Given the care burden of family members or paid caregivers in residential settings, a wearable’s ease of use was paramount when asking caregivers to be involved in a study. It was the most frequently identified factor in studies, with 36% (21/58) of studies mentioning it. The wearable device must be easy to use [25-27,61-65] with an intuitive interface and features [28-31]. The device should require little maintenance or technical support for everyday use, and any interaction with the device required by the study should be simple [10,28,32-35,66]. Some studies explicitly noted that perceived ease of use was associated with more positive attitudes toward wearing the device and less effort or sense of inconvenience in participation [27,36-39]. As a person living with dementia exclaimed in the study by Gris et al [38], “Older people need to use simple things!”

Almost without exception, participants desired smaller and lighter wearables or expressed discontent about the size and weight of the device they were asked to wear in the study [34,35,40-42,63,64,66-68]. The influence of a wearable’s size and weight was the most frequent physical form factor, with 31% (18/58) of the studies including comments about it, and it was the fourth most common factor identified overall. While rare, there were some exceptions to participants desiring smaller devices overall. Some suggested enlarging certain facets of a device, such as having a larger face or font to read [43] or larger buttons to interact with [27].

The physical ease of wearing the device was important [28,31-33,38,41,44,67,69], with discomfort specifically cited as a reason why participants removed the device in several studies [34,45,66]. Comfort was sometimes explicitly linked with unobtrusive, as complementary qualities [20,29,61]. Nevertheless, prototype devices that were bulky or wearables with a more invasive application (eg, required taping to limbs or backs) were mostly tolerated in the short term. However, simply put, “If residents would show discomfort related to the wearable, the wearable would not be used” [61].

Studies found that if a device type was already familiar or similar to what caregivers and persons living with dementia already used regularly, the wearable could be seen as convenient and more easily fit into a participant’s lifestyle [10,30,32,33,46,67,70]. Wristwatches were the most frequently cited as meeting these criteria [20,29,35,38,41,47]. At the same time, devices might also be removed if accessory removal is also part of a participant’s routine [20,32,41]: “To tackle such barriers [to using mHealth devices] will likewise require (informal) caregivers to change their attitudes towards using digital technologies and the integration of these technologies into routine care” [30].

A wearable that is not obvious or can be hidden was considered a distinct positive [25,29,35,38,70,71]. Having the ability to conceal a wearable alleviated some worry about a person living with dementia being resistant to wearing the device or removing it (refer to the Self-Removal subsection), which could be especially pertinent in studies involving individuals with more advanced stages of dementia [61,66,68]. Unobtrusive devices were also seen as reducing the potential of drawing attention to themselves or experiencing stigma associated with wearing a device [10,42,61] (refer to the Stigma subsection). Like the fits into routine factor, wristwatches were commonly cited as an unobtrusive solution [10,20], but something that could be slipped onto a belt or into a shoe was also noted as a viable option [10,29].

Having the option to use a wearable in a way that fits a person’s particular style preferences was desired, from format (eg, neck pendant or watch) to style (eg, colors and design) [10,29,34,35,38,61,62,71], as some had concerns with the particular format that was provided in the study and desired a different way to wear the device [26,31,68]. Alternative device forms can include a spectrum of participants and their day-to-day presentations (eg, gender and culture) [10,18]. Offering a wearable in several different forms could help a device suit the fits into routine factor, but the tailorable factor highlights that singular forms may not fit into everyone’s routine equally: “Several members in all four groups expressed a desire for more options in device styles...all groups asked if alternative styles could include a broach, belt clip, small bracelet, or ankle bracelet” [31].

Nonspecific material concerns or durability were cited as important considerations for wearables to be satisfactory to participants and researchers alike [29,41,63]. Specific material issues such as softness [34,63,66] and the need to make wearables safe for those with skin sensitivities or allergies were also mentioned [10,28,34,61]. Some participants stopped wearing the device altogether because it caused irritation [22] or even skin abrasions [48].

The general appearance of the device design in its look and feel could be a barrier to everyday use and, thus, adherence [41,43,47,63,64]. Size, form, color, and device material all play a role in the aesthetic attractiveness of a wearable [31,34,35]. For example, participants in the study conducted by Jacklin et al [31] were dissatisfied with the prototype wearable they were testing, describing it as “big and clumsy looking” and “rubbery.”

