Cognitive function is associated with the development of mobility impairments in community-dwelling elders

Age-related decrements in dual-task performance: Comparison of different mobility and cognitive tasks. A cross sectional study

This cross-sectional study investigated the age-related differences in dual-task performance both in mobility and cognitive tasks and the additive dual-task costs in a sample of older, middle-aged and young adults. 74 older adults (M = 72.63±5.57 years), 58 middle-aged adults (M = 46.69±4.68 years) and 63 young adults (M = 25.34±3.00 years) participated in the study. Participants performed different mobility and subtraction tasks under both single- and dual-task conditions. Linear regressions, repeated-measures and one-way analyses of covariance were used, The results showed: significant effects of the age on the dual and mobility tasks (p<0.05) and differences among the age-groups in the combined dual-task costs (p<0.05); significant decreases in mobility performance under dual-task conditions in all groups (p<0.05) and a decrease in cognitive performance in the older group (p<0.05). Dual-task activity affected mobility and cognitive performance, especially in older adults who showed a higher dual-task cost, suggesting that dual-tasks activities are affected by the age and consequently also mobility and cognitive tasks are negatively influenced.

Cognitive functioning is more closely related to real-life mobility than to laboratory-based mobility parameters

Increasing evidence indicates that mobility depends on cognitive resources, but the exact relationships between various cognitive functions and different mobility parameters still need to be investigated. This study examines the hypothesis that cognitive functioning is more closely related to real-life mobility performance than to mobility capacity as measured with standardized laboratory tests. The final sample used for analysis consisted of 66 older adults (72.3 ± 5.6 years). Cognition was assessed by measures of planning (HOTAP test), spatial working memory (Grid-Span test) and visuospatial attention (Attention Window test). Mobility capacity was assessed by an instrumented version of the Timed Up-and-Go test (iTUG). Mobility performance was assessed with smartphones which collected accelerometer and GPS data over one week to determine the spatial extent and temporal duration of real-life activities. Data analyses involved an exploratory factor analysis and correlation analyses. Mobility measures were reduced to four orthogonal factors: the factor 'real-life mobility' correlated significantly with most cognitive measures (between r = .229 and r = .396); factors representing 'sit-to-stand transition' and 'turn' correlated with fewer cognitive measures (between r = .271 and r = .315 and between r = .210 and r = .316, respectively), and the factor representing straight gait correlated with only one cognitive measure (r = .237). Among the cognitive functions tested, visuospatial attention was associated with most mobility measures, executive functions with fewer and spatial working memory with only one mobility measure. Capacity and real-life performance represent different aspects of mobility. Real-life mobility is more closely associated with cognition than mobility capacity, and in our data this association is most pronounced for visuospatial attention. The close link between real-life mobility and visuospatial attention should be considered by interventions targeting mobility in old age.

The Impact of Three Cognitive Training Interventions on Older Adults' Physical Functioning Across 5 Years

OBJECTIVE

Physical functioning is closely associated with cognition. The current study assessed the impact of three cognitive training programs on objective measures of physical functioning across 5 years.

METHOD

Older adults randomized to a processing speed ( n = 702), reasoning ( n = 694), or memory ( n = 703) training intervention were compared with those randomized to a no-contact control condition ( n = 698). Intention-to-treat (ITT) and treatment-received/dosage (time-varying number of training sessions) analyses were conducted.

RESULTS

There were no transfer effects in the ITT analyses. Treatment-received models demonstrated that training sessions (i.e., higher dosage) across all intervention arms transferred to better maintained Digit Symbol Copy and Turn 360 performance relative to the control group. More reasoning training transferred to better grip strength.

DISCUSSION

This is the first study to demonstrate differential longitudinal cognitive training transfer effects to three performance-based physical functioning measures. Future research should investigate mechanisms of far-transfer effects.

A systematic review and meta-analysis of cross-sectional studies examining the relationship between mobility and cognition in healthy older adults

Ageing is associated with declines in cognitive function and mobility. The extent to which this relationship encompasses the subdomains of cognition and mobility remains unclear, however. We searched MEDLINE and EMBASE databases for cross-sectional studies examining the association between objective mobility measures (gait, lower-extremity function, balance) and cognitive function (global, executive function, memory, processing speed) in healthy older adults. Of the 642 studies identified, 26 studies met the inclusion criteria, with a total of 26,355 participants. For each feature of physical mobility, the relation to each aspect of cognition was reviewed. In the context of each association, we summarised the results to date and performed random-effects meta-analyses of published data. Reviewed findings suggest that individuals with better mobility perform better on assessments of global cognition, executive function, memory and processing speed. Not all measures of mobility were equally associated with cognitive function, however. Although there was a larger number of gait and lower-extremity function studies, and this may have driven findings, most studies examining balance and cognition measures reported no significant results. Meta-analyses on reported associations supported results by revealing significant, albeit small, effect sizes in favour of a positive association between performance on mobility measures and cognitive assessments. Future research should aim to establish the mechanisms driving this relationship, as this may identify predictors of age-related impairments.

Cortisol Awakening Response and Walking Speed in Older People

In older people, less diurnal variability in cortisol levels has been consistently related to worse physical performance, especially to slower walking speed (WS). The cortisol awakening response (CAR) is a discrete component of the hypothalamic-pituitary-adrenal axis that has been related to several health problems, such as cardiovascular disease and/or worse performance on executive function and memory. The relationship between the CAR and physical performance in older people is poorly understood. In this study, in 86 older people (mean age = 64.42, SD = 3.93), we investigated the relationship between the CAR and WS, a commonly used measure of physical performance in the older population that has also been related to health problems, such as cardiovascular disease and executive function performance in older people. Additionally, we studied whether the relationship between the CAR and WS was independent from cortisol levels on awakening and several possible confounders. Results showed that a CAR of reduced magnitude (measured with 3 samples each day, for two consecutive days, and calculated as the area under the curve with respect to the increase), but not cortisol levels on awakening, was related to slower WS. In addition, this relationship was independent from cortisol levels on awakening. It is possible that a CAR of reduced magnitude would contribute to less diurnal cortisol variability, affecting physical performance. Additionally, it is possible that a CAR of reduced magnitude affects WS through a possible negative effect on executive function, or that the association between the CAR and WS is due to the fact that both are related to similar health problems and to changes in cognitive performance in older people.

