The Usability Issues Encountered in the Design Features of Intelligent Products for Older Adults in China: A Scoping Review

Abstract

This study aims to expand upon the understanding of the multifaceted usability issues older adults encounter when using intelligent products. This was achieved by synthesizing extant research findings to come to an understanding of why usability issues still exist in intelligent products for older adults in China, even when appropriate design features are incorporated. This review was conducted by searching the literature on the Scopus, Springer, ScienceDirect, and China National Knowledge Infrastructure databases as well as Google Scholar using the terms “older adults in China”, “intelligent products”, and “usability.” Forty-three studies from between 2007 and 2022 were included in the review. The results reveal three salient aspects directly related to the usability issues of intelligent products experienced by older adults in China: (1) the usefulness of the product; (2) the ease of use of the product; and (3) the impact of the policy. The first two impact the effectiveness of the use of intelligent products, while the lack of policy intervention in the management system of intelligent products results in product clutter. This review provides insights for designers by proposing a conceptual framework for an intelligent product service platform for older adults, which will help researchers and research teams better understand the usability issues according to older adults’ feedback on intelligent products. We suggest a unified standard for intelligent product management in the future that is compatible across systems and reduces older adults’ learning stress.

1. Introduction

By 2050, the world will have twice as many people over 60 as in 2000 [1]. As people are living longer, the proportion of older people worldwide is expanding rapidly. By the end of 2016, China’s population aged 65 and above had already reached 150 million, accounting for 10.8% of the population [2]. Furthermore, the period between 2020 and 2034 will usher in the rapid development of aging, and the proportion of the older adult population will peak in 2059, with there being one older adult for every three people [3]. Occurring alongside the aging trend is the “empty nesting” phenomenon, which deserves attention. This phenomenon entails older adults living alone or not living with their children. Due to the accelerated pace of urbanization and social development, the centuries-old extended family structure being observed in Chinese society has recently been declining [4]. The number of older people who do not live with their children has increased significantly, which is paralleled by the increased proportion of households in which only one couple resides [5].

However, the expansion in the aging population has also brought attention to the market of intelligent products for older adults. This niche market is still underdeveloped and undersupplied in China due to the lack of consumer demand [6]. This is evident in, for example, there only being a few age-appropriate intelligent products on the market. Moreover, the human–computer interaction between intelligent products and older adults must be improved [7]. One common issue is that older adults often need to spend more time learning and operating high-tech products [8,9,10]. Additionally, usability is one of the most critical factors affecting older users’ acceptance and usage of intelligent products or new technologies [11,12,13].

Similarly, user experience significantly influences user satisfaction and intention to use [14]. Older people are generally less enthusiastic about intelligent products with new technologies and functions, which leads to high reluctance and low receptivity in terms of using those products. Part of the reason is that older adults believe that intelligent products are complex devices to operate and have too many functions to remember [15]. In addition to older adults’ behavioral and psychological characteristics that impact the use effect, intelligent products also have issues regarding light technology, complex operation, many functions with weak practicality, and more [16]. Indeed, researchers in China have previously explained the design process for intelligent products for older adults, but limited research has been conducted on the usability of intelligent products for older adults. As an essential aspect of intelligent product usage, usability plays a major role in determining product effectiveness [12] and older adults’ willingness to use them.

Hence, to better design intelligent products for older adults specifically, it is necessary to gain insights into their usability issues. In this context, the primary purpose of this paper is to understand the usability issues of the design features by reviewing the literature on intelligent products for older adults in China. These aims are derived from the following questions:

• Why do usability issues still exist in intelligent products for older adults in China, even when appropriate design features are incorporated?
• What are the essential design features when designing intelligent products for older adults in China?

Several gaps have been identified in the extant literature on intelligent products for older adults in China [17,18,19,20]. Firstly, these reviews focus on the future development of intelligent products for older adults rather than their usability aspects. In addition, most of them concentrate on standalone intelligent products and smart care spaces, with the primary users of the products being care professionals. Thus, they do not discuss the impact of user experience on older adults’ use of intelligent products. Finally, the existing literature focuses on summarizing usability testing methods without fully considering older adult users’ needs. Therefore, this study foregrounds usability issues by focusing on its different factors to address these shortcomings. This is achieved by comprehensively reviewing the research conducted on intelligent products for older adults in China in a contemporary context.

When starting the review, we found that the keywords “smart products” and “intelligent products” were used interchangeably by different researchers. One author described “intelligent products” as being more concerned with connectivity and information exchange, with an emphasis on the Internet of Things (IoT) perspective [21]. Their explanation of this term appears more like the concept of whole-house IoT (Li Jiang et al., 2004), which is a “smart home” that controls household appliances and achieves environmental intelligence through sensors and the like. Therefore, a smart home is also referred to as whole-house IoT control as well as internet control of smart devices and other intelligent products for home living [22]. Although most smart home studies focus on whole-house environment-connected scenarios, some explore independent intelligent products [23,24,25]. In addition to these concerns, “smart products” and “intelligent products” have the same meaning and did not conflict with each other in the searching and screening process of the literature. Eventually, “intelligent products” was chosen as a keyword throughout this review given that the term “intelligent” highlights the study of products, while “smart” concentrates more on sensing technology [26].

