Decline In Cognitive Abilities Research Articles

Concept Development of Grief-Focusing on the Process of Spousal Bereavement

This study was done to develop the concept of grief focusing on the process of spousal bereavement in Korea. The Hybrid model was used for analysis according to the 3 phases. An extensive literature review was done for the Theoretical phase. In-depth interviews were conducted with 15 participants whose spouses died within the past 3 years in the Field phase. In the Final analytic phase, the results in the Theoretical and the Field phases were compared, analyzed, and integrated according to the process of grief. The antecedent of the concept of spousal grief was spousal death. The dimensions of grief were classified to inner dimensions related to oneself, relational dimensions related to family and others, and existential dimensions related to the meaning of being. The attributes of grief were physical suffering, decline of cognitive ability, heartbreaking sorrow, expectations and conflicts of a new life, social stigma, dependence on or resentment towards God, etc. The empirical referent of grief was physical, psychological, social, and spiritual health status. The grieving progressed through 3 phases-shock-emancipation, suffering, and integration. Nurses should recognize the importance of their unique position as supporters for grievers, and try to assess individual characteristics and to provide tailored nursing interventions.

Cholinergic Basis of Memory-Strengthening Effect ofFoeniculum vulgareLinn.

Alzheimer's disease is a neurodegenerative disorder associated with a decline in cognitive abilities. Dementia is one of the age-related mental problems and a characteristic symptom of Alzheimer's disease. Nootropic agents are used in situations where there is organic disorder in learning abilities. The present work was undertaken to assess the potential of Foeniculum vulgare Linn. extract as a nootropic and anticholinesterase agent in mice. Methanolic extract of the whole plant of F. vulgare Linn. administered for eight successive days ameliorated the amnesic effect of scopolamine (0.4 mg/kg) and aging- induced memory deficits in mice. The passive avoidance paradigm served as the exteroceptive behavioral model for assessing memory. F. vulgare extract increased step-down latency and acetylcholinesterase inhibition in mice significantly. Hence, F. vulgare can be employed in treatment of cognitive disorders such as dementia and Alzheimer's disease.

Cognitive Development in Schizophrenia: Follow-Back from the First Episode

Despite consensus that schizophrenia is a neurodevelopmental disorder characterized by cognitive deficits, objective data documenting the course of cognitive development remain sparse. We conducted a follow-back study of patients ascertained at the time of their initial episode of schizophrenia or schizoaffective disorder, and a group of demographically matched healthy volunteers. We obtained school records containing standardized achievement test scores from the 1st through 12th grades, and scholastic aptitude test results from the 11th and 12th grades, and examined the developmental trajectories of cognitive performance with respect to prospective examinations conducted following participants’ enrollment in our study. We found significant differences in academic achievement tests as early as the first grade, with scores from participants who would later develop schizophrenia lagging behind their peers by 0.8 to 1.1 grade equivalents. This gap widened resulting in a difference between groups of 1.5 to 1.8 grade equivalents by the 12th grade. In the subset of patients for whom SAT scores were available, we found that WAIS-R Full Scale IQ was 11.5 points lower than predicted from earlier SAT scores, suggesting a substantial decline in cognitive ability accompanying the initial episode of illness. These findings suggest that schizophrenia is marked by substantial cognitive deficits in the first grade, that there may be additional subtle decline preceding the overt onset of psychotic symptoms, and that the initial episode of illness is marked by additional decline. These observations may help advance concepts of premorbid cognitive ability in the schizophrenia syndrome and constrain models of pathophysiology.

A review of behavioral treatments for persons with dementia.

