## 4 Discussion
### Reclaiming Lost Opportunities: Current Approaches to Subacute Rehabilitation  
IRFs are typically constrained by Medicare reimbursement limitations to provide intensive multidisciplinary therapy up to 3 h/day, 5 days/week. Even though this may seem like a relatively high therapy dosage, subacute stroke survivors in IRFs spend an average of 74% of their daily time sedentary [22]; this exceeds the 55% estimated average sedentary time of children and adults in the general population [47]. Further concerning is that sedentary bouts are often prolonged among stroke survivors, with bouts lasting greater than 1 h accounting for 44% of daily time on average [22]. In adults, there is accumulating evidence that greater sedentary behavior increases the risk for mortality, cardiovascular disease, and type 2 diabetes [48]. Among stroke survivors specifically, sedentary behavior has been associated with an increased risk of stroke recurrence [49]. Multiple definitions exist for classifying behavior as sedentary, but it is generally agreed that sedentary behavior encompasses activities that do not substantially increase energy expenditure above resting levels, such as lying down, sleeping, or sitting while watching television [50]. Reducing sedentary behavior in this population and setting is challenging, particularly because many stroke survivors face cognitive and physical impairments that limit their capacity to independently engage in activity. Inactivity also contributes to the deleterious cycle of learned non-use in the paretic upper limb, leading to worsening functional outcomes over time. Skilled intervention targeting paretic upper limb function, such as task-specific training, has been shown to significantly improve arm function post-stroke [10]. Yet, the usual care dose for upper limb task practice post-stroke has been found to be highly variable, with reported doses ranging only between 8 and 44 min spent on upper limb tasks per day [13]. This situation necessitates a solution that promotes increased upper extremity activity doses without demanding increased personnel resources in an already overburdened system. Remote wearable technology affords an opportunity to convert sedentary idle time into upper limb activity without significantly increasing the burden on clinician time. Ours is not the first study to capitalize on this idea; a related study by [PERSON] et al. (2023) investigated whether the timing and frequency of occasional vibrotactile \"nudges\" affect upper limb movement response in a cohort of 20 stroke survivors receiving care in an IRF. The authors found that stroke survivors were more likely to respond to haptic nudges delivered during periods of higher activity (e.g., around lunch) compared to times of typical inactivity [35]. They also reported that haptic nudges induced an immediate increase in upper limb movement, although the effects were limited to a duration of less than 1 min [35]. In contrast, the current study assessed the immediate responses to frequent cues--i.e., in the 5 s immediately preceding and following each delivered cue--to determine if cues successfully elicited movement in the correct limbs. The activity program and wearable system _Souvenir_ described in this study are novel in their delivery of high-dose cues that can evoke upper limb activities graded by user functional capacity. The activity program described in this report was specifically designed to allow stroke survivors with severe motor impairments and/or mild to moderate cognitive deficits to participate in upper limb activity in the absence of caregiver oversight. Although we found that cues did successfully elicit upper limb movement as intended (Figure 4A), we also noticed a gradual reduction in the average cue response rate both within a given session as well as over the course of each day (Figure 4B); the results indicate that participant engagement with _Souvenir_'s cued activity program wanes as the day progresses. Our time-varying response rate results, along with findings from [PERSON] et al.