2. Materials and Methods

This review was carried out according to the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA). Based on specific search strategies, eligibility criteria, data extraction guidelines, and analysis methods, a scoping review was conducted, as illustrated in Figure 1. The Scopus, Springer, ScienceDirect, and China National Knowledge Infrastructure (CNIK) databases as well as Google Scholar were all systematically searched. This study also reviewed the literature from journalistic studies and reports, with all articles that were potentially relevant being read.

Figure 1. The PRISMA flowchart diagram.

2.1. Search Strategy

Firstly, the most important search conditions in this study were derived from the research questions. The review centered on four broad concepts: (1) “intelligent products”; (2) “older adults in China”; (3) “design features”; and (4) “usability issues”. Technical articles that were related to the methodological analysis of usability algorithms, which were derived from searching “usability issues”, were excluded if their content was beyond the study scope of this paper. The synonyms for these three broad terms were then searched to identify the alternative spellings used in current research (see Table 1). The electronic databases selected for this review include the Scopus, Springer, ScienceDirect, and CNKI databases as well as Google Scholar, all of which include extensive research in the social sciences and on aging and intelligent geriatric products that is pertinent to the review. Subsequently, using the terms identified in this study, specific search strings were compiled, which were then applied to the field titles, abstracts, and keywords of scholarly articles and conference papers written in English and published in peer-reviewed scientific journals between 2007 and 2022 in each database. In the fourth step, we imported the obtained studies into Mendeley. After this, the search strategy was discussed, formulated, and verified by the two authors.

Table 1. The search string used.

Concept	Search Term
Population	“older adult*” OR “older person” OR “older people” OR “older user” OR “old person” OR “old people” OR “old user” OR “aged person” OR “aged adult*” OR “aged people” OR “aged user” OR “aging person” OR “aging people” OR “aging user” OR “senior” OR “elderly”
Type	AND “intelligent product*” OR “smart product” OR “smart home*” OR “intelligent home” OR “smart appliance*” OR “intelligent appliance” OR “smart furniture” OR “intelligent furniture” OR “smart devices*” OR “intelligent devices” OR “digital products”
Factors	AND “design factor*” OR “design characteristic” OR “design influences” OR “design feature” OR “design principle*” OR “design framework” OR “design cause” AND “usability”
Area of Study	AND China

Table 1 shows related terms for each concept that were included in the search string. To retrieve multiple related terms, an asterisk (*) was used. Using the “OR” and “AND” features, terms from each concept were combined for the literature search.

2.2. Inclusion and Exclusion Criteria

The inclusion and exclusion criteria for this study are shown in Table 2. The review included studies involving intelligent products for older adults in China who were over 55 years of age as well as studies that reported on at least one aspect of usability and design features for older adults.

Table 2. The Inclusion and Exclusion Criteria.

Criteria	Included	Excluded
Year	Empirical studies and reviews, reports, etc. from 2007–2022	Empirical studies and reviews, reports, etc. not from 2007–2022
Population	Articles that involve older adults in China (aged 55 and above), i.e., studies that focused on caregivers, family members, patients, or others who are older adults	Articles that do not involve older adults in China (aged 55 and above), i.e., studies focused on caregivers, family members, patients, or those who are not older adults
Outcome	The usability, design features, and factors of intelligent products for older adults	Articles on unrelated themes
Design	Empirical publications, including review articles, discussions, demonstrations, theoretical contributions, and reports	Non-empirical publications, including review articles, discussions, demonstrations, theoretical contributions, and reports

2.3. Study Screening and Selection

In the final review stage, we included studies that clearly described the design process or policy development for improving intelligent product systems for older adults in China. Moreover, the review process incorporated the results reported by the consumer market to increase the robustness of the evidence. Through the search strategy and strict eligibility criteria described above, efforts were made to ensure a high-quality review. Additionally, since some of the studies on smart homes also examine individual intelligent products, as stated above, they were included to gain a comprehensive understanding of the topic. Those eligibility criteria were determined after continuous consultation between the two authors. The first author completed the literature screening that was based on keywords and relevant phrases that described product usability. After thoroughly reviewing the accessed articles, the second author decided on the final eligible articles to be included in this review.

2.4. Data Extraction

We created data extraction tables for the set of full-text articles. The data collected included the following: year, name, study content, the sample size, target population and region, and preliminary findings. Each study was methodologically assessed before the data extraction began. The keywords in the research questions were used to determine the research data, which were then compared and organized to form themes. The studies were explicitly examined to identify the themes related to the usability of intelligent products for older adults in China, specifically empirical studies and reported findings.

2.5. Presentation of Data

After the title, abstract, and keywords were screened, a total of 152 papers on intelligent products for older adults in China published between 2007 and 2022 were selected. These articles were then further reviewed based on their relevance to the three concepts: (1) “intelligent products”; (2) “older adults in China”; and (3) “usability issues”. After the full articles were individually evaluated, only 43 articles met all eligibility criteria and were thus included in this review. Table 3 provides a summary of the retrieved data on the influencing factors, design principles, and innovative designs related to intelligent products for older adults in China.

Table 3. The main influencing factors, design principles, and innovative designs for intelligent products for older adults in China.

