Six-Minute Walk Test Vs. Three-Minute Step Test for Measuring Functional Endurance.

The purpose of this study was to compare 2 practical measures of functional endurance. Specifically, the six-minute walk test (SMWT) and three-minute step test (TMST) were compared to determine their appropriateness for use as field tests and inclusion in the NIH Toolbox for the assessment of neurological and behavioral function. Individuals between 14 and 85 years performed both the SMWT and TMST in random order. We documented completion rates, criterion performance, heart rate responses, and subjective exertion associated with the 2 tests. All 189 participants completed the SMWT, but only 73.0% completed the TMST. Those completing the TMST were more likely to be male, report better health, and have a younger age and lower body mass index. The SMWT distance was greater for those who did vs. those who did not complete the TMST. For those completing both tests, the average distance walked in 6 minutes was 595.9 m; the average cumulative heart beats during the minute after the TMST was 107.4. Distance walked and cumulative heart beats correlated weakly. Average heart rate and perceived exertion were significantly higher after the TMST than the SMWT. Posttest heart rate and perceived exertion for the 2 tests correlated significantly but not strongly. We conclude that the SMWT is more likely to be completed and is usually less stressful physiologically than the TMST and therefore may be a better option for field testing functional endurance and inclusion in the NIH Toolbox.

Effect of interactions between a child and a robot on the imitation and praxis performance of typically devloping children and a child with autism: a preliminary study.

Interactions between a robot and a child (robot-child interactions) provide a unique context to engage children in whole body movements through a reciprocal imitation game. The effects of a novel, 8-session, robot-child interaction protocol on the imitation and praxis skills of 15 typically developing children and one child with autism between 4 and 7 years of age were examined. A quasi-experimental observational comparison of pretest and posttest performance was conducted. A task-specific robot imitation test and a standardized praxis measure were coded for changes in imitation and praxis errors at pretest and posttest. All children showed improvements in task-specific imitation and generalized praxis. Interpretation is limited by the lack of a control group. These findings serve as a foundation for further investigation of robot-child interactions as a potential training tool for children with dyspraxia.

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.

Adequacy of belt-stabilized testing of knee extension strength.

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.

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.

Relative reliability of three objective tests of limb muscle strength.

If measures of muscle strength are to be broadly applied, they should be objective, portable, quick, and reliable. Through this component of the NIH Toolbox study we sought to compare the test-retest reliability of 3 tests of muscle strength that are objective, portable, and quick: the five-repetition sit-to-stand test (FRSTST), hand-grip dynamometry (HGD), and belt-stabilized hand-held dynamometry (BSHHD) of knee extension. Three sets of each test were performed- 1 warm-up and 2 maximal. Measures from the maximal tests obtained 4 to 10 days apart were compared. Reliability was described using descriptive statistics, intraclass correlation coefficients (ICCs) and 4 measures of response stability: standard error of measurement (SEM), method error (ME), coefficient of variation of SEM (SEM CV ), and coefficient of variation of variation of ME (ME CV ). The ICCs of all tests were good (≥ 0.853). Measures of response stability showed less variability between test and retest for FRSTST and HGD than for BSHHD. In conclusions all 3 tests demonstrated good test-retest reliability. However, greater differences would need to be observed between tests sessions to conclude that a real change had occurred in measures obtained by BSHHD.

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.

Motor assessment using the NIH Toolbox.

Motor function involves complex physiologic processes and requires the integration of multiple systems, including neuromuscular, musculoskeletal, and cardiopulmonary, and neural motor and sensory-perceptual systems. Motor-functional status is indicative of current physical health status, burden of disease, and long-term health outcomes, and is integrally related to daily functioning and quality of life. Given its importance to overall neurologic health and function, motor function was identified as a key domain for inclusion in the NIH Toolbox for Assessment of Neurological and Behavioral Function (NIH Toolbox). We engaged in a 3-stage developmental process to: 1) identify key subdomains and candidate measures for inclusion in the NIH Toolbox, 2) pretest candidate measures for feasibility across the age span of people aged 3 to 85 years, and 3) validate candidate measures against criterion measures in a sample of healthy individuals aged 3 to 85 years (n = 340). Based on extensive literature review and input from content experts, the 5 subdomains of dexterity, strength, balance, locomotion, and endurance were recommended for inclusion in the NIH Toolbox motor battery. Based on our validation testing, valid and reliable measures that are simultaneously low-cost and portable have been recommended to assess each subdomain, including the 9-hole peg board for dexterity, grip dynamometry for upper-extremity strength, standing balance test, 4-m walk test for gait speed, and a 2-minute walk test for endurance.

Deterministic and stochastic postural processes: effects of task, environment, and age.

Upright standing is always environmentally embedded and typically co-occurs with another (suprapostural) activity. In the present study, the authors investigate how these facts affect postural dynamics in an experiment in which younger (M age = 20.23 years, SD = 2.02 years) and older (M age = 75.26 years, SD = 4.87 years) participants performed a task of detecting letters in text or maintaining gaze within a target while standing upright in a structured or nonstructured stationary environment. They extracted the coefficients of drift (indexing attractor strength) and diffusion (indexing noise strength) from the center of pressure (COP) time series in anteroposterior (AP) and mediolateral (ML) axes. COP standard deviation decreased with drift and increased with diffusion. The authors found that structure reduced AP diffusion for both groups and that letter detection reduced younger SDAP (primarily by diffusion decrease) and increased older SDML (primarily by drift decrease). For older and younger participants, ML drift was lower during letter detection. Further, in older letter detection, larger visual contrast sensitivity was associated with larger ML drift and smaller SDML, raising the hypotheses that ML sway helps information detection and reflects neurophysiological age.