Rena Rosalind, S B (2008) Screening and Diagnosis of Dementia in the Hospital and the Community. Masters thesis, Christian Medical College, Vellore.
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Abstract
Introduction: Dementia (from the Latin de mens—from the mind) is not a specific disease itself, but Rather a group of psychological and behavioral symptoms associated with a variety of Diseases and conditions that affect the brain (Rabins, Lyketsos, and Steele 1999). Generally, dementia is characterized as the loss or impairment of mental abilities. With Dementia, these cognitive losses (e.g., in reasoning, memory, and thinking) are severe Enough to interfere with a person's daily life. Additionally, such losses are noticeable in A person who is awake and alert—the term dementia does not apply to cognitive Problems caused by drowsiness, intoxication or simple inattention (American Psychiatric Association 1994). Although often associated with later life, the symptoms of dementia can affect people Of any age. Before age sixty-five, however, the incidence of dementia is low—affecting One-half to 1 percent of the population (Rabins et al. 1999). As people get older, the Risk of dementia rises. It is estimated that dementia affects less than 10 percent of the Sixty-five-and-over population globally (Ikels 1998). The prevalence doubles every 5 Years among people in this age group. Despite its prevalence, up to three fourths of dementia goes unrecognized or Misdiagnosed in its early stages (Sternberg, et al., 2000). Many health care Professionals mistakenly view the early symptoms of dementia as inevitable Consequences of ageing or Minimal Cognitive Impairment (MCI). Dementia continues To be one of the most common causes of institutionalization, morbidity, and mortality Among the elderly. 1.1 DEMENTIA 1.1.1 DEFINITION Dementia is defined as global impairment of cognitive function that interferes with Normal activities (APA, 1994). Although impaired memory -both short term and long Term- are typical of dementia, deficits in other cognitive functions such as abstract Thinking, judgment, speech, coordination, planning and organization are required to Make a diagnosis. There are many definitions of dementia. The Royal College of Physicians (1982), Define dementia as the acquired global impairment of higher cortical functions Including memory, the capacity to solve problems of day-to-day living, the Performance of learned perceptual and motor skills, the correct use of social skills, all Aspects of language and communication and the control of emotional reaction, in the Absence of clouding of consciousness. The condition is often progressive though not Necessarily irreversible. 1.1.2 DIAGNOSTIC CRITERIA DSM IV DIAGNOSTIC CRITERIA The diagnosis of dementia can be made according to the DSM-IV classification as Stated below: A. The development of multiple cognitive deficits manifested by:- Memory impairment (impaired ability to learn new information or to Recall previously learned information) One (or more) of the following cognitive disturbances Aphasia Apraxia Agnosia Disturbance in executive functioning B. The cognitive deficits in criteria A1 and A2 each cause significant impairment in Social and occupational functioning and represent a significant decline from a previous Level of functional (APA, 2000). INTERNATIONAL CLASSIFICATION OF DISEASES (ICD – 10) DIAGNOSTIC CRITERIA: Dementia is a syndrome due to disease of the brain, usually of a chronic or progressive Nature, in which there is disturbance of multiple higher functions, including memory, Thinking, orientation and comprehension, calculation, learning capacity, language and Judgment. Consciousness is not clouded. Impairments of cognitive function are Accompanied and occasionally preceded by deterioration in emotional control, social Behavior or motivation (WHO, 1992). 1.1.3 TYPES Dementing disorders can be classified in many different ways. These classification Schemes attempt to group disorders that have particular features in common, such as Whether they are progressive or what parts of the brain are affected. Examples of types Of dementia include the following: I. Cortical Dementia: Dementia caused due to damage to the cortex or outer layer is cortical dementia. Cortical dementias tend to cause problems with memory, language, thinking and Social behavior. Some example of cortical dementias are Alzheimer's disease, Vascular dementia (also known as multi-infarct dementia), Binswanger's Disease, Dementia with Lewy bodies (DLB), Alcohol-Induced Persisting Dementia, Frontotemporal lobar degenerations (FTLD), including Pick's Disease, Creutzfeldt-Jakob disease and Dementia pugilistica. II. Subcortical Dementia: Dementia affecting parts of the brain below cortex is subcortical dementia. This type Causes changes in emotions and movement in addition to problems with memory. Some Examples of sub-cortical dementias are Dementia due to Huntington's disease, Dementia due to Hypothyroidism, Dementia due to Parkinson's disease, Dementia due To Vitamin B1 deficiency, Dementia due to Vitamin B12 deficiency, Dementia due to Folate deficiency, Dementia