The Association of Specific Executive Functions and Falls Risk in People with Mild Cognitive Impairment and Early-Stage Dementia

Executive functions in patients with bilateral and unilateral peripheral vestibular dysfunction

Previous research suggests that patients with peripheral vestibular dysfunction (PVD) suffer from nonspatial cognitive problems, including executive impairments. However, previous studies that assessed executive functions are conflicting, limited to single executive components, and assessments are confounded by other cognitive functions. We compared performance in a comprehensive executive test battery in a large sample of 83 patients with several conditions of PVD (34 bilateral, 29 chronic unilateral, 20 acute unilateral) to healthy controls who were pairwise matched to patients regarding age, sex, and education. We assessed basic and complex executive functions with validated neuropsychological tests. Patients with bilateral PVD performed worse than controls in verbal initiation and working memory span, while other executive functions were preserved. Patients with chronic unilateral PVD had equal executive performance as controls. Patients with acute unilateral PVD performed worse than controls in the exact same tests as patients with bilateral PVD (verbal initiation, working memory span); however, this effect in patients with acute PVD diminished after correcting for multiple comparisons. Hearing loss and affective disorders did not influence our results. Vestibular related variables (disease duration, symptoms, dizziness handicap, deafferentation degree, and compensation) did not predict verbal initiation or working memory span in patients with bilateral PVD. The results suggest that bilateral PVD not only manifests in difficulties when solving spatial tasks but leads to more general neurocognitive deficits. This understanding is important for multidisciplinary workgroups (e.g., neurotologists, neurologists, audiologists) that are involved in diagnosing and treating patients with PVD. We recommend screening patients with PVD for executive impairments and if indicated providing them with cognitive training or psychoeducational support.

The effects of strEngth aNd BaLance exercise on Executive function in people living with Dementia (ENABLED): Study protocol for a pilot randomized controlled trial

BACKGROUND

Exercise may improve executive function among people living with all-cause dementia (PWD), but more evidence is needed. The aim of this pilot randomized controlled trial (RCT) is to examine whether exercise plus usual care improves the primary outcome of executive function, and secondary physiological (inflammation, metabolic aging, epigenetics) and behavioral (cognition, psychological health, physical function, and falls) outcomes compared to usual care alone among PWD.

METHODS AND STUDY DESIGN

The strEngth aNd BaLance exercise on Executive function in people living with Dementia (ENABLED) protocol is a pilot parallel, 6-month assessor-blinded RCT (1:1) in residential care facilities, including n = 21 receiving exercise plus usual care and n = 21 usual care alone [NCT05488951]. We will collect primary (Color-Word Stroop Test) and secondary physiological (inflammation, metabolic aging, epigenetics) and behavioral (cognition, psychological health, physical function, and falls) outcomes at baseline and 6 months. We will obtain falls monthly from medical charts. We will collect physical activity, sedentary behavior, and sleep via wrist-worn accelerometers over 7 days at baseline and 6 months. The physical therapist-led adapted Otago Exercise Program will involve 1-h of strength, balance and walking 3×/week for 6 months in groups of 5-7. We will use generalized linear mixed models to examine differences over time in primary and secondary outcomes between groups and examine potential interactions with sex and race.

DISCUSSION

This pilot RCT will examine the direct effects and potential underlying physiological mechanisms of exercise on executive function and other behavioral outcomes in PWD, which may have implications for clinical care management.

Executive function and prospective falls: a 6-year longitudinal study in community-dwelling older adults

BACKGROUND

Older people with impaired executive function (EF) might have an increased fall risk, but prospective studies with prolonged follow-up are scarce. This study aimed to investigate the association between a) EF at baseline; b) 6-year decline in EF performance; and fall status 6 years later.

METHODS

Participants were 906 community-dwelling adults aged 65-69 years, enrolled in the Lausanne 65 + cohort. EF was measured at baseline and at 6 years using clock drawing test (CDT), verbal fluency (VF), Trail Making Test (TMT) A and B, and TMT ratio (TMT-B - TMT-A/TMT-A). EF decline was defined as clinically meaningful poorer performance at 6 years. Falls data were collected at 6 years using monthly calendars over 12 months.

RESULTS

Over 12-month follow-up, 13.0% of participants reported a single benign fall, and 20.2% serious (i.e., multiple and/or injurious) falls. In multivariable analysis, participants with worse TMT-B performance (adjusted Relative Risk Ratio, adjRRR_{TMT-B worst quintile} = 0.38, 95%CI:0.19-0.75, p = .006) and worse TMT ratio (adjRRR_{TMT ratio worst quintile} = 0.31, 95%CI:0.15-0.64, p = .001) were less likely to report a benign fall, whereas no significant association was observed with serious falls. In a subgroup analysis among fallers, participants with worse TMT-B (OR:1.86, 95%CI = 0.98-3.53, p = .059) and worse TMT ratio (OR:1.84,95%CI = 0.98-3.43,p = .057) tended to have higher odds of serious falls. EF decline was not associated to higher odds of falls.

