Executive Function In Older Adults Research Articles

Tai Chi exercise training enhances executive function and fluid intelligence of healthy older adults: Cross-sectional and longitudinal evidence

Executive function and fluid intelligence are two of the crucial frontal lobe functions susceptible to aging. Tai Chi as a mind-body exercise has been proposed for preventing cognitive aging. However, whether Tai Chi has similar effects on multiple components of executive functions in older adults remains underspecified. Moreover, it is not currently known whether Tai Chi exercise training improvements in lower-order executive functions are able to explain improvements in higher-order fluid intelligence. Study 1 included a cross-sectional design based on a large sample of healthy older adults (55–79 years old). Modeling results showed that experience of Tai Chi training exerted significantly positive effects on fluid intelligence, inhibition and updating after controlling for age and education. Both inhibition and updating mediated effects of Tai Chi on fluid intelligence. Study 2 carried out a 12-month Tai Chi training intervention on a novice group and an experienced group of older adults. Results indicated that only the novices exhibited significant improvements in inhibition and fluid intelligence. In addition, improvements in fluid intelligence were no longer significant after controlling for improvements in inhibition. These results shed lights on the mechanism by which mind-body training enhances intelligence.

Assessment of executive functions in older adults: Translation and initial validation of the Swedish version of the Frontal Assessment Battery, FAB-Swe

Objectives The Frontal Assessment Battery (FAB) is a screening test for executive functions. The purpose of this study was to describe the translation process and to make an initial evaluation of the reliability and convergent validity of the Swedish version of the FAB, the FAB-Swe. Methods The FAB-Swe was translated and adapted to Swedish using a translation and back-translation procedure. Seventy community-dwelling participants aged 65 years or older participated. Participants completed the FAB-Swe, the Mini-Mental State Examination – Swedish Revision (MMSE-SR), three established tests of executive functions (FAS, Trail Making Test—part B [TMT-B] and Stroop), and self-ratings of executive abilities. Reliability of the FAB-Swe was measured using Cronbach’s alpha. Convergent validity was measured using Spearman’s rank correlation. Results Internal consistency was moderately high (.675). Statistically significant correlations were found between the FAB-Swe and MMSE-SR, FAS, TMT-B, Stroop, and education. No significant correlations were found between the FAB-Swe and age or self-rated executive functioning. Conclusions This study indicates that the FAB-Swe has acceptable reliability and convergent validity. Further normative studies are needed to further investigate the effect of age and educational level. Studies are also needed to evaluate the diagnostic accuracy in clinical populations.

Cardiovascular risk moderates the effect of aerobic exercise on executive functions in older adults with subcortical ischemic vascular cognitive impairment

Aerobic training (AT) can promote cognitive function in adults with Subcortical Ischemic Vascular Cognitive Impairment (SIVCI) by modifying cardiovascular risk factors. However, pre-existing cardiovascular health may attenuate the benefits of AT on cognitive outcomes in SIVCI. We examined whether baseline cardiovascular risk moderates the effect of a 6-month progressive AT program on executive functions with a secondary analysis of a randomized controlled trial in 71 adults, who were randomized to either: (1) 3×/week progressive AT; or (2) education program (CON). Three executive processes were measured: (1) response inhibition by Stroop Test; (2) working memory by digits backward test; and (3) set shifting by the Trail Making Test. Baseline cardiovascular risk was calculated using the Framingham cardiovascular disease (CVD) Risk Score (FCRS), and participants were classified as either low risk (< 20% FCRS score; LCVR) or high risk (≥ 20% FCRS score; HCVR). A complete case analysis (n = 58) was conducted using an analysis of covariance (ANCOVA) to evaluate between-group differences in the three executive processes. A significant interaction was found between cardiovascular risk group and intervention group (AT or CON) for the digit span backward and the Trail Making Test. AT improved performance compared with CON in those with LCVR, while in those with HCVR, AT did not improve performance compared with CON. Baseline cardiovascular risk significantly moderates the efficacy of AT on cognition. Our findings highlight the importance of intervening early in the disease course of SIVCI, when cardiovascular risk may be lower, to reap maximum benefits of aerobic exercise.

