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1.
Effect of a Fibroin Enzymatic Hydrolysate on Memory Improvement: A Placebo-Controlled, Double-Blind Study.
Kang, YK, Lee, BY, Bucci, LR, Stohs, SJ
Nutrients. 2018;(2)
Abstract
The consumption of a specifically prepared silk fibroin protein enzymatic hydrolysate (FPEH) has been reported to improve cognitive function in healthy humans. The objective of the current study is to evaluate the dose-dependent effects of the FPEH on memory. Healthy adults with an average age of approximately 55 years were administered doses of 0, 280, 400 and 600 mg of FPEH per day in two divided doses for 3 weeks. The Rey-Kim Auditory Verbal Learning Test and the Rey-Kim Complex Figure Test of the Rey-Kim Memory Test were used to evaluate memory at baseline and after 3 weeks. The scores for each test were combined into the memory quotient score (MQ). Learning gradient, memory maintenance, retrieval efficacy, and drawing/recall scores were also compared. After 3 weeks of FPEH, dose-dependent increases were observed for the MQ, the learning gradient, the numbers of words remembered, the retrieval efficiency, and drawing/recall. The optimal dose for FPEH was 400 or 600 mg, depending on the end point measured. No adverse effects were reported. FPEH significantly improved measurements of memory in healthy adults by 3 weeks at doses over 280 mg daily, with an apparent plateau effect at 400-600 mg daily.
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2.
Complex antioxidants in a randomized single-blinded study of memory in seniors.
Summers, WK, Martin, RL, Liu, Y, Peña, B, Marsh, GM
Aging clinical and experimental research. 2018;(4):395-405
Abstract
INTRODUCTION Oxidative injury to the brain and aging are theoretical co-causes of Alzheimer's Disease (AD). Amyloid plaques and tangles are then secondary phenomenon. The preclinical state would then be 'normal' elderly. METHODS A potent complex antioxidant (antiOx) was tested against a popular one-a-day multivitamin (mV) in a randomized single blind design in 'normal' senior subjects over 6 months. Memory testing was done at baseline, 1, 3, and 6 months. The generalized estimating equation (GEE) approach was used to compare the change score of NLT100 and 20WR between two groups over time. RESULTS Analysis of the antiOx group (30 subjects) demonstrated significant improvement in declarative memory (change score for NLT100 at month 6 = 6.36 p < 0.0001) and working memory (change score for 20WR at month 6 = 3.23, p < 0.0001). A change-score analysis over 6 months suggests possible neurogenesis in the antiOx group. The mV group (33 subjects) had a change score of the NLT100 and 20WR on the sixth month of 2.20 and 0.32 (p = 0.07, 0.35). CONCLUSIONS A complex antioxidant blend, sold as an over-the-counter (OTC) supplement, can improve memory in elder subjects. Antioxidants may be beneficial in AD and other neurodegerative diseases.
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3.
The effect of spermidine on memory performance in older adults at risk for dementia: A randomized controlled trial.
Wirth, M, Benson, G, Schwarz, C, Köbe, T, Grittner, U, Schmitz, D, Sigrist, SJ, Bohlken, J, Stekovic, S, Madeo, F, et al
Cortex; a journal devoted to the study of the nervous system and behavior. 2018;:181-188
Abstract
INTRODUCTION Nutritional intervention with the natural polyamine spermidine, an autophagy-enhancing agent, can prevent memory loss in aging model organisms. This is the first human study to evaluate the impact of spermidine supplementation on memory performance in older adults at risk for the development of Alzheimer's disease. METHODS Cognitively intact participants with subjective cognitive decline (n = 30, 60-80 years of age) were included in this three-months, randomized, placebo-controlled, double-blind Phase IIa pilot trial with a spermidine-rich plant extract supplement. Effects of intervention were assessed using the behavioral mnemonic similarity task, measured at baseline and post-intervention visits. Data analysis was focused on reporting and interpreting effectiveness based on effect sizes. RESULTS Memory performance was moderately enhanced in the spermidine group compared with placebo at the end of intervention [contrast mean = .17, 95% confidence interval (CI): -.01, .35, Cohen's d = .77, 95% CI: 0, 1.53]. Mnemonic discrimination ability improved in the spermidine-treated group with a medium effect size (mean difference = -.11, 95% CI: -.19, -.03, Cohen's d = .79, 95% CI: .01, 1.55). A similar effect was not found in the placebo-treated group (mean difference = .07, 95% CI: -.13, .27, Cohen's d = -.20, 95% CI: -.94, .54). DISCUSSION In this pilot trial, nutritional spermidine was associated with a positive impact on memory performance in older adults with subject cognitive decline. The beneficial effect might be mediated by stimulation of neuromodulatory actions in the memory system. A follow-up Phase IIb randomized controlled trial will help validate the therapeutic potential of spermidine supplementation and delineate possible neurophysiological mechanisms of action. TRIAL REGISTRATION Registered in ClinicalTrials.gov with the Identifier NCT02755246.