Abstract The term is used to describe the widespread decline in cognitive abilities that results from an organic process such as Alzheimer's disease, stroke, or Huntington's disease. Regardless of the cause, dementia is characterized by a decline in various intellectual abilities that is sufficient to interfere with normal daily functioning (Hutton, 1991). Dementia is also characterized by changes in behavioral functioning that can be very challenging for caregivers and patients alike. The purpose of this paper will be to briefly review the most common causes of dementia and common symptoms of dementia. Next, the paper will describe behavioral excesses and deficits that are most often associated with dementia and a review of empirically-supported interventions will be provided. Finally, the effectiveness of behavioral interventions as it related to public policy issues will be discussed. Keywords: Dementia, Alzheimer's disease, stroke, Huntington's disease, empirically-supported interventions, public policy Causes of Dementia and Prevalence Alzheimer's disease. Alzheimer's disease (AD) is the most common cause of degenerative dementia, accounting for up to 65% of all cases of dementia (Hendrie, 1997). It is estimated that approximately 4.5 million Americans suffer from AD currently, with projections of about 13 million by the year 2050 if no cure is found (Hebert, Scherr, Bienias, Bennet, & Evans, 2003). AD is characterized by gradual and continual declines in intellectual functioning, although the rate of decline varies greatly across individuals. As the disease progresses, cognitive and behavioral functioning deteriorate to the point where the individual becomes increasingly dependent on others to complete most tasks of daily living such as money management, driving, cooking, bathing, dressing and/or toileting. The median survival from initial diagnosis is 4.2 years for men and 5.7 years for women (Larson et al., 2004). Other causes of dementia. Several other conditions also can cause dementia. For example, dementia can be caused by a series of small strokes that destroy specific areas of the brain (i.e., vascular dementia). Other conditions that can cause dementia include Parkinson's disease, Pick's disease, Huntington's disease, AIDS, brain tumors, exposure to toxins such as carbon monoxide, viral infections of the brain such as meningitis or encephalitis, a history of trauma to the brain, normal pressure hydrocephalus (abnormal flow of spinal fluid) and Multiple Sclerosis (Hutton, 1991). Prevalence. If one considers all causes of dementia, approximately 6-10% of individuals over the age of 65 suffer from dementia (Hendrie, 1997). For most causes of dementia, onset is rare before age 65 (onset is earlier for those causes that primarily affect the frontal lobes first). For those ages 65-70, prevalence estimates are approximately 1-2%, while for those ages 85 and older, most prevalence estimates are between 25% and 30% (Albert & Drachman, 2000; Hendrie, 1997). These figures are particularly alarming given that the population of those 85 and older is estimated to increase by about 1.7 million by the year 2010 and will account for about 2.3% of the total population (Albert & Drachman, 2000). Behavioral Problems There are numerous behavior problems that can occur in persons with dementia, with the severity of these problems varying widely across individuals. Common behavior problems include physical and verbal aggression; disruptive vocalizations such as repetitive statements or screaming; disrobing or other sexually inappropriate behaviors such as masturbating in public areas; wandering and exit seeking; paranoia; incontinence; and eating difficulties such as food refusal. Increasing socialization among residents and increasing independence are also common targets for behavioral interventions, particularly in long-term care settings. …

Differential effects of voluntary physical exercise on behavioral and brain-derived neurotrophic factor expression deficits in huntington’s disease transgenic mice

Huntington’s disease is a fatal neurodegenerative disorder caused by a mutation of the huntingtin gene and involves progressive motor abnormalities (including chorea), cognitive deficits (dementia) as well as psychiatric symptoms. We have previously demonstrated that environmental enrichment slows the onset and progression of Huntington’s disease in transgenic mice. Here, we investigated the effects of enhanced physical exercise on disease progression and brain-derived neurotrophic factor expression. Standard-housed Huntington’s disease mice developed phenotypic rear-paw clasping by 16 weeks of age, displayed abnormal rearing behavior, deficits in motor co-ordination and of spatial working memory. Huntington’s disease mice with access to running wheels exhibited delayed onset of rear-paw clasping, normalized levels of rearing behavior and amelioration of the cognitive deficits. However, in contrast to our previous environmental enrichment studies, there was no rescue of motor coordination deficits in wheel-running Huntington’s disease mice. An abnormal accumulation of brain-derived neurotrophic factor protein in the frontal cortex of Huntington’s disease mice was unaffected by running. Striatal and hippocampal brain-derived neurotrophic factor protein levels were unchanged. Brain-derived neurotrophic factor mRNA levels were reduced in the anterior cortex, striatum and hippocampus of Huntington’s disease mice, and only striatal deficits were ameliorated by running. Overall, we show that voluntary physical exercise delays the onset of Huntington’s disease and the decline in cognitive ability. In addition, our results reveal that some aspects of hippocampal dependent memory are not entirely reliant on sustained hippocampal brain-derived neurotrophic factor expression.

Behavioural profiles of inbred mouse strains used as transgenic backgrounds. II: cognitive tests

One of the characteristic manifestations of several neurodegenerative diseases is the progressive decline in cognitive ability. In order to determine the suitability of six mouse strains (129S2/Sv, BALB/c, C3H/He, C57BL/6j, CBA/Ca and DBA/2) as transgenic background strains, we investigated the performance on a variety of tasks designed to identify subtle changes in cognition. In addition, a test of exploratory behaviour was used to probe the level of underlying anxiety in these mouse strains, as anxiety can be a confounding factor on behavioural performance generally. The C3H/He mice exhibited the least anxiogenic behavioural profile spending most time on the open arms of the maze, in contrast to the 129S2/Sv mice which spent the least amount of time in this location and were the quickest to move into a closed arm. The C3H/He mouse strain failed to acquire a visual discrimination task and failed to demonstrate learning on a water maze spatial learning task, in contrast to the CBA/Ca, DBA/2 and C57BL/6j strains which demonstrated a degree of learning in both tasks. No significant strain differences were identified on the object recognition task. These data, taken together, suggest that care must be taken when choosing cognitive tasks to be used with particular mouse strains and that task sensitivity must be considered as a critical element to research protocols with regard to these mouse strains.

