Cochrane Database Syst Rev. 2011 Jan 19;1:CD006220.

Martin M, Clare L, Altgassen AM, Cameron MH, Zehnder F.
Psychologisches Institut, Universität Zürich, Lehrstuhl Gerontopsychologie, Binzmühlestrasse 14/24, Zürich, Switzerland, CH-8050.
Abstract
BACKGROUND: Evidence from some, but not all non-randomised studies suggest the possibility that cognitive training may influence cognitive functioning in older people. Due to the differences among cognitive training interventions reported in the literature, giving a general overview of the current literature remains difficult.
OBJECTIVES: To systematically review the literature and summarize the effect of cognitive training interventions on various domains of cognitive function (ie memory, executive function, attention and speed) in healthy older people and in people with mild cognitive impairment.
SEARCH STRATEGY: The CDCIG Specialized Register was searched on 30 September 2007 for all years up to December 2005. The Cochrane Library, MEDLINE, EMBASE, PsycINFO and CINAHL were searched separately on 30 September 2007 to find trials with healthy people. These results were supplemented by searches from January 1970 to September 2007 in PsychInfo/Psyndex, ISI Web of Knowledge and PubMed.
SELECTION CRITERIA: RCTs of interventions evaluating the effectiveness of cognitive training for healthy older people and people with mild cognitive impairment from 1970 to 2007 that met inclusion criteria were selected.
DATA COLLECTION AND ANALYSIS: Authors independently extracted data and assessed trial quality. Meta-analysis was performed when appropriate.
MAIN RESULTS: Only data on memory training could be pooled for analysis. Within this domain, training interventions were grouped according to several outcome variables. Results showed that for healthy older adults, immediate and delayed verbal recall improved significantly through training compared to a no-treatment control condition. We did not find any specific memory training effects though as the improvements observed did not exceed the improvement in the active control condition. For individuals with mild cognitive impairment, our analyses demonstrate the same pattern. Thus, there is currently little evidence on the effectiveness and specificity of memory interventions for healthy older adults and individuals with mild cognitive impairment.
AUTHORS’ CONCLUSIONS: There is evidence that cognitive interventions do lead to performance gains but none of the effects observed could be attributable specifically to cognitive training, as the improvements observed did not exceed the improvement in active control conditions. This does not mean that longer, more intense or different interventions might not be effective, but that those which have been reported thus far have only limited effect. We therefore suggest more standardized study protocols in order to maximize comparability of studies and to maximize the possibility of data pooling – also in other cognitive domains than memory.

Neurology. 2011 Feb 2. [Epub ahead of print]

Raffaitin C , Féart C , Le Goff M , Amieva H , Helmer C , Akbaraly TN , Tzourio C , Gin H , Barberger-Gateau P .

From the Diabetology-Nutrition Unit (C.R., H.G.), University Hospital of Bordeaux, Pessac; INSERM, U897 (C.R., C.F., M.L.G., H.A., C.H., P.B.-G.), Bordeaux; Victor Segalen Bordeaux 2 University (C.R., C.F., M.L.G., H.A., C.H., H.G., P.B.-G.), Bordeaux; INSERM, U888 (T.N.A.), Montpellier; Montpellier 1 University (T.N.A.), Montpellier; University Hospital of Montpellier (T.N.A.), CMRR Languedoc Roussillon, France; and INSERM, U708 (C.T.), Paris, France.

Abstract

OBJECTIVE: To examine associations between metabolic syndrome (MetS) and its individual components with risk of cognitive decline on specific cognitive functions.

METHODS: Participants were 4,323 women and 2,764 men aged 65 and over enrolled in the longitudinal Three-City Study. Cognitive decline, defined as being in the worst quintile of the distribution of the difference between baseline score and either 2- or 4-year follow-up, was assessed by the Mini-Mental State Examination (MMSE, global cognitive function), the Isaacs Set Test (IST, verbal fluency), and the Benton Visual Retention Test (BVRT, visual working memory). MetS was defined by National Cholesterol Education Program-Adult Treatment Panel III criteria (at least 3 of 5 cardio-metabolic abnormalities: hypertension, high waist circumference, hypertriglyceridemia, low high-density lipoprotein [HDL] cholesterol, hyperglycemia). Proportional hazards models were adjusted for age, gender, educational level, center, baseline cognitive score, APOE4 genotype, and other potential confounders.

