Validation of Proprietary and Novel Step-counting Algorithms for Individuals Ambulating With a Lower Limb Prosthesis.

OBJECTIVE: To compare the accuracy and reliability of 10 different accelerometer-based step-counting algorithms for individuals with lower limb loss, accounting for different clinical characteristics and real-world activities. DESIGN: Cross-sectional study. SETTING: General community setting (ie, institutional research laboratory and community free-living). PARTICIPANTS: Forty-eight individuals with a lower limb amputation (N=48) wore an ActiGraph (AG) wGT3x-BT accelerometer proximal to the foot of their prosthetic limb during labeled indoor/outdoor activities and community free-living. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Intraclass correlation coefficient (ICC), absolute and root mean square error (RMSE), and Bland Altman plots were used to compare true (manual) step counts to estimated step counts from the proprietary AG Default algorithm and low frequency extension filter, as well as from 8 novel algorithms based on continuous wavelet transforms, fast Fourier transforms (FFTs), and peak detection. RESULTS: All algorithms had excellent agreement with manual step counts (ICC>0.9). The AG Default and FFT algorithms had the highest overall error (RMSE=17.81 and 19.91 steps, respectively), widest limits of agreement, and highest error during outdoor and ramp ambulation. The AG Default algorithm also had among the highest error during indoor ambulation and stairs, while a FFT algorithm had the highest error during stationary tasks. Peak detection algorithms, especially those using pre-set parameters with a trial-specific component, had among the lowest error across all activities (RMSE=4.07-8.99 steps). CONCLUSIONS: Because of its simplicity and accuracy across activities and clinical characteristics, we recommend the peak detection algorithm with set parameters to count steps using a prosthetic-worn AG among individuals with lower limb loss for clinical and research applications.

Impact of the COVID-19 pandemic on the rate of lower limb amputation in Veterans.

BACKGROUND: The COVID-19 pandemic led to changes in health care, including postponement of nonurgent appointments. These changes, combined with overall decreased activity levels, may have placed individuals with vascular disease at increased risk for skin ulceration and amputation. OBJECTIVE: To determine the rates of lower limb amputation in Veterans due to complications of diabetes and/or vascular disease in the year following onset of the COVID-19 pandemic (March 2020-March 2021) compared to the previous 3 years (March 2017-March 2020). DESIGN: Retrospective chart review. SETTING: Minneapolis Veterans Affairs Health Care System. PARTICIPANTS: Veterans with a vascular consult appointment note between March 1, 2017, and February 28, 2021. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Primary outcome was lower limb amputation rate in the year following onset of the COVID-19 pandemic compared to the previous 3 years. Secondary outcome was the rate of lower limb wounds in the same time frame. We hypothesized that rates of lower limb amputation and wounds increased during the pandemic. RESULTS: Vascular consult appointments (n = 4183) were reviewed between March 1, 2017, and February 28, 2021. Significantly higher rates of amputation (7.52% vs. 5.19%; p = .006) and wound presence (16.77% vs. 11.66%; p < .001) were found 1 year postpandemic compared to the previous 3 years. Amputation and wound rates did not significantly increase between pairs of consecutive years prior to the pandemic but significantly increased between the year preceding the pandemic and the first year of the pandemic (amputation p = .047; wound p = .004). CONCLUSIONS: Increased rates of amputation and wounds in Veterans following the onset of the COVID-19 pandemic are likely due to disruption of care, lifestyle changes, and other pandemic-related factors. Awareness of COVID-19-related negative health effects is imperative for health care providers to ensure appropriate allocation of resources and alternate models for care delivery for amputation and preventative care as part of disaster response.

Design refinement and evaluation of a mobile manual standing wheelchair.

PURPOSE: There are no manually propelled wheelchairs on the market that are mobile in both seated and standing positions. In response to this product gap, our group formerly designed a mobile manual standing wheelchair (MMSW) and gathered stakeholder feedback. The purpose of this study was to refine the MMSW based on feedback, including weight and width reduction, and evaluate its performance. MATERIALS AND METHODS: The MMSW was subjected to ANSI/RESNA stability testing, and three male participants completed a subset of the wheelchair skills test, including a 100-m roll test in the MMSW (seated and standing) and in their ultralight wheelchair. RESULTS: The MMSW met ANSI/RESNA stability safety standards. During the 100-m roll test, participants reached speeds with the MMSW in both the standing and sitting postures similar or greater than those typical of moving in the home environment (1.11 m/s seated; 0.79 m/s standing). Mobility speeds in the MMSW in the standing position were about three times faster than average walking speeds in exoskeletons (0.26 m/s exoskeletons). With the addition of chain drive bracing to the MMSW, one user was able to reach speeds in the standing position similar to average neurotypical walking speeds indicating the possibility for wheelchair users to be able to move in pace with family and friends. CONCLUSION: All participants expressed interest in the MMSW to facilitate improved quality of life. Further work is needed to test the utility of the MMSW in home and community settings, and its potential effects on standing time and health outcomes.Implications for rehabilitationManual standing wheelchairs with standing mobility may increase functional utility and length of standing time for manual wheelchair usersIncreased standing time may lead to several health benefits for manual wheelchair users.