Neurophysiologic Bases of Alzheimer's Disease - Essay Example

A brief outline of the neurophysiologic bases of Alzheimer’s disease According to a work published by Ritchie & Kildea in 1995 it was found that Alzheimer’s disease strikes 8 to 15 percent of people over the age of 65. Alzheimer’s disease is a disorder of fundamental importance to older adults and it is most notorious among old age disease because this aliment affects the function of the brain by gradually and surely decreasing the brain’s ability to perform tasks. The focal attack of this ailment is predominantly on the memory (Ritchie & Kildea, 39). But memory is not the only part of the brain that id affected by the Alzheimer’s disease, symptoms extend to other cognitive deficits in language, object recognition, and executive functioning. Behavioural symptoms—such as psychosis, agitation, depression, and wandering—are common and impose tremendous strain on caregivers. Diagnosis is challenging because of the lack of biological markers, insidious onset, and need to exclude other causes of dementia. (Mental Health, 1) Dementia is a prominent healthcare issue for primary care physicians and specialist services. Over 90% of patients with dementia experience a “behaviour disturbance,” often referred to as behavioural or psychological signs in dementia in accordance with the recommendation of the International Psycho geriatric Association. These symptoms are distressing to patients and troublesome to carers and often precipitate admission to residential facilities. What is the evidence that any of the several drugs that are currently used to treat these symptoms are effective? Managing the behavioural and psychological signs of dementia is a major problem for healthcare professionals. Narcoleptic drugs are the mainstay of pharmacological treatment, although their use is justified largely on the basis of clinical anecdote, and they have many harmful side effects. These include Parkinsonism, drowsiness, tardive dyskinesia, falls, accelerated cognitive decline, and severe narcoleptic sensitivity reactions. It is therefore not surprising that the chief medical officer has recommended judicious use of these agents in patients with dementia. In 1990 Schneider published a landmark study showing the paucity of large, placebo controlled, double blind trials of narcoleptic agents in treating behavioural and psychological signs in dementia. Since then research in the subject has increased, but most treatment studies have used an open or active comparison design, a major methodological flaw given the high placebo response rates (40%). Two large multi-centre studies with risperidone have recently been completed, showing a significant advantage over placebo for overall reduction of behaviour disturbances, although in one of the studies psychotic symptoms did not improve significantly. In addition, psychosis and aggression responded preferentially to different doses. (Ballard CG, 21) While assessment and diagnosis of Alzheimer’s disease it should be remembered that declines in cognitive functioning have been identified both as part of the normal process of aging and as an indicator of Alzheimer’s disease. DSM-IV first designated this as “age-related cognitive decline” and, more recently, as “mild cognitive impairment” (MCI). MCI characterizes those individuals who have a memory problem but do not meet the generally accepted criteria for Alzheimer’s disease such as those issued by the National Institute of Neurological and Communicative Disorders and Stroke–Alzheimer’s Disease and Related Disorders Association or DSM-IV. MCI is important because it is known that a certain percentage of patients will convert to Alzheimer’s disease over a period of time probably in the range of 15 to 20 percent per year. (Mental Health, 1) Alzheimer’s disease would appear to typically start in the entorhinal cortex, spread to other parts of the hippocampus and than progress to the temporal cortex, parietal cortex, and frontal cortex. What the functional magnetic resonance imaging does is to provide a better look at smaller parts of the brain as they are being activated providing evidence of the progressive nature of this disease. There is growing need of evidence that can distinguished Alzheimer’s disease from other dementias because drugs used to treat Alzheimer’s disease may not be effective in treating other dementias—even may worsen the condition. There is no gold standard for diagnosis of Alzheimer’s disease except on autopsy where an accumulation of neurofibrillary tangles and plaque density are found as a distinguishing marker of Alzheimer’s disease. It takes highly skilled professionals to make the diagnosis. It involves using neuropsychological testing and skilful clinical interviewing of the individual and family to establish the type of memory that is functionally impaired