Analysis of the alpha activity envelope in electroencephalography in relation to the ratio of excitatory to inhibitory neural activity.

Alpha waves, one of the major components of resting and awake cortical activity in human electroencephalography (EEG), are known to show waxing and waning, but this phenomenon has rarely been analyzed. In the present study, we analyzed this phenomenon from the viewpoint of excitation and inhibition. The alpha wave envelope was subjected to secondary differentiation. This gave the positive (acceleration positive, Ap) and negative (acceleration negative, An) values of acceleration and their ratio (Ap-An ratio) at each sampling point of the envelope signals for 60 seconds. This analysis was performed on 36 participants with Alzheimer's disease (AD), 23 with frontotemporal dementia (FTD) and 29 age-matched healthy participants (NC) whose data were provided as open datasets. The mean values of the Ap-An ratio for 60 seconds at each EEG electrode were compared between the NC and AD/FTD groups. The AD (1.41 ±0.01 (SD)) and FTD (1.40 ±0.02) groups showed a larger Ap-An ratio than the NC group (1.38 ±0.02, p<0.05). A significant correlation between the envelope amplitude of alpha activity and the Ap-An ratio was observed at most electrodes in the NC group (Pearson's correlation coefficient, r = -0.92 ±0.15, mean for all electrodes), whereas the correlation was disrupted in AD (-0.09 ±0.21, p<0.05) and disrupted in the frontal region in the FTD group. The present method analyzed the envelope of alpha waves from a new perspective, that of excitation and inhibition, and it could detect properties of the EEG, Ap-An ratio, that have not been revealed by existing methods. The present study proposed a new method to analyze the alpha activity envelope in electroencephalography, which could be related to excitatory and inhibitory neural activity.

Relationship between duration of sick leave and time variation of words used in return-to-work programs for depression.

BACKGROUND: Return-to-work (RTW) programs are provided as rehabilitation for people who have taken sick leave from work because of mental health problems. However, methods to present this information to workplaces objectively remain limited. OBJECTIVE: This study aimed to conduct an exploratory investigation of the relationship between duration of sick leave and time variation of words used in RTW programs for depression from textual data collected from electronic medical records as a new evaluation indicator. METHODS: The study subjects were those who had taken sick leave because of major depressive or adjustment disorder and had participated in an RTW program. The study data comprised demographic characteristics and texts. Textual data were collected from electronic medical records and classified based on the SOAP note. Thereafter, the textual data were quantified into category scores based on a standard text analysis dictionary. A generalized linear mixed model was used for the statistical analysis, with the score for each category (emotional, social, cognitive, perceptual, biological, motivational, relativity, and informal) as the dependent variable and the duration of sick leave, time, and interaction between the duration of sick leave and time as the independent variables. The level of statistical significance was set at 0.05. RESULTS: In total, 42 participants were included in the analysis. The results revealed a significant interaction between the social (p = 0.001) and emotional (p = 0.002) categories. CONCLUSION: The findings suggest a relationship between word changes in electronic medical records and the duration of sick leave.

Pandemic-Induced Occupational Disruption and Association With Health in Japanese Community-Dwelling Older Adults.

The COVID-19 pandemic caused occupational disruption and adverse health outcomes in community-dwelling older adults. This study aimed to investigate the extent of occupational disruption in older adults and its relationship to health-related quality of life (QOL), depression, and frailty. In this cross-sectional study, retention rates in four activity domains and relationships with health outcomes were examined in Japanese older adults aged ≥65 years (n=163) using canonical correlation analysis (CCA) and mixed linear models. More than 25% of activities were restricted compared with the pre-pandemic period. CCA demonstrated correlations between four retention rates and health outcomes (canonical correlation = .42, p = .0003). Retention in instrumental and social activities independently predicted QOL and depression (p < .05). This study highlights that different activities may have different effects on health outcomes and can provide community occupational therapy practitioners with a perspective to assess occupational disruption and identify activities for intervention.

Pandemic-Induced Changes of Daily Routine and Its Association with Health for Japanese Older AdultsWe investigated the changes in daily activity due to the COVID-19 pandemic among community-dwelling older adults in Japan and examined their association with health outcomes. The results showed that more than 25% of activity was reduced due to the pandemic. There was a moderate association between changes in activity and physical, mental, and subjective health. Especially, instrumental and social activities were strongly associated with mental and subjective health. This study highlights the possibility that different types of activities may have different effects on health. Our study can provide occupational therapy practitioners supporting community-dwelling older adults with a perspective to assess changes in daily activities due to the pandemic and identify activities to target for future intervention. As this study was conducted at a single point in time, future studies should be conducted at multiple points in time.

Identification of Subgroups of Activity Participation in Group of Community-Dwelling Older Adults.

