Satoko Nakashita

Prevalence of Dementia and Mild Cognitive Impairment in the Rural Island Town of Ama-cho, Japan

Aims: In order to determine the prevalence of dementia and mild cognitive impairment (MCI), we conducted a population-based study in Japan. Methods: Participants included 924 subjects aged 65 years or older who resided in the town of Ama-cho. In phase 1 of the study, the Mini-Mental State Examination and Clinical Dementia Rating were administered for screening purposes. In phase 2 of the study, the subjects who screened positive were further examined by neurologists. Dementia and MCI were diagnosed by means of DSM-IV and International Working Group on MCI criteria, respectively. Results: By the prevalence date of June 1, 2010, 24 subjects had deceased or lived outside the town. In total, 723 of the remaining 900 subjects received a phase 1 test. In phase 2, 98 subjects were diagnosed with amnestic MCI, 113 subjects with non-amnestic MCI, and 82 subjects with dementia. Of the subjects who did not receive the phase 1 test, 66 subjects were diagnosed as having dementia according to data from their town medical card or the Long-term Care Insurance System. The crude prevalence of amnestic MCI, non-amnestic MCI, and dementia were 10.9, 12.6, and 16.4%, respectively. Conclusion: Consistent with the striking increase in the number of elderly individuals, we report higher prevalence of MCI and dementia in Japan than previously described.

Mild parkinsonian signs in a community-dwelling elderly population sample in Japan

Mild parkinsonian signs (MPS) may represent the mild end of a disease spectrum that spans from normal aging to neurodegenerative diseases. We conducted a population-based study in a rural island town in western Japan, Ama-cho. Participants included 1129 subjects, aged 60 years and older, residing in the town. Participants were classified according to a modified Unified Parkinsons Disease Rating Scale (mUPDRS) score. MPS was determined to be present if any of the following conditions were met: (1) two or more mUPDRS ratings=1 [MPS-mild]; (2) one mUPDRS rating≥2; or (3) mUPDRS rest tremor rating≥1; [(2) and (3): MPS-severe]. Subjects wore a uniaxial accelerometer (Actiwatch), resulting in the measurement of actigraphic activity counts (AC). Of the 804 participants with complete data, 178 subjects (22.1%) were classified as demonstrating MPS. AC was significantly lower in the MPS-severe group compared with both the CTL and the MPS-mild groups. Diagnostic sensitivity for MPS-severe became 100% when we adopted a cutoff point of low physical activity, as measured by actigraphy, combined with the presence of subjective depression. We established the prevalence of MPS in a community-dwelling elderly population sample in Japan. Actigraphy may be a useful objective tool for screening MPS-severe.

Depression and cognitive impairment in patients with mild parkinsonian signs

Mild parkinsonian signs (MPS) are reported to be associated with increased risk of dementia, Parkinsons disease, parkinsonism, and vascular lesions of white matter and are also a significant predictor of mortality. Although more than 20% of subjects aged 60 years and older suffer from MPS in Japan, it is often unrecognized and underestimated by patients and medical physicians. We used neuropsychological methods to examine cognitive function and depressive symptoms in subjects with MPS.

Association of cerebral white matter lesions with cognitive function and mood in Japanese elderly people: a population-based study

To determine the relationships between regional white matter lesions (WMLs), lifestyle factors, and cognitive, motor function and mood.

Epidemiological Survey of Frontotemporal Lobar Degeneration in Tottori Prefecture, Japan

Background: The prevalence of frontotemporal lobar degeneration (FTLD) in Japan is unknown. An epidemiological survey study of FTLD was undertaken in Tottori Prefecture, a district in the western region of Japan. Methods: Hospitals in Tottori Prefecture were surveyed by a two-step questionnaire in 2010, and the prevalence of FTLD per 100,000 inhabitants was calculated using the actual number of patients and inhabitants in Tottori Prefecture on the prevalence day of October 1, 2010. Results: In this survey, 66 patients were diagnosed with FTLD. The subtypes of FTLD were as follows: 62 cases of frontotemporal dementia (FTD), 3 cases of progressive nonfluent aphasia, and 1 case of semantic dementia. Among the FTD cases, 5 cases were FTD with motor neuron disease and 1 case was FTD with parkinsonism linked to chromosome 17. The prevalence of FTD in the total population of Tottori Prefecture was 11.2 per 100,000 inhabitants. Based on these results, the prevalence of FTLD in Japan in 2008 was estimated to be 9.5 per 100,000 individuals. Conclusions: Our epidemiological survey results suggest that there are at least 12,000 FTLD patients in Japan, indicating that FTLD is not a rare disease.

