The effect of interventions with board games
In the present review, the selected studies were divided into the following three categories regarding the effects of board games and programs that use board games: educational knowledge (11 articles), cognitive functions (11 articles), and other conditions (five articles).
An overview of the findings about the effects of board games and programs that use board games related to educational knowledge is shown in Table 1 [10, 11, 15,16,17,18,19,20,21,22,23]. Board games in this category were used for the purpose of improving educational knowledge, and the effect sizes (Cohen’s d) between pre- and post-tests or between pre-tests and follow-up tests ranged from 0.12 to 1.81 and between the mean gain of the main intervention group and the other groups ranged from 0.81 to 0.93 and − 1.84 to − 1.65.
An overview of the findings about the effects of board games and programs that use board games on cognitive functions is shown in Table 2 [6, 24,25,26,27,28,29,30,31,32,33]. This category included board games such as Go, Ska, and chess, and the effect sizes (Cohen’s d) between pre- and post-tests of cognitive function ranged from 0.04 to 2.60 and − 1.14 to − 0.02. The effect size of the exacerbation was calculated in only the chess group of Sala et al. . The effect sizes (Cohen’s d) between the mean gain of the main intervention group and the other groups ranged from 0.06 to 2.36 and − 1.38 to − 0.22.
An overview of the findings about the effects of board games and programs that use board games on other conditions is shown in Table 3 [7, 8, 34,35,36]. This category addressed the impacts of board games on physical activity, anxiety, ADHD symptoms, and the severity of Alzheimer’s Disease. The effect sizes (Cohen’s d) between pre- and post-tests or between pre-tests and follow-up tests ranged from 0.06 to 0.65 for physical activity and from − 0.87 to − 0.61 for ADHD symptoms.
Board games and educational knowledge
Eleven studies that used board games to increase educational knowledge were selected for this review. The present findings showed that board games influence educational knowledge and concomitant outcomes, with the effect sizes for educational knowledge ranging from very small to large.
Board games can be used as a tool to encourage learning. In previous studies, specialized board games aimed at improving knowledge in the field of education were targeted and subsequently developed and investigated. For example, Wanyama et al.  conducted a study of the Make a Positive Start Today game, which is a board game aimed at improving knowledge about human immunodeficiency virus (HIV) and sexually transmitted infections (STIs). Similarly, Kalèdo is an educational board game used to increase nutrition knowledge [10, 19, 21]. It has been shown that these board games contribute to increasing knowledge related to each particular field.
Board games are also efficacious for goals other than increasing knowledge. According to Charlier and De Fraine , board games can be an enjoyable and motivational method for learning content and enhancing group interactions, competition, and fun. Martins et al.  reported that board games teach educational content in a playful and enjoyable way and involve interactions with family and friends; thus, they favor knowledge acquisition by enabling exchanges of experiences and learning. Furthermore, Wanyama et al.  showed that, as a method of health education, board games increase the acquisition of knowledge as well as result in more positive experiences than do health talks among both participants and facilitators. Amaro et al.  found that class teachers noted improvements in student interest and appreciation of the board game. Taken together, these findings suggest that board games may improve the motivation of participants. Furthermore, Karbownik et al.  showed that a board game was warmly welcomed by students; in their opinion, it facilitated clinical thinking and peer communication. Therefore, board games may also have a positive influence on interpersonal interactions among participants.
Based on the above findings, board games can be used as a tool to encourage learning as well as to enhance motivation and interpersonal interactions. In clinical treatment, it is important to increase motivation because low motivation to cooperate with a particular intervention may lead to a patient dropping out of treatment or to interference with the therapeutic effects. Based on the above findings, the use of board games may help increase the benefit of treatment for less motivated patients.
Board games and cognitive functions
In the present review, 11 of the assessed studies investigated the effects of board games and programs that use board games on cognitive functions. These studies used Go, chess, and Ska, which are not educational games but abstract strategy games. Studies investigating the use of Go found that older adults experiencing cognitive decline and/or living in nursing homes showed improvements in attention and working memory after regularly playing the game . Studies assessing the use of Ska found that the game appeared to enhance the cognitive functioning of older adults in terms of memory, attention, and executive function . Studies evaluating chess showed that training with the game improved the planning ability of patients with schizophrenia and the mathematical ability of children [25, 26]. But, Sala & Gobet  indicated that interventions that use chess are not significantly different from interventions that use checkers and regular school activities that address the mathematical and metacognitive ability of children.
