Number Of Cognitive Domains Research Articles

Nicotinic α7 and α4β2 agonists enhance the formation and retrieval of recognition memory: Potential mechanisms for cognitive performance enhancement in neurological and psychiatric disorders

Cholinergic dysfunction has been shown to be central to the pathophysiology of Alzheimer’s disease and has also been postulated to contribute to cognitive dysfunction observed in various psychiatric disorders, including schizophrenia. Deficits are found across a number of cognitive domains and in spite of several attempts to develop new therapies, these remain an unmet clinical need.In the current study we investigated the efficacy of donepezil, risperidone and selective nicotinic α7 and α4β2 receptor agonists to reverse a delay-induced deficit in recognition memory. Adult female Hooded Lister rats received drug treatments and were tested in the novel object recognition (NOR) task following a 6h inter-trial interval (ITI). In all treatment groups, there was no preference for the left or right identical objects in the acquisition trial. Risperidone failed to enhance recognition memory in this paradigm whereas donepezil was effective such that rats discriminated between the novel and familiar object in the retention trial following a 6h ITI. Although a narrow dose range of PNU-282987 and RJR-2403 was tested, only one dose of each increased recognition memory, the highest dose of PNU-282987 (10mg/kg) and the lowest dose of RJR-2403 (0.1mg/kg), indicative of enhanced cognitive performance. Interestingly, these compounds were also efficacious when administered either before the acquisition or the retention trial of the task, suggesting an important role for nicotinic receptor subtypes in the formation and retrieval of recognition memory.

Examining the effect of oral contraceptive use on verbal learning and memory, verbal fluency and mental rotation

Event Abstract Back to Event Examining the effect of oral contraceptive use on verbal learning and memory, verbal fluency and mental rotation Andrea Gogos1*, Loic Tse1, Amy Scarlett2, Jane Ackerl2, Tracey Woodhead2 and Linda Byrne2 1 University of Melbourne, Florey Institute of Neuroscience and Mental Health, Australia 2 Deakin University, School of Psychology, Australia The oral contraceptive pill (OC) is the most widely employed form of reversible contraception. It commonly contains a combination of a synthetic estrogen and progestin. While a substantial body of literature has been dedicated to understanding the physical effects associated with OC use, less is known about the effects of the OC on cognitive function. This study investigated the effects of OC use on several cognitive domains in healthy, pre-menopausal women. The effects of these exogenously administered, synthetic sex hormones were compared with endogenous sex hormone variations in naturally-cycling women. Women were tested twice, during the follicular phase/inactive pill (low estradiol/progesterone) and the luteal phase/active pill (high estradiol/progesterone). While a number of cognitive domains were measured, here we present verbal memory (as measured with the California Verbal Learning Test), verbal fluency (letter and category) and mental rotation (Vandenberg and Kuse 3D figures). Currently, we have completed testing in 10 OC-using women (age 26 ± 4 years) and 11 naturally-cycling women (age 28 ± 5 years). As expected, at both time points, blood concentrations of estradiol/progesterone revealed that OC use significantly reduced circulating estradiol (76 ± 12 pmol/L) and progesterone (0.8 ± 0.5 nmol/L). Hormone assays confirmed that naturally-cycling women were tested during the early follicular phase, a time of low circulating estradiol (189 ± 60 pmol/L) and progesterone (1.3 ± 0.4 nmol/L), and during the mid-luteal phase, a time of high circulating estradiol (409 ± 112 pmol/L) and progesterone (25.9 ± 10.2 nmol/L). With such a small number of participants, we did not find any significant changes in verbal memory, verbal fluency or mental rotation. More participants are needed before any conclusions can be made on the effects of exogenous versus endogenous hormones on cognitive function in healthy, pre-menopausal women. Keywords: Cognition, Estradiol, Menstrual Cycle, Progesterone, mental rotation, verbal memory, ethinylestradiol, verbal fluency, oral contraceptive pill, Healthy women Conference: XII International Conference on Cognitive Neuroscience (ICON-XII), Brisbane, Queensland, Australia, 27 Jul - 31 Jul, 2014. Presentation Type: Poster Topic: Cognition and Executive Processes Citation: Gogos A, Tse L, Scarlett A, Ackerl J, Woodhead T and Byrne L (2015). Examining the effect of oral contraceptive use on verbal learning and memory, verbal fluency and mental rotation. Conference Abstract: XII International Conference on Cognitive Neuroscience (ICON-XII). doi: 10.3389/conf.fnhum.2015.217.00143 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 19 Feb 2015; Published Online: 24 Apr 2015. * Correspondence: Dr. Andrea Gogos, University of Melbourne, Florey Institute of Neuroscience and Mental Health, Parkville, Australia, agogos@unimelb.edu.au Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Andrea Gogos Loic Tse Amy Scarlett Jane Ackerl Tracey Woodhead Linda Byrne Google Andrea Gogos Loic Tse Amy Scarlett Jane Ackerl Tracey Woodhead Linda Byrne Google Scholar Andrea Gogos Loic Tse Amy Scarlett Jane Ackerl Tracey Woodhead Linda Byrne PubMed Andrea Gogos Loic Tse Amy Scarlett Jane Ackerl Tracey Woodhead Linda Byrne Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Lack of synaptic vesicle protein SV2B protects against amyloid-β25–35-induced oxidative stress, cholinergic deficit and cognitive impairment in mice

