Cond Res 25(7): 1963-1967, 2011—Tester strength can limit the forces that can be measured using a hand-held dynamometer (HHD). A solution is to use belt stabilization in conjunction with an HHD. The purposes of this study were to determine if a portable belt-stabilized HHD (BSHHD) setup was capable of measuring a broad range of isometric knee extension torques and whether isometric knee extension torques measured using a portable BSHHD system were comparable to those obtained using a Biodex isokinetic dynamometer. Participants in the study were 113 women and 71 men (14-85 years of age) community-dwelling enrollees in the National Institutes of Health Toolbox for the Assessment of Neurological and Behavioral Function. Knee extension torques measured using a BSHHD ranged from 35.0-416.0 N·m. Torques measured with the BSHHD were significantly lower (p < 0.001) than those measured using the isokinetic dynamometer (mean difference: 35.6 N·m left, 33.7 N·m right). However, the measures were highly correlated (r > 0.86, p < 0.001). Torques obtained with a BSHHD may not equal the maximum that individuals can generate, but they reflect such torques. We conclude, therefore, that a portable BSHHD setup is a viable option for measuring a wide spectrum of knee extension torques in diverse settings.

Clinical Interpretation of Outcome Measures Generated From a Lumbar Computerized Adaptive Test

Background A computerized adaptive test (CAT) provides a way of efficiently estimating functional status in people with specific impairments. Objective The purpose of this study was to describe meaningful interpretations of functional status (FS) estimated using a lumbar CAT developed using items from the Back Pain Functional Scale (BPFS) and selected physical functioning items. Design and Setting This was a prospective longitudinal cohort study of 17,439 patients with lumbar spine impairments in 377 outpatient rehabilitation clinics in 30 states. Outcome Measures Patient self-reports of functional status were assessed using a lumbar CAT (0–100 scale). Methods Outcome data were interpreted using 4 methods. First, the standard error of the estimate was used to construct a 95% confidence interval for each CAT estimated score. Second, percentile ranks of FS scores were presented. Third, 2 threshold approaches were used to define individual patient–level change: minimal detectable change (MDC) and clinically important change. Fourth, a functional staging model, the Back Pain Function Classification System (BPFCS), was developed and applied. Results On average, precision of a single score was estimated by FS score±4. Based on score distribution, 25th, 50th and 75th percentile ranks corresponded to intake FS scores of 44, 51, and 59, and discharge FS scores of 54, 62, and 74, respectively. An MDC95 value of 8 or more represented statistically reliable change. Receiver operating characteristic analyses supported that changes in FS scores of 5 or more represented minimal clinically important improvement. The BPFCS appeared clinically logical and provided insight for clinical interpretation of patient progress. Limitations The BPFCS should be assessed for validity using prospective designs. Conclusions Results may improve clinical interpretation of CAT-generated outcome measures and assist clinicians using patient-reported outcomes during physical therapist practice.