CONCLUSIONS

Participants with worse EF were less likely to report a single benign fall at follow-up, while fallers with worse EF tended to report multiple and/or injurious falls more frequently. Future studies should investigate the role of slight EF impairment in provoking serious falls in active young-old adults.

Working memory assessment using cambridge neuropsychological test automated battery can help in the diagnosis of mild cognitive impairment: a systematic review and meta-analysis

ABSTRACT Mild cognitive impairment (MCI) is an interstitial state between normal aging and dementia. Objective: In this study, we investigated working memory (WM) profiles of MCI patients using the Cambridge Neuropsychological Test Automated Battery (CANTAB). We also examined the diagnostic accuracy and possible associated factors as secondary outcomes of the study. Methods: We conducted an electronic search on EMBASE, PubMed, and ScienceDirect databases. Studies with MCI participants and using CANTAB battery subtests for the assessment of WM were included. Meta-analysis was conducted using the CMA2 software. Results: Out of 1537 records, 14 studies were covered in this systematic review, and 7 of them were included in the meta-analysis. There was a significant difference between MCI patients and healthy controls in spatial working memory (SWM) (SDM: 0.535; 95%CI 11–96; p-value=0.014), spatial span (SSP) (SDM: 0.649 95%CI 0.297–0.100; p-value<0.01), and rapid visual information processing (RVP) (SDM: 0.52; 95%CI 0.386–0.654; p-value<0.01). WM function of MCI patients was associated with the cerebrospinal fluid (CSF) levels of tau-protein and amyloid-beta (Aβ). Conclusions: WM is an impaired cognitive domain in MCI. CANTAB WM subtests including SSP, SWM, and RVP are accurate enough to be used as a proper assessment tool for the diagnosis of MCI in clinical settings. Tau-protein and Aβ are associated with lower WM scores in MCI patients; however, sex, age, psychiatric disorders, apolipoprotein 4 allele, and functional activity scores cannot affect WM.

The contribution of functional cognition screening during acute illness hospitalization of older adults in predicting participation in daily life after discharge

Background

Cognitive assessment in acutely hospitalized older adults is mainly limited to neuropsychological screening measures of global cognition. Performance-based assessments of functional cognition better indicate functioning in real-life situations. However, their predictive validity has been less studied in acute hospital settings. The aim of this study was to explore the unique contribution of functional cognition screening during acute illness hospitalization in predicting participation of older adults one and three months after discharge beyond traditional neuropsychological measures.

Methods

This prospective longitudinal study included 84 older adults ≥ 65 years hospitalized in internal medicine wards due to acute illness, followed by home visits at one month and telephone interviews at three months (n = 77). Participation in instrumental activities of daily living, social and leisure activities was measured by the Activity Card Sort. In-hospital factors included cognitive status (telephone version of the Mini-Mental State Examination, Color Trails Test), functional cognition screening (medication sorting task from the alternative Executive Function Performance Test), emotional status (Hospital Anxiety and Depression scale), functional decline during hospitalization (modified Barthel index), length of hospital stay, the severity of the acute illness, symptoms severity and comorbidities.

Results

Functional cognition outperformed the neuropsychological measures in predicting participation declines in a sample of relatively high-functioning older adults. According to a hierarchical multiple linear regression analysis, the overall model explained 28.4% of the variance in participation after one month and 19.5% after three months. Age and gender explained 18.6% of the variance after one month and 13.5% after three months. The medication sorting task explained an additional 5.5% of the variance of participation after one month and 5.1% after three months, beyond age and gender. Length of stay and the Color Trails Test were not significant contributors to the change in participation.

Conclusions

By incorporating functional cognition into acute settings, healthcare professionals would be able to better detect older adults with mild executive dysfunctions who are at risk for participation declines. Early identification of executive dysfunctions can improve continuity of care and planning of tailored post-discharge rehabilitation services, especially for high-functioning older adults, a mostly overlooked population in acute settings. The results support the use of functional cognition screening measure of medication management ability in acute settings.

Executive and Motor Functions in Older Individuals with Cognitive Impairment

Background: A current research trend is the examination of the interplay between cognitive functioning, higher-order processes, and motor efficiency in late adulthood. However, the association between motor and cognitive functions when cognitive decline occurs has not been extensively explored. This study investigated whether gait features, functional mobility, and handgrip strength were associated with executive functions in older people with mild cognitive impairment (MCI) or dementia. Methods: 127 older participants (M_age = 77.9 years, SD = 5.8 years) who had received a diagnosis of MCI and dementia voluntarily took part in the study. A battery of tests assessing global cognitive function, executive functions, muscular strength, functional mobility, and spatio-temporal parameters of gait was completed by the participants. Results: Statistically significant correlations were obtained between global cognitive function, executive functions, and motor efficiency measures. Moreover, a series of regression analyses showed that 8–13% of the variance of several motor parameters was predicted by several executive functions. Additionally, walking, functional mobility, and global cognitive function predicted 53–71% of the variance relative to the occurrence of dementia. In conclusion, motor functioning is closely related to cognitive functioning in late adulthood. Conclusions: The assessment of muscular strength and functional mobility should be promoted in clinical settings.