Reference (n = 43)	Research Method	Intelligent Product Type	Sample Size, Target Population, and Study Area	Outcome Measured	Indicative Findings
Huang [6]	Quantitative method	Smart appliances	Shandong, Qingdao 397 people, 257 valid questionnaires Those living alone or with an elderly partner: 55.5%	Principles of intelligent products for older adults in China	Proposed PD-STAM model design method: functional utility, appearance, ease of use, interaction, and perception of safety.
Liu et al. [7]	Mixed methods	Intelligent products	Interviews Focus groups Questionnaire completed by 232 people	Easy to learn, safe and reliable, beautiful and emotional design framework	Intelligent sleep aid product design.
Chen and Or [9]	Experimental method	Mouse Touch screen	18 young people 18 middle-aged people 18 elderly people Community recruitment	Suggestions for manipulating interactions Innovative design	The mouse is faster and more accurate than touch screen operation. Physical buttons and prominent visual reminders can help older adults complete operational tasks.
Qi and Zhou [10]	Mixed methods	Wearable products	Older adults aged 60–80 in seven cities	Suggestions for functionality	There should not be too many functions. Try to focus on the core functions and the healthy core functions. Design a UCD-based smart wearable watch for the elderly.
Dou et al. [12]	Mixed methods	Smart TV	15 older adults aged 60–75 without physical or eye impairments	Interaction suggestions for smart TVs	The intelligent voice function may have limitations due to dialect and environmental factors. In interface guidance, icons work best, while substantive text search input works best in practice.
Liu et al. [22]	Quantitative method	Smart home	371 questionnaires based on the Kano model Familiarity with smart appliances Elderly and young people	Suggestions for guiding the use of intelligent products	Strengthening older adults’ ability to build connections. Reducing difficulties and barriers to establishing relationships in terms of products and services. Increase opportunities to make connections. Improve the quality of based connectivity.
Chen [23]	Semi-structured interviews	Assistive technology	50 community elders in Hong Kong	Suggestions for guiding the use of intelligent products	In product development, it is essential to consider the emotional experiences and psychological needs associated with AT use and usability.
Li [24]	Quantitative method	Intelligent products	120 questionnaires, 100 of which were valid	Design principles of intelligent products for older adults in China	Product features and functions for older adults should include large buttons, emergency alerts, high-contrast displays, compatibility with other interfaces and applications, clear images, and simple step-by-step instructions.
Wang and Dai [25]	Quantitative method	Smart health products	Baoji, Yan’an, Hanzhong, Shaanxi Province, China 984 older adults Average age of 72 years old	Factors influencing willingness to use	Not a strong demand for intelligent health products. The older the period, the weaker the demand (influenced by individual perception). The higher the income, the stronger the market. The higher the education level, the stronger the need for intelligent health products.
Chen and Zou [27]	Interviews and focus groups (6 experts)	Intelligent products	36 seniors	Policy factors	Reasonable and active policy regulations are needed to promote the design and development of intelligent products that are suitable for the elderly.
Li [28]	Thematic analysis method	Smart home	N/A	Principles of intelligent products for older adults in China	The design should include voice channels, simplified operation, and visual and haptic feedback to facilitate interaction. The usability of intelligent products for older adults is influenced by the design of functional buttons and the effectiveness of sensory feedback.
Lin et al. [29]	Experimental method	Smart insoles	N/A	Innovative design	New material intelligent insole design.
Ma et al. [30]	Mixed methods	Wearable products	20 older adults	Factors influencing willingness to use	Due to the mismatch between the actual needs of older adults and the low convenience of use, the elderly’s willingness to use wearable products is low.
Talukder et al. [31]	Quantitative method	Wearable products	Wuhan, Xinyu, Ningbo 295 questionnaires Male respondents: 63%; female respondents: 37%	Factors influencing willingness to use	Because of the mismatch between the actual needs of older adults and the low convenience of use, the elderly’s willingness to use wearable products is low. Adding features that enhance the user’s positive emotional experience will make wearable products more effective for older adults.
Tseng and Hsu [32]	Mixed methods	Smart furniture	15 participants: 6 children and 9 people over 65 years old	Innovative design	A caring and interactive intelligent chair was created to encourage parent–child interaction while increasing the elderly’s acceptance of high-end technology.
Wu and Hu [33]	Mixed methods	Smart TV	Guangzhou, Wuhu, Maanshan 150 copies, 117 of which were recovered	Factors influencing willingness to use	The physical and mental differences between the elderly in new urban areas, small cities, and big cities are insignificant. The trend of the elderly using smart TVs is apparent. There is no significant geographical difference between the groups; all are willing to use a smart TV. There is a positive correlation between the use of intelligent devices such as smartphones and the use of smart functions on TVs. The longer the time spent watching TV, the higher the frequency of using TV intelligent functions.
Zhang et al. [34]	Mixed methods	Robot	Suzhou, Xi’an, Beijing 3,060 questionnaires and 50 interviews	Factors influencing willingness to use	79.39% said they refused robot care and did not want robots to touch their limbs. Suggest increasing robot humanized design.
Luo and Meng [35]	Quantitative method	Satisfaction with intelligent aging services	Elderly population over 60 years old in 15 districts in Shanghai 500 adults older than 18 550 questionnaires, 531 of which were returned	Factors influencing willingness to use	Need a bit of life care and health care as well as spiritual comfort. Age, number of children, and living conditions significantly impact needs. Lack of awareness of intelligent products. The poor linkage between products.
Song et al. [36]	Case study	N/A	News releases from February 2020 to February 2021 293 stories involving cases of the age-related digital divide	Factors influencing willingness to use	Personal attitudes and motivations, education and income, government policies, and family and social support significantly impact of the age-related digital divide for older adults during the pandemic.
Zhou et al. [37]	Experimental design	Smart home	17 middle-aged and older adults aged 53–76: 9 males and 8 females	Design principles of intelligent products for older adults in China	Visual controls, simple interactions, and feedback and alerts in an emergency must all be considered. It is recommended that older adults have a more precise visual representation of the interface buttons. In terms of guidance, icons work best, while substantive text search input works best in practice.