Cholinergic drugs for Alzheimer's disease enhance in vitro dopamine release.

Alzheimer's disease is a neurodegenerative disorder associated with a decline in cognitive abilities. Patients also frequently have noncognitive symptoms, such as anxiety, depression, apathy, and psychosis, that impair daily living. The most commonly prescribed treatments for Alzheimer's disease are acetylcholinesterase inhibitors, such as donepezil and galantamine. Enhanced cholinergic functions caused by these compounds are believed to underlie improvements in learning, memory, and attention. The noncognitive aspects of dementia, however, are usually linked to serotonin and dopamine rather than acetylcholine because those neurotransmitter systems most directly influence mood, emotional balance, and psychosis. Fast-scan cyclic voltammetry applied to mouse striatal brain slices was used to measure the real-time release of dopamine arising from spontaneous activity or from single electrical stimulations. At concentrations that include their prescribed dosage ranges, donepezil (1-1000 nM) and galantamine (50-1000 nM) increase action potential-dependent dopamine release. Consistent with previous literature, the data support slightly different modes of action for donepezil and galantamine. The ability of these commonly prescribed drugs to alter catecholamine release may underlie their influence over noncognitive symptoms of dementia. Furthermore, these results suggest that acting via nicotinic receptors, these drugs may serve presently untapped therapeutic roles by altering dopamine release in other disorders involving dopaminergic systems.

Rate of Decline in Social and Cognitive Abilities in Dementing Individuals with Down's Syndrome and Other Learning Disabilities

Sixteen clients with learning disabilities, 8 Down's syndrome (DS), 8 non-Down's syndrome (NDS), diagnosed with dementia, were assessed using specially selected neuropsychological assessment tools at two time points separated by six months. DS individuals showed decline in cognitive abilities (p < .005; 1-tailed) (hypothesis 1); NDS showed decline in cognitive abilities (p < .01; 1 -tailed; p < .005; 1 -tailed) (hypothesis 2); DS individuals showed decline in social abilities (p < .005; 1-tailed) (hypothesis 3), but the NDS did not (hypothesis 4); No significant differences were found in the ability score changes of the two groups (hypotheses 5 & 6). Findings (1-3) support previous studies with participants over 12 months. Hence, the rate of change in these abilities is faster than previously suspected.

Bayesian estimation of cognitive decline in patients with alzheimer's disease

AbstractRecently, there has been great interest in estimating the decline in cognitive ability in patients with Alzheimer's disease. Measuring decline is not straightforward, since one must consider the choice of scale to measure cognitive ability, possible floor and ceiling effects, between‐patient variability, and the unobserved age of onset. The authors demonstrate how to account for the above features by modeling decline in scores on the Mini‐Mental State Exam in two different data sets. To this end, they use hierarchical Bayesian models with change points, for which posterior distributions are calculated using the Gibbs sampler. They make comparisons between several such models using both prior and posterior Bayes factors, and compare the results from the models suggested by these two model selection criteria.

Chapter 37 Selective vulnerability of corticocortical and hippocampal circuits in aging and Alzheimer's disease

Alzheimer's disease (AD), a classic neurodegenerative disorder, is characterized by extensive yet selective neuron death in the neocortex and hippocampus that leads to dramatic decline in cognitive abilities and memory. Crucial subsets of pyramidal cells and their projections are particularly vulnerable. A more modest disruption of memory occurs often in normal aging, yet such functional decline does not appear to be accompanied by significant neuron death. However, the same circuits that are devastated through degeneration in AD are vulnerable to sublethal age-related biochemical and morphologic shifts that alter synaptic transmission, and thereby impair function. For example, in the monkey neocortex, pyramidal cells that are homologous to those that degenerate in AD do not degenerate with aging, yet they lose spines, suggesting that an age-related synaptic disruption has occurred. Such age-related synaptic alterations have also been reported in hippocampus. For example, NMDA receptors are decreased in certain hippocampal circuits with aging. NMDA receptors are also responsive to circulating estrogen levels, thus interactions between reproductive senescence and brain aging may also affect excitatory synaptic transmission in the hippocampus. Thus, the aging synapse may be the key to age-related memory decline, whereas neuron death is the more prominent and problematic culprit in AD.

