Sho Nakakubo

Impact of Cognitive Frailty on Daily Activities in Older Persons.

ObjectivesTo identify the relationships between physical and/or cognitive frailty and instrumental activities of daily living (IADL) functioning in community living older persons.DesignCross sectional observation study.SettingData extracted from the 2011–2013 of the National Center for Geriatrics and Gerontology–Study of Geriatric Syndromes (NCGG-SGS) database.ParticipantsA total of 8,864 older adults aged ≥ 65 years who were enrolled in the NCGG-SGS.MeasurementsWe characterized physical frailty as limitations in three or more of the following five domains: slow walking speed, muscle weakness, exhaustion, low activity and weight loss. To screen for cognitive impairment, we used the National Center for Geriatrics and Gerontology-Functional Assessment Tool (NCGG-FAT) which included tests of word list memory, attention and executive function (tablet version of the Trail Making Test, part A and B), and processing speed (tablet version of the Digit Symbol Substitution Test). Two or more cognitive impairments indicated by an ageadjusted score of at least 1.5 standard deviations below the reference threshold was characterized as cognitive impairment. Each participant reported on their IADL status (use of public transportation, shopping, management of finances, and housekeeping) and several potential confounders such as demographic characteristics.ResultsThe overall prevalence of physical frailty, cognitive impairment, and cognitive frailty, i.e. co-occurrence of frailty and cognitive impairment, was 7.2%, 5.2%, and 1.2%, respectively. We found significant relationships between IADL limitations and physical frailty (Odds Ratio (OR) 1.24, 95% confidence interval (95% CI) 1.01 to 1.52), cognitive impairment (OR 1.71, 95% CI 1.39 to 2.11), and cognitive frailty (OR 2.63, 95% CI 1.74 to 3.97).ConclusionUsing the NCGG-SGS frailty criteria, we found more participants with physical frailty than with cognitive frailty. The individuals with cognitive frailty had the highest risks of IADL limitations. Future investigation is necessary to determine whether this population is at increased risk for incidence of disability or mortality.

Driving continuity in cognitively impaired older drivers

Cognitive impairment can negatively affect driving performance and increase the risk of driving errors, leading to vehicle crashes. We used a population‐based survey to identify the prevalence of cognitive impairments in older drivers.

Cognitive function and falling among older adults with mild cognitive impairment and slow gait.

To examine the association of the combination of slow gait and mild cognitive impairment (MCI) with cognitive function and falling in community‐dwelling older people.

Social Frailty in Community-Dwelling Older Adults as a Risk Factor for Disability

OBJECTIVE To determine social frailty status using simple questions and to examine the association between social frailty and disability onset among community-dwelling older adults. DESIGN Prospective cohort study. SETTING Japanese community. PARTICIPANTS A total of 4304 adults age ≥65 years living in the community participated in a baseline assessment from 2011 to 2012. They were followed monthly for incident certification of care needs during the 2 years after the baseline assessment. MEASUREMENTS Care-needs certification in the national long-term care insurance system of Japan; a self-reported questionnaire including 7 items to define social frailty status, adjustment for several potential confounders such as demographic characteristics; and Kaplan-Meier survival curves for disability incidence by social frailty. RESULTS During the 2 years, 144 participants (3.3%) were certified as requiring long-term care insurance in accordance with incident disability. Five of the 7 items in the self-reported questionnaire were significantly associated with disability incidence. In the adjusted model including potential covariates, participants who were defined as having social frailty (≥2/5) (hazard ratio 1.66, 95% confidence interval 1.00-2.74) and prefrailty (=1/5) (hazard ratio 1.53, 95% confidence interval 1.02-2.531), based on 5 items at the baseline assessment, had an increased risk of disability compared with nonfrail participants (=0/5). CONCLUSIONS Social frailty, assessed using simple questions regarding living alone, going out less frequently compared with the prior year, visiting friends sometimes, feeling helpful to friends or family, and talking with someone every day, has a strong impact on the risk of future disability among community-dwelling older people.