Validity of the Timed Up and Go Test as a Measure of Functional Mobility in Persons With Multiple Sclerosis

OBJECTIVE

To examine the validity of the timed Up and Go (TUG) test as a measure of functional mobility in persons with multiple sclerosis (MS) by using a comprehensive framework based on construct validity (ie, convergent and divergent validity).

DESIGN

Cross-sectional study.

SETTING

Hospital setting.

PARTICIPANTS

Community-residing persons with MS (N=47).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Main outcome measures included the TUG test, timed 25-foot walk test, 6-minute walk test, Multiple Sclerosis Walking Scale-12, Late-Life Function and Disability Instrument, posturography evaluation, Activities-specific Balance Confidence scale, Symbol Digits Modalities Test, Expanded Disability Status Scale, and the number of steps taken per day.

RESULTS

The TUG test was strongly associated with other valid outcome measures of ambulatory mobility (Spearman rank correlation, rs=.71-.90) and disability status (rs=.80), moderately to strongly associated with balance confidence (rs=.66), and weakly associated with postural control (ie, balance) (rs=.31). The TUG test was moderately associated with cognitive processing speed (rs=.59), but not associated with other nonambulatory measures (ie, Late-Life Function and Disability Instrument-upper extremity function).

CONCLUSIONS

Our findings support the validity of the TUG test as a measure of functional mobility. This warrants its inclusion in patients' assessment alongside other valid measures of functional mobility in both clinical and research practice in persons with MS.

Mobility in Old Age: Capacity Is Not Performance

Background. Outcomes of laboratory-based tests for mobility are often used to infer about older adults' performance in real life; however, it is unclear whether such association exists. We hypothesized that mobility capacity, as measured in the laboratory, and mobility performance, as measured in real life, would be poorly linked. Methods. The sample consisted of 84 older adults (72.5 ± 5.9 years). Capacity was assessed via the iTUG and standard gait parameters (stride length, stride velocity, and cadence). Performance was assessed in real life over a period of 6.95 ± 1.99 days using smartphone technology to calculate following parameters: active and gait time, number of steps, life-space, mean action-range, and maximum action-range. Correlation analyses and stepwise multiple regression analyses were applied. Results. All laboratory measures demonstrated significant associations with the real-life measures (between r = .229 and r = .461). The multiple regression analyses indicated that the laboratory measures accounted for a significant but very low proportion of variance (between 5% and 21%) in real-life measures. Conclusion. In older adults without mobility impairments, capacity-related measures of mobility bear little significance for predicting real-life performance. Hence, other factors play a role in how older people manage their daily-life mobility. This should be considered for diagnosis and treatment of mobility deficits in older people.

Cognitive dysfunction and health-related quality of life among older Chinese

We aimed to assess the association of cognitive dysfunction with health-related quality of life (HRQOL) among older adults in China. We analyzed community-based cross-sectional data of 5,557 Chinese individuals aged 60 years and above in the Weitang Geriatric Diseases Study. Cognitive dysfunction and HRQOL were assessed using the Abbreviated Mental Test (AMT) and the European Quality of Life-5 dimensions (EQ-5D), respectively. We estimated the impacts of cognitive dysfunction on the EQ-5D index and visual analogue scale (VAS) scores using linear regression models, and the association between cognitive dysfunction and self-reported EQ-5D health problems using logistic regression models. The EQ-5D index and VAS scores were significantly lower for individuals with cognitive dysfunction than their counterparts. After controlling for covariates, the differences in EQ-5D index and VAS scores between individuals with and without cognitive dysfunction were −0.016 (95% confidence interval [CI]: −0.024, −0.008), and −3.4 (95% CI: −4.5, −2.4), respectively. Cognitive dysfunction was associated with reporting of problems in pain/discomfort (odds ration [OR]: 1.37; 95% CI: 1.12, 1.69), and anxiety/depression (OR: 2.13; 95% CI: 1.41, 3.23). The negative impact on HRQOL increased with the severity of cognitive dysfunction. The results indicate cognitive dysfunction was associated with worse HRQOL in older adults.

Self-Reported Hearing Status Is Associated with Lower Limb Physical Performance, Perceived Mobility, and Activities of Daily Living in Older Community-Dwelling Men and Women

OBJECTIVES

To explore the associations between self-reported hearing problems and physical performance and self-reported difficulties in mobility and activities of daily living (ADLs) in community-dwelling older adults.

DESIGN

Cross-sectional cohort study.

SETTING

Community.

PARTICIPANTS

Men and women aged 75 to 90 (N = 848).

MEASUREMENTS

Structured face-to-face interviews to assess perceived hearing problems in the presence of noise, mobility difficulties (moving indoors, stair-climbing, 0.5-km walk, 2-km walk), and difficulties in ADLs and instrumental ADLs. The Short Physical Performance Battery (SPPB) was administered. Age; years of education; cognitive functioning; and self-reported cardiac, circulatory, and locomotor diseases were used as covariates.

