Validity and Reliability of a Smartphone Application for Home Measurement of Four-Meter Gait Speed in Older Adults

The four-meter gait speed (4MGS) is a recommended physical performance test in older adults but is challenging to implement clinically. We developed a smartphone application (App) with a four-meter ribbon for remote 4MGS testing at home. This study aimed to assess the validity and reliability of this smartphone App-based assessment of the home 4MGS. We assessed the validity of the smartphone App by comparing it against a gold standard video assessment of the 4MGS conducted by study staff visiting community-dwelling older adults and against the stopwatch-based measurement. Moreover, we assessed the test-retest reliability in two supervised sessions and three additional sessions performed by the participants independently, without staff supervision. The 4MGS measured by the smartphone App was highly correlated with video-based 4MGS (r = 0.94), with minimal differences (mean = 0.07 m/s, ± 1.96 SD = 0.12) across a range of gait speeds. The test-retest reliability for the smartphone App 4MGS was high (ICC values: 0.75 to 0.93). The home 4MGS in older adults can be measured accurately and reliably using a smartphone in the pants pocket and a four-meter strip of ribbon. Leveraging existing technology carried by a significant portion of the older adult population could overcome barriers in busy clinical settings for this well-established objective mobility test.

Highly Visible Wall-Timer to Reduce Endovascular Treatment Time for Stroke

BACKGROUND

Endovascular therapy for acute ischemic stroke has revolutionized clinical care for patients with stroke and large vessel occlusion, but treatment remains time sensitive. At our stroke center, up to half of the door-to-groin time is accounted for after the patient arrives in the angio-suite. Here, we apply the concept of a highly visible timer in the angio-suite to quantify the impact on endovascular treatment time.

METHODS

This was a single-center prospective pseudorandomized study conducted over a 32-week period. Pseudorandomization was achieved by turning the timer on and off in 2-week intervals. The primary outcome was angio-suite-to-groin time, and secondary outcomes were angio-suite-to-intubation time, groin-to-recanalization time, and 90-day modified Rankin scale. A stratified analysis was performed based on type of anesthesia (ie, endotracheal intubation versus not).

RESULTS

During the 32-week study period, 97 mechanical thrombectomies were performed. The timer was on and off for 38 and 59 cases, respectively. The timer resulted in faster angio-suite-to-groin time (28 versus 33 minutes; P=0.02). The 5-minute reduction in angio-suite-to-groin was maintained after adjusting for intubation status in a multivariate regression (P=0.02). There was no difference in the 90-day modified Rankin scale between groups. The timer impact was consistent across the 32-week study period.

CONCLUSIONS

A highly visible timer in the angio-suite achieved a meaningful, albeit modest, reduction in endovascular treatment time for patients with stroke. Given the lack of risk and low cost, it is reasonable for stroke centers to consider a highly visible timer in the angio-suite to improve treatment times.

Measuring Gait Parameters from Structural Vibrations

Measuring gait parameters (e.g. speed, cadence, step duration) accurately is invaluable for evaluation during treatment of older adults who struggle with disability onset, disease progression, balance, and injurious falls. Traditionally stopwatches or timing gates are used to measure gait speed in clinical settings, and these are limited to measuring gait speed. Other wearable and non-wearable technologies offer the ability to measure additional gait parameters though patients are known to walk differently with the devices and even tend to slow down before engaging with a non-wearable such as a floor mat. Floor vibrations are a promising option to measuring gait parameters while not being intrusive and not requiring line-of-sight to the patient for measurements. This paper presents methodology for extracting gait parameters using vibrations with comparisons to APDM Wearable Technologies Mobility Lab sensors and stopwatch measurements. Performance is examined across 97 participants for self-selected speed forward, full speed forward, and backwards walks at three different testing sites for a total of 1039 walks. Gait speed vibrations measurements demonstrated excellent reliability with APDM Mobility Lab (ICC: 0.98; 99% CI: 0.01±0.01 m/s) and stopwatch (ICC: 0.97; 99% CI: -0.01±0.01 m/s) measurements. Similar excellent results are reported for cadence, gait cycle duration, step duration, and stride length parameters.