Keywords

1 Older Adults and Technology

Smartphones, smart home devices such as Amazon Alexa and Google Home, and even our personal vehicles include technology that aim at making our daily routines easier. As these technologies become more mainstream, more populations such as older adults begin to adopt these technologies. According to a recent study of older adults’ technology usage, 67% of adults aged 65-year-old or older stated that they use the internet, 42% owned a smartphone, and 32% owned a tablet computer [1]. All of these technologies have shown an increase in use since 2013 within the older adult population, especially smartphone use which more than doubled [2]. It is projected that older adults will continue to increase their use of technology as they see it to be useful and perceive it to have a positive impact on society [1].

New technologies have begun to emerge and have been deemed the next innovation to replace our current smartphone and desktop experience for everyday activities. They are known as virtual, augmented, and mixed reality. Virtual Reality (VR) is commonly implemented using a head-mounted display (HMD) device, like the HTC Vive, Oculus Rift, or Oculus Quest where the user is immersed in a virtual environment. The user’s environment, objects around them and their interactions are digitized while the user is immersed in the virtual world. Augmented reality (AR) superimposes computerized objects on top of the users’ physical world. Through the use of mobile devices or AR glasses, users can see their physical environment around them as well as the digital artifacts. Mixed Reality (MR) fills the gap between VR and AR by creating virtual elements that adapt to the user’s physical environment. MR can be experienced through mobile devices as well as head-mounted displays, such as the Microsoft HoloLens and Magic Leap One. While VR remains a popular technology for gaming and immersive activities, it is limited in its portability and applicability to workplace settings since users are unable to view their surrounding environment. AR and MR have been used for more everyday activities. For example, online shopping, examination of health information, and interior decorating have been demonstrated to be enhanced by these technologies [3,4,5,6, 8]. The use of VR, AR, and MR is widespread, and expected to grow exponentially in the coming years. The global augmented and virtual reality market value is approximated around 26.7 billion dollars and has been projected to reach 814.7 billion dollars by 2025 [9].

For older adult populations, AR is a technology that has the potential to enhance their mental, physical, and social wellbeing. It has been proposed that use of this technology may allow them to become more independent and less dependent on their caregivers. For example, small and hard to read instructions and prescription labels can be augmented through a smartphone to produce larger, bolder text or even translated to a different language [10]. In another example, wayfinding directions could be given to an older adult using augmented step-by-step directions on a screen. AR applications could also be connected to health apps, like MyFitnessPal, allowing older adults to scan food labels and receive recommendations based on salt, iron, or other dietary requirements in real time. AR applications have also been used to promote hydration habits in older adults with dementia and have shown promise for medical uses, cognitive aids, education, and promotion of spiritual beliefs [11].

1.1 AR Medical Applications for Older Adults

Within the medical domain, AR applications are often focused on rehabilitation, encouraging a healthy lifestyle, and medication management. Papegaaij and colleagues described the benefits of an AR app for rehabilitation exercises such as balance and gait training by providing instant feedback, external cues for corrections, easily adjustable variation and intensity of trainings, and increased motivation through games [12]. AR game applications have also been shown to be useful for early cognitive screening for dementia and cognitive training [13]. CogARC, an application with AR cube mini-games helped physicians with cognitive screening of older adults and was reported to be fun and engaging by users [13]. AR has also been applied to medication management. By pairing it with intelligent assistive systems, researchers were able to create a projection-based AR prototype that focused on older adults’ and caregivers’ needs and abilities [10]. Older adults were able to dispense their own medication and receive instructions on how to take the prescription through the use of gesture commands [10]. This technology allowed older adults to take their medication correctly, without the need of a caregiver’s assistance.