Zheng et al. [38]	Review	Products for older adults	13 articles	Design principles of intelligent products for older adults in China	The functions of products for older adults should be designed with physical and psychological needs in mind, with clear and intuitive operation methods and simple guidelines.
Yu et al. [39]	Experimental design	Smart home	34 young people and 18 elderly people Physically healthy and right-handed	Design principles of intelligent products for older adults in China	Product features and functions for older adults should include large buttons, emergency alerts, high-contrast displays, compatibility with other interfaces or applications, clear images, and simple step-by-step instructions.
Fang et al. [40]	Mixed methods	Wearable products	13 older adults	Interface design features for older adults	Older adults can use text and graphical interfaces more easily.
Chen et al. [41]	Mixed methods	Wearable products	Liaoning, Hebei, Beijing, Tianjin, Shandong, Heilongjiang, and Jilin 73 questionnaires Interviews with 10 older adults	Design principles of intelligent products for older adults in China	Product appearance (i.e., color scheme, materials, and shape) and social markers (i.e., clear instructions, targeted graphics, and traditional style) can cause dissatisfaction in older adults.
Wavmaker [42]	Report	Intelligent product	N/A	The seniors’ market is not receiving attention	Most older adults dislike overly tailored designs, such as bright colors and large text.
Cho and Kim [43]	Thematic analysis method	Smart home	N/A	A framework of user interface design principles to ensure interaction designs for older adults	Interaction design for older adults requires consideration of tangible operations, intuition, representation, contextual awareness, spatial interaction, and social interaction. The supporting attributes are digital literacy, accessibility, sensory support, safety and security, self-control, and stimulation.
Ferron et al. [44]	Case study	Smart phone	30 participants: 10 for each age group, 5 females and 5 males for each group	Innovative interaction design	Hollow gestures can increase the frequency of use by making interactions with older adults more intuitive and inclusive.
Song et al. [45]	Literature review	N/A	N/A	Policy factors	Policy-driven products, not technology-driven or demand-driven products. Quasi-public goods rather than private interests. Poor awareness and many stakeholders lead to insufficient demand for smart homes. Lack of standards and quality regulation leads to disorderly development. Development causes more waste of public and private resources at this stage.
Zhou et al. [46]	Experimental method	Senior care procedures	16 non-disabled older adults aged 55 years or older from three nursing homes in Nanjing, China	Design principles of intelligent products for older adults in China	The usability of intelligent products for older adults is influenced by the design of functional buttons and the effectiveness of sensory feedback.
Zhao et al. [47]	Experimental method	Robot	N/A	Innovative design	A mobility assistance robot was created to make it easier for the elderly to travel safely. Sensors and Light Detection and Ranging (LIDAR) should be used to help the elderly walk-through speech signals.
Hu et al. [48]	Experimental method	Smart furniture	N/A	Innovative design	A line of intelligent furniture has been developed that can be configured modularly to meet the needs of older adults.
Zhuo and Sun [49]	Quantitative	Personalized service system design	N/A	Innovative design	A more personalized platform for elder care that uses data integration and computing to help older adults transfer knowledge and information.
Song et al. [50]	Mixed methods	Intelligent product	N/A	Innovative design	A music service intelligent product system was created to generate a community music-sharing and entertainment platform. Using software and robots, an intelligent system for lifestyle and diet services based on older adults’ habits was created, thereby improving the quality of their home life.
Hu et al. [51]	Mixed methods	Smart photo album	7 interviews with older adults	Innovative design	An intelligent photo album was developed to improve older adults’ memory and well-being.
Wang et al. [52]	Quantitative	Intelligent elderly products	Anhui Province elderly institutions 300 questionnaires distributed, 241 of which were returned Empirical analysis Older adults over 55 years old in large care institutions	Factors influencing willingness to use	A theoretical model of the elderly’s willingness to use intelligent senior care products was constructed and validated.
Meng et al. [53]	Content analysis methods	Intelligent elderly assistance equipment	198 news articles on the opportunities and challenges in the smart aging industry from June 2018 to June 2019	Factors influencing willingness to use	Some intelligent product services cannot meet urgent needs, and the complicated operation process will not achieve the goal, leading to these products being abandoned.
Song et al. [54]	Quantitative	The dietary life service model	257 samples, 200 of which were valid Older urban areas over 80 years old	Factors influencing willingness to use	Some intelligent product services cannot meet urgent needs, and the complicated operation process will not achieve the goal, leading to these products being abandoned.
Li and Luximon [55]	Mixed methods	Smart phone	22 seniors Usability testing and in-depth interviews	A framework of user interface design principles for interaction design for older adults	A content-oriented navigation interface design that is more appropriate for seniors is recommended.
Sha et al. [56]	Experimental method	Mobile devices	24 retired university teachers	A framework of user interface design principles for interaction design for older adults	It is recommended that older adults have a more precise visual representation of the interface buttons. In terms of guidance, icons work best, while substantive text search input works best in practice.
Qi and Zhou [57]	Mixed methods	Wearable products	Shanghai, Hangzhou, Sichuan, Hubei, Guangdong, Shanxi, Shandong, Liaoning 160 (20 from each region) 2 months 60–85 years old	Design principles of intelligent products for older adults in China	Wearable products should be equivalent to a watch (40%). Wearable products should be as light as possible to reduce the burden on the wrist. The material must be able to be worn against the skin (leather or rubber materials) Prefer dark colors.
Zhu et al. [58]	Experimental method	Smartwatch	N/A	The materials and sizes of wearable designs should change as older adults’ bodies change	Redesigned an elderly smartwatch that integrates systems to allow users to self-manage. A physician will provide daily monitoring assistance and a customized preventive rehabilitation program based on the most recent data.
Guner and Albayrak [59]	Experimental method	Smartwatch	N/A	Innovative design	Wearable watch interaction design accelerates data recognition to capture information accurately and transmit it to relatives promptly.
Zeng and Chen [60]	Mixed methods	Smart home	185 questionnaires Semi-structured interviews with 12 people	Policy factors	China’s lack of industry technical standards for smart home systems has hampered the industry’s effective development.