RESULTS

Persons who reported major hearing problems had a lower SPPB total score than those who reported good hearing (mean 9.8 vs 10.9, P = .009), indicating poorer performance, and more difficulties in ADLs (mean 1.8 vs 1.4, P = .002) and IADLs (mean 4.6 vs 3.4, P = .002), after controlling for covariates. They were also more likely to have more difficulty in stair-climbing (odds ratio (OR) = 2.8, P < .001) and walking 2 km (OR = 2.1, P = .003) and tended to have more difficulty in walking 0.5 km (OR = 1.7, P = .05) but not moving indoors (P = .18). Persons who reported only some hearing problems did not differ from those who reported good hearing in any of the variables studied.

CONCLUSION

Perceived major hearing problems in older adults may contribute to poorer lower limb performance and difficulties in mobility and ADLs. Longitudinal studies are needed to determine whether poor hearing is a risk factor for decline in physical performance.

An Examination of Lower Extremity Function and its Correlates in Older African American and White Men

OBJECTIVE

Maintaining functional status and reducing/eliminating health disparities in late life are key priorities. Older African Americans have been found to have worse lower extremity functioning than Whites, but little is known about potential differences in correlates between African American and White men. The goal of this investigation was to examine measures that could explain this racial difference and to identify race-specific correlates of lower extremity function.

METHODS

Data were analyzed for a sample of community-dwelling men. Linear regression models examined demographics, medical conditions, health behaviors, and perceived discrimination and mental health as correlates of an objective measure of lower extremity function, the Short Physical Performance Battery (SPPB). Scores on the SPPB have a potential range of 0 to 12 with higher scores corresponding to better functioning.

RESULTS

The mean age of all men was 74.9 years (SD=6.5), and the sample was 50% African American and 53% rural. African American men had scores on the SPPB that were significantly lower than White men after adjusting for age, rural residence, marital status, education, and income difficulty (P<.01). Racial differences in cognitive functioning accounted for approximately 41% of the race effect on physical function. Additional models stratified by race revealed a pattern of similar correlates of the SPPB among African American and White men.

CONCLUSIONS

The results of this investigation can be helpful for researchers and clinicians to aid in identifying older men who are at-risk for poor lower extremity function and in planning targeted interventions to help reduce disparities.

Longitudinal Relationships Between Cognitive Decline and Gait Slowing: The Tasmanian Study of Cognition and Gait

BACKGROUND

Gait slowing and cognitive decline are both common in older people. Although cross-sectionally related, the longitudinal associations between specific cognitive functions and gait speed are less well understood. We aimed to determine whether decline in specific cognitive domains are associated with change in gait speed.

METHODS

Participants aged 60-85, randomly selected from the electoral roll, were assessed twice over 3 years. Gait speed was obtained using the GAITRite walkway. Raw scores from a cognitive battery were subjected to principal component analyses deriving summary domains of executive function, processing speed, memory, and visuospatial ability. Multivariable linear regression was used to examine the associations between change in each cognitive domain and change in gait speed, adjusting for covariates and stratifying for the presence of baseline cognitive impairment.

RESULTS

Mean age at baseline was 71.1 years (SD = 6.7) and 56% (159/284) were men. Mean follow-up was 2.55 (0.47) years. Decline in executive function, but not other cognitive domains (p > .05), was associated with decline in gait speed, cm/s (β = -3.55, 95% CI = -5.49, -1.61; p < .001), both in the presence and absence of baseline cognitive impairment. Stronger associations were seen for those with baseline multiple domain cognitive impairment (β = -6.38, 95% CI = -12.49, -0.27) and nonamnestic single-domain cognitive impairment (β = -7.74, 95% CI = -14.76, -0.72).

CONCLUSION

Decline in nonamnestic function (specifically executive function) was associated with decline in gait speed irrespective of the presence of baseline cognitive impairment. Strategies to improve or maintain executive function may prevent gait slowing.

Reliability and validity of the German translation of the de Morton Mobility Index (DEMMI) performed by physiotherapists in patients admitted to a sub-acute inpatient geriatric rehabilitation hospital

BACKGROUND

Mobility is a key outcome in geriatric rehabilitation. The de Morton Mobility Index (DEMMI) is an internationally well-established, unidimensional measure of mobility with good psychometric properties. The aim of this study was to examine the reliability and construct validity of the German translation of the DEMMI in geriatric inpatients.

METHODS

This cross-sectional study included patients admitted to a sub-acute inpatient geriatric rehabilitation hospital (reliability sample: N = 33; validity sample: N = 107). Reliability, validity, and unidimensionality were investigated.

RESULTS

Inter-rater reliability between two graduate physiotherapists was excellent, with intra-class correlation coefficient of 0.94 (95% confidence interval: 0.88-0.97). The minimal detectable change with 90% confidence was 9 points. Construct validity for the DEMMI was evidenced by significant moderate to strong correlations with other measures of mobility and related constructs (Performance Oriented Mobility Assessment: rho = 0.89; Functional Ambulation Categories: rho = 0.70; six-minute walk test: rho = 0.73; gait speed: rho = 0.67; Falls Efficacy Scale International: rho = -0.68). Known-groups validity was indicated by significant DEMMI mean group differences between independent versus dependent walkers and walking aid users versus non-users. Unidimensionality of the German DEMMI translation was confirmed by Rasch analysis.

CONCLUSIONS

The German translation of the DEMMI is a unidimensional instrument producing valid and reproducible measurement of mobility in an inpatient geriatric rehabilitation setting.

Dietary patterns and cognitive decline in Taiwanese aged 65 years and older

OBJECTIVE

This study examines the association between dietary patterns and cognitive decline in Taiwanese aged 65 years and older.

METHODS

Data were from a population-based longitudinal study, the Taiwan Longitudinal Study of Aging, with a nationally representative sample.