and extrapolating a diagnosis from this information. In the early stages of Alzheimer’s disease both episodic and semantic memory are affected. Episodic memory involves recall of days events, while semantic memory involves the ability to remember names, words or historical events. Further down the line, working memory (ability to briefly hold information and manipulate it before storing it more permanently) becomes vulnerable leading to difficulty doing check books or driving safely. Concomitantly, visuospatial skills (sense of direction) deteriorate and the individual becomes disoriented. Interestingly, social behaviours are usually preserved in the early stages of the disease with agitation more significant in later stages of the disease. (Some recent studies are showing the effectiveness of anticonvulsant drugs i. e. carbamazepine, divalproex, neurontin etc., in controlling this symptom as opposed to Haldol, which appears to have a wider range of adverse side effects. Individual variations in these stages may occur and may be correlated to premorbid personality and the etiology of the disease i. e. early (familial) or late (sporadic) onset. (In the future parts of this series, more information about anticonvulsants will be presented as well as alternative therapies. Contrast Alzheimer’s disease with frontal temporal dementias where memory, comprehension and sense of direction are spared, while planning, organizing, or contemplating and achieving a complex series of activities are impaired. Along with evidence of ritualistic compulsive behaviour, social withdrawal, apathy and dis-inhibition and you begin to see how a good diagnostician can make the important diagnostic distinction on basis of indirect evidence. With functional magnetic resonance imaging, direct markers might be found which might make for more objective diagnosis and competent treatment regimens. Research in this area will not show fruition for about five years. According to Mental Health report psychosocial interventions are extremely important in Alzheimer’s disease. Although there has been some research on preserving cognition, most research has focused on treating patients’ behavioural symptoms and relieving caregiver burden. Support for caregivers is crucial because caregivers of older patients are at risk for depression, anxiety, and somatic problems. Psychosocial interventions targeted either at patients or family caregivers can improve outcomes for patients and caregivers alike. Psychosocial techniques developed for use in patients with cognitive impairment may be helpful in Alzheimer’s disease. Strengthening ways to deal with cognitive losses may reduce functional limitations for patients with the early stages of Alzheimer’s disease, before multiple brain systems become compromised. For example, training in the use of memory aids, such as mnemonics, computerized recall devices, or copious use of note taking, may assist patients with mild dementia. While initial research on the use of cognitive rehabilitation in dementia is promising, further studies are needed. Of the behavioural symptoms experienced by patients with Alzheimer’s disease, depression and anxiety occur most frequently during the early stages of dementing disorders, whereas psychotic symptoms and aggressive behaviour occur during later stages. Early evidence suggested that cognitive and behavioural therapies are beneficial in treating depressed older patients with dementia. Cognitive therapy, seen as more promising for the early stages of dementia, strives to help patients cope with depression by reducing cognitive distortions and by fostering more adaptive perceptions. Behavioural therapy, seen as more promising for more moderately or severely affected adults with dementia, targets family caregivers directly—and patients indirectly—by helping caregivers identify, plan, and increase pleasant activities for the patient, such as taking a walk, designed to improve their mood. In short, people suffering from Alzheimer’s disease suffer from a wide range of memory impairments like loss of working memory, semantic memory, episodic memory, memory of skills and even autobiographical memory. Careful studies revealed that patients of Alzheimer’s disease tend to reveal the existence of tangles of amyloid beta protein. This is absent in normal brains. So, ultimately it is somewhat unclear about the where about of this disease Alzheimer’s. Constant researches are taking place to unearth different clues to lead us to the decisive goal of understanding the nature and cure of the Alzheimer’s disease. References: Ritchie C & Kildea A.1995. Abnormal Psychology. National Book Trust. Mental Health: A Report from the Surgeon General. 2004. SAMHSAs National Mental Health Information Center Ballard CG. 2006. Psychotic symptoms and behavioural disturbances in dementia Revue Neurologique Read More