3. Results

3.1. Selection of Articles for Review

These 43 studies employed multiple methodologies to address the development of various Chinese intelligent products for older adults. The most frequent topics include smart home appliances (36%), smart health detection products and smart wearable devices (18%), surveys of Internet product use (13%), smartphones and interfaces (9%), policies, platforms, and others (6%), and intelligent robots (4%). Most studies discussed a single intelligent product, with questionnaires and semi-structured interviews being the most common research methods. Many studies used more than one method [7,10,12,24,27,28,29].

3.2. Intelligent Products for Older Adults in China

3.2.1. Categories of Intelligent Products

Based on the comprehensive review of the 43 articles, the categories of intelligent products for older adults in China are smart home appliances (e.g., intelligent furniture, smart TVs), intelligent detection products (e.g., wearable devices, smart walkers, smart shoe insoles, smart hand grips, smart robots, etc.), smartphones, intelligent music service systems, intelligent diet systems, and community service platforms, amongst others. Most of these studies examined intelligent health testing products, and they focused on wearable testing products. Among these studies, the user experience feedback from older adults on intelligent detection products was insufficient, especially in terms of meeting the elderly’s functional and psychological needs, while the market of intelligent health products sees scant demand [10,23,25,34]. Additionally, due to a broad spectrum of intelligent product categories, research directions and results vary greatly.

According to these identified categories, the intelligent products included in the studies fulfill three purposes: (1) health assistance; (2) life care; and (3) spiritual comfort (cultural education and recreational fitness). Generally, the users of these intelligent products are urban older adults that are in good health and have high educational and cognitive backgrounds. Most of them acquired the basic knowledge of intelligent products and lived alone or with a partner but not with their children. However, the results show that they still need assistance from family members or friends when they have difficulty using the intelligent products, even if they have high education and cognitive backgrounds [35,36]. However, older adults usually need fewer smartphone features as they age [54,55]. In addition, intelligent features are often found in intelligent mass products for older adults, such as smart TVs and intelligent furniture [6,12,28,29]. These studies proposed personalized designs that cater more to the needs of older adults, which were results based on surveys and interviews. However, customized designs are still challenging to realize due to older adults’ variability and other issues such as policies and system operations.

3.2.2. Design Features of Intelligent Products for Older Adults in China

Some studies have proposed design principles for intelligent product for older adults [6,24,30]. For instance, visual controls, simple and easy-to-understand interactions, and feedback and alerts for emergencies must be considered. Zheng et al. [38] proposed that the functions of products for older adults should take both physiological and psychological needs into account, and there should be clear and intuitive operation methods as well as easy-to-use guides. In the same vein, Chen and Or [9] pointed out that physical buttons and conspicuous visual reminders can encourage older adults to complete operational tasks, despite them usually facing more difficulties when using virtual products than younger adults. Similarly, Li and Yu et al. [24,38] suggested that design teams should consider the physical characteristics of older adults. Therefore, some product features and functions should be included, such as large buttons, alerts for emergencies, good contrast display, compatibility with other interfaces or applications, clear images, and easy-to-follow step-by-step instructions. These findings resonate with other research, which highlighted that textual and diagrammatic interfaces are more acceptable to older adults, even though loaded information may reduce the products’ perceived usability [40].

In contrast to the above arguments, some studies pointed out that overly catering to older adults’ characteristics when designing intelligent products may cause negative impacts. Chen et al. [41] used a mixed methods approach to argue that the attractiveness of the product appearance (e.g., color scheme, material, and shape), social markers (e.g., clear instructions, unique meaningful graphics, and old style), and operational burden might induce operational stigma in older adults. Therefore, gaining a good understanding of product semantics is essential when products are being designed. Likewise, most older adults do not prefer designs that are targeted to them in a large degree, such as overly exaggerated colors with large text [42]. In this regard, Cho and Kim [43] described a framework of user interface design of intelligent products for older adults, which was built on the finding that existing design principles are divorced from older adults’ interactional attributes and practical needs.