AR game applications also has been used to motivate older adults to lead a more active and independent lifestyle. In one example, an AR game was projected onto the floor and older adults could sit in a wheelchair or stand and use their arms to play the game and, as a result, exercise their arms [14]. Researchers found that this game was easy for nursing home staff to set up and usable for those with cognitive deficits. It also promoted physical and cognitive rehabilitation and allowed personalization by adapting to the physical and cognitive abilities of the user through game selection and changing the height of the device [14]. AR also has been used to assist older adults who have Alzheimer’s disease and their caregivers. Through this system, caregivers could easily tag everyday objects with auditory or visual information that people with Alzheimer’s disease could use to assist in everyday tasks through the combination of a smartphone device, headphones, and a video camera [15].

In addition to motivating older adults to become more physically active, AR applications have been used to encourage them to play a more prominent role in medical decision-making. Falls, unfortunately, are a common occurrence that many older adults face. In order to prevent falls, home modifications such as the installation of handlebars are often suggested by healthcare professionals. When planning these home modifications, older adults can become compliant. As one older adult user stated, “I could have designed it better… but I didn’t think that it was my place. You know when people are doing things for you go along with what they say” [16]. AR applications can help older adults visualize home modifications during the planning process and empower them to take a more active role in the decision making.

1.2 AR Applications as Cognitive Aids

AR also has been developed to help people perceive and react to situations that they may otherwise miss. For example, a prototype of an AR car windshield heads-up display has been used to assist older adults with recognizing roadway hazards [17]. Older adults are more at risk for roadway accidents due to worsening visual acuity and slower reaction times. This AR application assisted older adult drivers in a driving simulation by making important roadway signs and hazards more salient by encapsulating them with an outline of a virtual rhombus, referred to as an AR cue. AR cuing enabled the older adult participants to increase their response rates and decrease response times, specifically with low visibility hazards such as warning signs and pedestrians [17]. One concern when using AR heads up displays, however, especially when driving, is that the AR display could distract the driver from the roadway. While this may occur with some applications, Schall et al. demonstrated that older adults could still identify secondary objects on the opposite side of the roadway after the AR heads-up display had been triggered [17]. Another study investigating AR cues for gap estimation for left-turns found a similar result. AR cueing involving a transparent sign, when placed in a fixed region that was important to the driver such as the traffic lane, helped drivers perform better in a simulator and drivers reported that the cue was not distracting [18]. AR displays such as this and similar applications developed by Porsche and GMC are helping drivers become more aware of hazards to decrease the potential for roadway accidents [19, 20].

1.3 AR Applications for Education and Spiritual Beliefs

Educational AR applications have been developed to work alongside magazines, such as Time and National Geographic, as well as museum experiences. They can be designed to give the user supplemental information, such as videos [21]. User scan the magazine within the application and it triggers a video that would provide the same information as the magazine article. This is beneficial for people who are blind or older adults who have a more difficult time reading, as they can experience the content without struggle [21]. Content can also be added through AR. A museum application at the Svevo Museum in Italy was able to pair statues with external links containing narrations, historical audio recordings, and interactive animations on smartphone devices [22]. Participants in these studies enjoyed the applications and recognized the benefits. However, it was challenging for older adults to hold the mobile devices in place for longer periods of time, which is necessary to interact with these applications, and they stated this would be increasingly difficult for those who suffer from Parkinson’s disease [21, 22].

AR has also been shown to help support a persons’ spiritual beliefs. For example, a Qibla AR application was developed to assist in finding a Qibla prayer direction towards Mecca. The application scanned the users’ location and pointed out the direction of Qibla based on where the phone was being held [21]. Older adults found the application overall to be useful. However, they also stated that it was difficult to use at first due to a lack of clear instructions during the application start-up [21]. AR can be extremely beneficial to older adults, however, for it to be useful, it is essential that these AR applications are designed so this population can easily understand and enjoy this technology.

