Shuzo Kumagai

Background: Autobiographical memory undergoes qualitative changes across the lifespan, influencing self-understanding, emotional regulation, and psychological adaptation. Research shows memory is a dynamic process, reconstructed through retrieval, narration, and social interaction. How narrative construction and empathic engagement shape memory reconsolidation and self-continuity remains insufficiently integrated. Objectives: This narrative review synthesizes theoretical, empirical, and applied findings on autobiographical memory, narrative processes, and empathy, proposing an integrative model linking memory reconsolidation, identity reconstruction, and adaptive functioning. Methods: A theory-oriented narrative review was conducted across psychology, neuroscience, gerontology, and narrative research, drawing on literature from PubMed, PsycINFO, Web of Science, Scopus, J-STAGE, and CiNii. Peer-reviewed empirical studies, systematic reviews, and theoretical papers were organized around three interrelated conceptual domains: (1) autobiographical memory and self-related processes, (2) neurobiological and emotional mechanisms relevant to memory updating and reconsolidation, and (3) narrative construction within empathically mediated social interaction contexts, with additional consideration of evidence from narrative-based and creative interventions. Results: The reviewed literature suggests that autobiographical memory functions as a plastic, socially embedded system supporting self-continuity, although the strength and consistency of evidence vary across studies and contexts. Narrativization within empathically responsive and psychologically safe contexts enhances narrative coherence, emotional integration, and perspective-taking, promoting psychological stability, although these effects are not uniformly observed across all populations and study designs. Creative narrative activities further facilitate retrieval and meaning reconstruction, extending memory updating beyond recall, while the underlying mechanisms and causal pathways remain to be fully established. Conclusions: We propose an empathy-mediated narrative reconstruction model in which creative activity, narration, empathic response, and retelling interact cyclically to support memory reconsolidation and self-narrative updating. By integrating cognitive, social, and creative dimensions, this model provides a theoretically grounded framework with implications for clinical, educational, gerontological, and creative applications.

Background: Autobiographical memory undergoes qualitative changes across the lifespan, influencing self-understanding, emotional regulation, and psychological adaptation. Research shows memory is a dynamic process, reconstructed through retrieval, narration, and social interaction. How narrative construction and empathic engagement shape memory reconsolidation and self-continuity remains insufficiently integrated. Objectives: This narrative review synthesizes theoretical, empirical, and applied findings on autobiographical memory, narrative processes, and empathy, proposing an integrative model linking memory reconsolidation, identity reconstruction, and adaptive functioning. Methods: A theory-oriented narrative review was conducted across psychology, neuroscience, gerontology, and narrative research, drawing on literature from PubMed, PsycINFO, Web of Science, Scopus, J-STAGE, and CiNii. Peer-reviewed empirical studies, systematic reviews, and theoretical papers were organized around four domains: (1) autobiographical memory and the self, (2) neurobiological mechanisms of emotion and reconsolidation, (3) narrative construction and empathic social interaction, and (4) evidence from narrative-based and creative interventions. Results: Reviewed literature indicates autobiographical memory functions as a plastic, socially embedded system supporting self-continuity. Narrativization within empathically responsive and psychologically safe contexts enhances narrative coherence, emotional integration, and perspective-taking, promoting psychological stability. Creative narrative activities further facilitate retrieval and meaning reconstruction, extending memory updating beyond recall. Conclusions: We propose an empathy-mediated narrative reconstruction model in which creative activity, narration, empathic response, and retelling interact cyclically to support memory reconsolidation and self-narrative updating. By integrating cognitive, social, and creative dimensions, this model provides a theoretical framework with implications for clinical, educational, gerontological, and creative applications.

Background/Objectives: There is still no clear consensus regarding the efficacy of exercise interventions in maintaining or improving cognitive function among independent older adults, as well as individuals with mild cognitive impairment (MCI) or dementia. This review explores the potential mechanisms underlying cognitive decline prevention and dementia mitigation from the perspective of motor learning theory, with a particular focus on aerobic-oriented open-skill exercise (OSE) and electronic sports (e-sports). Methods: Comprehensive literature searches were conducted using databases such as PubMed, Scopus, Web of Science, CiNii, and J-Stage (all available years) to identify studies examining the relationship between OSE, e-sports, and cognitive function. Results: Although various intervention studies have investigated aerobic exercise, resistance training, and other multifactorial exercise programs, a unified conclusion has not been reached regarding their effectiveness in enhancing cognitive function in the general elderly population or in patients with MCI or dementia. However, sports involving dynamic interaction with opponents (OSE) have shown a positive association with the maintenance and enhancement of cognitive abilities. Furthermore, e-sports present an accessible exercise modality, unrestricted by age, gender, time, or location, and are expected to support cognitive health in older adults. Conclusions: Aerobic-oriented OSE appears more effective than closed-skill exercise in preventing age-related cognitive decline and dementia. Additionally, e-sports may offer a comprehensive approach to brain health by integrating cognitive stimulation, physical engagement, social interaction, and stress reduction, though caution is advised regarding potential mental health concerns stemming from excessive use.