Occupational therapy in public health is advancing for groups of older adults, but few studies have focused on measuring population-based activity engagement. This study aimed to identify subgroups based on the daily activity pattern of community-dwelling older adults. Japanese older adults aged ≥65 years responded to a 128-activity-item questionnaire. Sparse principal component analysis was applied to summarize the activities, and k-means clustering was used to identify subgroups. Respondents were divided into three subgroups (subgroup 1: n = 39, high instrumental/leisure and social/cognitive activity; subgroup 2: n = 51, high instrumental/leisure and low social/cognitive activity; subgroup 3: n = 44, low instrumental/leisure and social/cognitive activity). The three subgroups were associated with sociodemographics (sex, area, education, and activity level) (p < .05). This study highlighted the activity-based subgroups of older adults and provided a novel viewpoint regarding occupation-based community assessments in addition to previous community occupational therapy practice.

Gender differences in psychosocial factors related to severe stress in a construction company in Japan.

BACKGROUND: In Japan, women's participation in the workforce has been increasing. However, there are few studies about gender differences in stress factors in the workplace. OBJECTIVES: We aimed to clarify gender differences in psychosocial factors in the workplace related to severe stress. METHODS: In total, 930 male and 339 female employees working in a construction company in Japan participated in this study. We used individual responses to the Brief Job Stress Questionnaire (BJSQ) conducted by their company for the most recent year between 2016 and 2019. Data were categorized by gender, and we extracted the factors contributing to severe stress using logistic regression. RESULTS: We identified 142 men and 32 women who had severe stress. Logistic regression analysis showed that six factors ("Qualitative job overload", "Job control", "Interpersonal conflict", "Poor physical environment", "Supervisor's support", and "Job satisfaction and life satisfaction") were significantly associated with the presence of severe stress in men. In women, five factors ("Qualitative job overload", "Job control", "Interpersonal conflict", "Suitable work", and "Job satisfaction and life satisfaction") showed a significant association with severe stress. CONCLUSION: Factors associated with severe stress were "Poor physical environment" and "Supervisor's support" in men, and "Suitable work" in women.

Pre-stimulus alpha oscillation and post-stimulus cortical activity differ in localization between consciously perceived and missed near-threshold somatosensory stimuli.

Conscious perception of a near-threshold (NT) stimulus is characterized by the pre- and post-stimulus brain state. However, the power of pre-stimulus neural oscillations and strength of post-stimulus cortical activity that lead to conscious perception have rarely been examined in individual cortical areas. This is because most previous electro- and magnetoencephalography (EEG and MEG, respectively) studies involved scalp- and sensor-level analyses. Therefore, we recorded MEG during a continuous NT somatosensory stimulus detection task and applied the reconstructed source data in order to identify cortical areas where the post-stimulus cortical activity and pre-stimulus alpha oscillation predict the conscious perception of NT somatosensory stimuli. We found that the somatosensory hierarchical processing areas, prefrontal areas and cortical areas belonging to the default mode network showed stronger cortical activity for consciously perceived trials in the post-stimulus period, but the cortical activity in primary somatosensory area (SI) is independent of conscious perception during the early stage of NT stimulus processing. In addition, we revealed that the pre-stimulus alpha oscillation only in SI is predictive of conscious perception. These findings suggest that the bottom-up stream of somatosensory information flow following SI and pre-stimulus alpha activity fluctuation in SI as a top-down modulation are crucial constituents of conscious perception.

Chronic pain-related cortical neural activity in patients with complex regional pain syndrome.

Quantitative objective measurement of chronic pain is important. We elucidated chronic pain-related cortical neural activity and neural connectivity among pain-related brain regions in complex regional pain syndrome (CRPS). Resting-state magnetoencephalography recordings were performed. Cortical current density and neural connectivity, revealed by amplitude envelope correlation (AEC), were estimated on standardized brain magnetic resonance imaging. Intra-experiment pain was assessed subjectively using a visual analogue scale (VAS). The correlation between current density and VAS scores was calculated for the occipital areas and pain-related cortices. Current density in the primary (SI) and secondary (SII) somatosensory cortex and precuneus in both hemispheres was negatively correlated with the pain VAS score. The AEC and VAS values were significantly correlated for the SII and the precuneus and for the SII and insular cortex in the alpha frequency band in the right hemisphere. In the theta frequency band, the AEC and VAS values correlated for the SII and posterior cingulate cortex in the right hemisphere. Our results suggested that disruption of pain processes and functions in the default mode network occurs in CRPS. Our method targeting the neural mechanism of pain has the potential to offer a clinically objective means of evaluating it.

Relationship between lower limb function and functional connectivity assessed by EEG among motor-related areas after stroke.

Background: Neural connectivity in brain has been known as indicators for neural function and recovery of brain. Although previous studies reported that neural connectivity predicted the recovery of upper limb function after stroke, the relationship between neural connectivity and lower limb function has not been clear.Objectives: To clarify whether functional connectivity (FC) assessed by electroencephalographiy (EEG) with five electrodes placed on motor-related areas could be related to the functional motor recovery of the lower limbs in patients after stroke.Methods: Twenty-four patients with stroke during the recovery phase were recruited. Motor function of the lower limbs was assessed using Fugl-Meyer Assessment lower limb section (FMAL). EEG signals were recorded by five electrodes (C3, C4, FC3, FC4, and FCz) at rest and during ankle movement. Amplitude envelope correlations, as values for FC, were calculated in α (8-12 Hz), ß (13-30 Hz), low-ß (13-19 Hz), and high-ß (20-30 Hz) frequency bands. The predictive regression equation of the FMAL score in the eighth week after stroke (8 W) was created by FCs in the fourth week (4 W).Results: The higher intra-hemispheric FC in both hemispheres in the resting state and during the ankle movement at 4 W was related to a higher lower limb function at 8 W. Additionally, the higher inter-hemispheric FC between M1 on both sides during the ankle movement was related to a higher function recovery.Conclusions: The intra- and inter-hemispheric FC among motor-related areas at 4 W after stroke might be related to the functional recovery of the lower limbs at 8 W.