Diminishing fine motor skills in persons living with dementia made easy to wear, or how simply one can put on or take off the wearable, an issue for day-to-day use [10,62,65]. Wearables that were difficult for the wearer to put on or take off by themselves required caregiver support that could add stress to both the person living with dementia and their caregiver, creating participation burden and a sense of lack of independence [34,48]. Some wearables were slightly more complicated and required specific sensor placement, which was either difficult to apply correctly or failed to remain securely attached [34,49,50].

The factor easy to wear is distinct from easy to use and may not play a role if a wearable is designed to be worn continuously. For example, a family caregiver reported that an accelerometer was “a little bit difficult to put on, so [the persons living with dementia] did do it but...it’s not easy.” The researchers echoed that “the wristband of the accelerometers could be difficult to fasten” but reported that afterward, “the accelerometers were not burdensome to wear” [65].

Water-resistant or waterproof wearables were recommended [28,61,64] to minimize potential disruptions to data collection. Along with charging the device, a common point of noncompliance occurred when participants forgot to put the wearable back on after removing it for bathing (refer to the Remembering the Device subsection) [29,34]. By selecting a waterproof device and asking participants not to remove it, study protocols do not have to rely on persons living with dementia or their caregivers remembering to take off the device during bathing and, therefore, can reduce the number of study task requirements and related burden impact [44,63]. Cruz-Sandoval et al [29] suggested that minimizing the need to remove a device can reduce instances of “resistance” from persons living with dementia, and therefore, waterproof devices “can ease some of the burden on caregivers” as well.

Many studies noted that privacy was an issue, with participants voicing concerns about data security and who had access to the wearable’s data [10,18,26,31,38,63,68,71]. For example, a caregiver’s spouse worried about third-party breaches of her wearable data, explaining that “privacy and security are important to his wife because ‘...she understands just how easily those systems can be hacked’” [71].

At the same time, some persons living with dementia and their caregivers stated explicitly that privacy concerns were outweighed by the personal or societal benefits of their study participation [25,33], or they reported no privacy concerns [27]. Participants understood that data sharing was often necessary to meet the goals of the study, and privacy concerns were ameliorated when researchers established trust around data management: “Both informal caregivers and the nursing staff were not concerned about privacy issues regarding the wearable, as they consider biomedical variables as de-individualized values. The participants trusted the researchers and nursing home regarding good data handling, as they felt well-informed” [61].

Researchers were able to build trust and attenuate privacy concerns through transparency about data access and security measures during the informed consent processes and throughout the study [61,72]. Empowering participants to have control over privacy options (eg, allowing the collection of some but not all data) and offering the ability to turn off or select what data to monitor also helped [51,73].

The ability of persons living with dementia to understand and actively affirm their study participation is an ethical imperative but was specifically mentioned as a potential difficulty by several studies [38,71]. Especially in longer-term studies, seeking ongoing consent to participate was highlighted as necessary, with suggestions to check in regularly to assess the cognitive capacity of the persons living with dementia and their willingness to participate [20,51,74]: “Fluctuating cognition can be a significant barrier to the remote monitoring of isolated patients as forgetting about one’s motivations to be monitored can lead to anxiety and agitation for being watched and, consequently, the disablement or destruction of equipment” [74].

At odds with fully informed consent was the general awareness of persons living with dementia regarding their participation or the device [32,43]. At this level of impairment, consent from a caregiver or another proxy for the persons living with dementia was sometimes sought instead, which could be an appropriate barrier to inclusion [22,69,70]. Another major challenge is reconciling what to do when a person living with dementia desires conflict with the caregiver’s desire for them to engage in the study and wear the device [10,68]. Under consideration is the issue of dignity, respect for autonomy, and how ignoring these or not obtaining assent could lead to agitation: “In one case, [the study staff] visited the participant after he had refused to wear it on his wrist, saying his wife was tagging him ‘like a dog’” [68]. In another study [10], a caregiver reported “[My husband] would have never given his consent even at the beginning—he liked the independence of making his own decisions and doing what he wanted. And I would have had to do it without his consent.”

It was recommended that, when possible, researchers, caregivers of persons living with dementia, and their proxies should attend to their care recipient’s wishes, whether from an explicit advanced directive [73] or knowledge of their comfort with similar technology [30].