due to Syphilis, Dementia due to Subdural hematoma, AIDS dementia complex III. Progressive Dementia: As the name indicates, the dementia that worsens over a period interfering with Cognitive abilities is called progressive dementia. IV. Primary Dementia: Primary dementia does not result from any other disease for example: Alzheimer’s Disease. V. Secondary Dementia: Dementia caused due to a physical disease or injury is called secondary dementia. (Karen Ritchie, 2002; Peter, 2003) REVERSIBLE DEMENTIAS Studies indicate that 10% to 33% of all dementias are potentially reversible (Rabins, et Al., 1983). The percentage is higher in inpatient and tertiary referral centers. Clearly, Age of onset is a very important consideration. Treatable causes of dementia occur in 21% of those under 65 and 5% of those over 65. Unfortunately, even in the potentially Treatable group of illnesses, response rate is not 100%. Common examples of reversible Causes of dementia are depression ("pseudo dementia"), dementia due to drug Intoxication, metabolic-endocrine derangements, Hypothyroidism and normal pressure Hydrocephalus (Rabin’s, 1983). In a prospective study done in India, 18% had reversible cause. However this was a Study done in a tertiary referral centre (Srikanth, et al., 2005). 1.1.4 RISK FACTORS FOR DEMENTIA The known risk factors for dementia are Age Genetic factors Head injuries (Mehta, 1999). History of stroke (Breteler, 1998) Vascular disease (Breteler, 1998) Alcohol Abuse Low education (Ott et al., 1995) Untreated infectious and metabolic disease Brain tumor Cardiovascular disease (e.g., hypertension, atherosclerosis) Kidney failure Liver disease and Thyroid disease, Vitamin deficiencies (B12, folic acid and thiamine). 1.1.5 MANAGEMENT OF DEMENTIA CLINICAL PRACTICE GUIDELINES - SUMMARY OF RECOMMENDATIONS (Doody, 2001) Dementia is often progressive and symptoms will change over time. Similarly, Treatment must evolve with time as new issues will emerged as symptoms change. At Each stage the physician should be alert and help the patient and family anticipate Future symptoms and care that may be required. Psychiatric Aspects of Management The core treatment of a patient with dementia is psychiatric care which must be based On a close alliance with the family/caregiver. A thorough psychiatric, neurological and General medical evaluation to determine the nature of deficits is required for every Patient. It is critical to identify and treat the general medical conditions that may Contribute to the dementia and associated behavioural symptoms. Ongoing assessment includes periodic monitoring of cognitive and non-cognitive Psychiatric symptoms and their responses to intervention. It is generally necessary to Routinely review patients every 3-6 months. More frequent visits may be required for Patients with complex or potentially dangerous symptoms or during administration of Specific therapies. Safety measures need to be constantly evaluated. Educating the Patient and family about the illness, treatment, sources of care and support, and Financial and legal issues is important. NON-PHARMACOLOGICAL INTERVENTIONS Non-pharmacological interventions should always be considered along with drug Options before treatment is started. These include behaviour oriented treatment Approaches, stimulation oriented treatment approaches and emotion oriented treatment Approaches. A care plan should be made for each individual and treatment reviewed Every 3-6 months. PHARMACOLOGICAL INTERVENTIONS Acetylcholinesterase inhibitors show modest efficacy in improving cognition in Patients with mild to moderate Alzheimer’s disease. Drugs like Donepezil, Rivastigmine, Memantine, etc., must only be used after a thorough discussion of their Potential risks and benefits. There is insufficient evidence at present to recommend the Routine use of other cognitive enhancers such as vitamin E, selegiline, gingko biloba Etc. Neuroleptic drugs are often required for the management of psychosis, serious Emotional distress or danger from behavioural disturbances. The choice of drug Depends on their side-effect profile. Low doses should be prescribed initially with a Slow and cautious increase, if necessary. Treatment should normally be short term and Should be reviewed regularly. Awareness of potential side-effects including akathisia And tardive dyskinesia is important; the risk of severe side-effects is greater in Lewy Body dementia. The routine use of anticholinergics should be avoided. Marked and persistent depression should be treated with antidepressant medication. Severe and persistent anxiety and insomnia may require short-term symptomatic Treatment. 