Relationship between upper limb function and functional neural connectivity among motor related-areas during recovery stage after stroke.

Backgrounds: Neural biomarkers to predict motor recovery have been used in the field of rehabilitation. Functional connectivity (FC) among the brain regions recorded by functional magnetic resonance imaging systems have been reported, but convenient method to estimate FC for clinical situation has not been established.Objectives: This observational study investigated the relationship between neural functional connectivity obtained by electroencephalography (EEG) and the upper limb function in patients during recovery stage after stroke.Methods: Twenty-four patients in the recovery stage between 4 and 8 weeks after the onset of stroke (mean age: 62 ± 12 (SD)) were enrolled. The EEG signals were obtained by five electrodes placed on the motor-related areas (C3, C4, FC3, FC4, and FCz in the International 10-20 system) for 60 sec at rest and during finger movement on the affected side, and amplitude envelope correlations as measures of FC among the areas were calculated. Fugl-Meyer Assessment (FMA) was used to assess upper limb motor function.Results: The FMA scores evaluated at 4W (33 ± 24 (SD)) were improved by 8W (42 ± 23) (p < .001). The FCs in α and ß bands calculated between the electrodes in the ipsi-lesional hemisphere were correlated negatively with the FMA score at 4W after stroke. The FCs obtained at 4W could be used to predict the FMA score at 8W after stroke.Conclusions: The FCs recorded at rest, as well as during the finger motor task, by the five electrodes placed on motor-related areas could be used to predict the motor function and recovery of the upper limb affected by stroke. The results indicate the possibility of using FCs recorded by conventional EEG with electrodes as biomarkers to predict motor recovery after stroke.

Selection of Activity Items for Development of the Activity Card Sort-Japan Version.

The Activity Card Sort (ACS) can both record the clients' participation and any changes, which is a useful tool for practitioners to establish tailored occupation-focused goals. However, there is a limitation to apply the ACS to Japanese older adults as it consists of culturally relevant activities in the United States. The aim of this study was to select activity items reflecting Japanese older adults' lifestyles and opinions to develop the Activity Card Sort-Japan Version (ACS-JPN). In the item selection process, a two-round questionnaire survey was conducted for community-dwelling Japanese older adults (Round 1: n = 177, M age = 69.9 years; Round 2: n = 178, M age = 74.9 years). Seventy-two activity items were finally included in the ACS-JPN and were classified into four domains. The ACS-JPN has some unique features compared with other ACS versions. This study only selected activity items. Further work on psychometric properties is needed.

Relationships between Depression and Stress Factors in Housework and Paid Work among Japanese Women.

OBJECTIVE/BACKGROUND: The prevalence of depression in women is two times as much as that in men. However, the rehabilitation programme for return to work for patients with depression in Japan mainly focuses on male individuals. Japanese working women usually have the central role in housework in addition to paid work. Therefore, we hypothesized that Japanese working women with depression need a support programme for housework as well as paid work. The purpose of this study was to investigate the stress factors relevant to the existence of depression, in both paid work and housework, among working women. METHODS: This study recruited 35 women with depression and 35 women without depression. We carried out a cross-sectional investigation with two questionnaires having the same structure: The National Institute for Occupational Safety and Health (NIOSH) Generic Job Stress Questionnaire (for paid work) and the NIOSH Generic Housekeeping Labor Stress Questionnaire (for housework). We extracted the stress factors contributing to the existence of depression using logistic regression. RESULTS: Three stress factors were found--two in housework, and one in paid work. In housework, variance in workload and underutilization of abilities were associated with the presence of depression. In paid work, interpersonal conflict was an associated factor. CONCLUSION: Rehabilitation programmes involving variance in workload and under self-evaluation in housework, and interpersonal conflict in paid work must be adequately addressed to support working women with depression.

Effects of emotional music on visual processes in inferior temporal area.

To investigate the effects of emotional music on visual processes, we analyzed visual evoked magnetic fields (VEF) on listening to emotional music in 14 healthy subjects. Positive and negative pieces of music were delivered during VEF recording following stimulation by emotionally neutral pictures of faces and landscapes. VEF components at 100 (M100) and 150 (M170)ms after stimulus onset were analyzed, and the estimated current strength for M170 following face stimulation was enhanced with negative compared to positive music in the right hemisphere. The equivalent current dipole for M100 and M170 was estimated in the primary visual cortex (V1) and inferior temporal area (IT), respectively. The present results indicate that background music showed a top-down control of the visual processes in IT, which is a core site responsible for the interpretation of facial expression. The emotional contents of music could alter visual processes, especially those involving the face.