The longevity of battery life and the ease of charging were noted as concerns for both researchers and participants [9,28,38,63,64,75]. Wearables with a battery life of at least several days were ideal [28,29,52,63], decreasing the need for participants to remember to charge the device [9,10,72] (ie, simplifying task requirements), which also minimized data collection interruptions for researchers. Low battery warnings from the device or study staff were seen as a useful tool to ensure an adequate charge of the battery [10,32,68]. Necessarily, the burden of charging was exacerbated when a caregiver was not on site to physically assist or when the charging mechanism was difficult to implement [35].

Participants may need time to acclimate to wearing the device (eg, establish wearing routines) and to resolve technical issues before consistent adherence and, therefore, consistent data quality, as adherence tended to improve after an initial period [9,29,32,33,41,53,61]. On the other hand, some studies found better compliance earlier in a study period [42,54,65], perhaps because of novelty. Adjustment periods featuring cognitive aids such as instructional pamphlets and study staff check-ins provided early troubleshooting and time to build new routines [9,29,33].

Cognitive impairment and caregiving burden were barriers to protocol adherence when participants were asked to do more than simply wear the device [55,56,74,75]. When a study protocol required additional activity from either the persons living with dementia or a caregiver, such as completing bedtime and wake-up event markers, they were less likely to remember or be able to comply [9,50,57,72].

Although many interacted with the study wearables and related technology platforms successfully, participants’ sense of a lack of technical proficiency and negative attitudes about technology were reported as a perceived barrier to enrollment [10,18,27,37,38,41,71] and adherence during the study [29,53,62]. Caregivers and persons living with dementia alike expressed concern about the complexity or technical know-how needed to operate the wearables [29,36,53,63,74]. Technical anxiety could present as worrying about damaging or losing the device [20,29,34]. The level of technical anxiety and attitudes toward the technology were related to age qualitatively and statistically [10,27,38,53,62] and previous experience with devices [36,46,76]. Participants in a study actually rated themselves as less technologically proficient at the end of the study because of difficulty with the wearable [42].

Participants saw the potential for the device and platform to offer more information or other uses to the wearer as a benefit of being involved in the research [27,71]. Being able to track their health and activity, signal health events or emergencies (eg, wandering or fall alerts), provide directions, or offer location services, among others, were cited as desirable features [10,25,27,29-31,34,63,64,67,74]. Simpler functions such as information about time, date, and alarm capacity were also ideal wearable facets [10,32,35,41,52,63]: “Participants with dementia indicated that multiple purposes for the locator device, such as being able to measure heart rate, blood pressure and activity level, is advantageous as it would streamline the number of devices that they and their caregivers must contend with” [10]. Stavropoulos et al [63] reported, “Feedback suggested that some people with dementia may be more willing to accept technology that supports them in their daily functioning, in addition to assessing it."

Caregivers especially liked the potential the wearables offered in terms of supporting their caregiving role and tasks, which, in turn, reduced related burden and stress [27,32,39,64,69]. Factors such as a wearable’s capacity for remote monitoring and providing health insights could improve quality of life or provide peace of mind [33,39,63,67,72]. However, when the wearable was technically difficult to use (easy to use) or researchers required additional time or study activity (refer to the Task Requirements subsection), being involved in the study was perceived as a cause of additional burden and a deterrent to both enrollment and continued participation [29,32,33,58,59,61,70,74]. Notably, participants in several studies reported experiencing a mix of both reduced and heightened burden, which varied according to specific facets of the research or from using the wearable [32,33,65,69]: “The nursing staff indicated that they did not want to spend valuable care-time if the foreseen benefit of the wearable for the specific resident was not evident to them. Likewise, also informal caregivers found it important to know the potential individual benefits, before deciding whether to bother the resident with the wearable, as they anticipated some level of resistance to wearing the wristband by the residents” [61].

Caregivers and persons living with dementia expressed concerns about the stigma associated with the wearable and the wearable identifying their care recipient (or themselves) as affected by the hidden disability [10,18,30,64]. There was concern about social acceptance and the visibility of the device, as well as the perceptions or comments that it might engender (eg, that they are under surveillance or need to be monitored) [33,34,61,72]. On the other hand, “social influence” was often a positive, with care providers or fellow persons living with dementia offering positive comments or encouraging the use of the wearable [29,37,39,76].

