Influential factors affecting age-related self-overestimation of step-over ability: Focusing on frequency of going outdoors and executive function

The influence of age and age simulation on task-difficulty choices in motor tasks

    Having a realistic perception of one's motor abilities is important for successful aging. We used two different motor tasks, carrying a tray with cube-towers (study 1; n = 20 young adults; n = 20 older adults), and stepping over a crossbar (study 2; n = 23 young adults; n = 21 older adults), to investigate how physical risk influences task-difficulty choices. We also investigated the effect of wearing an age simulation suit on young adults. For the tray-carrying task, older adults were more risk-tolerant in their task-difficulty choices. When stepping over the crossbar, older adults left a larger "safety-buffer" than young adults. When wearing the age suit, young adults adopted a more careful strategy in the stepping task. We conclude that healthy older adults flexibly adjust their strategies to postural risks, and that young adults' strategy-choices can be influenced by experimentally inducing some of the sensory-motor constraints of old age.

Changes in self-estimated step-over ability among older adults: A 3-year follow-up study

OBJECTIVES

There is a growing body of literature examining age-related overestimation of one's own physical ability, which is a potential risk of falls in older adults, but it is unclear what leads them to overestimate. This study aimed to examine 3-year longitudinal changes in self-estimated step-over ability, along with one key risk factor: low frequency of going outdoors (FG), which is a measure of poor daily physical activity.

METHOD

This cohort study included 116 community-dwelling older adults who participated in baseline and 3-year follow-up assessments. The step-over test was used to measure both the self-estimated step-over bar height (EH) and the actual bar height (AH). Low FG was defined as going outdoors either every few days or less at baseline.

RESULTS

The number of participants who overestimated their step-over ability (EH>AH) significantly increased from 10.3% to 22.4% over the study period. AH was significantly lower at follow-up than at baseline in both participants with low and high FGs. Conversely, among participants with low FG, EH was significantly higher at follow-up than at baseline, resulting in increased self-estimation error toward overestimation. Regression model showed that low FG was independently associated with increased error in estimation (i.e., tendency to overestimate) at follow-up.

DISCUSSION

The present study indicated that self-overestimated physical ability in older adults is not only due to decreased physical ability but also due to increased self-estimation of one's ability as a function of low FG. Active lifestyle may be critical for maintaining accurate estimations of one's own physical ability.

Influence of co-existing social isolation and homebound status on medical care utilization and expenditure among older adults in Japan

Objective

To examine whether co-existing social isolation and homebound status influence medical care utilization and expenditure in older adults.

Methods

Postal surveys on social isolation and homebound status were performed on older adults aged ≥65 years residing in a Japanese suburban city. Information on medical care utilization and expenditure was obtained from insurance claims data. These outcomes were examined over a three-year period (December 2008 to November 2011) for all participants (Analysis I, n = 1386) and during the last year of life for mortality cases (Analysis II, n = 107). A two-part model was used to analyze the influence of social isolation and homebound status on medical care utilization (first model: logistic regression model) and its related expenditure (second model: generalized linear model).

Results

Almost 12 % of participants were both socially isolated and homebound. Analysis I showed that these participants were significantly less likely to use outpatient and home medical care than participants with neither characteristic (odds ratio: 0.536, 95 % confidence interval: 0.303−0.948). However, Analysis II showed that participants with both characteristics had significantly higher daily outpatient and home medical expenditure in the year before death than participants with neither characteristic (risk ratio: 2.155, 95 % confidence interval: 1.338−3.470).

Discussion

Older adults who are both socially isolated and homebound are less likely to regularly utilize medical care, which may eventually lead to serious health problems that require more intensive treatment. Measures are needed to encourage the appropriate use of medical care in these individuals to effectively manage any existing conditions.

Mismatch of Subjective and Objective Risk of Falling in Patients with Dementia

BACKGROUND

Match or mismatch of objective physiological and subjectively perceived fall risk may have serious consequences in patients with dementia (PwD) while research is lacking.