In conjunction with the above, several studies have proposed new interactional features based on older adults’ characteristics. Ferron et al. [44] suggested that hollow gestures could make interactions with older adults more intuitive and inclusive, thereby increasing the frequency of usage. Nevertheless, this finding did not account for older adults with physical and cognitive impairments beyond a certain age who also suffer from chronic diseases that can cause difficulties with physical coordination. Other research [6,31] has also emphasized the principle that assistance should be combined with design. They proposed that design should incorporate voice channels, simplified manipulation, and visual and tactile feedback for easy interaction. These recommendations provide valuable insights but do not address some practical issues, such as the fact that intelligent speech functions may be limited by dialects and environmental factors [12].

3.3. Usability Factors

Jordan [61] stated that usability lies in the user’s interaction with the product or system and can only be accurately measured by assessing user performance, satisfaction, and acceptability. In other words, any change in the product or system characteristics, the user, the task, or the environment may produce different usability results. Likewise, usability is judged by the ease of learning, the efficiency of interaction, ease of remembering, error rate, and satisfaction [61,62]. Based on these criteria and the contents of the reviewed studies, we examined the usability issues according to three aspects: (1) product usefulness; (2) ease of use; and (3) policies.

3.3.1. The Usefulness of the Product

We found many studies that proposed innovative intelligent product designs that consider older adults’ characteristics. The design of functional buttons and the effectiveness of sensory feedback affect the usability of intelligent products for older adults [6,31,45]. In the same vein, several studies redesigned intelligent products based on older adults’ characteristics. For instance, Zhao et al. [47] designed a mobile assistance robot using an experimental method to assist older adults with traveling safely. The study proposed the application of sensors and Light Detection and Ranging to assist older adults with walking using voice signals. However, the application of robotics is not adequately supported. Moreover, most older adults refuse physical contact with robots, and older adults’ use of robots in Chinese households is still low even though smart robots have been in the market for many years [34,41].

Similarly, Tseng and Hsu [32] designed a caring and interactive smart chair to promote parent–child interactions while increasing older adults’ receptivity of high-end technology. However, the users of these chairs are limited to older adults with chronic illnesses, which contradicts the idea that the behavior of chronically ill older adults is more challenging to manipulate than that of the general population [15]. Implementing interactions within a limited range of interfaces is challenging for chronically ill older adults. Similarly, Hu et al. [48] developed a series of smart furniture for older adults that can be modularly set up to adapt to older adults’ individual needs. Nevertheless, this intelligent furniture system needs to be customized according to the living environment, the time needed and the cost are considerable, and the applicability in older adult households that already have standalone intelligent products is not high. From a different perspective, Zhuo and Sun [49] proposed a more personalized senior adult care platform that works through data integration and computing to facilitate knowledge and information transfer to older adults. However, they did not categorize and coordinate the different senior groups, and the platform’s operation was limited to independent community services.

On the other hand, many studies have designed entertainment and lifestyle-intelligent products based on older adults’ spiritual and social needs. Song et al. [50] designed a music service intelligent product system that can be used to create a music-sharing and entertainment platform in the community. They also developed an intelligent system for lifestyle and dietary services that align to older adults’ habits, which improved the quality of their home life through the combination of software and robots. Moreover, Hu et al. [51] developed an intelligent photo album to improve older adults’ memory and sense of happiness. Nevertheless, the adoption rates of the innovative intelligent product designs produced by these studies need further validation, contradicting the recent feedback on the sustainable adoption of intelligent products in the senior market. Many of the features for older adults are superficial and redundant, resulting in low adoption rates [63].

3.3.2. The Products’ Ease of Use

Intelligent products’ functionality is positively correlated to the frequency of use [10,29]. Li [24] pointed out that the current designs of intelligent products for older adults only cater to one aspect of their needs. Moreover, the complex interactive design results in the elderly taking a long time to learn how to operate the products, thereby ensuring that certain features are not fully engaged. In addition, Liu et al. [22] stated that there is a lack of guidance and assistance in using intelligent products. Hence, some older adults are somewhat resistant to using intelligent products [52]. Meng et al. and Song et al. [52,53] proposed that some intelligent products do not solve immediate needs, and the operation cannot meet the goals if the process is complicated, which can easily lead to these products being abandoned. However, these studies only cover the analysis of various factors and do not provide solutions and recommendations.

We found that intelligent products mostly favor software interface operations because it is easy to improve iterations based on feedback. The studies on this topic offer a series of recommendations based on experimental methods. For example, Li and Luximon [55] encouraged a content-oriented navigation interface design, which is more suitable for older adults. However, their design did not cover interaction styles for older adults. Likewise, others suggested the need for sharper visual representations in interface buttons for older adults [12,30,38,55]. Icons work best for guidance, and substantial text search inputs are most effective for practical use. However, these experimental results did not consider the bootstrapping of smart products’ hardware. Additionally the market stresses the “older” and stereotypical needs too much, thus ignoring the older adults’ universal and emerging needs as general consumers [42].

The wearable device is one of the typical intelligent products designed for older adults. However, some studies showed that older adults’ willingness to use wearable products is not high due to a mismatch with their actual needs as well as a low ease of use [27,33,56]. Therefore, some studies proposed better intelligent product designs of wearable devices for older adults. For instance, Zhu et al. [58] redesigned a smartwatch for older adults that integrated a system that allowed for user self-management. The design involved daily monitoring assistance from a physician and a customized preventive rehabilitation program based on the latest data. However, the study did not provide feedback from older adults on the device’s ease of use or discuss the interface data. Zhu et al. and Guner and Albayrak [57,58] demonstrated wearable watches’ interactive designs in terms of accelerated data recognition, which was used to capture information accurately and transmit it to relatives promptly. In another study, Lin et al. [29] created an improved design for smart insoles that allowed for activity recognition, telemedicine detection, and health assessment. However, both studies were oriented toward wearable sensing modalities and did not consider the ease of understanding in the data presentation. These studies share similarities with research conducted by others [27,33], in that they all consider the increased functionality of smart devices but do not consider the ease of use for seniors and do not include feedback on usability.