Comparison Between the Effects of Continuous and Intermittent Light-Intensity Aerobic Dance Exercise on Mood and Executive Functions in Older Adults.

There is a growing body of evidence suggesting that one bout of moderate-intensity exercise enhances executive functions in older adults. However, in terms of safety, feasibility, and continuity, older individuals prefer light, easy, and fun exercises to moderate and stressful exercises for improving executive functions. Therefore, light-intensity aerobic dance exercise (LADE) could be suitable if it produces potential benefits related to executive functions. As for continuous vs. intermittent exercise, intermittent exercise has received a lot of attention, as it results in greater effects on mood and executive functions than continuous exercise; however, its effects in older adults remain uncertain. Thus, in this study, we aimed to examine the acute effects of intermittent LADE (I-LADE) in comparison with those of continuous LADE (C-LADE) on mood and executive functions. Fifteen healthy older adults participated in 10-min I-LADE and C-LADE conditions on separate days. Perceived enjoyment following exercise was assessed using the Physical Activity Enjoyment Scale (PACES). The pleasantness of the mood during exercise and pleasure and arousal levels after exercise were assessed using the Feeling Scale and Two-Dimensional Mood Scale, respectively. Executive function was assessed using the Stroop task before and after exercise. As a result, pleasantness of the mood during exercise and exercise enjoyment levels were greater in I-LADE than in C-LADE. Arousal and pleasure levels and Stroop task performance increased after both LADEs and did not differ between the two exercise conditions. These findings suggest that although enhancement of mood and executive functions after exercise did not differ between C-LADE and I-LADE, I-LADE could be more enjoyable and fun than C-LADE. This study will help in the development of exercise conditions that can enable the elderly to enhance their executive functions in a fun way.

The Relations Between Physical Activity Level, Executive Function, and White Matter Microstructure in Older Adults.

The population of older adults is increasing, indicating a need to examine factors that may prevent or mitigate age-related cognitive decline. The current study examined whether microstructural white matter characteristics mediated the relation between physical activity and executive function in older adults without any self-reported psychiatric and neurological disorders or cognitive impairment (N = 43, mean age = 73y). Physical activity was measured by average intensity and number of steps via accelerometry. Diffusion tensor imaging was used to examine microstructural white matter characteristics, and neuropsychological testing was used to examine executive functioning. Parallel mediation models were analyzed using microstructural white matter regions of interest as mediators of the association between physical activity and executive function. Results indicated that average steps was significantly related to executive function (β = 0.0003, t = 2.829, P = .007), while moderate to vigorous physical activity was not (β = 0.0007, t = 1.772, P = .08). White matter metrics did not mediate any associations. This suggests that microstructural white matter characteristics alone may not be the mechanism by which physical activity impacts executive function in aging.

The impact of multimodal cognitive rehabilitation on executive functions in older adults with traumatic brain injury

This study evaluated the impact of a 12-week, 24-session multimodal group cognitive rehabilitation intervention, the Cognitive Enrichment Program (CEP), on executive functioning and resumption of daily activities after traumatic brain injury (TBI) in older individuals as compared with an active control group that received individual holistic rehabilitation as usual care. In total, 37 patients with a TBI and aged 57 to 90 years were assigned to experimental (n=23) and control (n=14) groups in a semi-randomized, controlled, before-after intervention trial with follow-up at 6 months, with blinded outcome measurement. The CEP's executive function module included planning, problem solving, and goal management training as well as strategies focusing on self-awareness. Efficacy was evaluated by neuropsychological tests (Six Elements Task-Adapted [SET-A], D-KEFS Sorting test and Stroop four-color version); generalization was measured by self-reporting questionnaires about daily functioning (Dysexecutive Functioning Questionnaire, forsaken daily activities). ANCOVA results showed significant group-by-time interactions; the experimental group showed a statistically significant improvement on Tackling the 6 subtasks and Avoiding rule-breaking measures of the SET-A, with medium effect sizes. The generalization measure, the Dysexecutive Functioning Questionnaire, showed a significant reduction in experimental patient-significant other difference on the Executive cognition subscale. The number of forsaken daily activities was reduced in the experimental versus control group, which was not significant immediately after the CEP but was significant 6 months later. Our study shows that older adults with TBI can improve their executive functioning, with a positive impact on everyday activities, after receiving multimodal cognitive training with the CEP. ClinicalTrials.gov Identifier: NCT04590911.