1.4 Barriers to Technology Adoption

As seen from these previous examples, there are many uses of AR that can be targeted for older adults, however it is a concern that older adults will not accept the technology, or even feel comfortable trying it. This stereotype stems from the idea that older adults do not want to use new technology because it is too difficult to learn to use. Davis’s technology acceptance model does state that the perceived ease of use correlates to continued system use [23]. However, this model as well as others also mentions that perceived usefulness plays a larger role in technology adoption [23,24,25]. Some people can overcome difficult and time-consuming technologies if it gives them great benefit, but adoption can be increased by making a system easier to use [23]. As older adults see benefits and usefulness in technology, they are more willing to spend time to learn and adopt it [23, 24].

2 Developing Technology for Older Adult Users

If technology is not designed with the user in mind, it can quickly turn from a thing of value to a complicated hindrance. One way to create a positive interaction between technology and the user is through usability evaluation. Usability is defined in ISO 9241-11 as, “the extent to which a product can be used by specified users to achieve specified goals with effectiveness, efficiency and satisfaction in a specified context of use” [26]. For AR to be accepted, it should be assessed through usability technique. One effective technique is a heuristic evaluation.

Heuristic evaluations are conducted by evaluators’ scoring a product using a set of validated guidelines or best practices, called heuristics. Through this scoring process, websites, applications, devices, or other products can be rated on a variety of dimensions based on the set of heuristics. Some heuristic lists are short and generic with five simple rules to follow, while others are very specific with over a hundred detailed checklist items. Based on the score from these heuristics, suggestions for redesign of the product can be proposed.

One set of heuristics that is commonly used are the Nielsen’s 10 usability heuristics for user interface design [27, 28]. These heuristics include 10 generalizable principles that can apply to any user interface: visibility of system status, match between system and real world, user control and freedom, consistency and standards, error prevention, recognition rather than recall, flexibility and efficiency of use, aesthetic and minimalist design, help users recognize, diagnose, and recover from errors, and help and documentation [28]. These heuristics consider people’s cognitive and perceptual limitations as well as their expectations in order to design the best experience for the user. For example, people have an easier time recognizing something that they have seen before rather than trying to recall where or what that item was, so it is important to design with recognition rather than recall. This can be done through the creation of a menu structure on a website with important key actions or providing a search term for a user rather than requiring them to recall it from memory [29]. People’s expectations also influence how they interact with interfaces. People tend to expect that an interface will work in a specific way. For example, if a user selects a menu button, they expect that an action will occur that will bring them to a new page that is relevant to the menu item they selected, and that it will have a similar theme to the previous page. This is where the heuristics of visibility of system status and match between the system and the real world are relevant. Nielsen’s 10 heuristics are useful, but generic, ambiguous, and do not account for issues specific to special populations like older adults.

Due to the perceptual changes that adults develop as they age, such as a decline in visual acuity, contrast sensitivity, auditory detection thresholds, reaction time, and cognitive processing, special considerations should be factored into the design process. The National Institute on Aging and National Library of Medicine created specific senior-friendly guidelines for developing websites for older adults to tackle this issue [6]. Many of the specifications could be easily applied and useful for AR applications. For example, to address visual acuity and contrast sensitivity issues, they suggest designers use fonts that are easy to read such as sans serif font types and larger sizes set at least 12–14 point font, to avoid specific color combinations or patterns that may be difficult to discriminate text information from [6]. It is also important to include simple language, positive statements, consistent layouts, large buttons, and subtitles to any videos or audio instructions to accommodate for users who may have cognitive or motor deficits [6]. When designing an AR application for older adults, all of these factors must be considered – as Evans and Koepfler accurately stated, “we need to apply user-centered design when it comes to AR, rather than technology-driven design, so that we don’t augment reality with a bunch of stuff no one needs” [30]. Standardized and validated AR heuristics can help providers design AR applications that are both easy to adopt and beneficial to older adults [7].