3.3.3. The Impact of Development Policies

Development policies are the third cause of intelligent products’ usability issues for older adults in China. Zeng and Chen [60] investigated the development of and problems with intelligent products for older adults in China. They found that the lack of industry technical standards for intelligent home systems in China hindered the effective development of the industry. Additionally, conflicting stakeholders and related policies led to a lack of demand for smart homes. Likewise, Xu [64] explained that the smart Chinese home is a policy-driven product because the technical foundation is not solid. Providing complex system services, such as integrated management and home systems, is difficult. In addition, policy regulations and product styling are factors that affect the use of technology by older adults. The need for clear and reasonable policy recommendations was suggested [27]. However, these studies did not consider the operational issues across different brands of intelligent products in older adults’ homes. Due to the lack of standards, some intelligent products may have unique operating systems and interface styles, which can be challenging for older adults when they must use different operating systems.

In conjunction with this, some studies illustrated that companies often disregard older people when developing new products as they design them mainly for younger people [12,41]. This is problematic since the primary user group of many intelligent products or smart appliances is older adults [12,46]. Moreover, the management of policies is limited only to the content displayed on the platform, and there is no standardization of the design nor guidance on the interaction with intelligent products. Zeng and Chen [60] proposed “Internet+” community platforms and strategies that combine big data, cloud computing, and artificial intelligence technologies with older adults’ care services. However, these studies did not consider the current situation characterized by individuals increasingly living alone due to the COVID-19 pandemic. Consequently, creating “Internet+” community platforms for the aging is very challenging.

4. Discussion

This paper is the result of a Chinese research project on the usability of intelligent products for older adults. The authors used Ibrahim’s [65,66] research question construct technique to classify journal articles based on the selected topic, using the novel “synthesis process of literature analysis”. The final theoretical construction was evaluated based on a synthesis of the various categories of the literature that were reviewed. Figure 2 depicts the points of departure (PODs). Each POD was created by combining different findings at each level. For example, POD 9 is the integration of family emotional interaction, professional technical assistance support, and design characteristics of older adults into the intelligent product’s design in order to generate a systematic service design that can enhance the use of intelligent products for older adults.

Figure 2. Theoretical proposition: interactive services design. Reprinted from reference [67].

4.1. Suitable Intelligent Product Design Features for Older Adults

Based on the above, we propose the following approaches to intelligent product design for older adults. The first is the appearance design of intelligent products. Drawing on the semantic expression of products [40,41], we argue that intelligent products should not have designs that are too evidently targeted, which could cause resistance among older adults and reduce the appearance value of intelligent products. Therefore, the design should focus on the control function settings and details rather than the overall product shape, and it should guide older adults to operate the product through material and color variations. Secondly, interface design is an important feature when designing an intelligent product. The layout planning of interface design for the elderly should consider the interface layout density and interaction hierarchy [31,38]. Intelligent product design should not include excessive interface manipulation, with two to three levels of interface interaction and simple swipe interaction being the most appropriate. Furthermore, Dou et al. [12] claimed that voice interaction is inappropriate for older adults. However, combining voice and visual design can guide older adults in using intelligent products and improve operational efficiency.

4.2. System Integration

Our findings allow us to further generalize the usability issues of intelligent products for older adults in China and to make recommendations for system integration. This review reveals three points in intelligent product usability for older adults in China: (1) product usefulness; (2) products’ ease of use; and (3) policy.

Some key findings are summarized here. Firstly, intelligent products involve system configurations, such as hardware, sensors, and interfaces, among which hardware appearance and functionality are more challenging to update and iterate than those of interfaces. Secondly, the importance of interactive feedback from older adults for intelligent products should be highlighted as well as the need to consider appearance design matching to enhance interaction features. In addition, older adults living alone in urban China lack trust and are reluctant to seek help from the outside world. Thirdly, personalization is the most desirable design for intelligent products for older adults. Therefore, it is recommended that the controllability of interfaces and sensory updates be concentrated on the design of intelligent product systems. Moreover, it is vital to increase the interaction between relevant professionals and family members in order to assist older adults with using different intelligent products. Furthermore, difficulties in implementing personalization are mainly due to system setup and management issues. Therefore, it is essential to integrate and collect information on older adults’ use of the products, which can be used by the development team to match the different usages with older adults’ needs.

Moreover, according to the review of products’ ease of use among older adults in China, a mismatch in demand for intelligent products can lead to low intention to use. One of the reasons for this is older adults’ lack of awareness and familiarity with using intelligent products. More importantly, there can be a significant difference between the feedback received in the ease-of-use tests of intelligent products before they formally enter the market and after they enter the market. There are various reasons for this, including that the actual use scenarios are not the same as the ease-of-use tests and because these tests are mismatched with older adults’ basic needs [39]. According to Borelli et al. [67], smart home appliances for older adults should focus on sensing and detection features, which should be incorporated into products based on individual habits to improve usability and acceptability. As a result, collecting real-time feedback and addressing issues with the system interactively can assist older adults in overcoming cognitive and user experience barriers.