Clinical evaluation of fatigue in Japanese patients with Parkinson's disease.

Fatigue is a common nonmotor symptom of Parkinsons disease (PD). Although the causes of fatigue were estimated in the previous reports, fatigue is not fully understood. To determine the frequency of and factors related to fatigue in patients with PD, we carried out clinical assessments in our university hospital.

Clinical assessment and prevalence of parkinsonism in Japanese elderly people.

Parkinsonism is often observed in the elderly. To clarify the prevalence of parkinsonism‐associated diseases and conditions, we conducted a population‐based study in a rural island town in western Japan, Ama‐cho.

Longitudinal course of mild parkinsonian signs in elderly people: A population-based study in Japan.

We aimed to clarify the longitudinal course of mild parkinsonian signs (MPS) and their association with dementia and functional disability by conducting a comprehensive epidemiological study, including brain MRI, and assessments of cognition, depression, and sleep, in people aged ≥65years living in Ama-cho. We diagnosed MPS and parkinsonism (PS) using a modified Unified Parkinsons Disease Rating Scale. The phase I study was conducted between 2008 and 2010 (n=729) and the phase II between 2011 and 2013 (n=436). By phase II, 8.5% of the phase I participants without PS had developed PS. In addition to older age, a lower Mini-Mental State Examination (MMSE) score, and lower body mass index, the MPS rigidity subtype was a significant independent predictor of PS onset. By phase II, 10.1% of the participants without dementia or PS at phase I had developed dementia. Older age, lower MMSE score, and the axial dysfunction and tremor MPS subtypes were significant independent predictors of dementia development. By phase II, 38.8% of participants with MPS at phase I showed no motor symptoms. Younger age and adequate sleep were significant predictors for this reversion. Periventricular and deep white matter hyperintensity Fazekas scores increased with the evolution of parkinsonian signs. MPS is therefore critically, although sometimes reversibly, associated with PS and dementia development in elderly people.

Egogram characteristics in Japanese patients with Parkinson's disease

Personality has been investigated as a possible onset risk factor for Parkinsons disease (PD). Recently, personality has attracted increasing attention because certain non‐motor aspects may be associated with patients’ personality and deterioration of their quality of life. The Tokyo University Egogram version II (TEGII) is a reliable questionnaire for assessing personality in Japanese people, but few studies have reported personality assessments in Japanese PD patients.

Association between exercise habits and subcortical gray matter volumes in healthy elderly people: A population-based study in Japan

Background and aims The relationship between exercise and subcortical gray matter volume is not well understood in the elderly population, although reports indicate that exercise may prevent cortical gray matter atrophy. To elucidate this association in the elderly, we measured subcortical gray matter volume and correlated this with volumes to exercise habits in a community-based cohort study in Japan. Methods Subjects without mild cognitive impairment or dementia (n = 280, 35% male, mean age 73.1 ± 5.9 years) were evaluated using the Mini-Mental State Examination (MMSE), an exercise habit questionnaire, and brain magnetic resonance imaging. Subcortical gray matter volume was compared between groups based on the presence/absence of exercise habits. The MMSE was re-administered 3 years after the baseline examination. Results Ninety-one subjects (32.5%) reported exercise habits (exercise group), and 189 subjects (67.5%) reported no exercise habits (non-exercise group). Volumetric analysis revealed that the volumes in the exercise group were greater in the left hippocampus (p = 0.042) and bilateral nucleus accumbens (left, p = 0.047; right, p = 0.007) compared to those of the non-exercise group. Among the 195 subjects who received a follow-up MMSE examination, the normalized intra-cranial volumes of the left nucleus accumbens (p = 0.004) and right amygdala (p = 0.014)showed significant association with a decline in the follow-up MMSE score. Conclusion Subjects with exercise habits show larger subcortical gray matter volumes than subjects without exercise habits in community-dwelling elderly subjects in Japan. Specifically, the volume of the nucleus accumbens correlates with both exercise habits and cognitive preservation.