A-3 Cingulo-Opercular and Frontoparietal Control Network Connectivity and Executive Functioning in Older Adults

Abstract Objective Executive functioning is a cognitive domain that typically declines with normal aging. Age-related disrupted connectivity in cingulo-opercular (CON) and frontoparietal control (FPCN) resting-state networks is associated with worse performance across various executive functioning tasks. This study examines the relationships between CON and FPCN connectivity and executive functioning performance in older adults across three subdomains: working memory, inhibition, and set-shifting. Methods 274 healthy older adults (age M = 71.7, SD = 5.1; 87% Caucasian) from a clinical trial at the University of Florida and University of Arizona completed tasks of working memory (Digit Span Backwards [DSB]; Letter Number Sequencing [LNS]), inhibition (Stroop), and set-shifting (Trail Making Test Part B [TMT-B]). Participants underwent resting-state functional magnetic resonance imaging. CONN Toolbox (18b) was used for extracting average within-network connectivity of CON and FPCN. Multiple linear regressions were conducted with average network connectivity predicting performance, controlling for age, sex, education, and scanner. Results Greater average CON connectivity was associated with better performance on DSB (β = 0.26, p &amp;lt; 0.001), LNS (β = 0.23, p &amp;lt; 0.001), Stroop (β = 0.24, p &amp;lt; 0.001), and TMT-B (β = −0.26, p &amp;lt; 0.001). Greater average FPCN connectivity was associated with better performance on DSB (β = 0.22, p &amp;lt; 0.001) and LNS (β = 0.18, p = 0.002). Conclusions CON connectivity was significantly associated with working memory, inhibition, and set-shifting. FPCN connectivity was significantly associated with working memory. Future research should conduct regional connectivity analyses within these networks to identify intervention targets to improve executive functioning in older adults.

The role of executive functions in older adults’ affective theory of mind

PurposeExecutive function (EF) has three subsystems: inhibition, updating, and shifting. Of these three, only inhibition is considered to be involved in affective theory of mind (ToM). This study investigated whether inhibition remains the sole driver for affective ToM in the three EF subsystems in older adults as well as in young people without functional reorganization via aging within EF. Materials and methodsThrough hierarchical multiple regression analysis, we examined how these three subsystems affect older participants’ performance in the Reading the Mind in the Eyes Test (RMET), a measure of affective ToM, after determining the effect of domain-specific cognitive (nonverbal and verbal) abilities. ResultsWe found that only inhibition influenced the participants’ performance in the RMET, with effects from nonverbal (fluid) ability but not from verbal ability. ConclusionsResults showed that inhibition continues to be essential for affective ToM after aging decline, and functional reorganization via aging is less likely to occur within EF.

Benefits of VR Physical Exercise on Cognition in Older Adults with and without Mild Cognitive Decline: A Systematic Review of Randomized Controlled Trials.

It is well known that physical exercise has beneficial effects on cognitive function in older adults. Recently, several physical exercise programs with virtual reality (VR) have been proposed to support physical exercise benefits. However, it is still unclear whether VR physical exercise (VR-PE) has positive effects on cognitive function in older adults. The purpose of this study was to conduct a systematic review (SR) of the effects of VR-PE on cognitive function in older adults with and without cognitive decline. We used academic databases to search for research papers. The criteria were intervention study using any VR-PE, participants were older adults with and without mild cognitive decline (not dementia), and cognitive functions were assessed. We found that 6 of 11 eligible studies reported the significant benefits of the VR-PE on a wide range of cognitive functions in aging populations. The SR revealed that VR-PE has beneficial effects on the inhibition of executive functions in older adults with and without mild cognitive decline. Moreover, VR-PE selectively leads to improvements in shifting and general cognitive performance in healthy older adults. The SR suggests that VR-PE could be a successful approach to improve cognitive function in older adults with and without cognitive decline.