2.1 Perceptual and Cognitive Considerations

When designing for older adults, it is important to keep in mind the decline of perceptual and cognitive abilities that many in this age group experience. Age-related changes to the eye, such as the development of cataracts, yellowing of the lens, lessened visual acuity due to the hardening of the lens, and a decline in contrast sensitivity can make using technology with small text or low contrast difficult [24]. This is important when creating menu structures, instructions, or any text in an AR application that could be difficult for some older adults to read. Some design recommendations that could alleviate this include customizable font sizes, sans serif fonts, and high contrast ratios between the background and text colors [24, 31]. Hearing loss is also common, affecting about 40% of older adults [27]. As a result, designing applications with customizable volume and the capability to work with hearing aids is important. Perceptual speed, working memory capacity, attention, and some executive functioning also have been shown to decline with age [24, 32]. This becomes important to consider when developing instructions for applications or asking for a user’s input. Typically, it is a recommended to keep auditory options below 7 items, minimize cluttered screens, give adequate amount of time if a user needs to shift their attention, and stress the use of consistency when developing applications for older adults [24, 31]. Perceptual and cognitive declines are common for this population, and it is important to keep these in mind in order to design usable interfaces and AR enhancements to combat these deficits.

3 Heuristics for Older Adults

Generic heuristics, such as Nielsen’s 10 are based on a general population and does not fully address the perceptual and cognitive differences of older adults. As a result, research has been conducted to developed heuristics aimed to address these issues. Researchers have combined general heuristics, such as Nielsen’s 10, alongside with W3C accessibility recommendations for older adults, and usability checklists developed by the National Institute of Aging [24, 33,34,35]. This has been done for smartphone applications targeted to older adults, social media platforms such as Facebook, and website design (see Table 1) [33, 35,36,37].

Table 1. Heuristics and guidelines commonly used for older adults
Full size table

AR heuristics for older adults have not been as prevalent in the literature. In fact, a recent publication by Dey and colleagues revealed that less than 10% of AR research studies published between 2005 and 2014 included any kind of user study or analysis [38]. Of those that did, only a handful used heuristic evaluation. To our knowledge, there is currently only one study that has been designed to create design principles for AR applications for older adult users [34].

Using iterative design and focus group testing, Liang adapted five AR heuristics and created an additional five design principles that applied to older adults [34] (see Table 2). For example, the Layer-focus augmentation (LA) design principle describes how large quantities of information should be organized into easy to understand groupings or layers to minimize clutter [34]. This helps older adults who may have declining eyesight or cognitive capabilities navigate through the application, but also benefits younger users by making the application simpler to use. These design principles are a good starting point for AR designers; however, they are only limited to mobile devices such as iPads and smartphones and do not include wearable AR devices such as head-mounted devices and/or glasses [34]. It can be difficult for some older adult users to use mobile AR due to physical limitations, Parkinson’s disease, decreased hand grip strength, or arthritis. Mobile AR applications require the user to hold the device to interact with the application [21, 34]. Since this population may find it easier to use a wearable AR application, guidelines should be developed to apply to both wearable and mobile AR. Wearable AR, however, introduces its own challenges related to interaction gestures, comfort, and visual integration of physical and virtual elements.

Table 2. Liang’s design principles for older adult AR applications [34]
Full size table

4 Next Steps

For older adults to accept AR applications, they must be designed in a way that is easy to use and deemed useful by this population. Heuristic evaluation is one method that can be used during the design process along with traditional usability testing. However, heuristics for older adults that cover the wide range of AR applications still need to be validated. To maximize the effectiveness of older adult AR heuristics, new heuristics should include information from guidelines such as those presented by the National Institute on Aging and National Library of Medicine and W3C Accessibility guidelines, the latest research considering older adult capabilities, and also be in the form of easy-to-use checklists that can be used by both developers and practitioners [6, 31]. It is also important to be able to generalize to different AR hardware such as head-mounted displays (HMDs), mobile AR (smartphones, iPads, etc.), and marker-based AR.

AR technology is still in its infancy of development. Proper attention to human factors principles and the validation of heuristics to evaluate the applications in the design and development process will help in the acceptance and realization of AR potential to enhance older adults’ quality of life.