Estrogen replacement therapy for the potential treatment or prevention of Alzheimer's disease.

Alzheimer's disease (AD) is an irreversible, progressive brain disorder that occurs gradually and results in memory loss, behavior and personality changes, and a decline in cognitive abilities. Although basic biological data suggest that estrogen may have neuroprotective and neuroenhancing functions, a number of studies have produced conflicting findings on the use of estrogen for maintaining cognitive function in older people. This review summarizes clinical studies that have examined the effects of estrogen in women with AD.

Evidence for cortical "disconnection" as a mechanism of age-related cognitive decline.

Normal aging is accompanied by a decline of cognitive abilities, and executive skills may be affected selectively, but the underlying mechanisms remain obscure and preventive strategies are lacking. It has been suggested that cortical "disconnection" due to the loss of white matter fibers may play an important role. But, to date, there has been no direct demonstration of structural disconnection in humans in vivo. The authors used diffusion tensor MRI to look for evidence of ultrastructural changes in cerebral white matter in a group of 20 elderly volunteers with normal conventional MRI scans, and a group of 10 younger controls. The older group also underwent neuropsychological assessment. Diffusional anisotropy, a marker of white matter tract integrity, was reduced in the white matter of older subjects and fell linearly with increasing age in the older group. Mean diffusivity was higher in the older group and increased with age. These changes were maximal in anterior white matter. In the older group, anterior mean diffusivity correlated with executive function assessed by the Trail Making Test. These findings provide direct evidence that white matter tract disruption occurs in normal aging and would be consistent with the cortical disconnection hypothesis of age-related cognitive decline. Maximal changes in anterior white matter provide a plausible structural basis for selective loss of executive functions. In addition to providing new information about the biological basis of cognitive abilities, diffusion tensor MRI may be a sensitive tool for assessing interventions aimed at preventing cognitive decline.

Diagnosis and Treatment of Vascular Dementia

Cerebrovascular disease is a leading cause of dementia worldwide, second only to Alzheimer’s disease (AD) in incidence and prevalence. Unlike the progressive decline of cognitive abilities in AD, the dementia that results from vascular disease reflects the cumulative effect of multiple brain insults. Recent advances in the treatment of cerebrovascular disease suggest that this process may be arrested and at least partially reversed. It has been shown that cognitive performance is enhanced when cerebral perfusion is improved by control of hypertension, cessation of cigarette smoking, correction of hyperlipidemia, and use of antiplatelet agents. Increasing numbers of these patients will become candidates for physical and cognitive rehabilitation.

Circadian rhythms, aging and memory

In human beings and animal models, cognitive performance is often impaired in natural and experimental situations where circadian rhythms are disrupted. This includes a general decline in cognitive ability and fragmentation of behavioural rhythms in the aging population of numerous species. There is some evidence that rhythm disruption may lead directly to cognitive impairment; however, this causal link has not been made for effects due to aging. We have tested this link by examining rhythms and performance on contextual conditioning with the conditioned place preference task, in elderly, age-matched hamsters. Young healthy hamsters developed a preference for a context that is paired with the opportunity to engage in wheel-running (experiment 1). Aged animals with consolidated locomotor rhythms developed similar degrees of preference, whereas the age-matched hamsters with fragmented rhythms did not (experiment 2). The degree of preference was also correlated with activity amplitude. These results support the notion that age-related rhythm fragmentation contributes to the age-related memory decline.

The Central Executive System in People with Down's Syndrome and Dementia

ABSTRACT Forty-one clients with learning disabilities (20 Down's Syndrome, 21 non-Down's Syndrome) were assessed using specially selected neuropsychological assessment tools at two time points separated by twelve months. Evidence for hypothesis 1 suggested that people with Down's Syndrome show a greater decline in cognitive abilities with age, compared with other groups of people with learning disabilities. A weak linear association (p < .004; r = .625; 2-tailed) between cognitive performance and social abilities was also found for the Down's Syndrome clients, supporting hypothesis 2. Findings were explained in terms of the link between declining cognitive abilities and dementia.

Amalgam fillings and cognitive abilities in a representative sample of the elderly population.