RESULTS

Nearly 2%, 8%, and 3% of participants had a western, traditional, and healthy dietary pattern, respectively. Western and traditional dietary patterns were negatively associated with subsequent short portable mental state questionnaire score over 4 and/or 8 years (all p < 0.05), whereas a healthy dietary pattern was not. Western dietary patterns significantly increased, by nearly threefold, the risk of subsequent cognitive decline over 8 years (adjusted odds ratio = 4.35, 95% confidence interval = 1.52-12.50, p < 0.05). For elders aged 65-74 years, a western dietary pattern was positively associated with increased, by eightfold, risk of cognitive decline over 8 years (adjusted odds ratio = 9.35, 95% confidence interval = 2.38-36.67, p < 0.05), whereas traditional and healthy dietary patterns were not. For elders aged ≥ 75 years, none of western, traditional, or healthy dietary patterns were associated with cognitive decline over 4 and 8 years.

CONCLUSIONS

Dietary patterns correlate with cognitive function in Taiwanese aged 65 years and older and can predict the occurrence of subsequent cognitive decline. Western dietary pattern increases the risk of cognitive decline over 8 years. This study suggests that a diet that involves frequent consumption of meat/poultry and eggs and infrequent consumption of fish, beans/legumes, and vegetables and fruits may adversely affect cognitive function in older Taiwanese.

Exercise, sedentary pastimes, and cognitive performance in healthy older adults

BACKGROUND

Moderately vigorous physical activity (MVPA) provides a protective affect against cognitive decline and cardiovascular risk factors. Less is known about sedentary pastimes or non exercise physical activity (NEPA) and cognitive performance.

METHOD

125 healthy adults 65 or older with no clinical evidence of cognitive impairment were enrolled. The CogState computerized neurocognitive battery was administered. Leisure activities were measured using the Community Health Activity Program for Seniors (CHAMPS).

RESULTS

Sedentary pastimes were associated with executive dysfunction (P = 0.01); MVPA with high memory scores (P = 0.05) and NEPA with improved working memory (P = 0.05). Only sedentary pastimes and executive dysfunction retained significance after correction for multiple comparisons. Smoking and alcohol confounded the association of memory with sedentary pastimes and MVPA.

CONCLUSIONS

Study highlights: negative impact of sedentary pastimes on executive function, need for additional investigation of sedentary behavior, NEPA, the impact of addictions upon activity in late life.

Effect of rivastigmine on mobility of patients with higher-level gait disorder: a pilot exploratory study

Background

Higher-level gait disorder (HLGD) in older adults is characterized by postural instability, stepping dysrhythmicity, recurrent falls and progressive immobility. Cognitive impairments are frequently associated with HLGD.

Objectives

The aim of this study was to compare gait and cognitive performance before and after the use of rivastigmine in patients with HLGD, free from cognitive impairment or Parkinsonism.

Methods

Fifteen non-demented patients with HLGD (age 79.2 ± 5.9 years; 11 women; Mini-Mental State Examination [MMSE] 28.3 ± 1.4) received escalating doses of rivastigmine for 12 weeks in an open-label, pilot study. They were assessed before and after treatment (week 0 and week 12), and after a 4-week washout period (week 16). Assessments included the Mindstreams computerized neuropsychological battery, Activities-specific Balance Confidence Scale, State-Trait Anxiety Inventory, Geriatric Depression Scale, Timed Up and Go (TUG) test, gait speed and stride time variability. One-way multiple analysis of variance tests for repeated measures were used, and Pillai’s trace test was considered as robust to investigate significant differences.

Results

The mean dose of rivastigmine during the 8–12 week period was 5.1 ± 2.3 mg/day. A positive effect was observed on the Mindstreams memory subscale and anxiety scores [Pillai’s trace: F(6,724) = 0.508, p = 0.010; and F(7,792) = 0.545, p = 0.006, respectively, over the course of the study] as well as on mobility (TUG test) [Pillai’s trace: F(4,863) = 0.448; p = 0.028], whereas gait speed and stride time variability did not change.

Conclusions

The use of relatively low-dose rivastigmine did not affect gait speed and stride time variability; however, the general mobility and anxiety were improved. These preliminary results warrant a larger, randomized, placebo-controlled study.

Quality of life across three groups of older adults differing in cognitive status and place of residence

BACKGROUND

Health-related quality of life (HRQOL) in older adults is determined by personal conditions, as well as by the social and physical environment. The purpose of the present study was to describe the factors related to health conditions and residential environment that influence HRQOL of older adults.

METHODS

Data from 1815 cases came from three cross-sectional surveys on quality of life in older adults in Spain: non-institutionalized older adults (n = 1106), institutionalized older adults without dementia (n = 234) and institutionalized older adults with dementia (n = 475). Assessment instruments used were: Barthel Index, Short Portable Mental Status Questionnaire, Comorbidity Index, EQ-5D-3L (5 dimensions, EQ-index and EQ-VAS), and information about sociodemographic characteristics and social networks. Partial correlation and multivariate logistic regression analyses were carried out.

RESULTS

In group comparisons, institutionalized older adults showed a higher percentage of problems in the EQ-5D-3L dimensions than the non-institutionalized ones. Also, older adults with dementia presented less pain/discomfort and anxiety/depression than the other groups, but showed more problems in mobility, self-care and usual activities. EQ-Index showed a high association with functional independence, perceived health status and comorbidity. According to the logistic regression models, the Barthel Index was the most common determinant for most of EQ-5D-3L dimensions in all groups.

CONCLUSION

Institutionalized older adults with dementia presented lower HRQOL than the other groups. Functional independence, comorbidity and cognitive status were the main HRQOL determinants in all groups. Maintenance and improvement of the functional condition might be translated into a higher HRQOL of older adults.

