Valentina A. Tesky

Combined omega-3 fatty acids, aerobic exercise and cognitive stimulation prevents decline in gray matter volume of the frontal, parietal and cingulate cortex in patients with mild cognitive impairment

Previous studies in older adults suggested beneficial effects of omega-3 fatty acid (FA) supplementation, aerobic exercise, or cognitive stimulation on brain structure and function. However, combined effects of these interventions in patients suffering from mild cognitive impairment (MCI) are unknown. Using a randomized interventional design, we evaluated the effect of combined omega-3 FA supplementation, aerobic exercise and cognitive stimulation (target intervention) versus omega-3 FA supplementation and non-aerobic exercise (control intervention) on cognitive function and gray matter volume in patients with MCI. Moreover, we analyzed potential vascular, metabolic or inflammatory mechanisms underlying these effects. Twenty-two MCI patients (8 females; 60-80years) successfully completed six months of omega-3 FA intake, aerobic cycling training and cognitive stimulation (n=13) or omega-3 FA intake and non-aerobic stretching and toning (n=9). Before and after the interventions, cognitive performance, magnetic resonance imaging of the brain at 3T (n=20), intima-media thickness of the internal carotid artery and serum markers of glucose control, lipid and B-vitamin metabolism, and inflammation were assessed. Intervention-related changes in gray matter volume of Alzheimers disease (AD)-related brain regions, i.e., frontal, parietal, temporal and cingulate cortex were examined using voxel-based morphometry of high resolution T1-weighted images. After the intervention period, significant differences emerged in brain structure between groups: Gray matter volume decreased in the frontal, parietal and cingulate cortex of patients in the control intervention, while gray matter volume in these areas was preserved or even increased after the target intervention. Decreases in homocysteine levels in the target intervention group were associated with increases in gray matter volume in the middle frontal cortex (p=0.010). No significant differences in cognitive performance or other vascular, metabolic and inflammatory parameters were observed between groups. This pilot study provides preliminary evidence that omega-3 FA intake combined with aerobic exercise and cognitive stimulation prevents atrophy in AD-related brain regions in MCI patients, compared to omega-3 FA intake plus the control condition of stretching and toning. These promising findings should now be validated in a larger interventional trial.

Vitamin B-12 concentration, memory performance, and hippocampal structure in patients with mild cognitive impairment

BACKGROUND Low-normal concentrations of vitamin B-12 (VitB12) may be associated with worse cognition. However, previous evidence has been mixed, and the underlying mechanisms remain unclear. OBJECTIVE We determined whether serum VitB12 concentrations within the normal range were linked to memory functions and related neuronal structures in patients with mild cognitive impairment (MCI). DESIGN In a cross-sectional design, we assessed 100 amnestic MCI patients (52 women; age range: 50-80 y) with low- and high-normal VitB12 concentration (median split: 304 pmol/L) for memory functions with the use of the Auditory Verbal Learning Test. MRI was performed at 3 tesla (n= 86) for the estimation of the volume and microstructure of the hippocampus and its subfields as indicated by the mean diffusivity on diffusion-weighted images. With the use of a mediation analysis, we examined whether the relation between VitB12 and memory performance was partially explained by volume or microstructure. RESULTS MCI patients with low-normal VitB12 showed a significantly poorer learning ability (P= 0.014) and recognition performance (P= 0.008) than did patients with high-normal VitB12. Also, the microstructure integrity of the hippocampus was lower in patients with low-normal VitB12, mainly in the cornu ammonis 4 and dentate gyrus region (P= 0.029), which partially mediated the effect of VitB12 on memory performance (32-48%). Adjustments for age, sex, education, apolipoprotein E e4 status, and total homocysteine, folate, and creatinine did not attenuate the effects. CONCLUSIONS Low VitB12 concentrations within the normal range are associated with poorer memory performance, which is an effect that is partially mediated by the reduced microstructural integrity of the hippocampus. Future interventional trials are needed to assess whether supplementation of VitB12 may improve cognition in MCI patients even in the absence of clinically manifested VitB12 deficiency. This trial was registered at clinicaltrials.gov as NCT01219244.