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4.
Tensor Representation of Topographically Organized Semantic Spaces.
Pomi, A, Mizraji, E, Lin, J
Neural computation. 2018;(12):3259-3280
Abstract
Human brains seem to represent categories of objects and actions as locations in a continuous semantic space across the cortical surface that reflects the similarity among categories. This vision of the semantic organization of information in the brain, suggested by recent experimental findings, is in harmony with the well-known topographically organized somatotopic, retinotopic, and tonotopic maps in the cerebral cortex. Here we show that these topographies can be operationally represented with context-dependent associative memories. In these models, the input vectors and, eventually also, the associated output vectors are multiplied by context vectors via the Kronecker tensor product, which allows a spatial organization of memories. Input and output tensor contexts localize matrices of semantic categories into a neural layer or slice and, at the same time, direct the flow of information arriving at the layer to a specific address, and then forward the output information toward the corresponding targets. Given a neural topographic pattern, the tensor representation will place a set of associative matrix memories within a topographic regionalized host matrix in such way that they reproduce the empirical pattern of patches in the actual neural layer. Progressive approximations to this goal are accomplished by avoiding excessive overlap of memories or the existence of empty regions within the host matrix.
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5.
Gastrointestinal hormones in regulation of memory.
Mandal, A, Prabhavalkar, KS, Bhatt, LK
Peptides. 2018;:16-25
Abstract
The connection between the gastrointestinal hormones and the brain has been established many years ago. This relation is termed the gut-brain axis (GBA). The GBA is a bidirectional communication which not only regulates gastrointestinal homeostasis but is also linked with higher emotional and cognitive functions. Hypothalamus plays a critical role in the regulation of energy metabolism, nutrient partitioning and control of feeding behaviors. Various gut hormones are released inside the gastrointestinal tract on food intake. These hormones act peripherally and influence the different responses of the tissues to the food intake, but do also have effects on the brain. The hypothalamus, in turn, integrates visceral function with limbic system structures such as hippocampus, amygdala, and cerebral cortex. The hippocampus has been known for its involvement in the cognitive function and the modulation of synaptic plasticity. This review aims to establish the role of various gut hormones in learning and memory, through the interaction of various receptors in the hippocampus. Understanding their role in memory can also aid in finding novel therapeutic strategies for the treatment of the neurological disorders associated with memory dysfunctions.
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6.
Efficacy and Safety of Tremella fuciformis in Individuals with Subjective Cognitive Impairment: A Randomized Controlled Trial.
Ban, S, Lee, SL, Jeong, HS, Lim, SM, Park, S, Hong, YS, Kim, JE
Journal of medicinal food. 2018;(4):400-407
Abstract
The efficacy and safety of Tremella fuciformis (TF) as a nutritional supplement were assessed in individuals with subjective cognitive impairment (SCI). Seventy-five individuals with SCI were enrolled in an 8-week, randomized, double-blind, placebo-controlled trial of TF (600 mg/day, n = 30 or 1200 mg/day, n = 30) or placebo (n = 15). The primary outcome measure was changes in total scores of the subjective memory complaint questionnaire. The secondary outcome measures were changes in performance on short-term memory and executive functions, which were assessed using standardized cognitive tests. In addition, voxel-based morphometry was performed to examine the effects of TF on changes in gray matter volume. The individuals in the TF group showed greater improvements in the total scores on the subjective memory complaint questionnaire compared with those in the placebo group. There were also significantly greater improvements in short-term memory and executive functions in the TF group relative to the placebo group. Exploratory analysis demonstrated that there were significant group-by-visit interactions on the left precuneus, right supramarginal gyrus, right middle frontal gyrus, and right postcentral gyrus at corrected P < .05. Overall frequency of adverse events did not differ among high-dose TF (40.4%), low-dose TF (35.1%), and placebo groups (41.4%). The current findings suggest that TF could be safely administered to relieve subjective memory complaints and enhance cognition in individuals with SCI.
