Using Wearable Monitors to Assess Daily Walking Limitations Induced by Ischemic Pain in PAD.

Purpose To develop, assess the feasibility of, and determine the clinical validity of an event-based analysis method using wearable monitors to quantify walking pain manifestations (WPMs) and stops induced by walking pain (SIWPs) during daily life walking in people with peripheral artery disease (PAD). Methods The following two conditions were studied: a standardized outdoor walking session (OWS) and a seven-day free-living measurement (FLM) period. The PAD participants (n = 23) wore an accelerometer and a watch. They were asked to press the event marker button on the watch to indicate events related to WPMs and SIWPs. To assess the clinical validity of the method, the computed pain-free walking time (PFWT) and maximal walking time (MWT) were compared with the PFWT and MWT assessed using standard treadmill walking protocols, respectively. Results Following OWSs, the PFWT[OWS] and MWT[OWS] were significantly correlated with the PFWT[Strandness] (r = .955, P < .001) and MWT[Strandness] (r = .821, P < .001), respectively. During the FLM, PAD participants experienced only 2 WPMs/day and 1 SIWP/day, although severely limited on the treadmill and during the OWS. The average WPMs/day were moderately correlated with the PFWT[Strandness] (r = -.54, P = .016). The PFWT[FLM] was on average 12 times longer than the PFWT[Strandness]. Interestingly, the intensity of the walking bouts as assessed by the accelerometer counts during the FLM was significantly lower than that during the OWS (45 +/- 15 vs 66 +/- 20 counts/s, P < .001). Conclusion This new method offers opportunities for studies investigating the experience of living with PAD and the assessment of daily life walking capacity for both diagnostic and therapeutic purposes.