OBJECTIVE

To analyze mismatch of objective and subjective fall risk and associated factors in PwD.

METHOD

Cohort study in a geriatric rehabilitation center. Objective and subjective risk of falling were operationalized by Tinetti's Performance Oriented Mobility Assessment and the Falls Efficacy Scale-International. Four sub-groups according to objective and subjective fall risk were classified. Subgroups were compared for differences in clinical, cognitive, psychological, and behavioral variables.

RESULTS

In geriatric rehab patients with mild to moderate dementia (n = 173), two-thirds showed a mismatch of subjective versus objective risk of falling, independently associated with previous falls. Underestimation of objective fall risk (37.6%) was determined by lower activity avoidance (OR 0.39), less concerns about falling due to previous falls (OR 0.25), and higher quality of life (OR 1.10), while overestimation (28.9%) was determined by higher rate of support seeking strategies (OR 50.3), activity avoidance (OR 15.2), better executive (OR 21.0) and memory functions (OR 21.5), and lower quality of life (OR.75) in multivariate logistic regression.

CONCLUSION

The majority of patients showed a mismatch between objective and subjective falls risk. Underestimation as well as overestimation of fall risk was associated with specific profiles based on cognitive- and psychological status, falls and fall-related behavioral consequences which should be included in the comprehensive assessment of fall risk, and planning of individualized fall prevention programs for this population.

Increased Time Difference between Imagined and Physical Walking in Older Adults at a High Risk of Falling

Walking motor imagery ability is thought to be associated with a fear of falling; however, no studies have compared fall risk and motor imagery ability. This study aimed to ascertain the time difference between imagined and physical walking in older adults at low and high risks of falling. Motor imagery ability was assessed using mental chronometry, which measures the imagined time required for movement. Participants included 31 older adults classified as having a high (n = 15) or low (n = 16) risk of falling based on single leg stance time. The time required for imagined and physical walking was measured using 5 m long walkways with three different widths (15, 25, and 50 cm), and the temporal errors (absolute and constant error) were compared. Physical walking time was significantly longer in the high-risk group than in the low-risk group for the 15 and 25 cm wide walkways. The absolute error between the imagined and physical walking times was significantly larger in the high-risk group than in the low-risk group for the 15 and 25 cm wide walkways. There was also a significant difference in the constant error between the high- and low-risk groups between the imagined and physical walking times for all three walkways. Older adults who may be at a higher risk of falling showed longer walking times during action execution but overestimated their performance (i.e., they believe they would be faster) during motor imagery. Therefore, the time difference between imagined and physical walking could, in part, be useful as a tool for assessing fall risk based on motor imagery.

Do Older People Accurately Estimate the Length of Their First Step during Gait Initiation?

Background/Study Context: Advancing age is associated with a decrease in step length. In line with previous studies showing that older adults often overestimate their motor abilities, we investigate whether older adults overestimate the length of their first step during gait initiation. The underlying effect could be a failure to update the internal model of motor action as a function of age-related motor decline. Methods: Without taking a step, community-dwelling older women (n = 22, age range: 68-87 years) and younger women (n = 19, age range: 19-33 years) estimated the length of their first step for both preferred step length and largest step length, which were performed without endangerment. Thereafter, the participants performed real gait initiation for both types of steps. The estimated step lengths were compared to the actual step lengths. Results: Older adults judged their first step as larger than it was (mean error: 30% for the preferred step and 9% for the largest step). A fine-grained analysis showed that this effect mainly concerned those for whom an increased risk of falling was suspected. These older adults were also among those who performed the shortest steps, and they presented with a slight decrease in cognitive functioning. Younger participants underestimated their preferred step length. Overall, the estimates were more accurate for the largest steps than for the preferred-length steps. Conclusion: Step length estimation revealed powerful evidence for overestimation in older adults. Those who overestimated step length presented with more signs of motor decline. While this result sustains the idea of an insufficient actualization of the motor-action model, the explanation also refers to more global appraisal processes. Further research should explore the relevance of this task as a clinical laboratory tool for assessing gait capacity and the risk of falling.