1.1.6 PROGNOSIS OF DEMENTIA The mode of onset and subsequent course of dementia depend on the underlying Etiology. Dementia may be progressive, static or remitting. The reversibility of Dementia depends on the underlying pathology, the availability and timely application Of effective treatment. The prognosis for reversible dementia related to nutritional or Thyroid problems is usually good once the cause has been identified and treated. The Prognoses for dementias related to alcoholism or HIV infection depend on the patient's Age and the severity of the underlying disorder (Wolfson, 2001). Irreversible causes of Dementia often result in gradual deterioration of the patient's functioning ending in Death. The natural history of the disease is that of a decline due to progressive damage To widespread areas of the brain. The length of time varies. Patients with Alzheimer's Disease may live from two–20 years with the disease, with an average of seven years. Patients with frontal lobe dementia or Pick's disease live on average between five and 10 years after diagnosis. The course of Creutzfeldt-Jakob disease is much more rapid, With patients living between five and 12 months after diagnosis (Wolfson, 2001) 1.1.7 BURDEN OF DISEASE Dementia was estimated to be the 10th leading cause of non-fatal burden in the world in 1990, accounting for 2.6% of total YLD (Years Lived with a Disability); this is around The same percentage as congenital malformations. In the Version 2 estimates for the Global Burden of Disease 2000 study, published in the World Health Report 2002, Dementia is the 11th leading cause of ylds at global level, accounting for 2.0% of total Global ylds. Despite the difficulties of determining its prevalence and incidence, it is Clear that dementia causes a substantial burden globally (Mathers, 2000). Dementia Poses considerable medical, social, and economic concerns as it impacts individuals, Families and health-care systems throughout the world (National Institute on Aging and National Institutes of Health 1999; O'Shea and O'Reilly 2000). The annual costs of Treating Alzheimer's disease alone, including medical and nursing costs and lost Productivity have been estimated to be $67 billion (Langa, et al., 2001) to $100 billion (Ernst, et al., 1994). With the majority of persons with dementia being cared for in the community, it has Been suggested that the coping mechanisms and resources of families may be severely Tested (O'Shea and O'Reilly 2000). During the prolonged care period characteristic of Alzheimer's disease and other demential conditions, caregivers face the potential for Social isolation; financial drain; and physical duress (Clyburn et al. 2000). Women are Particularly vulnerable, as they make up the majority of care providers (Gwyther 2000). 1.2 PREVALENCE OF DEMENTIA 1.2.1 INTERNATIONAL DATA Prevalence refers to the number of people with dementia in the population at a given Point in time. There are a large number of prevalence surveys, which have been carried Out throughout the world. These tend to give slightly different results depending on the Methods used in the study. However, all studies show a sharp rise in the prevalence of Dementia with age In the United States, approximately 5 to 8 percent of people over the age of sixty-five Suffer from dementia (Tinker 2000). For the oldest old (age seventy-five and over), the Risk of dementia is much greater. Approximately 18 to 20 percent of those over the age Of seventy-five have dementia and between 35 to 40 percent of people eighty-five years Of age or older are affected (Ikels 1998; Rabins et al. 1999; Tinker 2000). Thus the prevalence of dementia increases steadily with age, roughly doubling every 5 Years. Studies of community-dwelling elderly have reported dementia in 0.8-1.6% of Persons 65-74 years old, 7-8% of persons 75-84 years old, and 18-32% of persons over 85.5. Estimates of the annual incidence of dementia in community-based studies in the West are 0.6-1% for ages 65-74, 2-3% for ages 75-84, and 4-8% for ages 85 or older (Ritchie, et al., 1992). In the famous Rotterdam study 474 cases of dementia were detected, giving an overall Prevalence of 6.3%. Prevalence ranged from 0.4% (5/1181 subjects) at age 55-59 years To 43.2% (19/44) at 95 years and over. Alzheimer's disease was the main sub diagnosis (339 cases; 72%); it was also the main cause of the pronounced increase in dementia With age. The relative proportion of vascular dementia (76 cases; 16%), Parkinson's Disease dementia (30; 6%), and other dementias (24; 5%) decreased with age. A Substantially higher prevalence of dementia was found in subjects with a low level of Education (Ott, et al., 1995). In the Canadian study, 1994, the prevalence of dementia was 8.0% among all Canadians aged 65 and over and the female: male ratio was 2:1. The age-standardized Rate ranged from 2.4%, among those aged 65 to 74 years, to 34.5%, among those aged 85 and over. The corresponding figures for Alzheimer's disease were 5.1% overall, Ranging from 1.0% to 26.0%; for vascular dementia it was 1.5% overall, ranging from 0.6% to 4.8%. 