## 4 Discussion  
### Main Findings  
Our novel adapted training program with usual care elicited greater improvements in several single- and dual-task physical function measures than usual care alone among PWD. Similar findings between the ITT and Per Protocol analyses suggest that exercise with usual care in any amount may be a viable therapeutic intervention approach among PWD in residential care facilities. Our findings extend previous RCTs in healthy older adults [48; 49; 50], as well as community-dwelling PWD [12; 13; 20; 25; 29; 30; 31; 54], such that 6 months of adapted OEP training improved spatial (stride length) and temporal (velocity) measures of single- and dual-task mobility in PWD in residential care facilities compared to usual care alone. While both groups showed improvements in gait speed and dual-task performance, the OEP plus usual care group had notably greater gains in stride length, turn velocity, and lower leg double support during dual-tasking. Our results are in line with a pilot RCT that also found improved spatial (stride length) and temporal (gait speed, cadence, single support percentage) dual-task gait improvements but only during difficult dual-tasks in community-dwelling PWD following 12 weeks of exercise, relative to the control group who received low-intensity exercise [55]. A quasi-experimental study showed that a 10-week dance intervention and dual-task exercise intervention improved both spatial (stride length) and temporal (cadence) dual-task walking in community-dwelling females living with mild dementia; however, there was no control group [20]. Furthermore, the OEP plus usual care group experienced significant improvements in single-task gait and TUG performance, particularly in turn velocity and sit-to-stand lean angle. The improvements in single- and dual-task physical function reflect improved balance control, lower extremity strength, and functional performance [13]. Increased stride length may also correlate with fewer falls, as reduced stride length is predictive of fall risk in older adults due to a lack of lateral stability [56]. Impairments in cognitive-motor integration are common among PWD and affect the visuomotor processing needed for several daily activities, such as reaching movements, fine motor movements, and coordination during cognitive tasks [8]. The improvements observed by the OEP plus usual care group in cognitive-motor integration in dual-tasking are important to daily life for PWD because cognitive and physical function independently predict recurrent falls [57]. Interestingly, the usual care group exhibited significantly faster dual-task gait speed at 6 months compared to the OEP plus usual care group, which was also notably faster than the 6-month single-task gait speed. Previous work suggests that those with more severe dementia may be at a greater risk for falls during dual-tasking due to a reduced decision-making ability to select an appropriate gait strategy during dual-tasks, thereby inadvertently hurrying and increasing their risk for falls [4]. Our findings extend this work to suggest that 6 months of usual care may negatively impact appropriate attention prioritization during dual-tasking compared to 6 months of exercise. More specifically, the usual care group may have exhibited cognitive overload during dual-tasking and increased their gait speed as a risky compensatory strategy, which increased their likelihood of falls. In contrast, participants in the OEP plus usual care correctly employed a cautious gait pattern in response to greater attention demand in an effort to allocate attention resources to both tasks [58; 59]. Our results highlight the potential benefits of exercise in preserving both cognitive and motor functions in PWD in residential care facilities and inform therapeutic interventions. We examined whether there was a dose effect of exercise on outcomes, specifically if twice-per-week exercise improved outcomes more than any amount of exercise.