Hajime Tabuchi

Predictors of repeated sick leave in the workplace because of mental disorders

Introduction Mental disorders create a considerable burden to society. Previous studies have shown that productivity loss constitutes the largest proportion of the total societal burden. For depression and anxiety disorders, in particular, more than half of the associated productivity loss occurs in the workplace. Many previous studies have clarified the risk factors for the relapse/recurrence of mental disorders in health care settings. However, the risk factors for repeated sick leave among mental disorders prevalent in the workplace have not yet been adequately evaluated. Objective The objective of this study was to investigate which variables could predict repeated sick leave for workers with a history of sick leave because of mental disorders. Methods Data regarding 194 subjects employed at a manufacturing company were obtained. Mental disorders were defined as disorders listed in the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV). The duration between the return to work (RTW) and the repeated sick leave was regarded as a dependent variable. The subjects’ age at the RTW, sex, age at the time of employment, job tenure, diagnosis, number of previous sick leave days, duration of most recent sick leave, and employee rank were examined as explanatory variables. Univariate analyses using a log-rank test and a multivariate analysis using the Cox proportional hazard model were conducted. Results The results of the univariate analyses showed that the number of previous sick-leave episodes was a significant predictor of repeated sick leave. A multivariate analysis revealed that age at RTW and the number of previous sick-leave episodes were significant variables. Conclusion Age and the number of previous sick-leave episodes appeared to be predictors of repeated sick leave. Therefore, effective intervention to prevent repeated sick leave for those with high risk is quite crucial. Analyses including various work-related factors with subjects from multiple companies should be conducted in future studies.

Increased left anterior insular and inferior prefrontal activity in post-stroke mania

BackgroundPost-stroke mania is an infrequent complication after stroke, and the mechanisms underlying this disorder remain unclear. Although a contralesional release phenomenon has been implicated in post-stroke mania, empirical findings are lacking.Case presentationWe present a case report of post stroke mania. Single photon emission tomography (SPECT) was performed twice, during the manic state and during the remitted euthymic state. The first SPECT study performed during the manic state demonstrated hypoperfusion in the right temporal and frontal regions due to right putaminal hemorrhage. It also showed hyperperfusion in the inferior lateral prefrontal lobe, the temporal lobe, and the medial and lateral parts of the parietal lobe in the left hemisphere. The second SPECT study performed during the euthymic state demonstrated moderate improvement in the hypoperfusion in the right fronto-temporal regions. Furthermore, compared to the findings on the first SPECT study, the second study showed that the focal hyperperfusion in the anterior insular cortex, inferior lateral prefrontal lobes, and superior-middle temporal gyrus in the left hemisphere had vanished.ConclusionIncreased left inferior prefrontal and anterior insular activity and reduced extensive right fronto-temporal lobe activity are involved in the development of post-stroke mania.

Late-onset neurodegenerative diseases following traumatic brain injury: chronic traumatic encephalopathy (CTE) and Alzheimer's disease secondary to TBI (AD-TBI)

Chronic traumatic encephalopathy (CTE) is a neurodegenerative disease, which is associated with mild repetitive traumatic brain injury (TBI). This long-term and progressive symptom due to TBI was initially called punch-drunk syndrome or dementia pugilistica, since it was believed to be associated with boxing. However, serial neuropathological studies of mild repetitive TBI in the last decade have revealed that CTE occurs not only in boxers but also in a wider population including American football players, wrestlers, and military personnel. CTE has gained large public interest owing to dramatic cases involving retired professional athletes wherein serious behavioral problems and tragic incidents were reported. Unlike mild repetitive TBI, a single episode of severe TBI can cause another type of late-onset neuropsychiatric disease including Alzheimers disease (AD). Several epidemiological studies have shown that a single episode of severe TBI is one of the major risk factors of AD. Pathologically, both AD and CTE are characterized by abnormal accumulations of hyperphosphorylated tau proteins. However, recent neuropathological studies revealed that CTE demonstrates a unique pattern of tau pathology in neurons and astrocytes, and accumulation of other misfolded proteins such as TDP-43. Currently, no reliable biomarkers of late-onset neurodegenerative diseases following TBI are available, and a definitive diagnosis can be made only via postmortem neuropathological examination. Development in neuroimaging techniques such as tau and amyloid positron emission tomography imaging might not only enable early diagnosis of CTE, but also contribute to the interventions for prevention of late-onset neurodegenerative diseases following TBI. Further studies are necessary to elucidate the mechanisms of neurodegeneration in the living brain of patients with TBI.

