###### Abstract  
Cognitive decline is one of the primary concerns in the elderly population. Serious games have been used for different purposes related to elderly care, such as physical therapy, cognitive training and mood management. There has been scientific evidence regarding the relationship between cognition and the autonomic nervous system (ANS) through heart rate variability (HRV). This paper explores the changes in the ANS among elderly people of normal and impaired cognition through measured HRV. Forty-eight subjects were classified into two groups: normal cognition (NC) (\(n=24\)) and mild cognitive impairment (MCI) (\(n=24\)). The subjects went through the following experiment flow: rest for 3 min (Rest 1), play a cognitive arbittable game (Game 1), rest for another 3 min (Rest 2), then play two reaction-time games (Game 2&3). Ten HRV features were extracted from measured electrocardiography (ECG) signals. Based on statistical analysis, there was no significant difference on the HRV between the two groups, but the experiment sessions do have a significant effect. There was no significant interaction between sessions and cognitive status. This implies that the HRV between the two groups have no significant difference, and they will experience similar changes in their HRV regardless of their cognitive status. Based on the game performance, there was a significant difference between the two groups of elderly people. Tree-based pipeline optimization tool (TPOT) was used for generating a machine learning pipeline for classification. Classification accuracy of 68.75% was achieved using HRV features, but higher accuracies of 83.33% and 81.20% were achieved using game performance or both HRV and game performance features, respectively. These results show that HRV has the potential to be used for detection of mild cognition impairment, but game performance can yield better accuracy. Thus, serious games have the potential to be used for assessing cognitive decline among the elderly. elderly healthcare; cognitive decline; serious games; HRV; machine learning +
Footnote †: journal: _Sciences_
as Alzheimer's disease (AD) that over the years can cause cumulative damage to the brain leading to cognitive impairment. The frequency of Alzheimer's disease increases with age in older persons, and it is also the primary cause of cognitive deterioration [3]. According to a study in 2020, the global prevalence of cognitive impairment in older adults could range from 5.1% to as high as 41% [4]. While cognitive decline cannot be completely reversed, it can be delayed or even avoided. This can be accomplished by therapies such as exercise, cognitive training, nutritional counseling, and risk factor monitoring [5]. One of the ways to implement cognitive training is through the use of serious games. Interventions can benefit from early detection, but the onset of cognitive impairment might be very subtle and difficult to detect. The progression is slow and close relatives and friends may notice it more than the sufferers themselves [3]. Playing game requires cognitive abilities, depending on the game objectives. Some games may require problem solving, decision-making or quick reflexes, while some may require memory and language skills. Games provide a wide range of stimuli capable of eliciting cognitive activity and emotion in the player, depending on the game [6]. Due to this, they could be used as an alternative for evaluating a person's cognitive state. Common testing methods such as Mini-Mental State Examination (MMSE) and the Montreal Cognitive Assessment (MoCA) are great for detecting cognitive impairment, but the results can also be affected by the person's educational background [7]. As with the case of video games, different game genres and gameplay can affect the autonomic nervous system (ANS) activity, and conversely, the heart rate variability (HRV) [8]. There is a rapid growth in the field of serious games in the industry as well as in academic research.