Co-existence of social isolation and homebound status increase the risk of all-cause mortality

ABSTRACTBackground:Social isolation and homebound statuses are possible risk factors for increased mortality among older adults. However, no study has addressed the impact of accumulation of these two factors on mortality. The aim of this study was to examine whether such accumulation increased the risk of all-cause mortality.

METHODS

The analyzed sample was drawn from a mail survey of 1,023 older adults without instrumental activities of daily living disability. Participants were classified into four groups according to the frequency of both face-to-face and non-face-to-face interactions with others (social isolation and non-social isolation) and the frequency of going outdoors (homebound and non-homebound). Social isolation and homebound statuses were defined as having a social interaction less than once a week and going outdoors either every few days or less, respectively. All-cause mortality information during a six-year follow-up was obtained.

RESULTS

In total, 78 (7.6%) participants were both socially isolated and homebound. During the follow-up period, 65 participants died, with an overall mortality rate of 10.6 per 1000 person-years. Cox proportional hazards regression analyses demonstrated that older adults who were socially isolated and homebound showed a significantly higher risk of subsequent all-cause mortality compared with healthy adults who were neither socially isolated nor homebound, independent of potential covariates (aHR, 2.19; 95% CI: 1.04-4.63).

CONCLUSION

Our results suggest that the co-existence of social isolation and homebound statuses may synergistically increase risk of mortality. Both active and socially integrated lifestyle in later life might play a major role in maintaining a healthy status.

Poor Social Network, Not Living Alone, Is Associated With Incidence of Adverse Health Outcomes in Older Adults

OBJECTIVE

Although it has been suggested that living alone is a "social risk factor" for adverse health outcomes, poor social network may confound the association. This study aimed to examine whether the interactive effects of living alone and poor social network contribute to adverse health outcomes.

DESIGN

A 4-year prospective observational study.

SETTING AND PARTICIPANTS

Four hundred community-dwelling older adults living in Itabashi ward, an urban community in Tokyo. They participated in a health checkup (held in 2015 and 2017) and completed all the assessments.

METHODS

Participants were classified into 4 groups according to their living arrangements (living alone or not living alone) and social network size, which was assessed using an abbreviated version of the Lubben Social Network Scale-6. Poor social network was defined as the lowest quartile (4th quartile) of the Lubben Social Network Scale-6 score. Adverse health outcomes including disabilities, depressive symptoms, and physical and cognitive functions were measured.

RESULTS

Multiple and logistic regression models, adjusted for covariates such as financial status and educational level, showed that living alone and having a poor social network at baseline were significantly associated with increased depression symptoms, reduced grip strength, and disabilities of intellectual activity and social role at follow-up. Furthermore, older adults who did not live alone but had poor social networks showed significantly higher odds of subsequent homebound status and disability in activities of daily living.

CONCLUSIONS AND IMPLICATIONS

We found that living alone among older adults is not always a social risk factor for health, and adverse health outcomes among older adults living alone may be confounded by poor social network. Our results also suggest that the effect of poor social network on health status may exceed the effects of living alone. Health professionals must, thus, pay attention to poor social network among older adults.

Association between Hypometabolism in the Supplementary Motor Area and Fear of Falling in Older Adults

Background: A better understanding of the neural mechanisms that underlie the development of fear of falling (FoF) in seniors may help to detect potential treatable factors and reduce future falls. We therefore investigate the neural correlates of FoF in older adults using ¹⁸F-fluorodeoxyglucose-positron emission tomography (FDG-PET).

Methods: This cohort study included 117 community-dwelling older adults. At baseline, participants were assessed for FoF, psychiatric symptoms, walking speed, global cognition and cerebral glucose metabolism with FDG-PET. The incidence of FoF in the participants who did not report FoF (N-FoF) at baseline was again ascertained 2 years later. FDG uptake was compared between the FoF and non-FoF groups. Logistic regression analyses to examine the predictors of newly developed FoF (D-FoF) using normalized regional FDG uptake were then performed.

