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Individuals who carry the apolipoprotein E ϵ4 polymorphism have an increased risk of late-onset Alzheimer’s disease. However, because possession of the ϵ4 allele confers an increased risk for the diagnosis of dementia, it has proven problematic in older individuals to dissociate the influence of ϵ4 on cognitive capacity per se as distinct from its influence on clinical diagnostic status. We report a statistical approach that attempts to partial out the influence of diagnostic group membership (Alzheimer’s disease, mild cognitive impairment, healthy control) from the influence of apolipoprotein ϵ4 genetic status on cognitive functioning. The cognitive phenotype hypothesis predicts that ϵ4-positive individuals will show cognitive deficits (relative to matched ϵ4-negative individuals) independent of the development of Alzheimer’s disease. By contrast, the prodromal/preclinical Alzheimer’s disease hypothesis proposes that the effect of apolipoprotein E status on cognitive performance is a function of the increased risk of dementia in individuals with the ϵ4 allele. We evaluated these hypotheses in the Australian Imaging, Biomarkers and Lifestyle cohort (n = 1112). We first determined whether previously reported findings concerning ϵ4 status and age-related neuropsychological performance could be explained by the inadvertent recruitment of people with mild cognitive impairment into the healthy control group. We then tested each diagnostic group in isolation to identify any neuropsychological patterns that may be attributed to the ϵ4 allele. Finally, as interactions between the ϵ4 allele and age have previously been reported in cognitive functioning within healthy elderly populations, we attempted to determine whether the inclusion of mild cognitively impaired individuals in the sample may drive this relationship. An extensive battery of standardized, well-validated neuropsychological tasks was administered to a final sample of 764 healthy control subjects, 131 individuals with mild cognitive impairment and 168 individuals with Alzheimer’s disease. The effect of the ϵ4 allele on cognitive performance was assessed using a statistical mediation analysis and supplemented with Bayesian methods to address a number of the limitations associated with Fisherian/Neyman-Pearsonian significance testing. Our findings support the prodromal/preclinical Alzheimer’s disease hypothesis and do not support the concept of a distinctive ϵ4-related cognitive phenotype. [ABSTRACT FROM PUBLISHER]

Background: We aimed to examine the role of age and premorbid intelligence (IQ) in suppressing the relationship between subjective memory complaints (SMCs) and raw score memory performance.Methods: We used a community sample of older adults aged 66-90 years (N = 121) to test whether the inclusion of age and a premorbid IQ measure in multiple regression analyses increased semipartial correlations of raw score memory performance in predicting SMCs. Rank contrast correlations were also carried out to observe how age and premorbid IQ are related to complaint-performance congruency. Measures utilized in the study included the Memory Functioning Questionnaire (for SMCs), Visual Reproduction and Logical Memory Subtests (memory performance), and the National Adult Reading Test (premorbid IQ).Results: Inclusion of age and premorbid IQ in the multiple regression analyses increased semipartial correlations for all raw score measures of memory. Both age and premorbid IQ were significantly related to complaint-performance congruency, whereby older participants and those with lower premorbid IQ scores rated their memory abilities more leniently than younger and higher premorbid IQ participants.Conclusion: The results suggest differences in age and premorbid IQ play a small role in suppressing the relationship between SMCs and memory performance when utilizing raw score measures of memory. [ABSTRACT FROM AUTHOR]

Glucose administration is associated with memory enhancement in healthy young individuals under conditions of divided attention at encoding. While the specific neurocognitive mechanisms underlying this ′glucose memory facilitation effect′ are currently uncertain, it is thought that individual differences in glucoregulatory efficiency may alter an individual′s sensitivity to the glucose memory facilitation effect. In the present study, we sought to investigate whether basal hypothalamic—pituitary—adrenal axis function (itself a modulator of glucoregulatory efficiency), baseline self-reported stress and trait anxiety influence the glucose memory facilitation effect. Adolescent males (age range = 14—17 years) were administered glucose and placebo prior to completing a verbal episodic memory task on two separate testing days in a counter-balanced, within-subjects design. Glucose ingestion improved verbal episodic memory performance when memory recall was tested (i) within an hour of glucose ingestion and encoding, and (ii) one week subsequent to glucose ingestion and encoding. Basal hypothalamic—pituitary—adrenal axis function did not appear to influence the glucose memory facilitation effect; however, glucose ingestion only improved memory in participants reporting relatively higher trait anxiety. These findings suggest that the glucose memory facilitation effect may be mediated by biological mechanisms associated with trait anxiety. [ABSTRACT FROM PUBLISHER]

The article presents a study which discusses the predicts memory decline as a risk factor for Alzheimer's disease in older post-menopausal women. It mentions that the disease is characterized by a progressive loss of cognitive functioning and asserts that women also have a higher risk for developing the disease than men especially after their menopausal stage. It affirms that the relationship between reproductive hormones and follicle stimulating hormone serve as a major factor for the illness.

