Developed countries are aging, with the proportion of the population over 65 years standing at 17.5% worldwide (Padeiro et al., 2023) and at over 30% in Japan (Otsu and Shibayama, 2022). Accordingly, the number of people with dementia worldwide was projected to increase to 57.4 million in 2019, further rising to 152.8 million in 2050 (Nichols et al., 2022). In Japan, the total annual financial loss due to dementia exceeds approximately 12 trillion yen ($180 billion), placing a heavy burden on the nation’s finances (Ikeda et al., 2021). As Japan’s population ages, healthy life expectancy is increasing along with average life expectancy, and although the gap is narrowing, it is still large (about nine years for men and 12 years for women) (Ministry of Health, Labour and Welfare, 2019). Extending healthy life expectancy, defined as “the period during which people can live without having their daily lives restricted by health problems,” is necessary to realize a vibrant society in which each person can live a healthy and enriched life and to make the social security system sustainable. In addition, retired older adults have a lot of leisure time, and it is believed that spending time meaningfully and happily doing what each enjoys can improve their sense of well-being and extend their healthy life expectancy (Minagawa and Saito, 2023).

Many activities contribute to dementia prevention (Asteasu et al., 2017; Klimova et al., 2020; Marioni et al., 2015; Piolatto et al., 2022); music is one of them (Dingle et al., 2021). In addition to listening to music, playing has been shown to be effective in improving cognitive function (Gómez-Gallego et al., 2021). As many parts of the brain are activated in an integrated manner during performance, using multiple senses—auditory, visual, and tactile—simultaneously (Zatorre et al., 2007; Lappe et al., 2008), regularly playing musical instruments with such a multimodal component contributes to improved cognitive function and maintenance of gray matter volume in the frontal and temporal regions in old age (Böttcher et al., 2021; Böttcher et al., 2022). For example, in a cohort study of 1,570 older adults, experience playing a musical instrument was associated with significant improvements in cognitive function (working memory and executive function) (Vetere et al., 2024). In an intervention study of healthy older adults unfamiliar with music, piano lessons requiring bimanual coordination improved executive function and working memory (Bugos et al., 2007; Bugos, 2019). In healthy older adults with no musical experience, four months of keyboard harmonica lessons significantly improved memory performance on a test measuring verbal recall (Guo et al., 2021). Furthermore, the significant improvement in memory performance was associated with a significant reduction in the level of functional connectivity (FC) between the left putamen seed and right superior temporal gyrus (lPu-rSTG) in functional magnetic resonance imaging, suggesting improved neural efficiency. Working memory (WM) training has been reported to reduce resting-FC between medial prefrontal cortex and the right posterior parietal cortex/right lateral prefrontal cortex, which are key nodes of the external attention system in WM (Takeuchi et al., 2013). Patterns of activation resulting from cognitive training have been suggested to include patterns of increased activation, reduced activation, and a combination of increased and reduced activation, and among these, reduced activation has been attributed primarily to increased neural efficiency (Buschkuehl et al., 2012). This concept is closely related to the “neural efficiency theory” proposed by Haier (Haier et al., 1988; Haier et al., 1992a; Haier et al., 1992b). This theory assumes that when participants are performing a task well, fewer neurons are recruited than when they are not performing well. Therefore, less proficient performance could activate brain circuits that are unimportant or even detrimental to task performance. Previous studies have shown that WM training reduced BOLD responses in brain regions related to WM during WM performance. At the same performance level, reduced activation was observed, suggesting that WM training may increase neural efficiency (Brehmer et al., 2011; Vartanian et al., 2013; Heinzel et al., 2014).

In addition to dementia, mental health is another important issue that needs to be addressed in an aging society (Phongsavan et al., 2013). Aging potentially increases the risk of mental health problems. In areas with large older populations, a higher percentage of people experience depression and other mental illnesses, and mental illness among older adults is expected to increase (Zenebe et al., 2021). Depression is also considered a risk factor for dementia (Cantón-Habas et al., 2020; Zhang et al., 2021), and maintaining psychological health may help prevent dementia (Johansson et al., 2010). Music interventions have positive effects on the mental health of older adults. In healthy older adults, listening to music of their choice for 30 min each week for 4 weeks improved geriatric depression scores (Chan et al., 2010). Depressive symptoms improved when older adults with depression received active music therapy (in which participants played percussion instruments) once every two weeks for 60 min, for a total of 20 sessions (Erkkilä et al., 2011). Furthermore, healthy older participants showed improvements in mood state and quality of life after four months of piano lessons (Seinfeld et al., 2013). It is also known that older adults who are more likely to use music for emotional aspects, such as listening to music to make themselves feel better or for enjoyment, have higher subjective well-being (Wang and Suh, 2024).