Executive functions of sedentary elderly may benefit from walking: a systematic review and meta-analysis

OBJECTIVE

The goal of the present meta-analysis was to address studies that examined the relationship between walking as one of the most prevalent types of leisure-time activity and executive function being a higher-order cognitive function essential for independent functioning.

METHODS

The following data sources were used: English-language publications in PubMed, EMBASE, PsycINFO, Cinahl, and Cochrane; the last search took place in January 2012. From these data sources, only randomized controlled trials including older people with (N = 3) and without (N = 5) cognitive impairment were selected.

RESULTS

Walking has been shown to improve set-shifting and inhibition in sedentary older persons without cognitive impairment (d = 0.36; 95% confidence interval: 0.16-0.55; z = 3.56; p <0.0001). In older persons with cognitive impairment, walking did not show improvements in executive functioning (d = 0.14; 95% confidence interval: -0.36-0.64; z = 0.35; p = 0.56).

CONCLUSION

This finding is clinically relevant because participation in a walking program may prevent or postpone a (further) decline in executive function in those who are sedentary.

What physical attributes underlie self-reported vs. observed ability to walk 400 m in later life? An analysis from the InCHIANTI Study

OBJECTIVE

The aims of this study were to evaluate and contrast the physical attributes that are associated with self-reported vs. observed ability to walk 400 m among older adults.

DESIGN

Analysis of baseline and 3-yr data from 1026 participants 65 yrs or older in the InCHIANTI (Invecchiare in Chianti) study was conducted. Observed and self-reported ability to walk 400 m at baseline and at 3 yrs were primary outcomes. Predictors included leg speed, leg strength, leg strength symmetry, range of motion, balance, and kyphosis.

RESULTS

Balance, leg speed, leg strength, kyphosis, leg strength symmetry, and knee range of motion were associated with self-reported ability to walk 400 m at baseline (P < 0.001, c = 0.85). Balance, leg speed, and knee range of motion were associated with observed 400-m walk (P < 0.001, c = 0.85) at baseline. Prospectively, baseline leg speed and leg strength were predictive of both self-reported (P < 0.001, c = 0.79) and observed (P < 0.001, c = 0.72) ability to walk 400 m at 3 yrs.

CONCLUSIONS

The profiles of attributes that are associated with self-reported vs. observed walking ability differ. The factor most consistently associated with current and future walking ability is leg speed. These results draw attention to important foci for rehabilitation.

Cognitive contributions to gait and falls: evidence and implications

Dementia and gait impairments often coexist in older adults and patients with neurodegenerative disease. Both conditions represent independent risk factors for falls. The relationship between cognitive function and gait has recently received increasing attention. Gait is no longer considered merely automated motor activity but rather an activity that requires executive function and attention as well as judgment of external and internal cues. In this review, we intend to: (1) summarize and synthesize the experimental, neuropsychological, and neuroimaging evidence that supports the role played by cognition in the control of gait; and (2) briefly discuss the implications deriving from the interplay between cognition and gait. In recent years, the dual task paradigm has been widely used as an experimental method to explore the interplay between gait and cognition. Several neuropsychological investigations have also demonstrated that walking relies on the use of several cognitive domains, including executive-attentional function, visuospatial abilities, and even memory resources. A number of morphological and functional neuroimaging studies have offered additional evidence supporting the relationship between gait and cognitive resources. Based on the findings from 3 lines of studies, it appears that a growing body of evidence indicates a pivotal role of cognition in gait control and fall prevention. The interplay between higher-order neural function and gait has a number of clinical implications, ranging from integrated assessment tools to possible innovative lines of interventions, including cognitive therapy for falls prevention on one hand and walking program for reducing dementia risk on the other.

Association between performance on Timed Up and Go subtasks and mild cognitive impairment: further insights into the links between cognitive and motor function

OBJECTIVES

To assess whether different Timed Up and Go (TUG) subtasks are affected differently in older adults with mild cognitive impairment (MCI) and are specific to different cognitive abilities.

DESIGN

Cross-sectional.

SETTING

Community and home.

PARTICIPANTS

Older adults without dementia (N = 347; mean age 83.6 ± 3.5, 75% female, 19.3% with MCI) participating in the Rush Memory and Aging Project.

MEASUREMENTS

Subjects wore a small, light-weight sensor that measured acceleration and angular velocity while they performed the instrumented TUG (iTUG). Measures of iTUG were derived from four subtasks (walking, turning, sit-to-stand, stand-to-sit) and compared between participants with MCI and those with no cognitive impairment.

RESULTS

Participants with no cognitive impairment and those with MCI did not differ in age (P = .90), sex (P = .80), years of education (P = .48) or time to complete the TUG (no cognitive impairment 7.6 ± 3.7 seconds; MCI 8.4 ± 3.7 seconds; P = .12). Participants with MCI had less walking consistency (P = .009), smaller pitch range during transitions (P = .005), lower angular velocity during turning (P = .04) and required more time to complete the turn-to-walk (P = .04). Gait consistency was correlated with perceptual speed (P = .01), and turning was correlated with perceptual speed (P = .02) and visual-spatial abilities (P = .049).

CONCLUSION

Mild cognitive impairment is associated with impaired performance on iTUG subtasks that cannot be identified when simply measuring overall duration of performance. Distinctive iTUG tasks were related to particular cognitive domains, demonstrating the specificity of motor-cognitive interactions. Using a single sensor worn on the body for quantification of mobility may facilitate understanding of late-life gait impairments and their interrelationship with cognitive decline.