Behavioural evidence supports the notion that oral glucose ingestion enhances recognition memory judgements based on recollection, but not familiarity. The present study sought to clarify and extend upon these behavioural findings by investigating the influence of glucose administration on event-related potential (ERP) components that are thought to be differentially mediated by recollection and familiarity processes in healthy adolescents. In a within-subjects design, participants performed a recognition memory task, during which time electroencephalogram (EEG) was recorded, subsequent to ingestion of either (a) glucose or (b) placebo in a counterbalanced order. Response times during the recognition memory task were observed to be faster for the glucose condition, relative to a placebo control. Further, glucose ingestion was associated with an enhanced left parietal old/new ERP effect (a marker of recollection) and an enhanced mid-frontal old/new ERP effect (known to be mediated by familiarity). These findings (a) support the results of previous research that the ‘glucose memory facilitation effect’ can be extended to healthy adolescents, but (b) suggest that glucose enhances both the recollection and familiarity components of recognition memory. The observed ERP profile has important implications for the proposal that glucose specifically targets the hippocampus in modulating cognitive performance. [ABSTRACT FROM AUTHOR]

Context: Many observational studies have shown that physical activity reduces the risk of cognitive decline; however, evidence from randomized trials is lacking.Objective: To determine whether physical activity reduces the rate of cognitive decline among older adults at risk.Design and Setting: Randomized controlled trial of a 24-week physical activity intervention conducted between 2004 and 2007 in metropolitan Perth, Western Australia. Assessors of cognitive function were blinded to group membership.Participants: We recruited volunteers who reported memory problems but did not meet criteria for dementia. Three hundred eleven individuals aged 50 years or older were screened for eligibility, 89 were not eligible, and 52 refused to participate. A total of 170 participants were randomized and 138 participants completed the 18-month assessment.Intervention: Participants were randomly allocated to an education and usual care group or to a 24-week home-based program of physical activity.Main Outcome Measure: Change in Alzheimer Disease Assessment Scale-Cognitive Subscale (ADAS-Cog) scores (possible range, 0-70) over 18 months.Results: In an intent-to-treat analysis, participants in the intervention group improved 0.26 points (95% confidence interval, -0.89 to 0.54) and those in the usual care group deteriorated 1.04 points (95% confidence interval, 0.32 to 1.82) on the ADAS-Cog at the end of the intervention. The absolute difference of the outcome measure between the intervention and control groups was -1.3 points (95% confidence interval,-2.38 to -0.22) at the end of the intervention. At 18 months, participants in the intervention group improved 0.73 points (95% confidence interval, -1.27 to 0.03) on the ADAS-Cog, and those in the usual care group improved 0.04 points (95% confidence interval, -0.46 to 0.88). Word list delayed recall and Clinical Dementia Rating sum of boxes improved modestly as well, whereas word list total immediate recall, digit symbol coding, verbal fluency, Beck depression score, and Medical Outcomes 36-Item Short-Form physical and mental component summaries did not change significantly.Conclusions: In this study of adults with subjective memory impairment, a 6-month program of physical activity provided a modest improvement in cognition over an 18-month follow-up period.Trial Registration: anzctr.org.au Identifier: ACTRN12605000136606. [ABSTRACT FROM AUTHOR]

The issue of whether the hippocampus and related structures in the medial-temporal lobe (MTL) play a temporary or permanent role in autobiographical episodic memory remains unresolved. One long-standing belief is that autobiographical memory (AM), like semantic memory, is initially dependent on the MTL but ultimately can be retained and recovered independently of it. However, evidence that hippocampal amnesia results in severe loss of episodic memory for a lifetime of personally experienced events suggests otherwise. To test the opposing views, we conducted detailed investigations of autobiographical episodic memory in people with amnesia resulting from MTL lesions of varying extent. By combining precise quantification of MTL and neocortical volumes with sensitive measures of recollection of one's personal past, we show that the severity of episodic, but not semantic, AM loss is best accounted for by the degree of hippocampal damage and less likely related to additional neocortical compromise. [ABSTRACT FROM AUTHOR]