Cognitive intervention response is related to habitual physical activity in older adults

Background and aims: This study analysed the associations between physical activity and the effects of cognitive training on perceived cognitive functioning and life satisfaction in older adults. Methods: A sample of 114 intervention group participants (65–89 yrs) received weekly group sessions of cognitive stimulation for two months. This sample was stratified into groups according to habitual physical activity (PA) and matched with 45 controls. Participants completed the Memory Complaint Questionnaire (MAC-Q), Nuremberg Self-Rating List (NSL) and Alzheimer Disease Assessment Scale — Cognitive Subscale (ADAS-Cog) at three time-points (baseline, 2 months, and 6-month follow-up). Results: At baseline, groups did not differ in absolute MAC-Q, NSL or ADAS-Cog scores. NSL difference scores (follow-up score minus baseline NSL score) of the three cognitive intervention groups (>6.95h MVPA/wk; 3.64–6.95h MVPA/wk; <3.64h MVPA/wk) and controls were −3.8±7.3, −2.5±11.0, +0.3±12.0 and +0.1±9.1 over 2 months, and −4.2±7.6, −4.0±14.0, −1.8±7.7 and +0.5±9.7 over 6 months, respectively. MAC-Q difference scores were −1.1±2.9, −1.1±3.4, −0.3±3.9 and +0.3±2.7 over 2 months, and −1.5±3.2, −0.8±2.9, −0.3±2.9 and +0.3±2.2 over 6 months. The groups significantly (p<0.05) differed on NSL and MAC-Q difference scores. Specifically, the more active groups differed from controls, and in some cases from the least active group. Groups did not differ on ADAS-Cog difference scores. Conclusions: Our findings indicate a relation between amount of physical activity and the effects of a cognitive stimulation intervention on perceived cognitive functioning and life satisfaction. Physically more active persons may gain more benefit from cognitive stimulation than the physically less active.

Impact of Resveratrol on Glucose Control, Hippocampal Structure and Connectivity, and Memory Performance in Patients with Mild Cognitive Impairment

In healthy older adults, resveratrol supplementation has been shown to improve long-term glucose control, resting-state functional connectivity (RSFC) of the hippocampus, and memory function. Here, we aimed to investigate if these beneficial effects extend to individuals at high-risk for dementia, i.e., patients with mild cognitive impairment (MCI). In a randomized, double-blind interventional study, 40 well-characterized patients with MCI (21 females; 50–80 years) completed 26 weeks of resveratrol (200 mg/d; n = 18) or placebo (1,015 mg/d olive oil; n = 22) intake. Serum levels of glucose, glycated hemoglobin A1c and insulin were determined before and after intervention. Moreover, cerebral magnetic resonance imaging (MRI) (3T) (n = 14 vs. 16) was conducted to analyze hippocampus volume, microstructure and RSFC, and neuropsychological testing was conducted to assess learning and memory (primary endpoint) at both time points. In comparison to the control group, resveratrol supplementation resulted in lower glycated hemoglobin A1c concentration with a moderate effect size (ANOVARM p = 0.059, Cohens d = 0.66), higher RSFC between right anterior hippocampus and right angular cortex (p < 0.001), and led to a moderate preservation of left anterior hippocampus volume (ANOVARM p = 0.061, Cohens d = 0.68). No significant differences in memory performance emerged between groups. This proof-of-concept study indicates for the first-time that resveratrol intake may reduce glycated hemoglobin A1c, preserves hippocampus volume, and improves hippocampus RSFC in at-risk patients for dementia. Larger trials with longer intervention time should now determine if these benefits can be validated and extended to cognitive function.

Genetic variants of the FADS gene cluster are associated with erythrocyte membrane LC PUFA levels in patients with mild cognitive impairment