The Association Between Cognitive Impairment and Subsequent Falls Among Older Adults: Evidence From the China Health and Retirement Longitudinal Study

Introduction

Previous studies have suggested that cognitive impairment is associated with falls in older adults. However, the consistency of results among different subgroups defined by multiple characteristics of the elderly has not yet been tested. Additionally, results are inconsistent regarding the effects of different cognitive domains on falls. Therefore, this study sought to use representative data from a nationwide study to better understand the longitudinal association between cognitive impairment and subsequent falls in older adults.

Methods

The current study was conducted based on the China Health and Retirement Longitudinal Study (CHARLS) data of respondents aged ≥60 years in 2015 and the fall data in 2018. The respondents were divided into subgroups according to different demographic characteristics. Multiple logistic regression analysis was conducted to adjust for various confounding factors and evaluate the association between cognitive impairment and falls.

Results

Of the 5,110 respondents included in this study, 1,093 (21.39%) had falls within the last 2 years. A significant association was found between cognitive impairment and subsequent falls (OR = 0.97, 95% CI 0.95–0.99, P = 0.001) after adjusting for all of the covariates related to falls. Analysis of different cognitive domains showed that orientation (OR = 0.94, 95% CI 0.90–0.99, P = 0.013) and memory (OR = 0.93, 95% CI 0.90–0.97, P = 0.001) were significantly associated with falls. In subgroup analysis, the ORs of people aged 60–74 years, male, with lower education level were 0.97 (95% CI 0.95–0.99, P = 0.008), 0.96 (95% CI 0.93–0.98, P = 0.001), and 0.97 (95% CI 0.95–0.99, P = 0.001), respectively, suggesting that the associations were also statistically significant in these subgroups. There was also a significant association both in urban (OR = 0.97, 95% CI 0.95–0.99, P = 0.001) and in rural residents (OR = 0.97, 95% CI 0.95–0.99, P = 0.003).

Conclusions

Our results suggest that the associations between cognition and falls vary depending on the different demographic characteristics of older adults. These findings may be useful for designing more accurate identification and intervention for the fall risk for specific high-risk groups.

Cognitive inhibition tasks interfere with dual-task walking and increase prefrontal cortical activity more than working memory tasks in young and older adults

BACKGROUND

Prior work suggests there may be greater reliance on executive function for walking in older people. The pre-frontal cortex (PFC), which controls aspects of executive function, is known to be active during dual-task walking (DTW). However, there is debate on how PFC activity during DTW is impacted by ageing and the requirements of the cognitive task.

RESEARCH QUESTION

Functional near infrared spectroscopy, was used to investigate how PFC activity during walking was affected by (i) healthy ageing; and (ii) dual-tasks that utilise inhibition or working memory aspects of executive function.

METHODS

Young (n = 26, 16 females, mean 20.9 years) and older (n = 26, 16 females, mean 70.3 years) adults performed five conditions: normal walking; Reciting Alternate Letters of the alphabet (RAL, requiring cognitive inhibition and working memory) during standing and walking; and serial subtraction by threes (SS3, requiring working memory alone) during standing and walking. Walking speed, cognitive performance, the PFC haemodynamic response, and fear of falling ratings were analysed using linear mixed-effects modelling.

RESULTS

Compared to quiet standing, PFC activity increased during normal walking for older adults but decreased for young adults (p < 0.01). Across both groups, fear of falling contributed to higher PFC activity levels when walking (p < 0.01). PFC activity increased during DTW, and this increase was greater when performing RAL compared to the SS3 task (p < 0.01). Although the rate of correct responses was higher for RAL, walking speed reduced more with RAL than SS3 in the young group (p = 0.01), and the rate of correct responses reduced more when walking with RAL than SS3 in the older group (p < 0.01).

SIGNIFICANCE

Older adults have increased levels of PFC activation during walking compared to younger adults and fear of falling is a cofounding factor. The interference between gait and a concurrent cognitive task is higher when the cognitive task requires inhibition.

Bidirectional association between executive and physical functions among older adults: A systematic review

OBJECTIVE

We aimed to examine the bidirectional associations between specific executive function (EF) and physical function (PF) subdomains among older adults.

METHODS

A systematic literature search (MEDLINE, EMBASE, PsycINFO, EBSCOHOST, Scopus and EmCare) was undertaken from February 2018 to May 2020. Observational studies measuring associations between EF and PF subdomains among older adults were included.

RESULTS

Twenty-nine studies met the inclusion criteria. Twenty-seven studies reported associations between EF and PF. There were bidirectional associations between slower processing speed and slower gait speed; slower processing speed and lower muscle strength; and lower verbal fluency and slower gait speed. Lower muscle strength was unilaterally associated with lower working memory.

CONCLUSIONS

We found consistent bidirectional associations between processing speed with gait speed and muscle strength, and verbal fluency and gait speed. There was a unidirectional association between muscle strength and working memory. Common causal mechanisms for EF and PF require further studies.