RESULTS: MetS at baseline was associated with an increased risk of cognitive decline on MMSE (hazard ratio [HR] = 1.22 [1.08-1.37]; p = 0.001) and BVRT (HR = 1.13 [1.01-1.26]; p = 0.03) but not on IST (HR = 1.11 [0.95-1.29]; p = 0.18). Among MetS components, hypertriglyceridemia and low HDL cholesterol were significantly associated with higher decline on MMSE; diabetes, but not elevated fasting glycemia, was significantly associated with higher decline on BVRT and IST.

CONCLUSIONS: MetS as a whole and several of its components had a negative impact on global cognitive decline and specific cognitive functions in older persons.
PMID: 21288982 [PubMed - as supplied by publisher]

Proc Natl Acad Sci U S A. 2011 Jan 31. [Epub ahead of print]

Erickson KI , Voss MW , Prakash RS , Basak C , Szabo A , Chaddock L , Kim JS , Heo S , Alves H , White SM , Wojcicki TR , Mailey E , Vieira VJ , Martin SA , Pence BD , Woods JA , McAuley E , Kramer AF .

Department of Psychology, University of Pittsburgh, Pittsburgh, PA 15260.

Abstract

The hippocampus shrinks in late adulthood, leading to impaired memory and increased risk for dementia. Hippocampal and medial temporal lobe volumes are larger in higher-fit adults, and physical activity training increases hippocampal perfusion, but the extent to which aerobic exercise training can modify hippocampal volume in late adulthood remains unknown. Here we show, in a randomized controlled trial with 120 older adults, that aerobic exercise training increases the size of the anterior hippocampus, leading to improvements in spatial memory. Exercise training increased hippocampal volume by 2%, effectively reversing age-related loss in volume by 1 to 2 y. We also demonstrate that increased hippocampal volume is associated with greater serum levels of BDNF, a mediator of neurogenesis in the dentate gyrus. Hippocampal volume declined in the control group, but higher preintervention fitness partially attenuated the decline, suggesting that fitness protects against volume loss. Caudate nucleus and thalamus volumes were unaffected by the intervention. These theoretically important findings indicate that aerobic exercise training is effective at reversing hippocampal volume loss in late adulthood, which is accompanied by improved memory function.

The authors trained 4 older adults with probable Alzheimer’s disease to recall a name-face-occupation association using the spaced retrieval technique. Six training sessions were administered over a 2-week period. On each trial, participants selected a target photograph and stated the target name and occupation at increasingly longer retention intervals, contingent upon successful recall. Two transfer tasks were included to determine whether the trained association transferred to the person whose picture served as the training stimulus. Results yielded a positive effect of spaced retrieval on memory for the trained association. Analyses of errors revealed that participants remembered the target person’s occupation more often than his or her name. There was modest evidence of transfer of the name-face-occupation association to the actual person. Implications of these data for memory remediation and quality of life in cognitively impaired older adults are considered.

J Genet Psychol. 2010 Apr-Jun;171(2):168-81.

Cherry KE, Walvoord AA, Hawley KS.

Louisiana State University, Department of Psychology, 236 Audubon Hall, Baton Rouge, LA 70803, USA. pskatie@lsu.edu

Memory consolidation is a dynamic process. Reconsolidation theory assumes that reactivation during wakefulness transiently destabilizes memories, requiring them to reconsolidate in order to persist. Memory reactivation also occurs during slow-wave sleep (SWS) and is assumed to underlie the consolidating effect of sleep. Here, we tested whether the same principle of transient destabilization applies to memory reactivation during SWS. We reactivated memories in humans by presenting associated odor cues either during SWS or wakefulness. Reactivation was followed by an interference task to probe memory stability. As we expected, reactivation during waking destabilized memories. In contrast, reactivation during SWS immediately stabilized memories, thereby directly increasing their resistance to interference. Functional magnetic resonance imaging revealed that reactivation during SWS mainly activated hippocampal and posterior cortical regions, whereas reactivation during wakefulness primarily activated prefrontal cortical areas. Our results show that reactivation of memory serves distinct functions depending on the brain state of wakefulness or sleep.

Susanne Diekelmann, Christian Büchel, Jan Born & Björn Rasch,
Nature Neuroscience (2011)

University of Lübeck, Department of Neuroendocrinology, Lübeck, Germany.
University of Tübingen, Department of Medical Psychology and Neurobiology, Tübingen, Germany.
University Medical Center Hamburg-Eppendorf, Department of Systems Neuroscience, Hamburg, Germany.
University of Basel, Division of Cognitive Neuroscience, Basel, Switzerland.