Unlike playing a musical instrument alone, group music sessions provide a sense of togetherness, playing in tune and rhythm with others. Music sessions have been incorporated as loop work for patients with dementia, and there have been improvements in psychological state, such as anxiety levels, after six weeks of percussion group sessions among older adults with dementia (Sung et al., 2012). A three-month drum session program for patients with dementia, including mild cognitive impairment, residing in a nursing home showed significant improvement in Mini-Mental State Examination and Frontal Assessment Battery scores and improved cognitive function (Miyazaki et al., 2020). In healthy older adults, self-efficacy and processing speed improved after 8 weeks of percussion (mallet) group sessions (Bugos and Cooper, 2019). Lessons involving 10 weeks of piano ensembles have been reported to improve executive function in healthy older adults (MacRitchie et al., 2020). Sixteen weeks of piano lessons, including two group training sessions per week of 90 min each, improved general and musical self-efficacy (Bugos and Wang, 2022). In addition, physiological effects of enhanced immune function have been found in older adults who have participated in drumming group sessions (Koyama et al., 2009). However, to the best of our knowledge, there are no studies on the cognitive and psychological effects of group (band) music sessions with healthy older adults who have no previous experience with musical instruments. In addition, participating in group music sessions where each person plays a different instrument is expected to significantly enhance cognitive function. This improvement arises from the complex cognitive processing required to listen to others while simultaneously performing one’s own music.

We investigated the effects of a 16-week group music intervention on cognitive and psychological functions in healthy older adults who had never played a musical instrument. The results showed that cognitive function improved, with overall cognitive function and verbal memory improving because of the session-based intervention. In psychological functioning, the intervention had an effect on some indicators. The improvement in total MMSE scores between before and after the intervention suggests that the session-based format improved overall cognitive function in healthy older adults. These results are consistent with reports of MMSE score improvements in individuals with declining cognitive impairment, including a drum session intervention for patients with dementia and a group music intervention with rhythmic movement for nursing home residents (Miyazaki et al., 2020; Kim and Kang, 2021). Other studies have suggested the impact of multimodal activities on cognitive improvement (Hars et al., 2014; Nishiguchi et al., 2015). Playing a musical instrument itself is a multimodal activity that includes auditory, visual, and tactile senses (Zatorre et al., 2007; Lappe et al., 2008). Furthermore, during musical sessions, musicians need to use both auditory and visual cue modalities to enhance synchronization with others (Goebl and Palmer, 2009; Kawase, 2014; Bishop and Goebl, 2015). Tasks that need synchronization with others like as a music session require complex cognitive processing that involves a wider range of brain regions (Chen et al., 2006; Pollok et al., 2009; Hove et al., 2013), and therfore are assumed to place a higher multi-modal cognitive load than musical instrument performance, which does not require synchronization. Therefore, music sessions may have influenced improvements in overall cognitive function, as measured by the MMSE, even in healthy older adults without cognitive impairment. In the present study, significant improvements were found in the MMSE and in the WMS-LM II, suggesting a positive effect of music sessions on verbal memory. This is consistent with a previous study of keyboard harmonica training that reported improved WMS-LM II scores (Guo et al., 2021), suggesting that the activity of singing melodies with the keyboard harmonica is a kind of verbal memory practice. Although the participants did not sing during this study’s music sessions, it is possible that recalling the lyrics as they played familiar songs influenced the improvement in verbal memory (Wang, 2007; Lök et al., 2019; Cunningham et al., 2019). The keyboard harmonica training is known to correlate the neural efficiency of lPu-rSTG connectivity with improved verbal memory performance (Guo et al., 2021), and such neural efficiency improvement may have occurred in the background of the improved verbal memory in the current study. Professional musicians are also known to have a smaller range of fMRI BOLD signal activation during performance than amateur musicians, a view that long-term music training is associated with increased efficiency and reduced effort (Lotze et al., 2003). This suggests that musicians become more efficient at playing their instruments through long-term training, and may provide evidence to support the “neural efficiency theory” proposed by Haier (Haier et al., 1988; Haier et al., 1992a; Haier et al., 1992b). In addition, in the present study, a trend of improvement was observed in the POMS 2’s VA factor in psychological functioning. In a previous study of piano lessons, improvement in the mood state (FI factor) among healthy older adults was reported (Seinfeld et al., 2013). Music therapy for hospitalized patients improved scores on the POMS TMD and TA, AH, FI, and CB factors (Cassileth et al., 2003). While a certain mood-improving effect has been reported with individual performances in the literature, there have been no reports of improvement in VA; this is the first time it has shown a tendency to improve with music sessions. Although there have been other reports of music therapy improving mood and depression in hospitalized patients (Martí et al., 2023), there have been few previous studies on the effects of music sessions on positive mood, and the relationship between music sessions and mood should be investigated in the future.