Relationship between Speed of Response Inhibition and Ability to Suppress a Step in Midlife and Older Adults

In young adults, performance on a test of response inhibition was recently found to be correlated with performance on a reactive balance test where automated stepping responses must occasionally be inhibited. The present study aimed to determine whether this relationship holds true in older adults, wherein response inhibition is typically deficient and the control of postural equilibrium presents a greater challenge. Ten participants (50+ years of age) completed a seated cognitive test (stop signal task) followed by a reactive balance test. Reactive balance was assessed using a modified lean-and-release system where participants were required to step to regain balance following perturbation, or suppress a step if an obstacle was present. The stop signal task is a standardized cognitive test that provides a measure of the speed of response inhibition called the Stop Signal Reaction Time (SSRT). Muscle responses in the legs were compared between conditions where a step was allowed or blocked to quantify response inhibition of the step. The SSRT was significantly related to leg muscle suppression during balance recovery in the stance leg. Thus, participants that were better at inhibiting their responses in the stop signal task were also better at inhibiting an unwanted leg response in favor of grasping a supportive handle. The relationship between a seated cognitive test using finger responses and leg muscle suppression when a step was blocked indicates a context-independent, generalized capacity for response inhibition. This suggests that a simple cognitive test such as the stop signal task could be used clinically to predict an individual’s capacity for adapting balance reactions and fall risk. The present results provide support for future studies, with larger samples, to verify this relationship between stop signal reaction time and leg response during balance recovery.

Vestibular Function in Older Adults With Cognitive Impairment: A Systematic Review

IMPORTANCE

Given the rising prevalence of patients with dementia and those at risk for it, early identification is prioritized. As vestibular dysfunction is associated with Alzheimer's disease (AD) and may contribute to its onset, vestibular assessment may yield an opportunity in early dementia screening.

OBJECTIVE

This systematic review structures and compares the different raw outcome measures used to assess vestibular function while comparing older adults with preserved cognition to individuals with cognitive impairment, either suffering from mild cognitive impairment (MCI) or AD.

DESIGN

Two investigators independently and systematically searched publications performing objectively measured vestibular testing in a patient population consisting of either MCI or AD, compared with a control group of older adults with preserved cognition. No limitations regarding language or publication date were applied. References of the retrieved articles were hand searched for relevant articles.

RESULTS

Seven articles were included for analysis. A total of 235 older adults with impaired cognition (150 AD, 85 MCI) were compared with a control group of 481 older adults with preserved cognition. Evaluation of the peripheral vestibular function included video head impulse test (vHIT), videonystagmography (VNG), electronystagmography (ENG) including bithermal caloric irrigation and vestibular evoked myogenic potentials (VEMP). The VEMP test, assessing otolith function and the elicited vestibulocollic reflex (VCR), was able to differentiate subjects with AD and its prodromal stage from healthy controls, with p13 latency (p < 0.05) and amplitude (p < 0.05) having the most discriminating power.No correlation between cognitive decline and vestibulo-ocular reflex measurements in different frequency ranges of the semicircular canals (using vHIT, rotatory chair testing, and caloric irrigation) was found. Because of the limited number of available studies and the large heterogeneity in outcome measures, these results have to be interpreted with caution.

CONCLUSIONS

Measurements of the VCR, as evoked by the VEMP test, discriminate between patients with cognitive impairment (MCI and AD) and older adults with preserved cognition, whereas measurements of the vestibulo-ocular reflex do not. More studies are needed to further elaborate on these findings.

The Association Between Leukocyte Telomere Length and Cognitive Performance Among the American Elderly

Background

Age-related cognitive decline begins in middle age and persists with age. Leukocyte telomere length (LTL) decreases with age and is enhanced by inflammation and oxidative stress. However, whether shorter LTL correlates with cognitive decline remains controversial.

Aims

We aimed to investigate the relationship between LTL and cognitive decline in the American elderly.

Methods

We used data from the 1999 to 2002 U.S. National Health and Nutrition Examination Survey (NHANES). We included participants aged 65–80 with available data on LTL and cognitive assessments. The cognitive function assessment used the digit symbol substitution test (DSST). We applied multivariate modeling to estimate the association between LTL and cognitive performance. Additionally, to ensure robust data analysis, we converted LTL into categorical variables through quartile and then calculated the P for trend.

Results

After adjusting for age, cardiovascular disease (CAD) score, gender, race, body mass index (BMI), and educational level, LTL showed a positive correlation with DSST score (odds ratio [OR] 3.47 [0.14, 6.79], P = 0.04). Additionally, to further quantify the LTL–DSST interaction, we found a similar trend when LTL was regarded as a categorical variable (quartile) (P for trend = 0.03).

Conclusion

LTL was associated with cognitive capabilities among the elderly, implying that LTL might be a biomarker of cognitive aging.

Review of Gait, Cognition, and Fall Risks with Implications for Fall Prevention in Older Adults with Dementia

BACKGROUND

Older people with cognitive impairment are at increased risk of falls; however, fall prevention strategies have limited success in this population. The aim of this paper is to review the literature to inform a theoretical framework for fall prevention in older adults with dementia.