Spontaneous Eye Blinks Predict Executive Functioning in Seniors

As the world’s population is aging rapidly, cognitive training is an extensively used approach to attempt improvement of age-related cognitive functioning. With increasing numbers of older adults required to remain in the workforce, it is important to be able to reliably predict future functional decline, as well as the individual advantages of cognitive training. Given the correlation between age-related decline and striatal dopaminergic function, we investigated whether eye blink rate (EBR), a non-invasive, indirect indicator of dopaminergic activity, could predict executive functioning (response inhibition, switching and working memory updating) as well as trainability of executive functioning in older adults. EBR was collected before and after a cognitive flexibility training, cognitive training without flexibility, or a mock training. EBR predicted working memory updating performance on two measures of updating, as well as trainability of working memory updating, whereas performance and trainability in inhibition and switching tasks could not be predicted by EBR. Our findings tentatively indicate that EBR permits prediction of working memory performance in older adults. To fully interpret the relationship with executive functioning, we suggest future research should assess both EBR and dopamine receptor availability among seniors.

Milk, Yogurt, and Cheese Intake Is Positively Associated With Cognitive Executive Functions in Older Adults of the Canadian Longitudinal Study on Aging.

Dairy products provide essential nutrients such as calcium and vitamins B12 and D, and include bioactive peptides and fermented products, which may be beneficial for cognition, especially in older adults. Yet, few studies of large contemporary cohorts have investigated this relationship using sensitive domain-specific cognitive tests. In community-dwelling older adults of the Canadian Longitudinal Study on Aging (2011-2015), we examined cross-sectional associations between total and specific dairy product intake and performance in 3 cognitive domains (executive functions, memory, and psychomotor speed). Cheese, milk, yogurt, regular-fat, low-fat, and fermented dairy product intake frequencies were estimated using a food frequency questionnaire; participants were classified into quartiles. Multivariate analyses of covariance models were applied to estimate differences. In 7 945 participants (65-86 years, 49% women, 97% Caucasian), the mean dairy product intake was 1.9 (1.1) times/d. Total dairy product, cheese, and low-fat dairy product intakes were positively associated with the executive function domain and yogurt intake with the memory domain (all p < .05), independently of important covariates including age, gender, education, and diet quality. Intakes of total dairy product, cheese, and low-fat dairy product were associated with verbal fluency specifically (all p < .05). Participants with a dairy product intake >2.5 times/d had a higher score compared to those consuming less. No associations were found with psychomotor speed. This large cohort study suggests a specific role for dairy components in executive function phonemic verbal fluency and memory. Dairy product intake, a modifiable factor, may be targeted in cognitive health-promoting interventions.

Greater habitual moderate-to-vigorous physical activity is associated with better executive function and higher prefrontal oxygenation in older adults.

International physical activity guidelines recommend that older adults accumulate 150min/week of moderate-vigorous physical activity (MVPA). It is unclear whether meeting this recommendation is associated with better higher-order cognitive functions and if so, what are the neurophysiological mechanisms responsible for such a relationship. We tested the hypothesis that meeting MVPA guidelines is associated with better executive function in older adults, and explored if greater increases in prefrontal cortex oxygenation are implicated. Older adults who did (active, n = 19; 251 ± 79min/week) or who did not (inactive, n = 16; 89 ± 33min/week) achieve activity guidelines were compared. Executive function was determined via a computerized Stroop task while changes in left prefrontal cortex oxygenation (ΔO2Hb) were measured with functional near-infrared spectroscopy. Aerobic fitness ([Formula: see text] 2peak) was determined using a graded, maximal cycle ergometry test. MVPA and sedentary time were objectively assessed over 5days. Both groups had similar (both, P > 0.11) levels of aerobic fitness (24.9 ± 8.9 vs. 20.9 ± 5.6ml/kg/min) and sedentary time (529 ± 60 vs. 571 ± 90min/day). The active group had faster reaction times (1193 ± 230 vs. 1377 ± 239ms, P < 0.001) and greater increases in prefrontal cortex ΔO2Hb (9.4 ± 5.6 a.u vs. 5.8 ± 3.4 a.u, P = 0.04) during the most executively demanding Stroop condition than the Inactive group. Weekly MVPA was negatively correlated to executive function reaction times (r = - 0.37, P = 0.03) but positively correlated to the ΔO2Hb responses (r = 0.39. P = 0.02) during the executive task. In older adults, meeting MVPA guidelines is associated with better executive function and larger increases in cerebral oxygenation among older adults.