Although some items presented significant improvements in both cognitive and psychological functions, there is a possibility that neuroscience can explain the relationship between psychological and cognitive function improvements. Amyloid accumulation and tau-induced neurofibrillary changes are associated with the development of dementia (Bloom, 2014), and cerebrospinal fluid biomarkers such as amyloid-β42 and phosphorylated tau are known to be useful in the early diagnosis of Alzheimer’s disease. The ratio of tau/Aβ42 could indicate cognitive decline (Fagan et al., 2007; Chen et al., 2019), and regular exercise habits are known to be associated with improved tau/Aβ42 ratios (Hou et al., 2021). However, this ratio is not only related to dementia but also to mood status. In cognitively normal older adults, participants with higher cerebrospinal fluid tau/Aβ42 values have been found to have greater increases in mood disorder scores throughout the one-year follow-up period compared with participants with lower values (Babulal et al., 2016). In patients with mild cognitive impairment, smaller VA scores on the POMS 2 have been associated with more amyloid plaques and tau enrichment in brain regions involved in emotion regulation (Chen et al., 2014). It is also known that in older women at high risk for Alzheimer’s disease, greater negative mood symptoms are associated with higher tau enrichment and greater vitality with lower tau enrichment (Ahmadi et al., 2024). It is also possible that other brain substances were affected in this study’s music sessions, leading to the improvement in cognitive and psychological functions. Dopamine released in the brain is involved in reward system mechanisms and feelings of well-being (Alexander et al., 2021), and is also related to levels of brain-derived neurotrophic factor (BDNF), which is associated with the development of Alzheimer’s disease (Leo et al., 2018). In animal studies, listening to classical music in mice enhanced BDNF signaling, synaptic proteins, and neurogenesis (Cheng et al., 2024). In humans, functional magnetic resonance imaging and positron emission tomography studies have shown that listening to pleasant music increases dopamine activity in the striatum (Zatorre, 2015; Mueller et al., 2015). Other significant differences have also been found in the levels of BDNF in plasma between people who usually play music and those who do not (Minutillo et al., 2021). Although we did not measure tau enrichment or physiological indices of dopamine and BDNF, it is suggested that changes in intermediate indices such as the release and localization of neurotransmitters and proteins in the brain may have occurred behind the improvement in cognitive and psychological functions as phenotypes in this study.

There were no significant improvements in executive functions, as demonstrated by scores on the TMT, Stroop, and verbal fluency tests. Previous studies have reported improved and unimproved executive function depending on the total number of hours, frequency, type, intensity, and difficulty of musical instrument intervention (Seinfeld et al., 2013; Bugos, 2019; MacRitchie et al., 2020; Guo et al., 2021; Wang et al., 2023). Although several studies have reported positive effects with music sessions (Miyazaki et al., 2020; Kim and Kang, 2021), the optimal total number of hours, frequency, and intensity of music session for cognitive benefits remains unclear. Based on previous findings, we implemented weekly 90-minute sessions for 16 weeks (total number of hours is 24 h) in this study; however, our results suggest that enhancing executive function through neuroplasticity may require a greater total number of hours, more frequent sessions or the incorporation of more complex musical activities. In a previous study, an intervention of piano lessons with a high degree of difficulty using both hands significantly improved executive and other functions (Seinfeld et al., 2013). On the contrary, in another previous study, music training in relatively easy keyboard harmonica playing using one hand did not improve executive function (Guo et al., 2021). Other studies have reported that performance music training significantly improves executive function (Bugos, 2019; MacRitchie et al., 2020), but not significantly (Wang et al., 2023). Looking at the effect of playing a musical instrument on executive function in terms of the total number of hours of intervention, previous studies, including the current study, suggest that at least about 40 h or more of musical instrument intervention, including practice time, may be necessary to enhance executive function. In addition, there were no significant improvements in psychological measures other than the POMS 2, but this may be because the baseline scores were originally high given that the sample consisted of healthy older adults.

This study has several limitations, the first of which is using self-reports. The current study is an open-label intervention design and use self-reports to evaluate some effects of intervention. Therefore, there could be bias had occurred and effects results. The second is the relatively small sample size. Although previous studies have investigated the effects of playing musical instruments with sample sizes similar to the current study (Bugos et al., 2007; Seinfeld et al., 2013; MacRitchie et al., 2020), a larger sample size is necessary to increase the robustness of the results. Third, the cognitive and psychological improvements may be attributed to social interactions during music sessions, Therefore, we cannot conclude music sessions cause these improvements in this study. In the future, it will be necessary to add social interaction tasks to the control group and to control for the frequency and content of social interactions by conducting questionnaire surveys. Fourth, the effects of different instruments (keyboard, guitar, and drums) on the cognitive psychological indices in the intervention group may differ, but we were unable to analyze this aspect owing to the small sample size. However, as all instruments use both hands, we believe that bimanual coordination is consistent among the instruments. Finally, we did not directly compare and verify the direct effects of music sessions conducted by multiple people versus playing a single instrument alone, and future research should better clarify the direct effects of music sessions.

In this study, the activities of the music sessions improved cognitive and psychological functions. Although the music (band) session was conducted for 16 weeks with multiple types of instruments, future studies are needed to examine the content and intensity of the music session intervention to investigate what type of music sessions are more effective. In addition, it is expected that future studies of music sessions will collect data on neurophysiological data that will provide evidence to explain the effects of music sessions, thereby clarifying the mechanism of the relationship between music sessions and cognitive and psychological functions. These findings might provide insight into dementia prevention.