SUMMARY

A narrative review was conducted on fall risk factors in people with cognitive impairment, the relationship between cognition and gait, and their joint impact on the risk of falls. This was used to develop a theoretical framework for fall prevention for people with dementia. Executive function and motor function are closely related as they share neuroanatomy. This close relationship has been confirmed by observational studies including neuroimaging and intervention studies. Executive function is the cognitive domain most commonly associated with gait dysfunction. Attention, sensory integration, and motor planning are the sub-domains of executive function associated with risk of falls through gait dysfunction, whereas cognitive flexibility, judgement, and inhibitory control affect risk of falls through risk-taking behaviour. Key Messages: Gait, cognition, and falls are closely related. The comorbidity and interaction between gait abnormality and cognitive impairment may underpin the high prevalence of falls in older adults with dementia. Gait assessment and cognitive assessment, particularly executive function, should be integrated in fall risk screening. Assessment results should be interpreted and utilised using a multidisciplinary approach; specific strategies such as customised gait training and behavioural modulation should be considered as part of falls prevention for people with dementia.

The Association Between Social Engagement, Mild Cognitive Impairment, and Falls Among Older Primary Care Patients

OBJECTIVES

To examine associations between mild cognitive impairment (MCI) and falls among primary care patients, and to investigate whether social engagement (SE) modifies these associations.

DESIGN

Cross sectional analysis using baseline data from an observational cohort study.

SETTING

Primary care.

PARTICIPANTS

Community-dwelling older adults (N=430) at risk of mobility decline with a mean age of 76.6 years (range 65-96y).

MAIN OUTCOME MEASURES

The number of falls in the past year was reported at the baseline interview. MCI was identified using a cutoff of 1.5 SD below the age-adjusted mean on at least 2 of the standardized cognitive performance tests. SE (eg, keeping in touch with friends and family, volunteering, participating social activities…) was assessed with the Late Life Function and Disability Instrument, and required a score above the median value 49.5 out of 100.

RESULTS

MCI was present among 42% of participants and 42% reported at least 1 fall in the preceding year. Using generalized estimating equations, MCI was associated with a 77% greater rate of falls (P<.05). There was a statistically significant interaction between SE and MCI on the rate of falls (P<.01), such that at a high level of SE, MCI was not statistically associated with falls (P=.83). In participants with lower levels of SE, MCI is associated with 1.3 times greater rate of falls (P<.01).

CONCLUSIONS

While MCI is associated with a greater risk for falls, higher levels of SE may play a protective role.

Perspectives of healthcare professionals in England on falls interventions for people with dementia: a qualitative interview study

OBJECTIVE

To explore the experiences of healthcare professionals working in falls prevention and memory assessment services in providing assessments and interventions for falls risk reduction in people with dementia.

DESIGN

This is a qualitative study using 19 semistructured interviews. Interviews were analysed through thematic analysis.

SETTING

Community-based falls and memory assessment services in the East Midlands, UK.

PARTICIPANTS

Nurses (n=10), physiotherapists (n=5), occupational therapists (n=3) and a psychiatrist (n=1).

RESULTS

Three substantive themes were identified: challenges posed by dementia, adaptations to make falls prevention appropriate for people with dementia and organisational barriers. Patients' poor recall, planning and increased behavioural risk associated with dementia were key problems. Healthcare professionals provided many suggestions on how to overcome these challenges, such as adapting exercise interventions by using more visual aids. Problems associated with cognitive impairment created a need for additional support, for instance longer interventions, and supervision by support workers, to enable effective intervention, yet limited resources meant this was not always achievable. Communication between mental and physical health teams could be ineffective, as services were organised as separate entities, creating a reliance on third parties to be intermediaries. Structural and organisational factors made it difficult to deliver optimal falls prevention for people living with dementia.

CONCLUSIONS

Healthcare professionals experience challenges in providing falls prevention to people with dementia at the individual and organisational levels. Interventions can be adapted for people with dementia, but this requires additional resources and improved integration of services. Future research is needed to develop and test the effectiveness and cost-effectiveness of such services.

Why Do Individuals with Cirrhosis Fall? A Mechanistic Model for Fall Assessment, Treatment, and Research

Falls are prevalent for people with cirrhosis and commonly lead to loss of independence, reduced quality of life, and mortality. Despite a critical need for fall prevention in this population, cirrhosis-specific fall-related mechanisms are not well understood. We posit that most falls in this patient population are due to a coalescence of discrete subclinical impairments that are not typically detected at the point of care. The combined effect of these subtle age- and disease-related neurocognitive and muscular impairments leads to the inability to respond successfully to a postural perturbation within the available 300 to 400 ms. This article provides a conceptual model of physiological resilience to avoid a fall that focuses on attributes that underlie the ability to withstand a postural perturbation and their clinical evaluation. Evidence supporting this model in cirrhosis and other high fall risk conditions will be synthesized and suggestions for fall assessment and treatment will be discussed.