BackgroundLong-chain (> 20 C-atoms) polyunsaturated fatty acids (LC PUFAs) of both the omega-6 (n-6) and omega-3 (n-3) series are important for the functional integrity of brain and thereby cognition, memory and mood. Clinical studies observed associations between altered LC PUFA levels and neurodegenerative diseases such as Alzheimer´s disease and its prodromal stage, mild cognitive impairment (MCI).MethodsThe present study examined the LC PUFA status of MCI patients with specific view on the relative LC n-3 PUFA levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in erythrocyte membranes (omega-3 index). 12 single nucleotide polymorphisms (SNPs) of the FADS1, FADS2, and FADS3 gene clusters were genotyped in 111 MCI patients and evaluated associations with PUFA levels in erythrocyte membranes (primary outcome). In addition, the associations between FADS SNPs and LC PUFA levels with serum lipid levels as well as depressive symptoms were examined (secondary outcomes).ResultsMinor allele carrier of rs174546, rs174548 (FADS1), rs3834458, rs1535, rs174574, rs174575, rs174576, and rs174578 (FADS2) showed significant higher n-6 and n-3 precursor PUFA levels (linoleic acid, and alpha-linolenic acid, respectively) and lower arachidonic acid (AA) levels in erythrocyte membranes compared to the major allele carriers. Differences in EPA and DHA levels were not significant. Minor allele carriers of rs174574, rs174576 and rs174578 (FADS2) and rs174455 (FADS3) exhibited significant higher triglyceride levels, whereas minor allele carriers for rs174449 and rs174455 (FADS3) exhibited significant higher total- and LDL-cholesterol levels compared to the more common variant. The mean omega-3 index of the study cohort was 6.19 ± 1.55 %. In more than 85 % of the patients, the omega-3 index was below 8 % and in 23 % below 5 %. Moreover, it was shown that a low DHA status and omega-3 index was associated with depressive symptoms (Beck’s depression-inventory).Discussion and conclusionThese findings indicate an association between several FADS genotypes for higher n-6 and n-3 precursor PUFA and lower AA levels in erythrocyte membranes in minor compared to major allele carriers. To what extent FADS genotypes and a lower conversion of LA and ALA to biologically important LC PUFAs such as AA, EPA and DHA contributes to cognitive decline should be investigated in further trials. Nevertheless, the omega-3 index in this cohort of MCI patients can be classified as insufficient.

Effects of aerobic exercise on brain metabolism and grey matter volume in older adults: results of the randomised controlled SMART trial

There is mounting evidence that aerobic exercise has a positive effect on cognitive functions in older adults. To date, little is known about the neurometabolic and molecular mechanisms underlying this positive effect. The present study used magnetic resonance spectroscopy and quantitative MRI to systematically explore the effects of physical activity on human brain metabolism and grey matter (GM) volume in healthy aging. This is a randomised controlled assessor-blinded two-armed trial (n=53) to explore exercise-induced neuroprotective and metabolic effects on the brain in cognitively healthy older adults. Participants (age >65) were allocated to a 12-week individualised aerobic exercise programme intervention (n=29) or a 12-week waiting control group (n=24). The main outcomes were the change in cerebral metabolism and its association to brain-derived neurotrophic factor (BDNF) levels as well as changes in GM volume. We found that cerebral choline concentrations remained stable after 12 weeks of aerobic exercise in the intervention group, whereas they increased in the waiting control group. No effect of training was seen on cerebral N-acetyl-aspartate concentrations, nor on markers of neuronal energy reserve or BDNF levels. Further, we observed no change in cortical GM volume in response to aerobic exercise. The finding of stable choline concentrations in the intervention group over the 3 month period might indicate a neuroprotective effect of aerobic exercise. Choline might constitute a valid marker for an effect of aerobic exercise on cerebral metabolism in healthy aging.

Impact of leptin on memory function and hippocampal structure in mild cognitive impairment

Metabolic changes have been suggested to contribute to dementia and its precursor mild cognitive impairment (MCI), yet previous results particularly for the “satiety hormone” leptin are mixed. Therefore, we aimed to determine if MCI patients show systematic differences in leptin, independent of sex, adipose mass, age, and glucose and lipid metabolism, and whether leptin levels correlated with memory performance and hippocampal integrity. Forty MCI patients (20 females, aged 67 years ± 7 SD) were compared to 40 healthy controls (HC) that were pair‐wise matched for sex, age, and body fat. Memory performance was assessed using the auditory verbal learning test. Volume and microstructure of the hippocampus were determined using 3T‐neuroimaging. Fasting serum markers of leptin, glucose and lipid metabolism, and other confounding factors were assayed. MCI patients, compared with HC, showed lower serum leptin, independent of sex, age, and body fat (P < 0.001). Glucose and lipid markers did not attenuate these results. Moreover, MCI patients exhibited poorer memory and lower volume and microstructural integrity within hippocampal subfields. While leptin and memory were not significantly correlated, mediation analyses indicated that lower leptin contributed to poorer memory through its negative effect on right hippocampus volume and left hippocampus microstructure. We demonstrated that MCI is associated with lower serum leptin independent of sex, age, body fat, glucose, and lipid metabolism. Our data further suggest that inefficient leptin signaling could partly contribute to decreases in memory performance through changes in hippocampus structure, a hypothesis that should now be verified in longitudinal studies. Hum Brain Mapp 37:4539–4549, 2016.