Cognitive functioning and walking speed in older adults as predictors of limitations in self-reported instrumental activity of daily living: prospective findings from the Obu Study of Health Promotion for the Elderly.

Our aim was to determine whether baseline measures of cognitive functioning, walking speed, and depressive status are independent predictors of limitations in instrumental activities of daily living (IADL) in older adults. The cross-sectional study involved 1329 community-dwelling adults, aged 75 years or older. At baseline, the Mini-Mental State Examination (MMSE), Symbol Digit Substitution Test (SDST), Geriatric Depressive Scale (GDS), and a word list memory task were completed, and self-reported IADLs and walking speed were recorded. The longitudinal study involved 948 participants without baseline IADL limitation, which was assessed at baseline and 15-month follow up, using the three Kihon Checklist subitems. In cross-sectional analyses, participants with IADL limitation demonstrated greater GDS scores, slower walking speeds, and lower MMSE, word list memory task, and SDST (only for women) scores relative to those without IADL limitation. In the longitudinal analyses, baseline walking speed (men: OR 0.98; women: OR 0.97, p < 0.05) and word list memory task scores (men: OR 0.84; women: OR 0.83, p < 0.05) in both sexes and SDST scores in women (OR 0.96, p = 0.04) were independent predictors of subsequent IADL limitation. Walking speed, memory, and processing speed may be independent predictors of IADL limitation in older adults.

Objectively measured physical activity, brain atrophy, and white matter lesions in older adults with mild cognitive impairment

Physical activity may help to prevent or delay brain atrophy. Numerous studies have shown associations between physical activity and age-related changes in the brain. However, most of these studies involved self-reported physical activity, not objectively measured physical activity. Therefore, the aim of this study was to examine the association between objectively measured physical activity, as determined using accelerometers, and brain magnetic resonance imaging (MRI) measures in older adults with mild cognitive impairment (MCI). We analyzed 323 older subjects with MCI (mean age 71.4 years) who were recruited from the participants of the Obu Study of Health Promotion for the Elderly. We recorded demographic data and measured physical activity using a tri-axial accelerometer. Physical activity was classified as light-intensity physical activity (LPA) or moderate-to-vigorous physical activity (MVPA). Brain atrophy and the severity of white matter lesions (WML) were determined by MRI. Low levels of LPA and MVPA were associated with severe WML. Subjects with severe WML were older, had lower mobility, and had greater brain atrophy than subjects with mild WML (all P<0.05). Multivariate analysis revealed that more MVPA was associated with less brain atrophy, even after adjustment for WML (β=-0.126, P=0.015), but LPA was not (β=-0.102, P=0.136). Our study revealed that objectively measured physical activity, especially MVPA, was associated with brain atrophy in MCI subjects, even after adjusting for WML. These findings support the hypothesis that physical activity plays a crucial role in maintaining brain health.

Does arm swing emphasized deliberately increase the trunk stability during walking in the elderly adults

The purpose of this study was to determine whether trunk stability while walking changes when arm swing is deliberately altered in elderly individuals. Participants included 21 community-dwelling elderly individuals (7 men and 14 women; age, 81.8 ± 5.0 years). We measured trunk acceleration by using a wireless miniature sensor unit containing a tri-axial linear accelerometer under 3 walking conditions: normal walking (normal condition), deliberately walking without any arm swing (no swing condition), and walking with a deliberately emphasized arm swing (over swing condition). To evaluate trunk stability during walking, we calculated harmonic ratios (HRs) based on trunk tri-axial acceleration signals (anteroposterior: AP, vertical: VT, and mediolateral: ML). HR-AP and HR-VT were not significantly different across the 3 conditions, but HR-ML in the over swing condition was significantly higher than that in the other 2 conditions by generalized estimating equations (GEE) adjusted for walking speed (p<0.05). These findings indicate that trunk stability in the ML direction increased when the elderly individuals walked with a deliberately emphasized arm swing.