Cognitive Effects of Perioperative Pregabalin

EDITOR’S PERSPECTIVE

What We Already Know about This Topic

Perioperative administration of pregabalin has been associated with decreased postoperative pain and opioid requirements

What This Article Tells Us That Is New

This secondary analysis of data demonstrating that perioperative administration of pregabalin was associated with a reduction in opioid requirements and incisional hyperalgesia suggests that these benefits may be compromised by an increased risk of developing impaired postoperative cognitive performance

Background

Pregabalin has shown opioid sparing and analgesic effects in the early postoperative period; however, perioperative effects on cognition have not been studied. A randomized, parallel group, placebo-controlled investigation in 80 donor nephrectomy patients was previously performed that evaluated the analgesic, opioid-sparing, and antihyperalgesic effects of pregabalin. This article describes a secondary exploratory analysis that tested the hypothesis that pregabalin would impair cognitive function compared to placebo.

Methods

Eighty patients scheduled for donor nephrectomy participated in this randomized, placebo-controlled study. Pregabalin (150 mg twice daily, n = 40) or placebo (n = 40) was administered on the day of surgery and the first postoperative day, in addition to a pain regimen consisting of opioids, steroids, local anesthetics, and acetaminophen. Specific cognitive tests measuring inhibition, sustained attention, psychomotor speed, visual memory, and strategy were performed at baseline, 24 h, and 3 to 5 days after surgery, using tests from the Cambridge Neuropsychological Test Automated Battery.

Results

In the spatial working memory within errors test, the number of errors increased with pregabalin compared to placebo 24 h after surgery; median (25th, 75th percentile) values were 1 (0, 6) versus 0 (0, 1; rate ratio [95% CI], 3.20 [1.55 to 6.62]; P = 0.002). Furthermore, pregabalin significantly increased the number of errors in the stop-signal task stop-go test compared with placebo; median (25th, 75th percentile) values were 3 (1, 6) versus 1 (0, 2; rate ratio, 2.14 [1.13 to 4.07]; P = 0.020). There were no significant differences between groups in the paired associated learning, reaction time, rapid visual processing, or spatial working memory strategy tests.

Conclusions

Perioperative pregabalin significantly negatively affected subdomains of executive functioning, including inhibition, and working memory compared to placebo, whereas psychomotor speed was not changed.

Modulating functional connectivity with non-invasive brain stimulation for the investigation and alleviation of age-associated declines in response inhibition: A narrative review

Response inhibition, the ability to withhold a dominant and prepotent response following a change in circumstance or sensory stimuli, declines with advancing age. While non-invasive brain stimulation (NiBS) has shown promise in alleviating some cognitive and motor functions in healthy older individuals, NiBS research focusing on response inhibition has mostly been conducted on younger adults. These extant studies have primarily focused on modulating the activity of distinct neural regions known to be critical for response inhibition, including the right inferior frontal gyrus (rIFG) and the pre-supplementary motor area (pre-SMA). However, given that changes in structural and functional connectivity have been associated with healthy aging, this review proposes that NiBS protocols aimed at modulating the functional connectivity between the rIFG and pre-SMA may be the most efficacious approach to investigate-and perhaps even alleviate-age-related deficits in inhibitory control.

Combined Impact of Telomere Length and Mitochondrial DNA Copy Number on Cognitive Function in Community-Dwelling Very Old Adults

BACKGROUND

This study was conducted to investigate the combined impact of telomere length and mitochondrial DNA (mtDNA) copy number on cognitive function in community-dwelling very old adults.

METHODS

In total, 186 subjects over 75 years participated in this study. Cognitive function was assessed using the Korean Mini-Mental State Examination, and leukocyte telomere length and mtDNA copy number were measured using real-time polymerase chain reaction methods.

RESULTS

Both the fourth quartile of telomere length and mtDNA copy number were associated with cognitive dysfunction with an adjusted odds ratio of 0.23 (95% confidence interval (CI), 0.10-0.75) and 0.18 (95% CI, 0.03-0.54), respectively. Participants in the high telomere length/high mtDNA copy number group were more likely to have cognitive dysfunction than participants in the low telomere/low mtDNA copy number group with an adjusted odds ratio of 0.19 (95% CI, 0.07-0.58).

CONCLUSION

Our results collectively suggest that the combination of telomere length and mtDNA copy number may be useful for monitoring cognitive decline in older adults.

Does working memory training improve dietary self-care in type 2 diabetes mellitus? Results of a double blind randomised controlled trial

AIMS

Controlling food intake despite adequate knowledge remains a struggle for many people with type 2 diabetes. The present study investigated whether working memory training can reduce food intake and improve glycaemic control. It also examined training effects on cognition, food cravings, and dietary self-efficacy and self-care.

METHODS

In a double-blind multicentre parallel-group randomised controlled trial, adults with type 2 diabetes mellitus were randomly allocated to receive 25 sessions of either active (n = 45) or control (n = 36) working memory training. Assessments at baseline, post-training and 3-month follow-up measured cognition, food intake (primary outcomes), glycaemic control (HbA1c) and cholesterol (secondary outcomes). Semi-structured interviews assessed participants' experiences of the training.