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7.
Habitual coffee consumption and cognitive function: a Mendelian randomization meta-analysis in up to 415,530 participants.
Zhou, A, Taylor, AE, Karhunen, V, Zhan, Y, Rovio, SP, Lahti, J, Sjögren, P, Byberg, L, Lyall, DM, Auvinen, J, et al
Scientific reports. 2018;(1):7526
Abstract
Coffee's long-term effect on cognitive function remains unclear with studies suggesting both benefits and adverse effects. We used Mendelian randomization to investigate the causal relationship between habitual coffee consumption and cognitive function in mid- to later life. This included up to 415,530 participants and 300,760 coffee drinkers from 10 meta-analysed European ancestry cohorts. In each cohort, composite cognitive scores that capture global cognition and memory were computed using available tests. A genetic score derived using CYP1A1/2 (rs2472297) and AHR (rs6968865) was chosen as a proxy for habitual coffee consumption. Null associations were observed when examining the associations of the genetic score with global and memory cognition (β = -0.0007, 95% C.I. -0.009 to 0.008, P = 0.87; β = -0.001, 95% C.I. -0.005 to 0.002, P = 0.51, respectively), with high consistency between studies (Pheterogeneity > 0.4 for both). Domain specific analyses using available cognitive measures in the UK Biobank also did not support effects by habitual coffee intake for reaction time, pairs matching, reasoning or prospective memory (P ≥ 0.05 for all). Despite the power to detect very small effects, our meta-analysis provided no evidence for causal long-term effects of habitual coffee consumption on global cognition or memory.
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8.
Effect of resveratrol on cognitive and memory performance and mood: A meta-analysis of 225 patients.
Farzaei, MH, Rahimi, R, Nikfar, S, Abdollahi, M
Pharmacological research. 2018;:338-344
Abstract
Resveratrol is a natural dietary phenolic compound which is extensively present in many edible fruits, including grape, berries, pomegranates, and peanuts. Reseveratrol has a broad spectrum of biological activities including anti-aging, chemopreventive, anti-carcinogenic, anti-inflammatory and antioxidant effects and thus it is effective in related diseases. Particularly, the positive effects of resveratrol in neuropsychological diseases have been proven in in-vitro and in-vivo studies. Some clinical trials have reported that resveratrol possesses preventive and therapeutic effects in cognitive disorders. Therefore, the current systematic review and meta-analysis aimed to assess the effects of resveratrol on cognition and memory performance as well as mood state. Electronic databases including Scopus, PubMed, Science Direct, and Cochrane library were searched with the keywords "Memory", "Cognitive", "Cognition" or "Mood" with "Resveratrol" until June 2017. Only clinical studies were included in this review. We have provided the most reliable evidence to date counting results obtained from 226 individuals from four randomized clinical trials evaluating the mentioned specific effects of resveratrol. The results of this meta-analysis showed that resveratrol has no significant effect on memory and cognitive performance assessed by auditory verbal learning tests. Two parameters of Profile of Mood States (POMS) including vigor and fatigue, decreased significantly by resveratrol. However, decrease in other parameters of POMS including tense/anxiety, depression, anger, and confusion by resveratrol was not significant. The key findings from this meta-analysis are that resveratrol has no significant impact on factors related to memory and cognitive performance, including learning ability, delayed recall, retention, and recognition with all effect sizes non-significant and effectively at zero. However, it has the potential to enhance mood. Further randomized, controlled trials are needed to achieve more conclusive results.
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9.
Memory and Brain Amyloid and Tau Effects of a Bioavailable Form of Curcumin in Non-Demented Adults: A Double-Blind, Placebo-Controlled 18-Month Trial.
