Mild cognitive impairment is a term used to identify people who are at risk of developing dementia, but the cognitive impairment is so mild that it does not affect daily activities. Symptoms of mild cognitive impairment include memory impairment, language difficulties, attention deficits, disorientation, and altered visuospatial skills [1]. The prevalence of mild cognitive impairment in individuals older than 65 years is approximately 3% to 22% [2-4]. In addition, 5% to 15% of these cases progress to dementia annually, whereas the incidence of mild cognitive impairment in the general population is 1% to 2% per year [5-7].

Dementia is characterized by a group of chronic and progressive symptoms caused by various brain illnesses that affect memory, thinking, behavior, and ability to perform daily activities [8]. Dementia currently affects approximately 50 million people worldwide and is expected to affect 82 million people by 2030 and 152 million by 2050 [9,10]. Dementia is the second leading cause of disability in individuals aged 70 years or older and the seventh leading cause of death worldwide [10,11]. In 2015, the cost of dementia care was estimated at US $818 billion, equivalent to 1.1% of the global gross domestic product, which ranges from 0.2% for low- and middle-income countries to 1.4% for high-income countries. It is estimated that the cost of caring for people with dementia worldwide will increase to US $2 trillion by 2030, which could undermine social and economic development globally and overwhelm health and social services, especially long-term care systems [12].

Owing to the high medical and social burden of mild cognitive impairment and dementia, scientists in various fields have been searching for effective strategies to prevent or delay disease development. In view of the fact that current pharmacological treatments are not only expensive but are also accompanied by significant adverse effects [13], the Food and Drug Administration and experts in leading geriatric organizations recommended that nonpharmacologic approaches be used as the first-line treatment of cognitive impairment [14]. Nonpharmacologic approaches include, but are not limited to, reminiscence therapy [15], reality orientation [16], validation therapy [17], music therapy [18], doll therapy [19], pet therapy [20], and cognitive and physical exercise training [21]. These nonpharmacologic approaches are becoming increasingly preferred by the geriatric population because they have been shown to yield positive results, are easy to use in clinical or home settings, and are inexpensive.

In recent decades, an increasing number of studies have used games for cognitive training in people with mild cognitive impairment or dementia [22-27]. The aim of cognitive training is to maintain or improve specific cognitive functions such as attention, episodic memory, and problem-solving skills using guided training and repetitions of standardized tasks [28]. Game-based interventions are nonpharmacological readily accepted forms for training, and playing games could be an efficient mode to practice mental concentration and memory, making them appropriate for people with cognitive impairment [29-31].

Exergaming, defined as the combination of exercise and gaming, is a relatively new type of intervention in which users must perform physical movements to play games [32]. The design of the games is based on the cognitive enrichment hypothesis, which states that the behaviors of individuals (including cognitive activity, social engagement, exercise, and other behaviors) can influence their level of cognitive function [33]. One idea underlying this hypothesis is to use a rich environment to stimulate brain functioning. This rich environment is reflected when participants play these games, and there is usually a screen displaying information about the game scene. For example, the Kinect sensor incorporates an infrared light and a video camera to create a three-dimensional map in the front area, handheld controllers are also used to manipulate the games [34], and physical movements are captured by the video cameras [35] or weight-sensing platforms [36].

Exergames have been gradually implemented in rehabilitation [37,38], education [39], and other fields [40], and have been widely accepted by a range of populations from children [41,42] to the elderly [43,44]; moreover, positive results were found for individuals with various diseases such as dementia [45], stroke [46], Parkinson disease [34], multiple sclerosis [47], cystic fibrosis [48], and cancer [49]. Recent studies have demonstrated the feasibility, acceptability, and effectiveness of exergaming in improving physical functions such as gait and balance [50], motion control [51], and exercise capacity [52]. Exergaming has been found to be an acceptable method of exercising among older adults [53,54], and is also proven to be safe [55,56], easy to use [53], and enjoyable [53,54].