β-Lactolin Enhances Neural Activity, Indicated by Event-Related P300 Amplitude, in Healthy Adults: A Randomized Controlled Trial.

Background:Epidemiological studies have shown that dairy product consumption is beneficial for cognitive function in elderly individuals. β-lactolin is a Gly–Thr–Trp–Tyr lacto-tetrapeptide rich in fermented dairy products that improves memory retrieval, attention, and executive function in older adults with subjective cognitive decline and prevents the pathology of Alzheimer’s disease in rodents. There has been no study on the effects of β-lactolin on neural activity in humans.Objective:We investigated the effects of β-lactolin on neural activity and cognitive function in healthy adults.Methods:In this randomized, double-blind, placebo-controlled study, 30 participants (45–64 years old) consumed β-lactolin or placebo for 6 weeks. Neural activity during auditory and language tasks was measured through 64-channel electroencephalography. Moreover, verbal fluency tests were performed at baseline and after 6 weeks.Results:The β-lactolin group had a significantly higher P300 amplitude at the Cp2 site (a part of the parietal lobe near the center of brain, p = 0.011), and C4 site (the area between the frontal and parietal lobe, p = 0.02) during the auditory tasks after 6 weeks than the placebo group. Thus, β-lactolin supplementation promoted neural activity in the parietal area, which increases concentration and attention during auditory cognitive tasks. Compared with the placebo group, the β-lactolin group also showed significant changes in the scores of verbal fluency test after 6 weeks (p = 0.033).Conclusion:Our findings provide insight into the mechanisms underlying the effects of β-lactolin on attention in healthy adults.

Subclinical manic symptoms predict social cognitive impairment mediated by deficits in executive functioning in older adults with mood disorders

<h3>Introduction</h3> Bipolar disorder can impair executive functioning and social cognition which refers to the cognitive processes involved in understanding social cues (this includes theory of mind). However, little is known about the degree to which subclinical manic symptoms can impact social cognition in older adults and the role of executive functioning in this interaction. This cross-sectional study examined if transdiagnostic subclinical manic symptoms in older adults with mood disorders were related to impaired social cognition and if this relationship was mediated by executive functioning. <h3>Methods</h3> Ninety-five mood disorder patients (43 patients with bipolar disorder, 50 with major depressive disorder, 2 with schizoaffective disorder) ages 55 and above completed a battery of neuropsychological tests, mood and anxiety rating scales, clinical rating scales, functional and medical assessments. Total scores from the Mind in the Eyes task were used to assess social cognition. Executive functioning was assessed using the total correct scores from the Wisconsin Card Sorting Task (WCST). The Young Mania Rating Scale (YMRS), the Generalized Anxiety Disorder 7-item (GAD-7) scale and the Montgomery-Asberg Depression Rating Scale (MADRS) were used to assess mood and anxiety symptoms. <h3>Results</h3> All participants had subclinical manic symptoms based on the YMRS scores independent of their diagnosis. We used linear regressions to test mediation following the Baron and Kenny (1986) method. We found that greater subclinical manic symptoms (YMRS) were related to reduced executive functioning (path a, <i>p</i>=.043), and lower social cognitive functioning (Mind in the Eyes task), when controlling for depression and anxiety symptoms (path c, <i>p</i> = .002). The association between manic symptoms and social cognition was fully mediated by performance on an executive functioning task (the Wisconsin Card Sorting Task total correct scores, path b, <i>p</i>=.010, path c' <i>p</i>= .375). Mood diagnosis, depression and anxiety symptoms were not significantly related to performance on social cognitive or executive functioning tasks. <h3>Conclusions</h3> Executive functioning could explain social cognitive impairment related to subclinical manic symptoms. Our findings shed some light into the neuropsychological features of subclinical manic symptoms in older adults. <h3>Funding</h3> The Rogers Family Foundation

The Moderating Role of Sleep Quality on the Association between Neuroticism and Frontal Executive Function in Older Adults