Recent findings in physical activity epidemiology suggest that physical activity and exercise may help prevent cognitive decline and dementia. However, there is still no consensus on the causal relationship between cognitive function and physical activity or sedentary behavior, nor on the direction of this relationship. In addition to electronic sports (e-sports), which can be played without restrictions on age, sex, time, or location, recent research has examined the relationship between cognitive function and different types of sports and exercise, focusing on motor skill demands. This review explores the background and mechanisms underlying the recommendation of open-skill exercise (OSE) for preventing and mitigating cognitive decline, as well as maintaining and enhancing cognitive function. Furthermore, it discusses the role of OSE and e-sports as lifelong sports. Latent Heritable Confounder Mendelian Randomization has confirmed a causal relationship between physical activity and cognitive function in non-dementia patients, while finding no significant association between cognitive function and sedentary time. Prospective studies suggest that exercise habits, physical fitness, and performance may help inhibit cognitive decline and the onset of dementia. However, intervention studies have not reached a consensus on the effectiveness of exercise in improving cognitive function among the general elderly population or patients with mild cognitive impairment and dementia. In conclusion, aerobic OSE appears to be more effective in preventing cognitive decline and dementia associated with aging compared to closed-skill exercise. E-sports has the potential to integrate cognitive engagement with physical activity, social interaction, and stress reduction, making it a unique and holistic approach to brain health. In other words, e-sports represents a versatile intervention that simultaneously addresses multiple aspects of health.

Previous studies have found that the relationship between sedentary time (ST) and overweightness/obesity is unclear. The association between sedentary behavior and overweightness/obesity may depend on the type of sedentary behavior engaged in. Nowadays, in older Chinese adults, especially females, short video viewing (SVV) is the most popular leisure sedentary behavior. However, the association between SVV and overweightness/obesity remains to be determined. This study aimed to examine the associations between ST and SVV and overweightness/obesity in Chinese community-dwelling older women. A cross-sectional analysis of baseline data from the Physical Activity and Health in Older Women Study was carried out in this study. A total of 1105 older Chinese women aged 60–70 years were included. SVV was estimated using a self-reported questionnaire, and ST was objectively measured using a tri-axial accelerometer. Overweightness/obesity indicators, including body fat ratio (BFR), fat mass (FM), visceral fat mass (VFM), subcutaneous fat mass (SFM), trunk fat mass (TFM), and limb fat mass (LFM), were assessed using multi-frequency bioimpedance analysis. The covariates included socio-demographic data and a range of health-related factors. Multiple linear regression analyses were used to assess the association between ST and SVV and overweightness/obesity. ST was significantly positively associated with all indicators of overweightness/obesity; however, the associations disappeared after adjusting for moderate-to-vigorous-intensity physical activity (MVPA). A higher SVV time was associated with a higher body mass index (BMI) (β = 0.19, 95% confidence interval (CI): 0.05 to 0.32), BFR (β = 0.31, 95% CI: 0.07 to 0.56), FM (β = 0.33, 95% CI: 0.04 to 0.61), VFM (β = 0.09, 95% CI: 0.01 to 0.16), SFM (β = 0.24, 95% CI: 0.03 to 0.45), TFM (β = 0.21, 95% CI: 0.04 to 0.39), and LFM (β = 0.11, 95% CI: 0.00 to 0.23) in the fully adjusted models. Compared with non-food short videos, short food videos had a greater effect on overweightness/obesity. SVV was an independent risk factor for overweightness/obesity. A reduction in SVV (especially the food category) rather than ST might be an effective way to prevent overweightness/obesity when incorporated in future public health policy formulations.

Patients show subtle changes in daily behavioral patterns, revealed by traditional assessments (e.g., performance- or questionnaire-based assessments) even in the early stage of Alzheimer’s disease (AD; i.e., the mild cognitive impairment (MCI) stage). An increase in studies on the assessment of daily behavioral changes in patients with MCI and AD using digital technologies (e.g., wearable and nonwearable sensor-based assessment) has been noted in recent years. In addition, more objective, quantitative, and realistic evidence of altered daily behavioral patterns in patients with MCI and AD has been provided by digital technologies rather than traditional assessments. Therefore, this study hypothesized that the assessment of daily behavioral changes with digital technologies can replace or assist traditional assessment methods for early MCI and AD detection. In this review, we focused on research using nonwearable sensor-based in-home assessment. Previous studies on the assessment of behavioral changes in MCI and AD using traditional performance- or questionnaire-based assessments are first described. Next, an overview of previous studies on the assessment of behavioral changes in MCI and AD using nonwearable sensor-based in-home assessment is provided. Finally, the usefulness and problems of nonwearable sensor-based in-home assessment for early MCI and AD detection are discussed. In conclusion, this review stresses that subtle changes in daily behavioral patterns detected by nonwearable sensor-based in-home assessment can be early MCI and AD biomarkers.