Emergence of realism: Enhanced visual artistry and high accuracy of visual numerosity representation after left prefrontal damage

Over the last two decades, evidence of enhancement of drawing and painting skills due to focal prefrontal damage has accumulated. It is of special interest that most artworks created by such patients were highly realistic ones, but the mechanism underlying this phenomenon remains to be understood. Our hypothesis is that enhanced tendency of realism was associated with accuracy of visual numerosity representation, which has been shown to be mediated predominantly by right parietal functions. Here, we report a case of left prefrontal stroke, where the patient showed enhancement of artistic skills of realistic painting after the onset of brain damage. We investigated cognitive, functional and esthetic characteristics of the patient׳s visual artistry and visual numerosity representation. Neuropsychological tests revealed impaired executive function after the stroke. Despite that, the patient׳s visual artistry related to realism was rather promoted across the onset of brain damage as demonstrated by blind evaluation of the paintings by professional art reviewers. On visual numerical cognition tasks, the patient showed higher performance in comparison with age-matched healthy controls. These results paralleled increased perfusion in the right parietal cortex including the precuneus and intraparietal sulcus. Our data provide new insight into mechanisms underlying change in artistic style due to focal prefrontal lesion.

The psychological impact of disclosing amyloid status to Japanese elderly: a preliminary study on asymptomatic patients with subjective cognitive decline

ABSTRACTIn Japan, 4.6 million people are living with dementia and the number is expected to rise to 7 million by 2025. Amyloid-β (Aβ) positron emission tomography (PET) is used for cognitively normal Japanese people with or without subjective cognitive decline (SCD) for the purpose of clinical trials or diagnosis. Nevertheless, no empirical studies have been conducted on the safety of disclosing amyloid status to such populations. We conducted amyloid PET imaging on 42 participants (Aβ positive (n = 10) and negative (n = 32)). State anxiety and depression were measured at pre- and post-disclosure, and test-related distress at post-disclosure. Mean state anxiety and depression scores were below the cut-off through pre- and post-disclosure in the Aβ positive and negative groups. State anxiety and depression did not change over time and were not different between groups. Mean test-related distress scores were within normal limits at post-disclosure in both groups. No significant difference was found between groups. Disclosing Aβ positive results did not cause greater mood disturbance than negative results in a short period of time. The short-term psychological safety of disclosing Aβ PET results to asymptomatic Japanese adults with SCD was indicated.

Extremely Low Prevalence of Amyloid Positron Emission Tomography Positivity in Parkinson's Disease without Dementia

Background: Most cases of dementia with Lewy bodies (DLB) show Alzheimers disease pathology-like senile plaques and neurofibrillary tangles. Several studies have also revealed a high prevalence of positive amyloid imaging with positron emission tomography (PET) in DLB and moderate prevalence in Parkinsons disease (PD) with dementia. However, it remains unclear in PD without dementia as to when the brain β amyloid (Aβ) burden begins and progresses. Our study aimed to determine the prevalence of Aβ deposition in PD without dementia using amyloid PET. Methods: This was a cross-sectional study on 33 patients with PD without dementia, of whom 21 had normal cognition and 12 met the criteria for PD-mild cognitive impairment. All subjects underwent neuropsychological assessment and [18F] florbetaben (FBB) PET. Results: All subjects had Lewy body-related disorders, displaying a significantly reduced myocardial [123I] metaiodobenzylguanidine uptake. The cortical FBB-binding pattern in all subjects, including APOE e4 carriers, suggested negative Aβ deposition. Conclusion: Patients with PD without dementia exhibit an extremely low prevalence of Aβ positivity compared with those reported in cognitively normal elderly controls. Further longitudinal imaging studies and long-term follow-up are needed; however, our findings provide novel insights for understanding Aβ metabolism in PD.

Reverse Fox test for detecting visuospatial dysfunction corresponding to parietal hypoperfusion in mild Alzheimer's disease.

