Citations

Purpose: Clinicians and fitness professionals are increasingly recommending the use of activity trackers. This study compares commercially available activity tracking devices for step and distance accuracy in common exercise settings. Design: Cross sectional. Setting: Rochester, Minnesota. Participants: Thirty-two men (n = 10) and women (n = 22) participated in the study. Measures: Researchers manually counted steps and measured distance for all trials, while participants wore 6 activity tracking devices that measured steps and distance. Analysis: We computed the difference between the number of steps measured by the device and the actual number of steps recorded by the observers, as well as the distance displayed by the device and the actual distance measured. Results: The analyses showed that both the device and walking trials affected the accuracy of the results (steps or distance, P < .001). Hip-based devices were more accurate and consistent for measuring step count. No significant differences were found among devices or locations for the distance measured. Conclusions: Hip-based activity tracking devices varied in accuracy but performed better than their wrist-based counterparts for step accuracy. Distance measurements for both types of devices were more consistent but lacked accuracy.

Objectives To determine the cross‐sectional association between cerebral amyloid‐beta (A β ) deposition and gait. Design Cross‐sectional. Setting Population‐based cohort study in Olmsted County, MN . Participants Cognitively normal individuals (n = 611), aged 50 to 69 years, enrolled in the Mayo Clinic Study of Aging with concurrent PiB‐ PET imaging and gait assessment. Participants with a history of stroke, alcoholism, Parkinson's disease, subdural hematoma, traumatic brain injury, or normal pressure hydrocephalus were excluded. Measurements PiB‐ PET SUVR was measured in prefrontal, orbitofrontal, parietal, temporal, anterior cingulate, posterior cingulate, and motor‐specific regions of interest ( ROI s). Gait parameters (speed, cadence, stride length, double support time, and intra‐individual stance time variability) were measured using GAITR ite ® instrumentation. Linear regression models were adjusted for age, sex, body mass index, education, APOE ε 4 allele, Charlson comorbidity index, and depression. In secondary analyses, we additionally adjusted for neurodegeneration (hippocampal volume, FDG PET SUVR , and cortical thickness) in AD ‐associated regions. Results In fully adjusted models including neuroimaging measures of neurodegeneration, higher PiB‐ PET SUVR across all ROI s was associated with slower gait speed ( P < .05 except for the parietal ROI ), lower cadence and longer double support time ( P ≤ .05 except for the motor ROI ), and greater stance time variability ( P < .05). In sex‐stratified analyses, the association between higher PiB‐ PET SUVR across all ROI s and measures of gait was only present among women. Conclusion PiB‐ PET SUVR across ROI s, independent of general measures of AD ‐associated neurodegeneration, is associated with poorer performance on multiple gait parameters among cognitively normal women, aged 50 to 69 years. Longitudinal studies are needed to determine whether A β predicts gait decline in both women and men.