Background: The amounts of moderate-to-vigorous-intensity physical activity (MVPA), light-intensity physical activity (LPA), and sedentary time (ST) by sex, age, and body mass index (BMI) in older Japanese adults have not been known. We conducted this study to determine the actual physical activity (PA) and ST in this population. Subjects and Methods: A total of 3998 community-dwelling Japanese adults aged ≥65 years were investigated. Their levels of PA and ST and number of steps taken daily were assessed for seven consecutive days by a tri-axial accelerometer. Normative values of daily PA and ST were analyzed by age and BMI groups in the men and the women and are presented as mean, median, or decile. Results: The subjects generally adhered to the PA guideline, i.e., ≥10 metabolic equivalents (METs)·hour MVPA per week. Older age was associated with lower adherence to the PA guideline. Conclusions: Normative values (mean, median, or decile) were yielded for MVPA, LPA, and ST based on accelerometer readings in a large sample of older community-dwelling Japanese adults. One-half of the subjects’ waking time was spent being sedentary, and >70% of the subjects met the current PA guideline by engaging in MVPA.

Subjective cognitive decline (SCD) is recognized as a risk stage for Alzheimer`s disease (AD) and other dementias, but its prevalence is not well known. We aimed to use uniform criteria to better estimate SCD prevalence across international cohorts. Therefore, we combined individual participant data for 16 cohorts from 15 countries (members of the COSMIC consortium) and used qualitative and quantitative (Item Response Theory/IRT) harmonization techniques to estimate SCD prevalence. The sample comprised 39,387 cognitively unimpaired individuals above age 60. The prevalence of SCD across studies was around one quarter with both qualitative harmonization/QH (23.8%, 95%CI=23.3%-24.4%) and IRT (25.6%, 95%CI=25.1%-26.1%); however, prevalence estimates varied largely between studies (QH: 6.1%, 95%CI=5.1%-7.0%, to 52.7%, 95%CI=47.4%-58.0%; IRT: 7.8%, 95%%CI=6.8%-8.9%, to 52.7%, 95%CI = 47.4%-58.0%). Across studies, SCD prevalence was higher in men than women, in lower levels of education, in individuals with Asian and African ancestry compared to European ancestry, in lower- and middle-income countries compared to high-income countries, and in studies conducted in later decades. Data harmonization and application of uniform criteria across diverse cohorts yielded more accurate estimates of SCD prevalence. Having a quarter of older individuals with SCD warrants further investigation of its significance, as a risk stage for AD and other dementias, and of ways to help individuals with SCD who seek medical advice.

The objective of this study was to investigate the association between objectively measured patterns of sedentary behavior (SB) and physical activity (PA) and frailty status in Japanese community-dwelling older adults. Data was from 65-75 years older adults from the baseline of Itoshima Frail Study were used. Frailty was assessed using a Japanese version of the FRAIL scale. SB and PA were measured using an accelerometer. Multinomial logistic regression and receiver operating characteristic curve analyses were used to investigate the associations of SB and PA patterns with frailty status. Of the total 819 older adults, half were female (51.8%). The prevalence of robust, pre-frailty and frailty was 60.2%, 27.8%, and 12.0%, respectively. SB variables including total sedentary time, sedentary time in bouts of >= 10 min and >= 30 min, and mean sedentary bout duration were not associated with frailty status. Except LPA and moderate-to-vigorous physical activity (MVPA) in bouts of < 10 min, PA variables including total MVPA time, MVPA in bouts of >= 10 min (bouted MVPA), and steps were significantly associated with lower prevalence of frailty. Area under the curves (AUCs) of total MVPA time, bouted MVPA, and steps were 0.64 (P < 0.001), 0.67 (P < 0.001), and 0.66 (P < 0.001), respectively. The optimal cut-off value of total MVPA time, bouted MVPA, and steps to discriminate between frailty and non-frailty were 43.25 min/day, 9.13 min/day, and 3841 steps/day, respectively. Higher levels of total MVPA time, bouted MVPA, and daily steps were negatively associated with frailty. Lower amounts of bouted MVPA (70 min/week) or steps (4000 steps/day) may be achievable initial targets in older adults for frailty management.

PURPOSE: This review aimed to evaluate the relationship between objectively measured physical activity and sedentary behavior and frailty in community-dwelling older adults.METHODS: An electronic search was undertaken using the MEDLINE® databases from January 1st 2010 to December 31st 2019. Titles, abstracts, and full texts of the studies identified by the search were scrutinized by the author to determine eligibility for an inclusion in this review.RESULTS: The search identified 87 relevant articles resulted, of which eight studies from four cohorts met the inclusion requirements. Almost all the studies reported a significantly negative association between moderate-to-vigorous physical activity (MVPA) and frailty, while only one was a longitudinal study. Significant associations between sedentary time (ST) and higher severity of frailty were observed, however, the findings of associations of sedentary bouts were mixed.IMPLICATION: Higher amounts of ST and lower amounts of MVPA were associated with a higher prevalence of frailty or worse frailty levels. Replacing ST with MVPA may offset the detrimental consequences of ST on frailty. More longitudinal studies and quantitative researches are needed to investigate the association of MVPA and ST bouts with frailty.