Intraindividual variability in executive functions but not speed of processing or conflict resolution predicts performance differences in gait speed in older adults

BACKGROUND

The relationship between executive functions (EF) and gait speed is well established. However, with the exception of dual tasking, the key components of EF that predict differences in gait performance have not been determined. Therefore, the current study was designed to determine whether processing speed, conflict resolution, and intraindividual variability in EF predicted variance in gait performance in single- and dual-task conditions.

METHODS

Participants were 234 nondemented older adults (mean age 76.48 years; 55% women) enrolled in a community-based cohort study. Gait speed was assessed using an instrumented walkway during single- and dual-task conditions. The flanker task was used to assess EF.

RESULTS

Results from the linear mixed effects model showed that (a) dual-task interference caused a significant dual-task cost in gait speed (estimate = 35.99; 95% CI = 33.19-38.80) and (b) of the cognitive predictors, only intraindividual variability was associated with gait speed (estimate = -.606; 95% CI = -1.11 to -.10). In unadjusted analyses, the three EF measures were related to gait speed in single- and dual-task conditions. However, in fully adjusted linear regression analysis, only intraindividual variability predicted performance differences in gait speed during dual tasking (B = -.901; 95% CI = -1.557 to -.245).

CONCLUSION

Among the three EF measures assessed, intraindividual variability but not speed of processing or conflict resolution predicted performance differences in gait speed.

Cognitive aging and rate of hospitalization in an urban population of older people

BACKGROUND

The association of age-related cognitive change with hospitalization is not well understood.

METHODS

At 3-year intervals for a mean of 8.7 years, 2,273 older residents of a geographically defined urban community underwent cognitive testing from which a global measure was derived. Hospitalization data were obtained from Part A Medicare beneficiary records. The association of level of cognitive function and rate of cognitive decline in each 3-year interval with subsequent rate of hospitalization was assessed using mixed-effects count regression models.

RESULTS

There were 9,091 hospitalizations involving 1,810 of the 2,273 individuals in the cohort (79.6%). Rate of hospitalization increased by 9.7% (95% confidence interval [CI]: 7.2, 12.3) with each additional study year; by 32.7% (95% CI: 26.8, 38.0) for each 1 point lower on the global cognitive measure at the beginning of an observation interval; and by 24.3% (95% CI: 16.6, 32.6) for each 1-point decrease in the global cognitive measure during the previous observation period. These associations persisted after adjustment for comorbidities and exclusion of those with a Mini-Mental State Examination score less than 26.

CONCLUSION

Individual differences in trajectories of cognitive aging are associated with subsequent risk of hospitalization.

Applications of technology in neuropsychological assessment

Most neuropsychological assessments include at least one measure that is administered, scored, or interpreted by computers or other technologies. Despite supportive findings for these technology-based assessments, there is resistance in the field of neuropsychology to adopt additional measures that incorporate technology components. This literature review addresses the research findings of technology-based neuropsychological assessments, including computer- and virtual reality-based measures of cognitive and functional abilities. We evaluate the strengths and limitations of each approach, and examine the utility of technology-based assessments to obtain supplemental cognitive and behavioral information that may be otherwise undetected by traditional paper-and-pencil measures. We argue that the potential of technology use in neuropsychological assessment has not yet been realized, and continued adoption of new technologies could result in more comprehensive assessment of cognitive dysfunction and in turn, better informed diagnosis and treatments. Recommendations for future research are also provided.

The interacting effect of cognitive and motor task demands on performance of gait, balance and cognition in young adults

Mobility limitations and cognitive impairments, each common with aging, reduce levels of physical and mental activity, are prognostic of future adverse health events, and are associated with an increased fall risk. The purpose of this study was to examine whether divided attention during walking at a constant speed would decrease locomotor rhythm, stability, and cognitive performance. Young healthy participants (n=20) performed a visuo-spatial cognitive task in sitting and while treadmill walking at 2 speeds (0.7 and 1.0 m/s).Treadmill speed had a significant effect on temporal gait variables and ML-COP excursion. Cognitive load did not have a significant effect on average temporal gait variables or COP excursion, but variation of gait variables increased during dual-task walking. ML and AP trunk motion was found to decrease during dual-task walking. There was a significant decrease in cognitive performance (success rate, response time and movement time) while walking, but no effect due to treadmill speed. In conclusion walking speed is an important variable to be controlled in studies that are designed to examine effects of concurrent cognitive tasks on locomotor rhythm, pacing and stability. Divided attention during walking at a constant speed did result in decreased performance of a visuo-spatial cognitive task and an increased variability in locomotor rhythm.

Predictors of older adults' personal and community mobility: using a comprehensive theoretical mobility framework

PURPOSE OF THE STUDY

Forty-six percent of older adults report limitations in their mobility, and maintaining mobility is considered an important factor in keeping adults independent and active in later life. This study tests a comprehensive theoretical framework of mobility (Webber, S. C., Porter, M. M., & Menec, V. H. [2010]. Mobility in older adults: A comprehensive framework. The Gerontologist, 50[4], 443-450. doi:10.1093/geront/gnq013) identifying multiple determinants that additively influence mobility (financial, psychosocial, environmental, physical, and cognitive), as well as cross-cutting influences of gender, culture, and biography.

DESIGN AND METHODS

Structural equation modeling was used to examine several models of mobility using data from 6,112 respondents in the Health and Retirement Study (mean age: 74.74, 85% white, 41% male, 57% married).

RESULTS

The original measurement model fit the data well. When both personal and community mobility were simultaneously predicted, only the physical, cognitive, psychosocial, and environmental determinants were retained in the independent models. Age and marital status also predicted personal and community mobility. Although most of these relationships were in the expected direction, interestingly when both forms of mobility were included in the model, poorer cognitive ability was associated with greater personal mobility in the final model.