1.2.2 INCREASE IN PREVALENCE Because of the ageing of the world’s population, in the future there will be relatively More people in the age groups at most risk for dementia. In the absence of effective Prevention or treatment, the increase in the numbers of people with dementia will come About as a simple consequence of an increase in the size of the population most at risk, I.e. Of those aged 65 years and over. Between 1990 and 2010, the number of dementia Cases in the more developed countries is projected to increase from 7.4 million to 10.2 Million (a 37% increase), the elderly population (aged 65+) from 143 million to 185 Million (a 30% increase) and the total population in these countries is projected to Increase from 1,143 million to 1,213 million (6% increase). Because of the lack of Prevalence data from the less developed countries, it is difficult to make projections of The future number of dementia cases. However, these countries are also ageing rapidly And are therefore expected to show an increase in dementia cases. The prevalence rate Might also conceivably increase if, for example, better care of people with dementia Meant that they survived longer (Ferri, 2005). 1.2.3 INDIAN STUDIES Investigators have documented prevalence rates for dementia in various community Surveys in India. In a study conducted in an urban setting in South India to investigate The prevalence, psychosocial correlates and risk factors of various dementias, the Prevalence of dementia was 33.6 per 1000 (95% CI 27.3-40.7). Alzheimer's disease was The most common type (54%) followed by vascular dementia (39%), and 7% of cases Were due to causes such as infection, tumor and trauma. Family history of dementia was Found to be a risk factor for Alzheimer's disease while a history of hypertension was a Risk factor for vascular dementia. (Shaji, et al., 2005) In a 3-year epidemiological survey for dementia in an urban community-resident Population in Mumbai, India, the prevalence rates were as follows: the prevalence rate For dementia in those aged 40 years and more was 0.43% and for persons aged 65 and Above was 2.44%. The overall prevalence rate of dementia was 0.32% and a prevalence Rate of 1.81% for those aged 65 years and older. The overall prevalence rate for Alzheimer's disease (AD) in the population was 0.25%, and 1.5% for those aged 65 Years and above. AD (n = 62; 65%) was the most common cause of dementia followed By vascular dementia (n = 23; 22%). There were more women (n = 38) than men (n = 24) in the AD group (Sachdeva, 2001). 1.2.4 VARIATION IN RATES In various studies the reported prevalence has been lower in India (1.36% to 3.50%) Compared to the West (5.9% to 9.4%) (Chandra, et al., 1998; Ferri, et al., 2005). True Differences may be attributed to Differing genetic factors Environmental factors Life expectancy Duration with disease and age specific incidence (Prince, et al., 2000). Variation in rates may also be as a result of Different survey procedures (one stage/two stage) Diagnostic criteria used (Henderson,1994) Assessment schedules Diagnostic instruments used (most instruments not validated in developing World) (Jacob, 2007). In a study done to examine the effect of different diagnostic criteria on the prevalence Of dementia, 10000 subjects aged above 65 years were recruited in a community survey Using a one-stage procedure. The results showed that the prevalence of dementia was Different on using different diagnostic criteria. Minor differences in criteria had a Significant impact on the diagnosis. The assessment was influenced by Education (Ott, et al., 1995) Level of baseline function Lifestyle and demand on the person Tolerance of impairment Expectation by relatives Differences between hospital and community based populations. The prevalence according to this study showed wide variation in rates of prevalence When different criteria were used. Criteria for dementia Prevalence GMS (using AGECAT) 63.4 %( 60.3-69.6) 10/66 algorithm (Prince et al., 2003) 21.2% (18.7-23.9) Education adjusted 10/66 algorithm (Prince et al., 2004) 10.6% (8.8-12.7) DSM IV full criteria 0.8% (0.4-1.6%) (Jacob, et al., 2007) 1.3 ISSUES RELATED TO DIAGNOSIS OF DEMENTIA 1.3.1 ADVANTAGES OF EARLY DETECTION: There are several potential benefits of detecting dementia before patients are severely Impaired: Reversible causes of dementia may be identified and treated. Treatments to slow the progression of disease can be instituted. Measures can be taken to reduce the morbidity associated with dementia. Patients and their family members can anticipate, prepare for problems and plan For the future. Better control of risk factors for cerebrovascular disease. Treatment of associated disorders may improve function in patients with Dementia. Effective interventions can be planned to prevent falls or accidents. Decisions about durable power of attorney can be made while the patient is still Competent to participate. 