To the best of our knowledge, there is only one systematic review [57] that has synthesized the existing evidence of exergaming in individuals with dementia. However, due to the limitation of the retrieval strategy, the systematic review included only 3 articles involving a study with an exergaming-integrated training method and two studies using Nintendo Wii training methods. However, few systematic reviews have examined the effectiveness of exergames in improving the physical and cognitive functions in individuals with mild cognitive impairment or dementia. In addition, the latest classification of exergaming includes not only Wii but also handheld controllers, and physical movements captured by video cameras or weight-sensing platforms. Therefore, we conducted a systematic review with a high degree of evidence using the Joanna Briggs Institute methodology for systematic reviews of effectiveness evidence [58]. In reviewing the current literature, we focused on whether an exergaming intervention can indeed be beneficial to the rehabilitation of people with mild cognitive impairment and dementia.

This is the first systematic review that synthesized the existing evidence of exergaming interventions administered to elderly individuals with mild cognitive impairment or dementia and to explore the effect of exergaming interventions on their cognitive and physical functions. The interventions identified in this review differed greatly across studies. The duration and frequency of the interventions also varied greatly; the duration ranged from 4 to 24 weeks, and the total intervention duration ranged from 3 to 36 hours. The frequency ranged from 1 to 5 times a week, and the median was 3, which is consistent with the study of Manera et al [73]. However, after analysis, there was no evidence that longer and more frequent interventions lead to greater improvements in function. Although exergaming is a combination of gaming and exercise, due to the diversity of the platforms used to manage the exergame interventions, it was difficult to determine which exergame was the best for improving cognitive and physical functions. Nevertheless, many studies used sensor-based platforms such as Nintendo Wii. Half of the interventions were carried out in the community, and the rest were administered in hospitals, rehabilitation wards, or nursing homes, indicating that exergaming interventions could be implemented in both environments, but were more common in a community setting. Alzheimer’s Disease International estimated that globally, approximately 84% of elderly patients with dementia currently live in a community [74]. The World Health Organization’s “Rehabilitation 2030” campaign launched in 2017 pointed out that rehabilitation programs should follow a holistic approach for chronic disease management, optimize independence, and prolong community engagement [75]. Because it is inexpensive [49], safe [55,56], and easy to use [53], exergaming can be performed unsupervised even for community-dwelling healthy older adults [76,77]. Exergaming interventions are gradually being used as a physical cognitive rehabilitation tool for elderly people with mild cognitive impairment or dementia living at home in the community.

In a previous literature review, the effectiveness of exergaming training in improving cognitive function was investigated in people with mild cognitive impairment or dementia. The results were consistent with those reported in the study of Karssemeijer et al [69], showing that exergame training significantly improved the psychomotor speed in elderly people with dementia compared with the control group that adopted normal exercise. Moreover, positive results were found in the study of Amjad et al [66] in elderly individuals with mild cognitive impairment, showing improvements in overall cognitive abilities and executive function, and in the study of Bamidis et al [67] in elderly individuals who were healthy or had mild cognitive impairment.

Four of the five formal studies reported that the exergaming intervention improved cognitive function, which is encouraging. In recent years, more and more studies have applied exergames to the cognitive rehabilitation in elderly people with mild cognitive impairment or dementia. The aim of cognitive rehabilitation is to use individualized intervention strategies to address cognitive impairment [78]. Previous studies have shown that an effective approach to treating cognitive impairment requires a highly individualized approach that focuses on the common goals of patients and is interactive [79], and an exergaming intervention meets these criteria. Wiloth et al [45] assigned participants to tasks of different difficulty levels according to their cognitive performance and the intervention was implemented in the presence of the clinicians. In the study of Bamidi et al [67], a group of psychologists, physical education instructors, researchers, and nurses helped each elderly person design a plan that included aerobic, resistance, and strength exercises. However, due to the small sample size, short intervention duration [70-72], and lack of specific exercises [72], a positive result was not obtained in several other preliminary experiments [50,70-72]. In addition, some studies reported “small” to “moderate” effect sizes for the cognitive function results [50,52,72,80].