The ongoing controversial discussion about a possible negative effect of amalgam fillings on the cognitive abilities and the pathogenesis dementia was the objective of the present study. A total of 300 patients aged from 70 to 103 years were selected from the multidisciplinary 'Berlin Aging Study' (BASE). The sample was heterogeneous concerning lifestyle, education and social prestige. According to their dental state subjects were allocated into three groups: edentate > or = 20 years (I) and residual teeth without (II) or with (III) amalgam restorations. All groups were matched for age and gender. Dental examinations and various psychiatric as well as psychological assessments were carried out by professionals within the protocol of the BASE. Tests were chosen to reveal the presence and degree of dementia and assess cognitive abilities such as 'perceptual speed', 'reasoning', 'memory', 'fluency' and 'knowledge'. The present findings negate a correlation between the dental state and the pathogenesis of dementia and the physiological age-related decline in cognitive abilities. Thus the presence of amalgam fillings did neither correlate to a demented mental condition nor an impaired cognitive performance.

Circadian rhythms, aging and memory

In human beings and animal models, cognitive performance is often impaired in natural and experimental situations where circadian rhythms are disrupted. This includes a general decline in cognitive ability and fragmentation of behavioural rhythms in the aging population of numerous species. There is some evidence that rhythm disruption may lead directly to cognitive impairment; however, this causal link has not been made for effects due to aging. We have tested this link by examining rhythms and performance on contextual conditioning with the conditioned place preference task, in elderly, age-matched hamsters. Young healthy hamsters developed a preference for a context that is paired with the opportunity to engage in wheel-running (experiment 1). Aged animals with consolidated locomotor rhythms developed similar degrees of preference, whereas the age-matched hamsters with fragmented rhythms did not (experiment 2). The degree of preference was also correlated with activity amplitude. These results support the notion that age-related rhythm fragmentation contributes to the age-related memory decline.

Cognition After Major Surgery in the Elderly: Test Performance and Complaints

There is evidence that older people in particular have a higher risk of cognitive dysfunction after surgery under general anaesthesia. We have investigated the severity and character of postoperative cognitive dysfunction after major non-cardiac surgery in patients older than 65 yr. Also, cognitive complaints were studied. Cognitive function was assessed using cognitive tests measuring memory and attention, such as ability to shift between two sequences, ability to ward off distractions, simple cognitive speed and speed of general information processing. These tests were performed before, 1 week (short-term) and 3 months (long-term) after surgery. Cognitive performance of the patients was compared with that of healthy subjects not undergoing surgery who were also subjected to repeated cognitive measurements. After 1 week, patients had a poorer performance on tests measuring simple cognitive speed and speed of general information processing. Three months after surgery, patients and controls showed improved cognitive performance compared with the first measurement. These results suggest that major non-cardiac surgery in older patients causes short-term but not long-term cognitive dysfunction. However, after 6 months, 14 of 48 patients (29%) reported having experienced a decline in cognitive abilities after discharge from hospital. Eight of these 14 patients (17%) were still experiencing these cognitive complaints and reported ‘not being the same since the operation’. These findings emphasize that cognitive complaints after major surgery may not reflect actual changes in cognitive performance but may be caused by other factors such as depression or awareness of age-related changes.

Recent advances and future directions in the studies of cognitive functions on aged monkeys

The present paper reviewed recent studies on the cognitive functions of aged monkeys as an aging model of cognition. It has been questioned that the aged monkeys did not always show substantial decline in cognitive abilities in some tasks. I could summarize the cognitive deficits in aged monkeys as the following points such as in spatial cognition task, temporal integration abilities of memory, learning set, and inability of inhibition. It became apparent that the aged monkeys took different behavioral strategies from the young in the other intact tasks. The better performances in aged monkeys could be attributable to such behavioral complement. Therefore, not only the ultimate performance in cognitive tasks, but the behavioral observations on learning process will be important to investigate the ability of aged monkeys. The longitudinal and multi-task studies will also be required to reach into the deep knowledge of cognition in aged monkeys.

USING A COGNITIVE RATIONALE TO CONCEPTUALIZE ANXIETY IN PEOPLE WITH DEMENTIA

Dementia is characterized by a decline in cognitive abilities that is sufficient to impair functioning in daily living. There are a number of forms of dementia (Alzheimer’s, vascular, Lewy body, etc), each with its own cognitive profile and developmental course. The present paper deals with the progressive dementias, such as Dementia of the Alzheimer Type (DAT). The cognitive deterioration associated with advanced DAT is often accompanied by a decline in emotional control, social behaviour and motivation. The paper focuses particularly on the emotional features of the disorder, because this issue has a profound impact on both the sufferer and carer. A framework for conceptualizing anxiety is presented, and a model of how this conceptualization can be used effectively within a carer’s training programme is discussed.