ABSTRACT Objective/Background Personality traits are regarded as risk factors for cognitive impairment in older adults, while sleep disturbance and physical inactivity are also considered as modifiable risk factors. Therefore, it could be beneficial to investigate the effects of those modifiable risk factors on the relationship between personality traits and cognitive functions, to prepare appropriate strategies for mitigating cognitive impairment. Participants A total of 155 cognitively unimpaired older adults were included. Methods All participants underwent cognitive function tests using the Seoul Neuropsychological Screening Battery and examinations for personality traits using the Big Five Inventory. Individual physical activity and sleep quality were assessed using the International Physical Activity Questionnaire and Pittsburgh Sleep Quality Index, respectively. A hierarchical linear multiple regression analysis was performed to demonstrate the direct association between personality traits and cognitive functions, and the multiple moderator analysis was used to analyze the moderating effects of lifestyle factors on this association. Results Among the five personality traits, only neuroticism was negatively associated with the frontal executive and visuospatial functions after controlling age, sex, and years of education. Interestingly, the negative relationship between neuroticism and frontal executive function was alleviated in older adults with higher sleep quality. Conclusions Our findings demonstrated that higher sleep quality has significant moderating effects on the negative association between neuroticism and frontal executive functions in older adults, which suggests intervention for improving sleep quality such as cognitive behavioral therapy can be considered in older adults who have personality traits associated with a high risk of cognitive impairment.

Stability of Subjective Executive Functioning in Older Adults with aMCI and Subjective Cognitive Decline.

Subjective memory concerns are characteristic of individuals with amnestic mild cognitive impairment (aMCI) and subjective cognitive decline (SCD), though subjective changes in executive functions have also been reported. In a cohort study, we examined the temporal stability of subjective report of executive functioning in a high education (mean=16.8years) sample of cognitively normal (CN) older adults and those with aMCI or SCD. Participants (CN, n=22; aMCI, n=21; SCD, n=24) and their informants completed the BRIEF-A and neuropsychological tests at two time points separated by approximately 1 year. Analyses focused on those with diagnostic stability (95.7%). Participants with aMCI and SCD, and their informants, endorsed worse executive functions relative to CN at both time points. No group by time interaction was observed for subjective or objective measures of executive function. Diagnostically stable CN older adults, and those with prodromal dementia conditions, report stable executive functioning at 1-year follow-up.

Combining frontal tDCS with walking rehabilitation to enhance mobility and cognition: a pilot clinical trial

Walking function is compromised with older age, particularly for cognitively demanding complex walking tasks. Frontal lobe brain networks are important to both complex walking and cognitive function. There is a need for interventions that target this brain region. This pilot study assessed a novel intervention to enhance both walking and executive function in older adults. The primary hypothesis was that eighteen sessions of frontal lobe tDCS combined with complex walking rehabilitation would be feasible, safe, and show preliminary efficacy for improvements in walking and cognition. Eighteen participants were randomized to one of three intervention groups: active tDCS and rehabilitation with complex walking tasks (Active/Complex); sham tDCS and rehabilitation with complex walking tasks (Sham/Complex); or sham tDCS and rehabilitation with typical walking (Sham/Typical). Outcome measures included multiple tests of walking function, executive function, and prefrontal activity during walking measured by functional near infrared spectroscopy. For the walking tests, effect sizes for Active/Complex were generally higher than for Sham/Complex. The Sham/Typical group exhibited walking test effect sizes that were often larger than either of the complex walking groups, possibly due to higher intervention step count. For the executive function tests, effect sizes were largest for the Active/Complex group. Improvements in prefrontal activity during walking were observed, as conceptualized by the Compensation Related Utilization of Neural Circuits Hypothesis. These preliminary findings support that tDCS combined with complex walking rehabilitation in older adults is feasible and may enhance both walking function and executive function.