SV2B is a synaptic protein widely distributed throughout the brain, which is part of the complex vesicle protein machinery involved in the regulation of synaptic vesicle endocytosis and exocytosis, and therefore in neurotransmitters release. The aims of the present work were twofold: (1) phenotype SV2B knockout mice (SV2B KO) in a battery of cognitive tests; and (2) examine their vulnerability to amyloid-β25–35 (Aβ25–35) peptide-induced toxicity. SV2B KO mice showed normal learning and memory abilities in absence of Aβ25–35 injection. SV2B KO mice were protected against the learning deficits induced after icv injection of an oligomeric preparation of amyloid-β25–35 peptide, as compared to wild-type littermates (SV2B WT). These mice failed to show Aβ25–35-induced impairments in a number of cognitive domains: working memory measured by a spontaneous alternation procedure, recognition memory measured by a novel object recognition task, spatial reference memory assessed in a Morris water-maze, and long-term contextual memory assessed in a inhibitory avoidance task. In addition, SV2B KO mice were protected against Aβ25–35-induced oxidative stress and decrease in ChAT activity in the hippocampus. These data suggest that SV2B could be a key modulator of amyloid toxicity at the synaptic site.

The role of cognition in fitness to stand trial: a systematic review

The aim of the current paper was to systematically review the quality and design of the literature examining cognition and fitness to stand trial (FST). Ten empirical studies published between 1970 and July 2013 met the inclusion criteria. All studies utilised cross-sectional designs and six were prospective. Study quality was appraised based on FST research guidelines. The study quality was highly variable. Intelligence was controlled statistically in only half of the included studies. Cognitive processes, specifically, processing speed, verbal memory and visuoperceptual skills differentiated fit and unfit groups. Aspects of executive functioning, including social knowledge and abstract thinking, influenced FST. Future studies should use prospective consecutive designs and multivariate statistical strategies that control for potential confounds. Comprehensive assessment across a number of cognitive domains is needed in order to validate research conducted to date and guide forensic assessment of FST.

Available processing resources influence encoding-related brain activity before an event

Effective cognitive functioning not only relies on brain activity elicited by an event, but also on activity that precedes it. This has been demonstrated in a number of cognitive domains, including memory. Here, we show that brain activity that precedes the effective encoding of a word into long-term memory depends on the availability of sufficient processing resources. We recorded electrical brain activity from the scalps of healthy adult men and women while they memorized intermixed visual and auditory words for later recall. Each word was preceded by a cue that indicated the modality of the upcoming word. The degree to which processing resources were available before word onset was manipulated by asking participants to make an easy or difficult perceptual discrimination on the cue. Brain activity before word onset predicted later recall of the word, but only in the easy discrimination condition. These findings indicate that anticipatory influences on long-term memory are limited in capacity and sensitive to the degree to which attention is divided between tasks. Prestimulus activity that affects later encoding can only be engaged when the necessary cognitive resources can be allocated to the encoding process.