The effect sizes for cognitive functions ranged from very small to large, but the effect size of exacerbation on metacognitive ability was shown in the chess training of Sala & Gobet . The number of studies included in this category was relatively limited. Further investigations will be necessary to clarify the more detailed effects of board games on cognitive function. Articles about Shogi were not selected for this category in the present review. Because Shogi was also included with the abstract strategy games, this may influence cognitive functions. In the future, it will be necessary to use intervention studies to examine the effects of additional types of board games, including Shogi, on cognitive function.
Board games and other conditions
The “other studies” category in the present review included five studies that examined the effects of board games on physical activity, physical and psychological outcomes, ADHD symptoms, and the severity of Alzheimer’s Disease. Mouton et al.  showed that a giant board game intervention for nursing home residents led to significant increases in ambulatory physical activity, daily energy output, quality of life, balance and gait, and ankle strength. The effect sizes in the present review of studies related to physical activity ranged from very small to medium. Fernandes et al.  reported that board games used as educational preoperative materials decreased the preoperative anxiety of children. Additionally, the use of board games contributed to improvements in the ADHD symptoms of children [7, 35]. The effect sizes for ADHD symptoms in the present review ranged from medium to large. Lin et al.  showed that playing Go improved the symptoms of depression and anxiety and ameliorated the manifestations of Alzheimer’s Disease. Although a study by Barzegar and Barzegar  was not selected for the present review because it was a case report, these authors found that playing chess prevented panic attacks and contributed to the amelioration of this condition. Taken together, these findings indicate that board games might be an effective complementary intervention for the treatment of the clinical symptoms of ADHD and Alzheimer’s Disease.
In terms of Alzheimer’s disease, board games may also play a role in the prevention of the onset of this disorder. According to an epidemiological survey in Japan , the prevalence rates of dementia in 1980, 1990, and 2000 were 4.4, 4.5, and 5.9, respectively, for all types of dementia and 1.9, 2.5, and 3.6, respectively for Alzheimer’s Disease. In Japan, the number of patients with Alzheimer’s disease has increased, and the prevention of this disorder is a problem that must be addressed. Because playing board games ameliorates the manifestations of Alzheimer’s disease , these types of games may contribute to the prevention of this disorder. However, the number of studies in the present review that investigated the effects of board games on clinical symptoms was quite small, and further research will be required.
Possible clinical applications of board games
It is also important to note that board games can be played without the use of language. Language-based therapies may not be appropriate for people with underdeveloped linguistic functions, such as children and patients with speech disorders. However, board games may be a viable treatment option for these populations. In the present review, the subjects in 18 of the assessed studies included children, which is a group that is still developing linguistic functions and is more likely to have poor knowledge about diseases. The present review also revealed that board games and programs that use board games are effective for achieving various outcomes for children, including increasing educational knowledge, enhancing cognitive functions, and decreasing anxiety and the severity of ADHD. Furthermore, board games can be an enjoyable and motivational tool for children . Based on these findings, it is possible that board games can be a useful intervention for children in particular because such games can be expected to result in the maintenance and promotion of health and the prevention of disease.
Limitations and future directions
Several limitations of the present study must be considered. First, the number of studies assessed in the present review was rather limited. Therefore, further investigations of the effects of board games will be necessary. Second, many of the papers selected for the present review examined the effectiveness of board games by comparing pre- post intervention for a single group or by comparing with a control group without intervention. These research designs do not control for the possibility of placebo effects. Intervention studies must include an active control group to control for possible placebo effects , thus it will be necessary to compare the effect of board game groups and active control groups in future research. Third, in the articles selected for the present review, some studies were conducted with relatively small sample sizes. In cases in which the sample size is small, there is the possibility of increased sampling error. In order to reduce sampling error, it is necessary to do a power analysis to set an appropriate sample size in intervention studies. In addition, it is desirable that multiple assessment indicators be used to examine the effects of board games in various perspectives and to reduce measurement errors.