Results: At baseline, 50.4% (n = 59) of participants had FoF. The FoF group had significantly decreased glucose metabolism in the left superior frontal gyrus (supplementary motor area, SMA; BA6) compared to the non-FoF group. After 2 years, 19 out of the 58 participants in the non-FoF group developed FoF. Logistic regression analysis revealed that decreased cerebral glucose metabolism in the left SMA at the baseline was a significant predictor of the future development of FoF, independently of psychiatric symptoms and walking speed.

Conclusion: In healthy older adults, hypometabolism in the left SMA, which is involved in motor planning and motor coordination, contributes to the development of FoF. Our result might help elucidate underlying mechanism of the association between deficits in motor control and FoF.

Neural basis for the relationship between frequency of going outdoors and depressive mood in older adults

OBJECTIVE

Low frequency of going outdoors (e.g. being homebound) is associated with depressive mood; however, the underlying neural mechanism of this association is unclear. We therefore investigated the neural substrate involved in the relationship between frequency of going outdoors and depressive mood using positron emission tomography (PET), focusing on the frontal lobe and the limbic system.

METHODS

One hundred fifty-eight community-dwelling older adults aged 65-85 years underwent PET with ¹⁸ F-fluorodeoxyglucose to evaluate regional cerebral metabolic rates of glucose normalized in reference to cerebellar glucose metabolic value (normalized-rCMRglc) in six regions of interest. We also assessed depressive mood, frequency of going outdoors, and potential covariates. Depressive mood was assessed using the Geriatric Depression Scale (GDS).

RESULTS

The proportion of participants who reported low frequency of going outdoors (LG, every 2-3 days or less) was 36.1%. The LG group showed significantly higher GDS scores than those who reported high (once a day or more) frequency of going outdoors. A multiple linear regression analysis adjusted for potential covariates showed higher GDS scores were associated with lower normalized-rCMRglc in the ventrolateral prefrontal and orbitofrontal cortices. Adjusting for frequency of going outdoors, the association between GDS score and normalized-rCMRglc in the orbitofrontal cortex was attenuated.

CONCLUSIONS

Our results suggest that the orbitofrontal cortex may mediate the relationship between low frequency of going outdoors and depressive mood among community-dwelling older adults. These findings may help disentangle the role of going outdoors in regulating brain function to improve and/or maintain mental health among community-dwelling older adults. Copyright © 2016 John Wiley & Sons, Ltd.

Older Adults with Fear of Falling Show Deficits in Motor Imagery of Gait

OBJECTIVE

Understanding of the underlying mechanisms of Fear of Falling (FoF) could help to expand potential treatments. Given the nature of motor performance, the decline in the planning stage of motor execution may be associated with an expression of FoF. The aim of this study was to assess the planning/prediction accuracy in motor execution in people with FoF using gait-related motor imagery (MI).

DESIGN

Cross-sectional case/control study.

SETTING

Three health centers in Japan.

PARTICIPANTS

Two hundred and eighty-three community-dwelling older adults were recruited and stratified by presence of FoF as FoF group (n=178) or non-FoF group (n=107).

MEASUREMENTS

Participants were tested for both imagery and execution tasks of a Timed Up and Go (TUG) test. The participants were first asked to imagine the trial (iTUG) and estimate the time it would take, and then perform the actual trial (aTUG). The difference between iTUG and aTUG (Δ TUG) was calculated.

RESULTS

The FoF group was significantly slower in aTUG, but iTUG duration was almost identical between the two groups, resulting in significant overestimation in the FoF group. The adjusted logistic regression analysis showed that increased Δ TUG (i.e., tendency to overestimate) was significantly associated with FoF (OR = 1.05; 95% CI = 1.02-1.10). Low frequency of going outdoors was also associated with FoF (OR 2.95; 95% CI: 1.16-7.44).

CONCLUSIONS

Older adults with FoF overestimate their TUG performance, reflecting impairment in motor planning. Overestimation of physical capabilities can be an additional explanation of the high risk of falls in this population.