In the current study, the instrumental activities of daily living and activities of daily living were used to evaluate the independence in performing physical activities of the subjects for three interventions, but only one study showed positive results. However, variations in activities of daily living performance are expected since the extent to which patients with Alzheimer disease lose the ability to perform activities of daily living varies widely [81]. Balance and gait speed are the most widely used physical measurements for evaluating physical function since gait speed [82-84] and functional decline [85] are predictors of survival among elderly people. Four studies included balance in the outcome measures, three of which found positive results and the other found a moderate effect size in physical function among participants with neurodegenerative diseases. These results indicate that exergames do improve postural control in older adults compared to walking training [50,71,72,85]. This conclusion can be supported by the theory of planned behavior, which postulates that subjective norms and behavioral attitudes determine individual behavioral intentions and the latter determines individual behaviors [86]. An interesting result was found with respect to use of the same exergaming intervention (Nintendo Wii-Fit) and control intervention (walking program), both of which lasted for 8 weeks. One study showed no significant group-by-time interaction effects on the BBS scores (P=.56) [50], but the other showed that among the participants who completed the test, there was a significant group-by-time interaction effect on the primary outcome measure, the BBS score (P<.05) [71], which we consider to be a very promising result. This discrepancy may have been partly caused by a small sample size or low test efficiency. Additional studies with sufficient sample sizes and high quality should be conducted to verify the results.

According to the literature review, in addition to cognitive and physical functions, we also found that exergames affect other outcomes. Apathy is a common neuropsychiatric syndrome observed across many neurocognitive and psychiatric disorders. In the study of Valeria et al [87], 20 experts reported that information and communications technology is “very appropriate” for apathy nonpharmacological treatment. Among all the studies included in this review, none of the studies using measurement tools detected changes in apathy before and after the intervention; however, we found some benefits in terms of motivation and compliance.

Motivation or compliance was evaluated or explored in 70% of the studies reviewed. All 7 studies that evaluated motivation or compliance agreed that the exergames increased or enhanced the participants’ motivation to engage in rehabilitation activities. Although exercise therapy has been recommended to improve the cognitive and physical functions in people with dementia or mild cognitive impairment in recent years [88], there are still many barriers to exercise, such as lack of motivation and limited access to exercise facilities [89]. Exergames provide sensory feedback through auditory, visual, and tactile stimulation [90], and can further maintain the motivation of individuals [66]. Therefore, exergaming interventions have a high adherence rate among rehabilitation methods. Ben-Sadoun and colleagues [52] found that both groups in the study experienced only positive emotions, which was consistent with previous findings on exergames in subjects with mild cognitive impairment and Alzheimer disease. In the study of Hughes et al [68], the majority of participants were “very much” satisfied with the intervention. An open-label RCT among elderly people with mild cognitive impairment showed that exergaming interventions can reduce individuals’ fear of falling compared with no training [72].

Despite the positive impact, some limitations of our study must be considered when interpreting the results. The studies included in this review varied substantially in terms of the consoles used, games played, participants’ stages of mild cognitive impairment or dementia, and the outcomes assessed, making analyses of the effects of exergaming difficult, and a meta-analysis could not be performed. To gather comprehensive evidence, we included pilot studies with small sample sizes. Therefore, it is difficult to draw firm conclusions from the results of the analyses due to the limited statistical power.

This is the first systematic review that assessed the effectiveness of exergaming interventions in improving the cognitive and physical functions of elderly people with mild cognitive impairment or dementia. The studies included in the analysis were heterogenous in terms of the modalities used to administer the interventions, health outcome evaluations performed, and outcomes assessed. Overall, exergame interventions can improve cognitive and physical function to some extent, and more high-quality studies with more accurate outcome indicators are needed for further exploration.

Multimedia Appendix 1

Search strategy.