Small, GW, Siddarth, P, Li, Z, Miller, KJ, Ercoli, L, Emerson, ND, Martinez, J, Wong, KP, Liu, J, Merrill, DA, et al
The American journal of geriatric psychiatry : official journal of the American Association for Geriatric Psychiatry. 2018;(3):266-277
Abstract
OBJECTIVE Because curcumin's anti-inflammatory properties may protect the brain from neurodegeneration, we studied its effect on memory in non-demented adults and explored its impact on brain amyloid and tau accumulation using 2-(1-{6-[(2-[F-18]fluoroethyl)(methyl)amino]-2-naphthyl}ethylidene)malononitrile positron emission tomography (FDDNP-PET). METHODS Forty subjects (age 51-84 years) were randomized to a bioavailable form of curcumin (Theracurmin® containing 90 mg of curcumin twice daily [N = 21]) or placebo (N = 19) for 18 months. Primary outcomes were verbal (Buschke Selective Reminding Test [SRT]) and visual (Brief Visual Memory Test-Revised [BVMT-R]) memory, and attention (Trail Making A) was a secondary outcome. FDDNP-PET signals (15 curcumin, 15 placebo) were determined in amygdala, hypothalamus, medial and lateral temporal, posterior cingulate, parietal, frontal, and motor (reference) regions. Mixed effects general linear models controlling for age and education, and effect sizes (ES; Cohen's d) were estimated. RESULTS SRT Consistent Long-Term Retrieval improved with curcumin (ES = 0.63, p = 0.002) but not with placebo (ES = 0.06, p = 0.8; between-group: ES = 0.68, p = 0.05). Curcumin also improved SRT Total (ES = 0.53, p = 0.002), visual memory (BVMT-R Recall: ES = 0.50, p = 0.01; BVMT-R Delay: ES = 0.51, p = 0.006), and attention (ES = 0.96, p < 0.0001) compared with placebo (ES = 0.28, p = 0.1; between-group: ES = 0.67, p = 0.04). FDDNP binding decreased significantly in the amygdala with curcumin (ES = -0.41, p = 0.04) compared with placebo (ES = 0.08, p = 0.6; between-group: ES = 0.48, p = 0.07). In the hypothalamus, FDDNP binding did not change with curcumin (ES = -0.30, p = 0.2), but increased with placebo (ES = 0.26, p = 0.05; between-group: ES = 0.55, p = 0.02). CONCLUSIONS Daily oral Theracurmin may lead to improved memory and attention in non-demented adults. The FDDNP-PET findings suggest that symptom benefits are associated with decreases in amyloid and tau accumulation in brain regions modulating mood and memory.
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10.
Comparative effect of coffee robusta and coffee arabica (Qahwa) on memory and attention.
Alharbi, WDM, Azmat, A, Ahmed, M
Metabolic brain disease. 2018;(4):1203-1210
Abstract
The comparative effects of coffee robusta and coffee arabica (Qahwa) on different attention and memory related assignments were measured in a double-blind study of 300 healthy young adult women who were randomly assigned to one of three different drinks: Group I (coffee robusta sachet dissolved in 100 ml of hot water): Group II (coffee arabica): and group III (100 ml water only). Cognitive function was assessed by standardized tests. Several monitoring cognitive tests and tasks were specifically chosen and performed to investigate the comparative effects of coffee robusta (CR) and coffee arabica (Qahwa; AC) on sleepiness (sleep and clear headed scale), attention (trail A & B, symbol digit, letter cancellation), general cognitive ability (stroop test) and memory (card test). Data was interpreted by analysis of variance (ANOVA). The present study revealed that coffee robusta has beneficial effects on attention, general cognitive ability and memory. Higher though non-significant cognitive scores were associated with coffee robusta consumption. Although, consumption of coffee arabica (Qahwa) has significant effects (P < 0.05) on sleepiness, attention, general cognitive ability and memory and it significantly improve reaction time and correct responses. Since different tasks were related to the sustained attention and working memory processes, results would suggest that coffee arabica (qahwa) could increase the memory and efficiency of the attentional system might be due to the presence of chlorogenic acids (CGA) which are found in less quantity in coffee robusta. However, more studies using larger samples and different tasks are necessary to better understand the effects of coffee robusta and arabica (Qahwa) on attention and memory.