Cognition and HPA axis reactivity in mildly to moderately depressed outpatients. A case–control study

Background: Patients with depression display neurobiological changes of the hypothalamic–pituitary axis as well as cognitive disturbances. Aims: To assess any association between hypothalamus–pituitary–adrenal (HPA) axis reactivity and memory-related cognitive functions. Methods: Depressed outpatients (n = 83, ICD-10) were group-matched to healthy controls (n = 33), and tested on a number of cognitive domains. Salivary samples were collected at awakening, 30 min later and at 22:00 h. At 23:00 h, the participants ingested 1.0 mg of dexamethasone, and three saliva samples were collected the following day at the same times. Results: Patients and controls did not differ on any memory-related cognitive skills. After dexamethasone the cortisol level was 1.7 nmol/l higher (95% CI 0.0–2.8, P = 0.05) in depressed patients compared with controls. In the control group, but not in the patients, a positive association between post-DST cortisol and Rey's Complex figure test (1.3; 95% CI 0.3–3.6; P = 0.02) was found. We found no significant associations between other memory functions and cortisol measures. Conclusions: Contrary to our hypothesis, we found a positive association between cortisol levels after dexamethasone and visuo-spatial memory primarily driven by the healthy controls. Otherwise, no association were found between HPA axis reactivity and memory-related cognitive function.

Cognitive Dysfunction in Fibromyalgia Syndrome

ABSTRACTObjectives: Fibromyalgia syndrome [FMS] is characterized by chronic, widespread, musculoskeletal pain, but symptoms other than pain are common. Dyscognition is a term used to refer to subjective feelings and objective performance measures of cognitive dysfunction. In this paper, the evidence for dyscognition in FMS is reviewed.Findings: Dyscognition is a prevalent symptom among patients with FMS that can be very disruptive. Studies using self-report measures support patient reports of dyscognition, demonstrating perceived problems across a number of cognitive domains. Tests using performance-based measures of cognitive function also support patient reports of dyscognition. Furthermore, these tests have thus far revealed a pattern of impairment in working memory and attention/executive control as well as memory impairment.Conclusions: Dyscognition is a real and troubling symptom for many patients with fibromyalgia. However, the body of research on dyscognition in FMS is still quite small. More rese...

Cognitive Treatment of Obsessions: Enhancing Dissemination With Video Components

Contemporary cognitive treatment of obsessive-compulsive disorder (OCD) dates back to 1985, and rests on the premise that infrequent unwanted intrusions are essentially universal. As such, it is not the intrusion that is the focus of treatment but rather the interpretation or appraisal placed upon the intrusion. A number of cognitive domains are thought to be key areas, including inflated responsibility, overimportance of thoughts, need to control thoughts and overestimation of threat. Cognitive treatment of OCD is idiographic owing in part to the heterogeneous nature of the disorder as well as the cognitive domains implicated in the etiology and maintenance of the disorder. Cognitive treatment of an individual with ego-dystonic sexual and aggressive intrusions is illustrated in the current manuscript. Video clips are embedded at key moments during the treatment to ideally facilitate the illustration of this complex treatment. It is hoped that the addition of video clips will aid in the dissemination of this treatment that was recently tested and found to produce large effect sizes in a recent randomized controlled trial.