Background/Aim: We developed a novel visuospatial clinical task to detect parietal dysfunction in mild Alzheimer’s disease (AD). Methods: A total of 65 outpatients, including 47 with mild AD and 18 cognitively and neuroradiologically normal individuals with subjective memory impairment (NL), performed the “Reverse Fox” test and underwent brain single photon emission tomography. Patients with AD were divided into subgroups according to the results of the Reverse Fox test (successful vs unsuccessful). Results: Success in the Reverse Fox test was achieved by 31.9% of patients with AD and 94.4% of NL. The unsuccessful AD subgroup had reduced perfusion of the medial parietal and bilateral temporoparietal regions compared with the successful AD subgroup. Conclusions: Failure in the Reverse Fox test was related to parietal hypoperfusion in patients with mild AD. Our findings suggest that the Reverse Fox test may be one of the useful supporting tools for detecting mild AD at outpatient clinic.

Quantitative evaluation of the tracer distribution in dopamine transporter SPECT for objective interpretation

PurposeQuantification of the tracer distribution would add objectivity to the visual assessments of dopamine transporter (DAT) single photon emission computed tomography (SPECT) data. Our study aimed to evaluate the diagnostic utility of fractal dimension (FD) as a quantitative indicator of tracer distribution and compared with the conventional quantitative value: specific binding ratio (SBR). We also evaluated the utility of the combined index SBR/FD (SBR divided by FD).Materials and methodsWe conducted both clinical and phantom studies. In the clinical study, 150 patients including 110 patients with Parkinsonian syndrome (PS) and 40 without PS were enrolled. In the phantom study, we used a striatal phantom with the striatum chamber divided into two spaces, representing the caudate nucleus and putamen. The SBR, FD, and SBR/FD were calculated and compared between datasets for evaluating the diagnostic utility. Mann–Whitney test and receiver-operating characteristics (ROC) analysis were used for analysis.ResultsROC analysis revealed that the FD value had high diagnostic performance [the areas under the curve (AUC) = 0.943] and the combined use of SBR and FD (SBR/FD) delivered better results than the SBR alone (AUC, 0.964 vs 0.899; p < 0.001). The sensitivity, specificity, and accuracy, respectively, were 79.1, 85.0, and 80.7% with SBR, 84.5, 97.5, and 88.0% with FD, and 92.7, 87.5, and 91.3% with SBR/FD.ConclusionOur results confirmed that the FD value is a useful diagnostic index, which reflects the tracer distribution in DAT SPECT images. The combined use of SBR and FD was more useful than either used alone.

DISCLOSURE OF AMYLOID STATUS FOR RISK OF ALZHEIMER’S DISEASE TO COGNITIVELY NORMAL PERSONS WITH SUBJECTIVE COGNITIVE DECLINE

included gender, level of education, employment status, level and type of physical activity, volunteer status, hobbies/interests, sleep satisfaction, and supplement use. Results:Male/female ratio was evenly matched. 82% had an education level of 13 years and above. 72% were unemployed/retired. 68% engaged in moderate (3-4 times/week) or high (5 or more times/week) levels of physical activity; endurance activities (walking/hiking) were most popular at 61%. All subjects reported at least one hobby or interest; friends/family/church were the most common. 75% were satisfied with sleep. The highest utilized supplements were aspirin and multivitamin. Conclusions: This sub-study has given us a valuable profile of the cognitively healthy senior enrolled in the TOMMORROW study. While these patterns of behavior do not indicate causality, they suggest avenues for future research. Much information can be obtained from such a large community-based study, to enhance our knowledge beyond the primary intent of the study. Studying healthy seniors will help us gain a better understanding of those who are ill as well as potential insights into prevention.

Sustained Attention Function Evaluation During Cooking Based on Egocentric Vision

The attention function has been classified into (i) sustained attention, (ii) selective attention, (iii) controlled attention, (iv) distributed attention, and (v) capacity for attention. Ordinarily, in order to evaluate the function of attention, the digital cancellation test (D-CAT) or trail making test (TMT) are employed. However, these evaluations are in the form of paper tests, and cannot effectively evaluate small changes in activities daily of living in real time. Accordingly, we focus on human behavior during the act of cooking, in which multitasking is common and many types of ordinary movements are performed. We previously proposed a method of evaluating distributive attention during cooking and showed its effectiveness. In this study, a method for evaluating sustained attention is proposed. Specifically, we acquire an egocentric video by an egocentric vision and estimate line-of-sight based on the visual attention model that is integrated from the three kind of models (category-specific attention, top-down attention, and bottom-up attention). After that, we define line-to-sight information from high saliency area on the visual attention model.