Neural correlates of older adults' self-overestimation of stepping-over ability

A growing body of literature indicates that cognitively intact older adults tend to overestimate their physical functioning (e.g., step-over ability), which may lead to fall risk. However, the neural correlates underlying this phenomenon are still unclear. We therefore investigated the neural basis of older adults' self-overestimation of stepping-over ability. A total of 108 well-functioning community dwelling older adults (mean age = 73.9 years) performed step-over tests (SOT) in two ways: self-estimation of step-over ability and an actual step-over task. During the self-estimation task, participants observed a horizontal bar at a distance of 7 m and estimated the maximum height (EH) of successful SOT trials. The actual SOT was then performed to determine the actual maximum height (AH) of successful trials. Participants also underwent positron emission tomography with ¹⁸F-fluorodeoxyglucose at rest to assess cerebral neural activity. The SOT showed that 22.2 % of participants overestimated their step-over ability. A regression analysis adjusted for potential covariates showed that increased self-estimation error (difference between EH and AH) was correlated with lower glucose metabolism in the bilateral orbitofrontal cortex (OFC) and left frontal pole. Only the significant correlation between self-estimation error and OFC activity persisted after correcting for multiple comparisons. For well-functioning healthy older adults, overlooking one's own functional decline may be influenced by reduced metabolic activity in the anterior prefrontal cortex, particularly in the OFC. Our findings also suggest that functional decline in the OFC prevents older adults from updating the qualitative/quantitative values of their impaired physical abilities.

Self-estimation of physical ability in stepping over an obstacle is not mediated by visual height perception: a comparison between young and older adults

Older adults tend to overestimate their step-over ability. However, it is unclear as to whether this is caused by inaccurate self-estimation of physical ability or inaccurate perception of height. We, therefore, measured both visual height perception ability and self-estimation of step-over ability among young and older adults. Forty-seven older and 16 young adults performed a height perception test (HPT) and a step-over test (SOT). Participants visually judged the height of vertical bars from distances of 7 and 1 m away in the HPT, then self-estimated and, subsequently, actually performed a step-over action in the SOT. The results showed no significant difference between young and older adults in visual height perception. In the SOT, young adults tended to underestimate their step-over ability, whereas older adults either overestimated their abilities or underestimated them to a lesser extent than did the young adults. Moreover, visual height perception was not correlated with the self-estimation of step-over ability in both young and older adults. These results suggest that the self-overestimation of step-over ability which appeared in some healthy older adults may not be caused by the nature of visual height perception, but by other factor(s), such as the likely age-related nature of self-estimation of physical ability, per se.

Can You Ride a Bicycle? The Ability to Ride a Bicycle Prevents Reduced Social Function in Older Adults With Mobility Limitation

Background

The health benefits of bicycling in older adults with mobility limitation (ML) are unclear. We investigated ML and functional capacity of older cyclists by evaluating their instrumental activities of daily living (IADL), intellectual activity, and social function.

Methods

On the basis of interviews, 614 community-dwelling older adults (after excluding 63 participants who never cycled) were classified as cyclists with ML, cyclists without ML, non-cyclists with ML (who ceased bicycling due to physical difficulties), or non-cyclists without ML (who ceased bicycling for other reasons). A cyclist was defined as a person who cycled at least a few times per month, and ML was defined as difficulty walking 1 km or climbing stairs without using a handrail. Functional capacity and physical ability were evaluated by standardized tests.

Results

Regular cycling was documented in 399 participants, and 74 of them (18.5%) had ML; among non-cyclists, 49 had ML, and 166 did not. Logistic regression analysis for evaluating the relationship between bicycling and functional capacity revealed that non-cyclists with ML were more likely to have reduced IADL and social function compared to cyclists with ML. However, logistic regression analysis also revealed that the risk of bicycle-related falls was significantly associated with ML among older cyclists.

Conclusions

The ability and opportunity to bicycle may prevent reduced IADL and social function in older adults with ML, although older adults with ML have a higher risk of falls during bicycling. It is important to develop a safe environment for bicycling for older adults.