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Background. Existing self-report measures of mobility ignore important contextual features of movement and require respondents to make complex judgments about specific tasks. Thus, we describe the development and validation of a short form (sf) video-animated tool for assessing mobility, the Mobility Assessment Tool--MAT-sf. Methods. This study involves cross-sectional and longitudinal analyses examining the measurement properties of the MAT-sf. The MAT-sf consists of 10 animated video clips that assess respondents' level of proficiency in performing each task. The main outcome measures used for validation included the Pepper Assessment Tool for Disability (PAT-D), the Short Physical Performance Battery (SPPB), and 400-m walk test. Results. Participants (n = 234), 166 women and 68 men, had an average age of 81.9 years and a variety of comorbidities with 65.4% having high blood pressure. An average SPPB score of 8.6 (range 2-12) suggests that the study sample had evidence of compromised physical function but was quite heterogeneous. The MAT-sf had good content validity, excellent tes--retest reliability (r = .93), and criterion-related validity with the PAT-D. Moreover, the MAT-sf added considerable variance to the prediction of both SPPB scores and 400-m gait speed over and above the PAT-D mobility subscale. The MAT-sf also discriminated between older adults who completed or failed the 400-m walk test. Conclusion. The MAT-sf is an innovative psychometrically sound measure of mobility. It has utility in epidemiological studies, translational science, and clinical practice. Key Words: Mobility--Aging--Measurement--Disability. doi: 10.1093/gerona/glq055

Background. The purpose of the present study was to examine, first, whether heating acuity predicts falls and whether the potential association is explained by postural balance and, second, to examine whether shared genetic or environmental effects underlie these associations. Methods. Heating was measured using a clinical audiometer as a part of the Finnish Twin Study on Aging in 103 monozygotic and 114 dizygotic female twin pairs aged 63-76 years. Postural balance was indicated as a center of pressure (COP) movement in semitandem stance, and participants filled in a fall-calendar daily for an average of 345 days after the baseline. Results. Mean hearing acuity (better ear heating threshold level at 0.5-4 kHz) was 21 dB (standard deviation [SD] 12). Means of the COP velocity moment for the best to the poorest hearing quartiles increased linearly from 40.7 [mm.sup.2]/s (SD 24.4) to 52.8 [mm.sup.2]/s (SD 32.0) (p value for the trend = .003). Altogether 199 participants reported 437 falls. Age-adjusted incidence rate ratios (IRRs) for falls, with the best hearing quartile as a reference, were 1.2 (95% confidence interval [CI] = 0.4-3.8) in the second, 4.1 (95% CI = 1.1-15.6) in the third, and 3.4 (95% CI = 1.0-11.4) in the poorest hearing quartiles. Adjustment for COP velocity moment decreased IRRs markedly. Twin analyses showed that the association between hearing acuity and postural balance was not explained by genetic factors in common for these traits. Conclusion. People with poor hearing acuity have a higher risk for falls, which is partially explained by their poorer postural control. Auditory information about environment may be important for safe mobility. Key Words: Heating--Postural balance--Fall--Twin study--Heritability--Aging.

Background. The relationships between motor performance and age, anthropometric characteristics, and serum lipids were studied in a population-based sample of women (N = 865). Methods. Motor performance was measured by a precise laboratory test, the Postural-Locomotion-Manual test, using an optoelectronic technique. Anthropometric measurements included body mass index (BMI) and waist-to-hip ratio. Blood samples were drawn for the measurement of total cholesterol, high-density lipoprotein (HDL) cholesterol, and triglyceride concentrations. Results. Motor performance deteriorated with age in a curvilinear way. High BMI, high waist-to-hip ratio, high triglycerides and low HDL cholesterol were all correlated to poor motor performance after adjustment for age, vascular disease, hypertension, diabetes, smoking, physical exercise, and some chronic diseases. Stepwise regression analyses showed that age, waist-to-hip ratio, triglycerides, HDL cholesterol, physical exercise, and vascular diseases were independent predictors of motor performance. Conclusions. High age, high waist-to-hip ratio, high triglycerides, and low HDL cholesterol were associated with poor motor performance in women. Monitoring abdominal adiposity and serum lipids in clinical work might help us to identify people with early motor impairment and to prevent more severe mobility disability.

Background. The study addressed whether changes in gait speed in community-dwelling older adults were associated with changes in fitness (strength and aerobic capacity), physical health status, and/or depressive symptoms. Methods. The study sample comprised 152 community-dwelling adults aged 68-85 who had participated in an exercise study. Study measures at baseline and 6-month follow-up included gait speed, a leg strength score, maximal aerobic capacity [Mathematical Expression Omitted], CES-Depression scale, and physical health status (SIP Physical Dimension). Results. In cross-sectional regression analyses, leg strength, [Mathematical Expression Omitted], weight, and the strength by [Mathematical Expression Omitted] interaction term were significant independent predictors of gait speed ([R.sup.2] = 26%). Based upon the observed 7% increase in [Mathematical Expression Omitted] and 8% increase in strength in the exercise groups, the regression model predicted only a 2% (1.5 m/min) increase in gait speed, which did not differ significantly from the observed increase of 0% (.32 m/min). The strongest correlate of change in gait speed was change in CES-D scores (partial R = -.37). Change in physical health status also correlated with change in gait speed (partial R = -.28), while change in fitness did not. Conclusions. The results suggest, in the range of fitness of the study sample, that changes in gait speed are related to changes in depressive symptoms and physical health status, but not to modest changes in fitness. A model assuming nonlinear relationships may be appropriate for understanding how strength and aerobic capacity affect gait speed.