Families and professional care providers alike were sensitive to the negative connotation that some wearables might cause. An Alzheimer Society staff member reported that some families might avoid incorporating a MedicAlert bracelet in their care management plans because “It’s a signifier or something that’s perceived to bring stigma—[the persons living with dementia] don’t want to be out there clearly marked in some way, that there’s something wrong with them. Nor does the family” [18].

Caregiver buy-in underlies many facets of wearable studies featuring persons living with dementia, as many studies relied on caregiver commitment and coordination with the researchers to do study activities (refer to the Caregiver Support subsection) [20,36,57,61,70]. Moreover, they played significant roles in facilitating understanding of the study by persons living with dementia [29,47] and in encouraging them to wear the device [39,41]. Some studies specifically cited the need for caregivers to have perceived usefulness or reasons to commit to reducing perceived potential burden or risks to enroll themselves and their care recipient in the study [61,72,76]. Gaining caregiver buy-in could be enhanced by reducing participation burdens (eg, fewer task requirements, easy-to-use devices, and offering ongoing technical support) and experiencing personal benefit from the study (eg, remote monitoring and providing health insights).

Passive, remote monitoring is the defining advantage of wearable device studies. However, technical connectivity requirements can be a barrier to enrollment [10,31,61,69,74] and may create logistical problems for data transmission [18,31,56,77]. For example, requiring faster Wi-Fi or consistent Bluetooth linkage with a smartphone for more frequent data uploads [67,75,77] may introduce recruitment bias to individuals of higher socioeconomic status and those who are already technically inclined: “The lack of internet connection in patient homes and of funding for caregivers and family member to purchase assistive or communication devices are frequently coupled with skepticism or low abilities to engage with digital products” [74].

Remote monitoring was the most frequently cited desirable and useful feature (mentioned in 19/58, 33% of studies) when engaging in a wearable study among populations with dementia [10,25,27,34,59,61,69,76]. Geolocation-based remote monitoring enabled caregivers to track the movements of persons living with dementia when they were not present, including movement outside the home. Remote monitoring was also seen as a way to know about the well-being of persons living with dementia, for example, by the identification of agitated movement or interrupted sleep [32,40,77]. Remote monitoring enhanced the independence of the person living with dementia [27,38,63] while providing informal caregivers with peace of mind regarding the safety of persons living with dementia (eg, reduces burden impact) [46,63,64,67,72].

For some participants, the utility of the benefits of geolocation services conclusively outweighed potential privacy concerns [25,42]. However, for some, introducing the idea of being monitored could be seen as an infringement on autonomy and privacy [25,31], such as when “some participants feared that proud Anishinaabe older adults would be offended by the idea that their movements would be tracked” [31].

Providing health insight to the participants was one of the top factors mentioned as a benefit to ongoing participation and use of a study’s wearable. Paralleling the multifunctional factor as an aid to enrollment incentives, health insights included, for example, information on blood pressure, heart rate, sleep quality, and steps. Having ongoing access to this health data motivated participants’ personal activity, helped caregivers monitor for health crises, and provided more general insight into the well-being of persons living with dementia [10,25,27,29,32,33,38,53,54,58,61,63,69,74,77]. In addition, they appreciated that this health information could be useful to residential staff and physicians in informing care decisions [25,27,32,34,61,64,69]. A caregiver in the study by Lazarou et al [25] said that with the information from the wearable, “we could monitor her daily activity and communicate any problems to the doctors. It helped us a lot to understand what is going on.”

As technical anxiety was a barrier, providing initial technical training and ongoing technical support was identified as a complementary facilitator [20,26,37-39,50,74]. Staff availability to provide training at enrollment, support during an adjustment period, and assistance as needed throughout the study helped improve adherence [29,33,77]. Stand-alone instructional materials and cognitive aids were useful to participants who sought to troubleshoot issues on their own [9,10,47,66]. Along with data monitoring, regular proactive check-ins with participants made (or would have made) staff aware of technical problems and helped maintain better compliance [29,45,53,68,77].

For example, Gelonch et al [33] provided caregivers with initial training and ongoing technical assistance, and consequently, they supported their care recipient’s use of a lifelogging camera: “The [persons living with dementia] said that the support and supervision provided by their caregiver in certain tasks or actions, such as connecting and loading the camera, were also key for them continuing with the experiment.”