Art museum-based intervention to promote emotional well-being and improve quality of life in people with dementia: The ARTEMIS project:

ARTEMIS (ART Encounters: Museum Intervention Study) is an art-based intervention designed especially for people with dementia and their care partners that involves a combination of museum visits and artistic activity. This paper reports the results of a randomized wait-list controlled study on the influence of the ARTEMIS intervention on the emotional state, well-being, and quality of life of dementia patients. People with mild-to-moderate dementia (n = 44) and their care partners (n = 44) visited the Frankfurt Städel Museum once a week on six pre-arranged occasions. The intervention consisted of six different guided art tours (60 minutes), followed by art-making in the studio (60 minutes). Independent museum visits served as a control condition. A mixed-methods design was used to assess several outcomes including cognitive status, emotional well-being, self-rated aspects of quality of life, and subjective evaluations by informal caregivers. In a pre-post-assessment, we found significant improvements in participants’ self-rated quality of life (t = −3.15, p < .05). In a situational assessment of emotional well-being immediately before and after each of the museum sessions, we were able to demonstrate statistically significant positive changes with medium effect sizes (dcorr = .74–.77). Furthermore, the total Neuropsychiatric Inventory score as well as the affective (depressed mood and anxiety) and apathy subscales were significantly lower after the ARTEMIS intervention (tNPI total = 2.43; tNPI affective = 2.24; tNPI apathy = 2.52; p < .05). The results show that art museum-based art interventions are able to improve the subjective well-being, mood, and quality of life in people with dementia. This promising psychosocial approach deserves further attention in future studies and consideration in community-based dementia care programs.

Feasibility and first results of a group program to increase the frequency of cognitively stimulating leisure activities in people with mild cognitive impairment (AKTIVA–MCI)

AKTIVA-MCI is a program for patients with mild cognitive impairment (MCI) that aims to enhance participation in cognitively stimulating leisure activities. Participation in cognitively stimulating activities seems to be a potential strategy for people with MCI delaying cognitive decline for a while. In total, 35 MCI patients were enrolled in the pilot study of whom 29 completed the whole program (16 female, 71.1±7.5 years; Mini Mental Status Examination score: 28±2.2). Daily activity protocols were used to measure the frequency of participation in cognitively stimulating activities during the program (12 sessions). Additional standardized psychometric tests and questionnaires were used to assess cognition, mood, and subjective memory decline. Analyses of the daily activity protocols showed that during the intervention participants increased the frequency of several cognitively stimulating leisure activities. Comparison of pre-post data indicates no changes in cognitive status, mood, and subjective memory decline. These findings indicate that the program is suitable for patients with MCI.

EFFECTS OF AEROBIC EXERCISE ON BRAIN METABOLISM AND GREY MATTER VOLUME IN OLDER ADULTS: RESULTS OF THE SMART TRIAL

Background:Mild cognitive impairment (MCI) represents a transition between normal cognitive aging and dementia, and may represent a critical timeframe to promote cognitive health through behavioural strategies. Current evidence suggests physical activity (PA) and sedentary behaviour (SB) are important for cognition. However, it is unclear if PA and SB differences exist between individuals with and without MCI or if the relationships of PA and SB with cognitive function differ by MCI categorization. Thus, using cross-sectional data, we examined: 1) differences in PA and SB between individuals with and without MCI; and 2) whether associations of PA and SB with cognitive function differed by MCI categorization. Methods:We measured PA and SB in communitydwelling adults (N1⁄4150; aged 55+) using the MotionWatch8 . Using theMontreal Cognitive Assessment, we categorized individuals with MCI (<26/30) and without MCI ( 26/30). Cognitive function was indexed using the Alzheimer’s Disease Assessment Scale-Plus (ADAS-Cog Plus). We compared PA and SB based on MCI categorization, and examined relationships of ADAS-Cog Plus with PA and SB by MCI categorization. Results: Individuals with MCI (N1⁄483) had lower PA (p<0.01) and higher SB (p1⁄40.03) than individuals without MCI (N1⁄469). Higher PA and lower SB were associated with better ADAS-Cog Plus performance in the non-MCI group (b1⁄4-0.022, p1⁄40.02 and b1⁄40.012, p1⁄40.04 respectively), but not in the MCI group (b<0.001, p1⁄40.993 and b<0.001, p1⁄40.948, respectively). Conclusions: Individuals with MCI were less active and more sedentary. The relationships of these behaviours with cognitive function differed by MCI categorization; associations were only found in non-MCI individuals.