Inhibitory interneurons of the human prefrontal cortex display conserved evolution of the phenotype and related genes

Inhibitory interneurons participate in local processing circuits, playing a central role in executive cognitive functions of the prefrontal cortex. Although humans differ from other primates in a number of cognitive domains, it is not currently known whether the interneuron system has changed in the course of primate evolution leading to our species. In this study, we examined the distribution of different interneuron subtypes in the prefrontal cortex of anthropoid primates as revealed by immunohistochemistry against the calcium-binding proteins calbindin, calretinin and parvalbumin. In addition, we tested whether genes involved in the specification, differentiation and migration of interneurons show evidence of positive selection in the evolution of humans. Our findings demonstrate that cellular distributions of interneuron subtypes in human prefrontal cortex are similar to other anthropoid primates and can be explained by general scaling rules. Furthermore, genes underlying interneuron development are highly conserved at the amino acid level in primate evolution. Taken together, these results suggest that the prefrontal cortex in humans retains a similar inhibitory circuitry to that in closely related primates, even though it performs functional operations that are unique to our species. Thus, it is likely that other significant modifications to the connectivity and molecular biology of the prefrontal cortex were overlaid on this conserved interneuron architecture in the course of human evolution.

Cognition in healthy aging is related to regional white matter integrity, but not cortical thickness.

It is well established that healthy aging is accompanied by structural changes in many brain regions and functional decline in a number of cognitive domains. The goal of this study was to determine (1) whether the regional distribution of age-related brain changes is similar in gray matter (GM) and white matter (WM) regions, or whether these two tissue types are affected differently by aging, and (2) whether measures of cognitive performance are more closely linked to alterations in the cerebral cortex or in the underlying WM in older adults (OA). To address these questions, we collected high-resolution magnetic resonance imaging (MRI) data from a large sample of healthy young adults (YA; aged 18-28) and OA (aged 61-86 years). In addition, the OA completed a series of tasks selected to assess cognition in three domains: cognitive control, episodic memory, and semantic memory. Using advanced techniques for measuring cortical thickness and WM integrity, we found that healthy aging was accompanied by deterioration of both GM and WM, but with distinct patterns of change: Cortical thinning occurred primarily in primary sensory and motor cortices, whereas WM changes were localized to regions underlying association cortices. Further, in OA, we found a striking pattern of region-specific correlations between measures of cognitive performance and WM integrity, but not cortical thickness. Specifically, cognitive control correlated with integrity of frontal lobe WM, whereas episodic memory was related to integrity of temporal and parietal lobe WM. Thus, age-related impairments in specific cognitive capacities may arise from degenerative processes that affect the underlying connections of their respective neural networks.

Lifestyle, glucose regulation and the cognitive effects of glucose load in middle-aged adults

Interventions aimed at improving glucose regulatory mechanisms have been suggested as a possible source of cognitive enhancement in the elderly. In particular, previous research has identified episodic memory as a target for facilitation after either moderate increases in glycaemia (after a glucose drink) or after improvements in glucose regulation. The present study aimed to extend this research by examining the joint effects of glucose ingestion and glucose regulation on cognition. In addition, risk factors associated with the development of poor glucose regulation in middle-aged adults were considered. In a repeated measures design, thirty-three middle-aged adults (aged 35-55 years) performed a battery of memory and non-memory tasks after either 25 g or 50 g glucose or a sweetness matched placebo drink. To assess the impact of individual differences in glucose regulation, blood glucose measurements were taken on four occasions during testing. A lifestyle and diet questionnaire was also administered. Consistent with previous research, episodic memory ability benefited from glucose ingestion when task demands were high. Blood glucose concentration was also found to predict performance across a number of cognitive domains. Interestingly, the risk factors associated with poor glucose regulation were linked to dietary impacts traditionally associated with poor health, e.g. the consumption of high-sugar sweets and drinks. The research replicates earlier work suggesting that task demands are critical to the glucose facilitation effect. Importantly, the data demonstrate clear associations between elevated glycaemia and relatively poor cognitive performance, which may be partly due to the effect of dietary and lifestyle factors.