1.3.2 PROBLEM OF UNDERRECOGNITION Dementia continues to be under-recognized within community practice settings (Bair, 1998). Dementia is easily recognized in its advanced stages, but numerous studies Indicate that clinicians often overlook the early signs of dementia. Clinicians fail to Detect an estimated 21% to 72% of patients with dementia, especially when the disease Is early in its course. Thus around two thirds of the cases of dementia may remain Undetected. A population-based study found that the prevalence of undiagnosed Dementia among individuals aged 65 years and older was 1.8 percent (Sternberg, et al., 2000). Another population-based study found that about half of the relatives of men With mild dementia failed to recognize a problem with thinking or memory. Among the Undiagnosed patients the majority had dementia of were mild to moderate severity. These low detection rates, the availability of therapy, and the opportunity to elucidate Patients' preferences for future health planning drives the interest in dementia screening Programs in primary care. 1.3.3 BARRIERS TO DISEASE DIAGNOSIS The barriers to the diagnosis of dementia include: Difficulty in distinguishing early disease from normal aging Definitions usually depend upon the impact of the condition on social, Functional or occupational activities, which can be biased. Patients, fearing a label, deliberately minimize their symptoms Patients with more advanced dementia may not be aware of their deficits. The “homelessness” of clinical management of dementia between various Medical specialties Most psychiatrists do not incorporate a cognitive screen in daily practice. Clinicians in the primary care setting are even less inclined to incorporate Cognitive screening in routine clinical assessments (Knopman, et al., 1998). In addition to the above-mentioned reasons, the other factors which lead to under Recognition of dementia include. Patients and their caregivers do not often report cognitive difficulties. Cognitive difficulties may be masked by a continued ability to act in a socially Acceptable manner. Physicians fail to recognize early signs. The screening tests currently available are time-consuming Some of the most commonly used mental status tests lack the sensitivity and/or Specificity required for an accurate diagnosis. In a small number of cases, co-morbid conditions (especially depression and Delirium) can make differential diagnosis problematic. Lack of training Routine screening in primary care practice could, therefore, potentially increase the Number of patients diagnosed with dementia, and most newly discovered cases would Have mild to moderate forms of the disease. 1.3.4 BARRIERS TO SCREENING IN PRACTICE Implementation of screening programs would require screening of asymptomatic Elders, the capacity to conduct an accurate diagnostic assessment, and the resources to Provide education and management for patients with a confirmed diagnosis. Such Resources are not available in the typical primary care practice. The low predictive value of most screening tests for dementia raises the possibility that Unselective screening may have adverse effects. Many asymptomatic patients with Abnormal results on Mini Mental State Examination (MMSE) or other screening tests Will not have dementia; these patients may be subjected to further tests (e.g., Neuropsychological testing, blood tests, lumbar puncture, computed tomography [CT]) To confirm the diagnosis, rule out other reasons for altered mental status, and assign a Cause of dementia. Comprehensive follow-up, although posing little risk to patients, Will be time-consuming and expensive. If clinicians make a diagnosis based on Screening alone, patients may be incorrectly diagnosed as having a progressive, Incurable illness. Nonetheless, in the absence of screening, misdiagnosis of dementia is Common in outpatient practice. 1.4 SCREENING FOR DEMENTIA 1.4.1 ISSUES RELATED TO USE OF SCREENING AND CONFIRMATORY TESTS It has been highlighted that a screening test would require a high sensitivity, while a Diagnostic test would require a high specificity (Jacob, 2003). The sensitivity and Specificity of a diagnostic procedure is constant only when the test and the population Characteristics remain constant. Moreover the predictive values of tests are dependent On the prevalence of the disorder in the population. These predictive values are based On the probability of the presence or absence of the phenomenon in question. Thus the Prevalence of the condition in the population is a major determinant of the predictive Potential of the tests. Tests used in groups of people with low prevalence of the Condition to be detected would produce high false positive rates and low positive Predictive values. Confirmatory tests should be used on individuals who have tested positive on the Screening instrument. This method would artificially increase the prevalence of the Disorder in the group being tested and would result in more accurate prediction. Similarly a screening test employed in high prevalence area may generate high false Negative rates and low negative predictive values. Optimum test results would be Obtained when prevalence of the tested condition is around 50%. The use of Confirmatory tests in patients where the probability for the disease is either too low or Too high would demand caution in interpretation as it would increase the likelihood of Misclassification of subjects as diseased or non-diseased.
| Item Type: | Thesis (Masters) |
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| Uncontrolled Keywords: | Screening ; Diagnosis ; Dementia ; Hospital. |
| Subjects: | MEDICAL > Psychiatry |
| Depositing User: | Subramani R |
| Date Deposited: | 19 Aug 2017 02:33 |
| Last Modified: | 19 Aug 2017 02:33 |
| URI: | http://repository-tnmgrmu.ac.in/id/eprint/1908 |
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