However, due to the lack of industry standards, companies have no way of achieving a unified design strategy. Different brands of intelligent products have their own design styles and operate their own maintenance systems. In addition, due to the COVID-19 pandemic, home quarantine has become the new normal. As a result, face-to-face assisted use of intelligent products for older adults has become a challenge. A three-step strategy is therefore suggested: (1) coordinate the operation and management of different brands of intelligent products on the same platform; (2) reduce the functional interaction of older adults; and (3) integrate older adults’ family members’ interactions with brand professionals and community workers. All of these together will alleviate the usability problem of intelligent products for older adults. This procedure will help older adults acquire a more profound knowledge of intelligent products and enhance their interpersonal interactions.

4.3. Product Service Platform

An intelligent product service platform is proposed in this study (Figure 3). The inclusion of community members from various sectors aids in the upgrading and design of intelligent products and enhances the usability of intelligent products for older adults. Therefore, this study proposes the participation of intelligent product after-sales service personnel (direct-to-product after-sales assistance), volunteers with experience in intelligent product use (amateur assistance for operation), brand design departments (collection of feedback data), and community service personnel (departmental supervision).

Figure 3. Conceptual information framework of an intelligent product service platform for older adults.

An intelligent product service platform’s goals include improving emotional interactivity in older adults’ homes, aligning intelligent product services, integrating systems to coordinate different intelligent systems, and coordinating extensive data management. According to research, families and communities should provide more technical and emotional support to older adults to reduce their technology anxiety and allow them to gain more digital knowledge and skills in this information society [32,50]. Thus, we believe that involving family members and communities is essential. When dealing with technical issues, older adults can directly interact with professionals to resolve problems efficiently. The premise, however, is that family and community members cannot solve the problem. This is because older adults are less aware of and sensitive to product use than younger people, so they may encounter small issues that they cannot resolve independently. More importantly, different brands of intelligent products have various system operations and interface designs, so increasing volunteer participation can help older adults better understand intelligent products.

As an outcome of this research, a conceptual framework for an intelligent product service platform for older adults is proposed. The framework is primarily concerned with the nature of services, connecting various intelligent products to record the usage data of the products and the process of using them. It quickly solves the problem of older adults’ operational difficulties with big data, which are collected to identify and better understand critical needs and scenarios, and it also synthesizes various usability issues by analyzing the older adults’ feedback about the brand. This involvement of the community and back-end monitoring ensure the safeguarding of older adults’ data privacy.

4.4. Theoretical and Practical Implications

The usability issue can be analyzed from multiple perspectives. Unlike previous research, this review focused on older adults in China. Several empirical studies, reports, reviews, and summaries were collected on intelligent products for the aged in China, and the usability issue of intelligent products for older adults was elaborated on in terms of usefulness, ease of use, and policy. To some extent, it expanded the extant literature on intelligent products’ usage among older adults in China. Furthermore, considering the difference between older adults in China and those in other countries in terms of living contexts, environments, and family structures, this study specifically collected reports on the lives of older adults in China during the COVID-19 pandemic. In addition, since older adults face declining survivability due to their deteriorated physical condition and loss of memory, we included literature on older adults’ emotional interactions and psychological states to better understand their actual needs. In addition, we examined the design features of various intelligent products for older adults in China. This has important theoretical and practical implications for understanding the usability of different intelligent products and the older adult’s intent to use them. The study derives a final theoretical construction based on thematic analysis, which provides future researchers and designers with academic support for intelligent product design in various dimensions. Moreover, this study advances a conceptual framework of an intelligent product service system platform for older adults in China, as providing comprehensive services and feedback can better assist older adults in using intelligent products, reduce resource waste, and improve interactive relationships.

4.5. Limitations and Future Prospects

Although this study fills some research gaps and enriches the current studies on intelligent products for older adults in China, it relies solely on published articles and reports. Additionally, it does not consider the significant variations in intelligent product research across different regions. As a result, this study is mainly restricted by the research category and geographical area. Therefore, future research could collect and categorize data on intelligent products used by older adults in different regions to develop corresponding theoretical models for various types of analysis.

Moreover, even though the included studies cover a variety of disciplines, their findings may differ from the current state of the market and thus reduce the generalizability of this study’s results. Hence, future studies should conduct a systematic literature review with clearly defined review questions and synthetic data collection methods. Another limitation of this study is that it did not consider the demographic characteristics of people with chronic diseases. However, the challenges that older adults face are related to their age and health conditions, which further impact their ability and tendency to use intelligent products. Hence, future research on the factors influencing the usability of intelligent products among older adults can include older adults’ demographics and medical histories.

5. Conclusions

Despite having some limitations, this scoping review provides new insights and recommendations on the issue of intelligent product usability for older adults in China. Our findings suggest that the usability of intelligent products for older adults is influenced by usefulness, ease of use, and policy. Based on the synthesis of the shortcomings in the extant literature, this study suggests that system integration can improve the usability of intelligent products for older people. Therefore, we argue that systematically integrating service management across a range of intelligent products from different brands and designs is crucial. The review also reveals that family–emotional interactions can help alleviate the usability problems experienced in the products for older adults. Future research can therefore formulate a universal standard for intelligent product design and its management. This is to achieve compatibility across diverse systems while at the same time reducing older adults’ stress when learning about new products.