Is a plum a memory problem?: Longitudinal study of the reversal of concreteness effect in a patient with semantic dementia

The concreteness effect, which refers to the typically superior performance for concrete concepts compared to abstract ones, is a robust phenomenon that has been observed in normal and brain-damaged subjects in a number of cognitive domains. Reversal of this effect was also reported in a few neuropsychological studies, mainly in patients with semantic dementia (SD). In this article, we report the first longitudinal single-case study of a patient with SD, SC, who performed better for abstract than concrete concepts in various comprehension and production tasks. For concrete concepts, SC showed no category-specific deficit but was impaired in tasks exploring access to stored structural knowledge and semantic perceptual attributes. With the course of the disease, the semantic system progressively declined and the reversal of the concreteness effect, as well as the dissociation between perceptual and non-perceptual knowledge, vanished. We discuss the results and their implications for theoretical propositions of concreteness effect as well as theoretical models of semantic memory. We suggest that the reversal of concreteness in SC is a direct result of the degradation of visual feature knowledge, sustained by anatomical structures affected early in SD. With the time course of the disease, the atrophy extends to adjacent regions and the dissociation between abstract and concrete concepts was no longer observed.

Functional neuroimaging insights into how sleep and sleep deprivation affect memory and cognition

The review summarizes current knowledge about what fMRI has revealed regarding the neurobehavioral correlates of sleep deprivation and sleep-dependent memory consolidation. Functional imaging studies of sleep deprivation have characterized its effects on a number of cognitive domains, the best studied of these being working memory. There is a growing appreciation that it is important to consider interindividual differences in vulnerability to sleep deprivation, task and task difficulty when interpreting imaging results. Our understanding of the role of sleep and the dynamic evolution of offline memory consolidation has benefited greatly from human imaging studies. Both hippocampal-dependent and hippocampal-independent memory systems have been studied. Functional imaging studies contrasting sleep-deprived and well-rested brains provide substantial evidence that sleep is highly important for optimal cognitive function and learning. The experimental paradigms developed to date merit evaluation in clinical settings to determine the impact of sleep disruption in sleep disorders.

The Stability of Inhibitory and Working Memory Deficits in Children and Adolescents Who are Children of Parents With Schizophrenia

Cognitive deficits are a central feature of schizophrenia and occur in first-degree relatives of schizophrenic probands, even in the absence of psychotic symptoms. A number of cognitive domains have been implicated including measures of response inhibition and working memory. While the stability of cognitive deficits has been demonstrated in individuals with schizophrenia, stability of deficits has not been explored in first-degree relatives. This report focuses on 25 children (ages 6-15 years), all with at least one schizophrenic parent. The children were assessed twice, utilizing inhibitory and working memory tasks, with a mean 2.6 years between visits. Stop reaction time (a measure of motor inhibition) and performance on a counting span task (a measure of verbal working memory) were borderline to mildly impaired (compared with a typically developing comparison group) at both visits with similar effect sizes (stopping task time 1, effect size = 0.46, time 2 effect size = 0.50; counting span time 1 effect size = 0.53, time 2 effect size = 0.42). For these 2 tasks, individual age-adjusted scores also correlated across both time points (r = 0.41-0.76) suggesting that individual children maintained deficits across time. As etiologically driven strategies are developed for the cognitive deficits of schizophrenia, expansion of these treatments to relatives who share the cognitive but not the psychotic symptoms may be worth exploring.

Neuropsychological and psychiatric profiles in acute encephalitis in adults

Acute encephalitis is an inflammation of brain tissue that can result from activity in the central nervous system (CNS) of a number of viruses. Although the neurological and psychiatric effects of encephalitis in the acute phase of the illness are well-known (Caroff, Mann, Gliatto, Sullivan, & Campbell, 2001), larger scale studies of the pattern of neuropsychological and psychiatric impairment following recovery from the acute inflammatory phase are less apparent. This paper reports the results of neuropsychological testing with a range of standardised cognitive measures in a case series of long-term post-acute participants. Psychiatric abnormality is examined using the SCL-90-R self-report scale of distress (Derogatis, 1983). We also examined the role of emerging insight in the aetiology of depression in this population. Two clusters of cognitive dysfunction were observed, one group of primarily herpes simplex cases showing a severe generalised deficit across a number of cognitive domains and a second cluster showing a variety of more isolated disorders of executive function. Abnormally high levels of distress were reported by participants, with depression, obsessive-compulsive symptoms, interpersonal sensitivity and phobic anxiety most significantly increased. Depression was found to be least severe in those with most accurate insight into their problems. Examining the correlations between cognitive and psychiatric test results demonstrates a relationship between depression and interpersonal anxiety and specific cognitive measures. Obsessive-compulsive behaviour and phobic anxiety, however, appear to exist independently of the assessed cognitive deficits.