Learning of supra-span sequences was assessed in a densely amnesic individual (SJ) who suffers from a substantial circumscribed bilateral lesion to the hippocampus. SJ's ability to lay down information originating from repetitive memory recall episodes was assessed using Hebb's supra-span procedure. After assessment of short-term memory span, 25 sequences of span +1 items were presented to SJ for immediate serial recall (ISR), one sequence being presented repeatedly eight times. Learning was deduced by the comparison of ISR scores on the repeated versus nonrepeated sequences of span +1 items. SJ's learning capacity was examined using four different types of stimuli: digits, spatial locations (Corsi block tapping test), words, and pseudowords. Implicit learning of sensorimotor sequences was also assessed in SJ using a serial reaction time (SRT) paradigm. Findings with the supra-span ISR task revealed evidence of learning in SJ with all four types of stimuli. The learning magnitude, as well as learning rate, observed in SJ were comparable to those observed in matched control participants. SJ showed evidence of implicit learning on the SRT paradigm. We conclude that the hippocampus is not required to learn certain types of recurrent information, and that the supra-span ISR task can be considered as an implicit-based learning paradigm. These findings have significant implications for our conceptualisation of implicit learning, and for understanding of the role of the hippocampus in learning. [ABSTRACT FROM AUTHOR]

Rationale: Memory for a list of 20 words can be enhanced by preceding learning with consumption of 25 g glucose rather than an equally sweet aspartame solution. In previous studies, participants performed a secondary hand-movement task during the list-learning phase. Objective: The present placebo-controlled, double-blind study examined whether the additional cognitive load created by a secondary task is a crucial feature of the glucose memory facilitation effect. Methods: The effect of glucose administration on word recall performance in healthy young participants was examined under conditions where the primary memory task and a secondary task were competing for cognitive resources (across a range of secondary tasks), and where task difficulty was increased but dual task-mediated competition for cognitive resources did not exist. Measures of non-verbal and working memory performance were also compared under the different glycaemic conditions (glucose versus aspartame drinks). Results: In the present study, a beneficial effect of glucose on memory was detected after participants encoded a 20-word list while performing a secondary task, but not when participants encoded the list without a secondary task, nor when the 20 target words were intermixed with 20 non-target words (distinguished by gender of speaker). In addition, glucose significantly enhanced performance on spatial and working memory tasks. Conclusion: The data indicate that possible "depletion" of episodic memory capacity and/or glucose-mediated resources in the brain due to performing a concomitant cognitive task might be crucial to the demonstration of a glucose facilitation effect. Possible implications regarding underlying cognitive and physiological mechanisms are discussed in this article. [ABSTRACT FROM AUTHOR]

Three experiments provided validation data for an English language versionof the Amsterdam Short Term Memory Test (ASTM test) developed to detect feignedmemory impairment. Using a simulation design, the ASTM test compared favourablywith the Test of Memory Malingering (TOMM) and appeared better than a newly-devisedDigit Recognition Test (DRT). Feedback on the correctness of responses hadno significant effect on performance but notable trends were apparent. Simulatorswere significantly slower than controls on computerised versions of the ASTMtest and the TOMM. Convergent findings indicate that the English languageversion of the ASTM test may be useful in detecting malingering. [ABSTRACT FROM AUTHOR]

Rationale: Previous investigations have demonstrated increased performance after the administration of a glucose-load on certain aspects of cognitive functioning in healthy young adults. Generally these studies have used a procedure where participants were tested in the morning after an overnight fast. Objective: The aim of the present study was, for the first time, to investigate the glucose cognitive facilitation effect under more natural testing times and with shorter duration of the previous fast. Methods: Measures of verbal and non-verbal memory performance were compared under different fasting intervals (2-h fast versus overnight fast), times (morning versus afternoon) and glycaemic conditions (glucose versus aspartame drinks) in healthy young participants. Results: There was a significant glucose facilitation effect on long-term verbal memory performance. In addition, glucose significantly enhanced long-term spatial memory performance. The effect of glucose was essentially equivalent whether it was given after an overnight fast or a 2-h fast following breakfast or lunch. There was no effect of drink and time of day on working memory performance. Conclusions: The results of this study further support the hypothesis that glucose administration can enhance certain aspects of memory performance in healthy young adults. More significantly, the findings indicate that this cognitive facilitation effect persists under more naturalistic conditions of glucose administration and is not restricted to long fast durations or morning administration. [ABSTRACT FROM AUTHOR]