IMPLICATIONS

Results indicate the importance of accounting for and examining comprehensive models of mobility. The factors affecting older adults' mobility are complex, and these relationships need to be explored in more depth to ensure the maintenance of individuals' independence and quality of life.

The dynamic relationship between physical function and cognition in longitudinal aging cohorts

On average, older people remember less and walk more slowly than do younger persons. Some researchers argue that this is due in part to a common biologic process underlying age-related declines in both physical and cognitive functioning. Only recently have longitudinal data become available for analyzing this claim. We conducted a systematic review of English-language research published between 2000 and 2011 to evaluate the relations between rates of change in physical and cognitive functioning in older cohorts. Physical functioning was assessed using objective measures: walking speed, grip strength, chair rise time, flamingo stand time, and summary measures of physical functioning. Cognition was measured using mental state examinations, fluid cognition, and diagnosis of impairment. Results depended on measurement type: Change in grip strength was more strongly correlated with mental state, while change in walking speed was more strongly correlated with change in fluid cognition. Examining physical and cognitive functioning can help clinicians and researchers to better identify individuals and groups that are aging differently and at different rates. In future research, investigators should consider the importance of identifying different patterns and rates of decline, examine relations between more diverse types of measures, and analyze the order in which age-related declines occur.

Midlife physical activity preserves lower extremity function in older adults: age gene/environment susceptibility-Reykjavik study

OBJECTIVES

To examine the long-term association between midlife physical activity (PA) and lower extremity function (LEF) in late life.

DESIGN

Longitudinal study with an average of 25 years of follow-up.

SETTING

Community-dwelling old population in Reykjavik, Iceland.

PARTICIPANTS

Four thousand seven hundred fifty-three community-dwelling men and women (mean age 76 ± 6) in Reykjavik, Iceland.

MEASUREMENTS

On the basis of weekly hours of regular PA reported at the midlife examination, participants were classified as active or inactive. Measures of LEF in late life were gait speed on a 6-m walk, Timed Up and Go (TUG), and knee extension (KE) strength tests. Linear regression analysis was used to examine the association.

RESULTS

Participants who were active in midlife had significantly better LEF (faster gait speed, β = 0.50, P ≤ .001; faster TUG time, β = -0.53 P ≤ .001; stronger KE strength, β = 1.3, P ≤ .001) in late life than those who were not active in midlife after adjusting for sociodemographic and cardiovascular risk factors. After adjustment for cognitive function in late life (speed of processing, memory, and executive function), participants who were active in midlife had significantly faster gait speed (β = 0.04, P ≤ .001), faster TUG time (β = -0.34, P ≤ .001), and greater KE strength (β = 0.87, P ≤ .001) in old age than those who were not active in midlife.

CONCLUSION

Regular PA in midlife is associated with better performance of LEF in later life, even after controlling for late-life cognitive function.

Overview and findings from the rush Memory and Aging Project

The Memory and Aging Project is a longitudinal, epidemiologic clinical-pathologic cohort study of common chronic conditions of aging with an emphasis on decline in cognitive and motor function and risk of Alzheimer's disease (AD). In this manuscript, we first summarize the study design and methods. Then, we present data on: (1) the relation of motor function to cognition, disability, and death; (2) the relation of risk factors to cognitive and motor outcomes, disability and death; (3) the relation of neuropathologic indices to cognitive outcomes; (4) the relation of risk factors to neuropathologic indices; and (5) additional study findings. The findings are discussed and contextualized.

The right to move: a multidisciplinary lifespan conceptual framework

This paper addresses the health problems and opportunities that society will face in 2030. We propose a proactive model to combat the trend towards declining levels of physical activity and increasing obesity. The model emphasizes the need to increase physical activity among individuals of all ages. We focus on the right to move and the benefits of physical activity. The paper introduces a seven-level model that includes cells, creature (individual), clan (family), community, corporation, country, and culture. At each level the model delineates how increased or decreased physical activity influences health and well-being across the life span. It emphasizes the importance of combining multiple disciplines and corporate partners to produce a multifaceted cost-effective program that increases physical activity at all levels. The goal of this paper is to recognize exercise as a powerful, low-cost solution with positive benefits to cognitive, emotional, and physical health. Further, the model proposes that people of all ages should incorporate the "right to move" into their life style, thereby maximizing the potential to maintain health and well-being in a cost-effective, optimally influential manner.

Differences of the frontal activation patterns by finger and toe movements: a functional MRI study

It is well-known that physical exercise can affect cognition and the frontal lobe is an important structure involved in motor function and cognition. Furthermore, many functional neuroimaging studies have demonstrated that cortical activation patterns of hand and leg movements differ. However, no study has been undertaken to identify differences between the frontal activation patterns generated by hand and leg movements. In the present study, the frontal activation patterns associated with finger and toe movements, as visualized by functional MRI, were investigated and compared. Twelve healthy volunteers were recruited. Functional MRI was performed using a 1.5 T Philips Gyroscan Intera. Flexion-extension movements of fingers or toes were performed in one extremity. Regions of interest (ROIs) were set at the primary sensory-motor cortex (SM1: Brodmann area [BA] 1, 2, 3, 4), the premotor area (PMA: BA 6), and the prefrontal cortex (PFC: BA 8, 9, 10, 11, 46). In SM1, finger movements (10,809) induced more activation than toe movements (5349). On the other hand, in the PMA and PFC, toe movements (PMA: 4201, PFC: 921) induced more activation than finger movements (PMA: 2887, PFC: 912) respectively. In the analysis of relative voxel counts in the PMA and PFC versus the SM1, toe movements generated more activation in the PMA and PFC than finger movements. The PMA and PFC were more activated by toe than finger movements, although the SM1 was more activated by finger movements.