The development and validation of a carer questionnaire to assess cognitive function in neuropsychiatric patients

Objectives The carer history is an integral part of the assessment of patients with cognitive impairment. We aimed to develop a comprehensive yet concise carer questionnaire, the CogRisk, which captures actuarial risk variables for cognitive impairment in addition to key symptoms suggestive of cognitive decline in a number of cognitive domains, and to then assess its validity and reliability in a neuropsychiatric population. Method Carers of patients assessed for cognitive impairment completed the CogRisk, and patients were clinically assessed using the Mini-Mental State Examination (MMSE) and Neuropsychiatry Unit COGnitive assessment tool (NUCOG). Reliability was assessed using test–retest and interrater measures and measures of internal consistency. Construct and concurrent validity was assessed using correlation between total and subscale scores on the CogRisk, total scores on the NUCOG and MMSE, and subscale scores on the NUCOG. Predictive validity was determined using measures of sensitivity and specificity and using receiver operating characteristic (ROC) methods. Results The CogRisk was completed by all carers in less than 10 min. The total CogRisk score correlated significantly with total MMSE and NUCOG scores ( r=−0.511 and −0.563, respectively) and remained highly significant when age and education were controlled for. Internal consistency of CogRisk items was high ( α=0.943). Intrarater reliability of the CogRisk was high with an intraclass correlation coefficient of .978 ( P<.001), and interrater reliability between carers was also high at 0.868 ( P<.05). Sensitivity and specificity for the detection of dementia were .70 and .73, respectively, with area under the ROC curve not significantly different from that of the MMSE or NUCOG. Conclusion The CogRisk is a brief carer-rated tool of a patient's cognitive functioning developed for use within a neuropsychiatric setting. It exhibited good concurrent validity, internal consistency, and interrater and intrarater reliability. The CogRisk also demonstrated good sensitivity and specificity for dementia. The CogRisk provides carer information, which complements the clinical assessment and can be used to focus on direct carer interview.

The Other Side of Normal

Mild Cognitive Impairment: International Perspectives. Holly A. Tuokko and David F. Hultsch (Eds.). 2006. New York: Taylor &amp; Francis, 319 pp., $99.00 (HB).As neuropsychologists, it is our job to differentiate normal from abnormal. We act as arbiters of behavior, defining “impairments” and using normative data and estimates of premorbid functioning to delineate post-injury or post-disease decline. Although one is obviously inclined to steer the diagnostic process in such a way as to comply with the prevailing taxonomy, because of the categorical nature of our classification system, this task is most difficult at the border zones, those areas that lie somewhere between “normal” and “abnormal.” The categories applicable to “abnormal ageing” have varied greatly over the years and are still evolving. Mild cognitive impairment or MCI is one such border zone category, which is believed to be a precursor to dementia in some patients. As with most border zone diagnostic entities, those patients at the cusp of the border will always be most difficult to classify. There will be certain low functioning “normal” people who score marginally low on our tests. Likewise, there will be certain high functioning “abnormal” people who score similarly. Even when the line is drawn with confidence and the MCI diagnosis is rendered, what does one impart to the patient about prognosis given the lack of clear relationship between the diagnosis and conversion to dementia, as well as the lack of clear relationship between the diagnosis and underlying brain pathology? It is a difficult and uncomfortable label because we know that a certain percentage we assign this moniker will “get better” (or is it regression to the mean?), become demented (or do they have less cognitive reserve?), or stay the same (or do they have more cognitive reserve?). The research literature behind abnormal ageing is incredibly diverse with regard to populations studied, methods of assessment, cut-offs utilized, nature and number of cognitive domains considered, and the extent to which subjective patient complaints are considered. As the heterogeneity in this construct becomes more apparent, there is need to increase the number of available labels as evidenced by evolving concepts like “amnestic MCI.” Thus, from a historical and clinical perspective, applying the term “MCI” is a bit like throwing a rock at a moving target.