RESULTS

Intention-to-treat ANOVAs (N = 81) showed improved non-trained updating ability in active compared to control training from pre-test (active M = 34.37, control M = 32.79) to post-test (active M = 31.35, control M = 33.53) and follow-up (active M = 31.81, control M = 32.65; η² = 0.05). There were no overall effects of training on other measures of cognition, food intake, HbA1c, cholesterol, food cravings and dietary self-efficacy and self-care. In post-hoc analyses, those high in dietary restraint in the active training group showed a greater reduction in fat intake pre to post-test compared to controls. Interviews revealed issues around acceptability and performance of the training.

CONCLUSIONS

Transfer of working memory training effects to non-trained behaviour were limited, but do suggest that training may reduce fat intake in those who are already motivated to do so.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN22806944.

Promoting activity, independence and stability in early dementia and mild cognitive impairment (PrAISED): development of an intervention for people with mild cognitive impairment and dementia

This series of articles for rehabilitation in practice aims to cover a knowledge element of the rehabilitation medicine curriculum. Nevertheless, they are intended to be of interest to a multidisciplinary audience. The competency addressed in this article is an understanding of how to develop an intervention for people with mild cognitive impairment and dementia to promote their independence, stability, and physical activity.

INTRODUCTION

Older adults with dementia are at a high risk of falls. Standard interventions have not been shown to be effective in this patient population potentially due to poor consideration of dementia-specific risk factors. An intervention is required that addresses the particular needs of older people with dementia in a community setting.

METHODS

We followed guidelines for the development of an intervention, which recommend a structured approach considering theory, evidence and practical issues. The process used 15 information sources. Data from literature reviews, clinician workshops, expert opinion meetings, patient-relative interviews, focus groups with people with dementia and clinicians, a cross-sectional survey of risk factors, a pre-post intervention study and case studies were included. Data were synthesized using triangulation to produce an intervention suitable for feasibility testing. Practical consideration of how an intervention could be delivered and implemented were considered from the outset.

RESULTS

Elements of the intervention included individually tailored, dementia-appropriate, balance, strength and dual-task exercises, functional training, and activities aimed at improving environmental access, delivered using a motivational approach to support adherence and long-term continuation of activity. We focussed on promoting safe activity rather than risk or prevention of falls.

CONCLUSION

We used a systematic process to develop a dementia-specific intervention to promote activity and independence while reducing falls risk in older adults with mild dementia.

Cognitive Rehabilitation in Bilateral Vestibular Patients: A Computational Perspective

There is evidence that vestibular sensory processing affects, and is affected by, higher cognitive processes. This is highly relevant from a clinical perspective, where there is evidence for cognitive impairments in patients with peripheral vestibular deficits. The vestibular system performs complex probabilistic computations, and we claim that understanding these is important for investigating interactions between vestibular processing and cognition. Furthermore, this will aid our understanding of patients’ self-motion perception and will provide useful information for clinical interventions. We propose that cognitive training is a promising way to alleviate the debilitating symptoms of patients with complete bilateral vestibular loss (BVP), who often fail to show improvement when relying solely on conventional treatment methods. We present a probabilistic model capable of processing vestibular sensory data during both passive and active self-motion. Crucially, in our model, knowledge from multiple sources, including higher-level cognition, can be used to predict head motion. This is the entry point for cognitive interventions. Despite the loss of sensory input, the processing circuitry in BVP patients is still intact, and they can still perceive self-motion when the movement is self-generated. We provide computer simulations illustrating self-motion perception of BVP patients. Cognitive training may lead to more accurate and confident predictions, which result in decreased weighting of sensory input, and thus improved self-motion perception. Using our model, we show the possible impact of cognitive interventions to help vestibular rehabilitation in patients with BVP.

Saccular Impairment in Alzheimer's Disease Is Associated with Driving Difficulty

BACKGROUND/AIMS

Patients with Alzheimer's disease (AD) experience increased rates of vestibular loss. Recent studies suggest that saccular impairment in mild cognitive impairment (MCI) and AD patients is associated with impaired spatial cognitive function. However, the impact of saccular impairment on everyday behaviors that rely on spatial cognitive function is unknown.

METHODS

We recruited 60 patients (21 MCI and 39 AD) from an interdisciplinary Memory Clinic. Saccular function was measured, and a visuospatial questionnaire was administered to assess whether participants experienced impairments in terms of driving difficulty, losing objects, falls, and fear of falling.

RESULTS

In multiple logistic regression analyses, MCI and AD patients with bilateral saccular impairment had a significant, greater than 12-fold odds of driving difficulty (OR 12.1, 95% CI 1.2, 117.7) compared to MCI and AD patients with normal saccular function, and the association appears to be mediated by spatial cognition as measured by the Money Road Map Test.