The association between fear of falling and gait variability in both leg and trunk movements

The aim of this study was to explore whether FoF was associated with variability in both leg and trunk movements during gait in community-dwelling elderly. Ninety-three elderly people participated in this study. Each participant was categorized into either Fear or No-Fear group on the basis of having FoF. The participants walked 15m at their preferred speed. The wireless motion recording sensor units were attached to L3 spinous process and right posterior surface of heel during gait. Gait velocity, stride time and stride length were calculated. Variability in lower limb movements was represented by coefficient of variation (CV) of stride time. Trunk variability was represented by autocorrelation coefficients (AC) in three directions (vertical: VT, mediolateral: ML and anteroposterior: AP), respectively. Gait parameters were compared between groups, and further analyses were performed using generalized linear regression models after adjustment of age, sex, fall experience, height, weight, and gait velocity. Although gait velocity, mean stride time and stride length did not differ significantly between groups, stride time CV and all ACs were significantly worse in the Fear group after adjustment for variables, even including gait velocity (stride time CV: p=0.003, β=-0.793; AC-VT: p=0.011, β=0.053; AC-ML: p=0.044, β=0.075; AC-AP: p=0.002, β=0.078). Our results suggest that fear of falling is associated with variability in both leg and trunk movements during gait in community-dwelling elderly. Further studies are needed to prove a causal relationship.

Association of insulin-like growth factor-1 with mild cognitive impairment and slow gait speed

The decrease in serum insulin-like growth factor-1 (IGF-I) with aging is related to the neurobiological processes in Alzheimers disease. IGF-1 mediates effects of physical exercise on the brain, and cognition has a common pathophysiology with physical function, particularly with gait. The aim of this study was to examine whether mild cognitive impairment (MCI) and slow gait are associated with the serum IGF-1 level. A population survey was conducted in 3355 participants (mean age, 71.4 years). Cognitive functions (attention, executive function, processing speed, visuospatial skill, and memory), gait speed, and demographic variables were measured. All cognitive functions and gait speed were associated with the IGF-1 level (p < 0.001). The association of IGF-1 with slow gait was weakened by adjustment for covariates, but MCI and the combination of MCI and slow gait were independently related to the IGF-1 level in multivariate analysis (p < 0.05). Our findings support the association of a low IGF-1 level with reduced cognitive function and gait speed, particularly with a combination of MCI and slow gait.

Motoric Cognitive Risk Syndrome: Prevalence and Risk Factors in Japanese Seniors

OBJECTIVES Motoric cognitive syndrome (MCR), a newly described predementia syndrome characterized by cognitive complaints and slow gait, is associated with increased risk of developing dementia. Due to the potential differences in health, behavioral, and lifestyle factors between races that can influence dementia risk, it is important to examine risk factors for MCR in different countries. This study aimed to report the prevalence as well as modifiable factors associated with MCR in Japanese community-dwelling older adults. DESIGN A cross-sectional design. SETTING General community. PARTICIPANTS A total of 9683 older adults (52% women, mean age: 73.6 years) participating in the National Center for Geriatrics and Gerontology Study of Geriatric Syndromes. MEASUREMENTS Participants were screened for presence of MCR at baseline. The association of selected modifiable risk factors (medical illness, depressive symptoms, and falls) and lifestyle variables (obesity, physical inactivity, smoking, and alcohol consumption) with MCR was examined using multivariate logistic regression analysis. RESULTS At cross-section, 619 participants met criteria for MCR, with an overall prevalence 6.4% (95% CI 5.9-6.9). A higher prevalence of MCR was seen with advancing age (P < .001), but there were no sex differences. Diabetes (adjusted odds ratio [OR] 1.47, P = .001), depressive symptoms (OR 3.57, P < .001), and falls (OR 1.45, P < .001) were associated with increased risk of MCR. Among the lifestyle factors, obesity (OR 1.26, P = .018) and physical inactivity (OR 1.57, P < .001) were associated with increased risk of MCR. CONCLUSION MCR is common in the elderly Japanese population. The potentially modifiable risk and lifestyle factors identified for MCR should be further studied to develop interventions.