Impact of Alzheimer's pathology on cognitive trajectories in nondemented elderly

Some individuals who are asymptomatic for dementia while alive have substantial Alzheimer's disease (AD) neuropathology at autopsy. We investigated whether cognitive trajectories differ between clinically normal elderly individuals with and without AD neuropathology and how they compare with trajectories of clinically impaired individuals before dementia diagnosis. Eighty-one elderly participants in the Baltimore Longitudinal Study of Aging (BLSA) were followed prospectively with neurological and neuropsychological assessments before autopsy evaluation at death. Trajectories of cognitive change were estimated for a number of domains using cognitive data before a clinical diagnosis of dementia. Clinically normal elderly individuals with and without AD-type neuropathology have similar cognitive trajectories across different cognitive domains. In contrast, individuals with mild cognitive impairment/AD show steeper rates of longitudinal decline in several aspects of cognition compared with clinically normal elderly individuals regardless of whether the latter have AD neuropathology. Moreover, the cognitive differences between impaired and unimpaired groups can be detected years before a diagnosis of dementia. Clinically normal individuals with and without AD neuropathology do not differ in rates of cognitive decline across a number of cognitive domains. Understanding the factors that protect some individuals with AD pathology from cognitive impairment may contribute to the maintenance of cognitive health in the elderly.

Cognitive Function in Late Life Depression: Relationships to Depression Severity, Cerebrovascular Risk Factors and Processing Speed

A number of studies have examined clinical factors linked to worse neuropsychological performance in late life depression (LLD). To understand the influence of LLD on cognition, it is important to determine if deficits in a number of cognitive domains are relatively independent, or mediated by depression- related deficits in a basic domain such as processing speed. Patients who met DSM-IV criteria for major depression (n = 155) were administered a comprehensive neuropsychological battery of tasks grouped into episodic memory, language, working memory, executive function, and processing speed domains. Multiple regression analyses were conducted to determine contributions of predictor variables to cognitive domains. Age, depression severity, education, race and vascular risk factors all made significant and independent contributions to one or more domains of cognitive function, with all five making independent contributions to processing speed. Age of onset made no independent contribution, after accounting for age and vascular risk factors. Of the five cognitive domains investigated, changes in processing speed were found to most fully mediate the influence of predictor variables on all other cognitive domains. While slowed processing speed appears to be the most core cognitive deficit in LLD, it was closely followed by executive function as a core cognitive deficit. Future research is needed to help clarify mechanisms leading to LLD- related changes in processing speed, including the potential role of white matter abnormalities.

A statistical interpretive method for neuropsychological test data.

The accurate interpretation of large numbers of neuropsychological tests within a flexible battery approach is a difficult and sometimes controversial process. We present a statistically based method of interpretation (Rohling's Interpretive Method or RIM) and evaluation of neuropsychological data that allows for varying numbers of tests along a varying number of cognitive domains, yet remains psychometrically based. This method requires informed clinical judgment in that the level of confidence for tests, cognitive domains, and global indices are used as the backdrop for interpretive decisions. Specific procedures for use are presented in a systematic, detailed fashion to allow the interested reader to replicate the method. Two case examples are presented: a straightforward case of cerebrovascular insult and a more complicated case of mixed etiology. Examples include a variety of different neuropsychological tests commonly used in a flexible battery approach. A discussion of the practicality, ease of use, and potential limitations of this method are further presented.