CONCLUSION

This study suggests a novel link between saccular impairment and driving difficulty in MCI and AD patients and demonstrates that driving difficulty may be a real-world manifestation of impaired spatial cognition associated with saccular impairment.

Age-Related Changes in Bimanual Instrument Playing with Rhythmic Cueing

Deficits in bimanual coordination of older adults have been demonstrated to significantly limit their functioning in daily life. As a bimanual sensorimotor task, instrument playing has great potential for motor and cognitive training in advanced age. While the process of matching a person’s repetitive movements to auditory rhythmic cueing during instrument playing was documented to involve motor and attentional control, investigation into whether the level of cognitive functioning influences the ability to rhythmically coordinate movement to an external beat in older populations is relatively limited. Therefore, the current study aimed to examine how timing accuracy during bimanual instrument playing with rhythmic cueing differed depending on the degree of participants’ cognitive aging. Twenty one young adults, 20 healthy older adults, and 17 older adults with mild dementia participated in this study. Each participant tapped an electronic drum in time to the rhythmic cueing provided using both hands simultaneously and in alternation. During bimanual instrument playing with rhythmic cueing, mean and variability of synchronization errors were measured and compared across the groups and the tempo of cueing during each type of tapping task. Correlations of such timing parameters with cognitive measures were also analyzed. The results showed that the group factor resulted in significant differences in the synchronization errors-related parameters. During bimanual tapping tasks, cognitive decline resulted in differences in synchronization errors between younger adults and older adults with mild dimentia. Also, in terms of variability of synchronization errors, younger adults showed significant differences in maintaining timing performance from older adults with and without mild dementia, which may be attributed to decreased processing time for bimanual coordination due to aging. Significant correlations were observed between variability of synchronization errors and performance of cognitive tasks involving executive control and cognitive flexibility when asked for bimanual coordination in response to external timing cues at adjusted tempi. Also, significant correlations with cognitive measures were more prevalent in variability of synchronization errors during alternative tapping compared to simultaneous tapping. The current study supports that bimanual tapping may be predictive of cognitive processing of older adults. Also, tempo and type of movement required for instrument playing both involve cognitive and motor loads at different levels, and such variables could be important factors for determining the complexity of the task and the involved task requirements for interventions using instrument playing.

Association between CSF biomarkers, hippocampal volume and cognitive function in patients with amnestic mild cognitive impairment (MCI)

Few studies have examined the relationship between CSF and structural biomarkers, and cognitive function in MCI. We examined the relationship between cognitive function, hippocampal volume and cerebrospinal fluid (CSF) Aβ₄₂ and tau in 145 patients with MCI. Patients were assessed on cognitive tasks from the Cambridge Neuropsychological Test Automated Battery (CANTAB), the Geriatric Depression Scale and the Functional Activities Questionnaire. Hippocampal volume was measured using magnetic resonance imaging (MRI), and CSF markers of Aβ₄₂, tau and p-tau₁₈₁ were also measured. Worse performance on a wide range of memory and sustained attention tasks were associated with reduced hippocampal volume, higher CSF tau and p-tau₁₈₁ and increased tau/Aβ₄₂ ratio. Memory tasks were also associated with lower ability to conduct functional activities of daily living, providing a link between AD biomarkers, memory performance and functional outcome. These results suggest that biomarkers of Aβ and tau are strongly related to cognitive performance as assessed by the CANTAB, and have implications for the early detection and characterization of incipient AD.

Global cognitive function and processing speed are associated with gait and balance dysfunction in Parkinson's disease

Background

Our primary objective was to determine the relationship between global cognitive function and specific domains of gait and balance in a cohort of Parkinson’s disease (PD) subjects. In a secondary analysis, we determined whether specific cognitive domains correlated with gait and balance performance.

Methods

Fourteen PD subjects (mean age 61.1 ± 7.8 years) were recruited from the Rush University Medical Center Movement Disorders clinic. Subjects underwent clinical assessment using the motor subsection of the Unified Parkinson’s Disease Rating Scale (UPDRS) followed by quantitative gait and balance assessments using the APDM Mobility Lab™ system (Mobility Lab, APDM Inc., Portland, OR). Subjects completed global cognitive testing using the Mattis Dementia Rating Scale (MDRS) as well as domain specific cognitive measures. Spearman’s rho was used to assess correlations between cognitive measures and gait and balance function, with False Discovery Rate (FDR) correction for multiple comparisons.

Results

Global cognitive function had the strongest correlation with stride velocity (r = 0.816, p = 0.001), turn duration (r = −0.806, p = 0.001), number of steps to turn (r = −0.830, p = 0.001), and mean velocity of postural sway in the medio-lateral direction (r = −0.726, p = 0.005). A significant correlation was found between processing speed and two turning measures (turn duration, r = −0.884, p = 0.001; number of steps to turn, r = −0.954, p < 0.001), but no other associations were found between specific cognitive domains and gait domains.

Conclusions

This pilot study provides preliminary data regarding the association between global cognitive function and pace-related measures of gait, turning, and postural sway. Furthermore, reduced processing speed was found to be associated with difficulty in performing turns.