DELIRIUM, DEMENTIA, AMNESTIC AND OTHER COGNITIVE DISORDERS
Memory deficits are common, especially of the short-term memory (see glossary). During the space of the day however, these patients will have intervals of lucidity, during which they are vigil and coherent. These moments throughout the day contribute towards distinguishing delirium from dementia. Perceptive alterations are also frequent and sufferers may exchange unfamiliar situations for familiar ones: for example, thinking that they are at home rather than in hospital. Although delirious episodes and hallucinations are common, particularly of the visual and visual-auditory type, they are not always present in this condition. Individuals suffering from delirium are very unstable from the emotional point of view and may pass extremely rapidly from one emotional state to another, e.g., anxiety, depression, fear, anger, euphoria and irritability. Other frequent manifestations are high temperatures, hot flushes in the face, dilated pupils, tremor, tachycardia, unstable blood pressure and incontinence of the faeces and urine. Delirium may present in persons of all ages but it is more common amongst children and old people. It has been suggested that 10-15% of senior citizens admitted to general surgery wards develop a form of delirium after undergoing a surgical operation (Miller, 1981). Although rates of incidence are extremely variable, even if we accept the lower values, it is evident that delirium is a serious problem for older people. The mortality rate for delirium is high: about 40% of patients die, either on account of the condition which caused the delirium or for the onset of a severe state of asthenia (see glossary) (Rabins and Folstein, 1982).
Dementia, inappropriately also referred to as senile behaviour, consists of a gradual deterioration of the intellectual capacities until social and occupational functioning is compromised. The difficulty in remembering things, especially recent events, is the most significant symptom of dementia. Some individuals suffering from dementia may leave tasks before they have been completed as after a casual interruption they will easily forget to go back to what they were doing. It may occur that parents no longer recall the name of their son or daughter or even forget they actually have children and when their son or daughter go to visit them, they may not recognise them. People with dementia may get lost in a familiar environment. Their judgement is often altered and they find it difficult to comprehend situations, plan activities or make decisions.They no longer behave in a normal way and lose control over their impulses. They my use vulgar language, tell dirty jokes, indulge in shoplifting and make sexual advances to strangers. Their capacity to engage in abstract thought becomes impaired, while alterations at the emotional level are common and include symptoms of depression, a dulling of affect and sporadic emotional crises. They may also present a deterioration of linguistic functions, which manifests in vague or empty speech and an inability to recall the names of familiar objects. These patients may also present alterations in motor capacities, such as washing their teeth with a toothbrush or getting dressed. Dementia may be progressive, static or remitting, depending on the cause. Many people affected by progressive dementia remain isolated and apathetic. In the final stage of the disease the personality loses former traces of liveliness and its integrity. Relations and friends will often refer that the person is no longer his or her former self. In the last phases these individuals are no longer aware of what is going on around them. The prevalence of dementia increases in a manner proportional to age. A study conducted in the United States established a value of 1% for the age group 65 – 74, 4% between the ages of 75 and 80 and 10% in people over 80 (George et al., 1991).
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George, L.K., Landoman, R., Blazer, D.G., Anthony, J.C. (1991). Cognitive impairment. In L.N. Robins & D.A. Regier, Psychiatric Disorders in America. New York: Free Press.
Miller, H.R. (1981). Psychiatric morbidity in elderly surgical patients. British Journal of Psychiatry, 128, 17-20.
Rabins, P.V., Folstein, M.F. (1982). Delirium and dementia: Diagnostic criteria and fatality rates. British Journal of Psychiatry, 140, 149-153.