Combining tDCS With a Motor-Cognitive Task to Reduce the Negative Impact of Dual-Tasking on the Gait of Older Adults

The simultaneous performance of a secondary task while walking (i.e., dual tasking) increases motor-cognitive interference and fall risk in older adults. Combining transcranial direct current stimulation (tDCS) with the concurrent performance of a task that putatively involves the same brain networks targeted by the tDCS may reduce the negative impact of dual-tasking on walking. We examined whether tDCS applied while walking reduces the dual-task costs to gait and whether this combination is better than tDCS alone or walking alone (with sham stimulation). In 25 healthy older adults (aged 75.7±10.5yrs), a double-blind, within-subject, cross-over pilot study evaluated the acute after-effects of 20 minutes of tDCS targeting the primary motor cortex and the dorsal lateral pre frontal cortex during three separate sessions:1) tDCS while walking on a treadmill in a virtual-reality environment (tDCS+walking), 2) tDCS while seated (tDCS+seated), and 3) walking in the virtual-reality environment with sham tDCS (sham+walking). The complex walking condition taxed motor and cognitive abilities. During each session, single- and dual-task walking and cognitive function were assessed before and immediately after stimulation. Compared to pre-tDCS performance, tDCS+walking reduced the dual-task cost to gait speed (p=0.004) and other gait features (e.g., variability p=0.02), and improved (p<0.001) executive function (Stroop interference score). tDCS+seated and sham+walking did not affect the dual-task cost to gait speed (p>0.17). These initial findings demonstrate that tDCS delivered during challenging walking ameliorates dual-task gait and executive function in older adults, suggesting that the concurrent performance of related tasks enhances the efficacy of the neural stimulation and mobility.

FNIRS Outcomes for a Pilot Clinical Trial Combining Frontal tDCS With Walking Rehabilitation in Older Adults

This pilot study assessed a novel intervention to enhance both walking and executive function in older adults. The primary hypothesis was that eighteen sessions of frontal lobe tDCS combined with walking rehabilitation would be feasible, safe, and show preliminary efficacy. Eighteen participants were randomized to one of three intervention groups: active tDCS and rehabilitation with complex walking tasks (Active/Complex); sham tDCS and rehabilitation with complex walking tasks (Sham/Complex); or sham tDCS and rehabilitation with typical walking (Sham/Typical). Outcome measures included multiple tests of walking function, executive function, and prefrontal activity during walking as measured by functional near infrared spectroscopy (fNIRS). Of the three groups, the Active/Complex group demonstrated the broadest improvements across outcome measures including for prefrontal activity. The functional range of prefrontal activity in this group was increased considerably, as conceptualized by the Compensation Related Utilization of Neural Circuits Hypothesis. Frontal tDCS is a promising adjuvant to walking rehabilitation.

Associations between depression symptoms and executive function in older adults with mild cognitive impairment: One‐year follow‐up

AbstractBackgroundPsychiatric disorders are among etiologies for Mild Cognitive Impairment (MCI), one of the main one is depression. The relationship between depression and Alzheimer's disease (AD) is not yet fully understood and it is considered both, isolated risk factor and prodrome stage of AD. The aim of this work is to investigate if older adults with MCI associated with significant depressive symptoms, compared with those without these symptoms, will have different executive functions outcomes after one‐year follow‐up.MethodRepeated measures ANCOVA with Bonferroni post‐hoc analysis was used with cognitive variables at baseline and follow up evaluation as dependent, presence of significative depression symptoms at baseline as independent while controlling for covariates age, gender and years of formal education. Depressive symptoms were measured by 15‐item geriatric depression scale and the cutoff point was 6. Executive functions as inhibitory control e cognitive flexibility were assessed by Five Digit Test, working memory by Digit Span Test and phonemic verbal fluency by letter S. Patients started depression treatment at baseline.ResultWere included 170 participants (125 without depressive symptoms and 45 with symptoms), mean age 74.44, 68 women, mean years of formal education was 4,54. Among these, 99 (29 with depressive symptoms) complete all tests in the two assessments. Due to cognitive impairment, some of them were unable to even start cognitive flexibility test. Results indicated there was a significant effect of depression symptoms at baseline on cognitive flexibility ability [F (1.94) = 7,271, p = 0.008). Participants with depression presented a significant improvement (p = 0.006) on cognitive flexibility average from baseline (11.60) to the end of follow up (7.24). For those without symptoms of depression at baseline, the averages were 6.32 at baseline and 5.98 at follow‐up. There was no significant effect of depressive symptoms on the other cognitive skills assessed when considering these covariates.ConclusionComparing participants with and without depression symptoms at baseline, there was an improvement in cognitive flexibility in the former group. We think this result could be related to effect of depression treatment.