The protective effects of executive functions and episodic memory on gait speed decline in aging defined in the context of cognitive reserve

OBJECTIVES

To evaluate whether levels of cognitive reserve (CR), as measured using the Wechsler Adult Intelligence Scale (WAIS)-III vocabulary test, moderated longitudinal associations between cognitive functions and decline in gait speed in a community-based cohort of older adults without dementia, specifically, whether the protective effect of executive function (EF) and episodic memory against decline in gait speed would be greater in individuals with higher CR.

DESIGN

Longitudinal (median number of repeated annual gait speed measures, 3; maximum number of visits, 7).

SETTING

General community.

PARTICIPANTS

Seven hundred thirty-one community-residing individuals aged 70 and older without dementia were followed longitudinally with cognitive and gait evaluations at baseline and at annual visits.

MEASUREMENTS

Decline in gait speed (cm/s) served as the primary outcome. The Free and Cued Selective Reminding Test (FCSRT) was used to assess episodic memory. The Digit Symbol Substitution Test (DSST) was used to assess attention and EF. The vocabulary test served as a marker for CR.

RESULTS

Linear mixed effects model showed that gait speed declined over the follow-up period (P < .001). The significant three-way interactions of time by DSST by vocabulary (P = .01) and time by FCSRT by vocabulary (P = .02) revealed that levels of CR moderated the longitudinal associations between EF and episodic memory and gait speed decline.

CONCLUSION

The protective effects of EF and episodic memory against gait speed decline in aging are greater in individuals with higher CR.

The Minority Aging Research Study: ongoing efforts to obtain brain donation in African Americans without dementia

The Minority Aging Research Study (MARS) is a longitudinal, epidemiologic cohort study of decline in cognitive function and risk of Alzheimer's disease (AD) in older African Americans, with brain donation after death added as an optional component for those willing to consider organ donation. In this manuscript, we first summarize the study design and methods of MARS. We then provide details of ongoing efforts to achieve neuropathologic data on over 100 African Americans participating in MARS and in three other clinical-pathologic cohort studies at Rush University Medical Center. The results examine strategies for recruiting and consenting African Americans without dementia; (2) efforts to maintain high rates of follow-up participation; (3) strategies for achieving high rates of agreement to brain donation; and (4) the methodology of obtaining rapid brain autopsy at death. The implications of these efforts are discussed.

Depressive symptoms and gait dysfunction in the elderly

OBJECTIVE

Assess the association between depressive symptoms (not meeting the criteria for major depression) and gait dysfunction in older adults.

DESIGN

Cross-sectional study.

SETTING

Einstein Aging Study, a community-based longitudinal aging study.

PARTICIPANTS

Six hundred ten nondemented and nondepressed community-residing adults age 70 and older.

MEASUREMENTS

Depressive symptoms measured using the 15-item Geriatric Depression Scale. To obtain a comprehensive assessment of gait, eight individual quantitative gait parameters were assessed: velocity (cm/s), stride length (cm), cadence (steps/min), swing phase (seconds), stance phase (seconds), double support phase (seconds), stride length variability (SD of stride length), and swing time variability (SD of swing time). Multiple linear regression analysis was applied to study the association of depressive symptoms with gait, adjusting for potential confounders including demographic variables, medical illnesses, and clinical gait abnormalities.

RESULTS

Increased level of depressive symptoms was associated with worse velocity, stride, and swing time variability. The relationship of the remaining five gait variables with depressive symptoms was not significant in the fully adjusted models.

CONCLUSIONS

Higher levels of depressive symptoms are associated with worse performance in specific quantitative gait variables in community-residing older adults.

Integration of immunity with physical and cognitive function in definitions of successful aging

Studies comparing chronologically "young" versus "old" humans document age-related decline of classical immunological functions. However, older adults aged ≥65 years have very heterogeneous health phenotypes. A significant number of them are functionally independent and are surviving well into their 8(th)-11(th) decade life, observations indicating that aging or old age is not synonymous with immune incompetence. While there are dramatic age-related changes in the immune system, not all of these changes may be considered detrimental. Here, we review evidences for novel immunologic processes that become elaborated with advancing age that complement preserved classical immune functions and promote immune homeostasis later in life. We propose that elaboration such of late life immunologic properties is indicative of beneficial immune remodeling that is an integral component of successful aging, an emerging physiologic construct associated with similar age-related physiologic adaptations underlying maintenance of physical and cognitive function. We suggest that a systems approach integrating immune, physical, and cognitive functions, rather than a strict immunodeficiency-minded approach, will be key towards innovations in clinical interventions to better promote protective immunity and functional independence among the elderly.

Loss of motor function in preclinical Alzheimer's disease

Accumulating evidence suggests that Alzheimer's disease (AD) has a long preclinical phase, during which time its characteristic pathology accumulates and patient function declines, but symptoms are insufficient to warrant a clinical diagnosis of dementia. There have been increasing reports of noncognitive symptoms, including loss of motor function, reported to be associated with incident AD. To understand the link between motor function and preclinical AD, this article examines: our understanding of motor function and its clinical assessment in cohort studies; the relationship of motor function and loss of cognition in older persons; risk factors for cognitive and motor decline; and the relation of post-mortem indices of AD and motor function prior to death. Together, these data suggest that age-related cognitive and motor decline may share a common causation. Furthermore, individuals with a clinical diagnosis of AD may represent the 'tip of the iceberg', since AD pathology may also account for a substantial proportion of cognitive and motor dysfunction currently considered 'normal aging' in older persons without dementia. Thus, AD may have a much larger impact on the health and wellbeing of our aging population.