Even when apprehensive about using the technology (refer to the Technical Anxiety subsection), participants commonly showed a readiness to learn how to operate the wearable devices and follow study protocol. As recounted by Anderson et al [36], “Many were not necessarily technologically proficient caregivers, but they wanted to be useful. None of the caregivers implied that the research should not continue to be refined.”

While the importance of caregiver buy-in was highlighted in recruitment, in this section, we underscore the importance of caregivers and their investment in the study for continued wearables adherence [36,39,71,77]. Many research protocols required caregiver activity to accomplish their goals by having them be the primary study participant or helping persons living with dementia complete study tasks [29,44] and, importantly, charging the wearable [35,77]. Many factors depend on the caregiver, such as helping persons living with dementia remember the device [20,41], assisting with putting it on (refer to the Easy to Wear subsection) [34,48], or understanding how to operate the wearable [33]. In addition, caregivers could be instrumental in explaining facets of the study and, in other ways, facilitating communication of research needs to their care recipient throughout the study [29,68].

Notably, relying on caregiver support can be a major ask (ie, increase burden impact): “The caregivers were able to be present almost all the time. They demonstrated personal investment in the care that the person living with dementia received. Their willingness to participate in, work with researchers, and use technology 24 hours a day for 30-60 days was a significant commitment” [36].

Broadly speaking, wearable technologies were seen as an instrument for enhancing the safety of persons living with dementia [45,46,71,72]. This potential positive was specifically identified as an ongoing benefit, often in tandem with or implied within remote monitoring and providing health insight. Wearables offer a sense of security to persons living with dementia and their care providers, aiding aging in place by alerting caregivers to life events or potential crises (eg, elopement or fall monitor) and detecting changes in health or behavioral patterns [28,31,34,59].

On rare occasions, the device itself was harmful, such as when an over-ear device caused skin abrasions [48] or when participants desired a different product or sensor design for safety reasons [69]. In contrast to other participants in their study, a caregiver in the study by Snyder et al [71] explained that they felt the wearable, an emergency response pendant, gave a false sense of security, saying, “My reluctance is that it doesn’t seem...It can’t stop something from happening to her. It just alerts you maybe if something does.”

Adherence in wearable studies was affected by persons living with dementia’s ongoing ability to remember what the device was for [22,29,42]. Not remembering the purpose of the device could also result in “confusion and agitation” [43]. More commonly, persons living with dementia simply forgot to wear the device [10,20,63,75], especially after removing it for bathing (if not water resistant) or sleep, often resulting in failure to put it back on [34,65]. Better adherence was reported earlier in the day [53,77], potentially because of sundowning: “Due to memory impairment participants had to be constantly reminded to wear the device and they could change their opinion from one day to the other. Activities that made wearing the device more salient, such as the need to take it off to charge it or bathing, proved challenging with some participants” [20].

Whether the device provided geolocating, physical activity monitoring, or health alerts, participants, especially caregivers, saw these devices and platform features as enhancing the independence and autonomy of persons living with dementia [10,27,39,63,67,71]. Participants’ ongoing access to the data and ability to turn off data collection at their discretion contributed to a sense of agency within the study itself [33,38]. Similar to the potential harms of remote monitoring, Synder et al [71] framed this positive as part of the “conundrum between the benefits of having peace of mind, a sense of self-efficacy, and greater independence versus perceiving (remote monitoring technologies) as an invasion of privacy, a security risk, a false sense of security, and a distraction.”

Taking off the device when not instructed was an issue in several studies [44,60]. This could be temporary, such as during bathing, or routine, such as removing accessories before sleep [32,72]. In some cases, removal was longer term, often due to agitation (possibly related to sundowning) or discomfort [22,32,66]. Some researchers and care providers suggested or chose to put the wearable out of reach (eg, on their back) to prevent self-removal by persons living with dementia [60,61].

This review identified barriers, facilitators, and preferences that could improve the quality of research studies featuring wearable devices and persons living with dementia. The review included studies encompassing a variety of study designs and perspectives from researchers, persons living with dementia, and their caregivers (both unpaid family members and paid professionals), ensuring broad inclusion of research experiences. We offer a qualitative synthesis of these findings to enhance enrollment and adherence in long-term wearable research featuring persons living with dementia. Recommendations for future research fall within 3 main categories: device selection, ethical study design, and technical and data management plans.