Dementia What Is Dementia Dementia Is An Organic Brain Syndrome Whic (8256 words) Essay Example For Students

Dementia What Is Dementia ? Dementia Is An Organic Brain Syndrome Whic (8256 words) Essay Dementia What is Dementia ?Dementia is an organic brain syndrome which results in global cognitive impairments. Dementia can occur as a result of a variety of neurological diseases. Some of the more well known dementing diseases include Alzheimers disease (AD), multi-infarct dementia (MID), and Huntingtons disease (HD). Throughout this essay the emphasis will be placed on AD (also known as dementia of the Alzheimers type, and primary degenerative dementia), because statistically it is the most significant dementing disease occurring in over 50% of demented patients (see epidemiology). The clinical picture in dementia is very similar to delirium, except for the course. Delirium is an acute transitory disorder. By contrast Dementia is a long term progressive disorder (with the exception of the reversible dementias). The course of AD can range anywhere from 1.5 to 15 years with an average of about 8.1 years (Terry , 1988). AD is usually divided into three stages mild, moderate, and severe.Throughout these stages a specific sequence of cognitive deterioration is observed (Lezak, 1993). The mild stage begins with memory, attention, speed dependent activities, and abstract reasoning dysfunction. Also mild language impairments begin to surface. In the moderate stage, language deficits such as aphasia and apraxia become prominent. Dysfluency, paraphasias, and bizzare word combinations are common midstage speech defects. In the severe stage the patient is gradually reduced to a vegetative state. Speech becomes nonfluent, repetitive, and largely non-communicative. Auditory comprehension is exceedingly limited, with many patients displaying partial or complete mutism. Late in the course of the disease many neuropsychological functions can no longer be measured. Also primitive reflexes such as grasp and suck emerge. Death usually results from a disease such as pneumonia which overwhelms the limited vegetative functions of the patient. Dementia is commonly differentiated along two dimensions: age and cortical level. The first dimension, age, distinguishes between senile and presenile dementia. Senile dementia is used to describe patients who become demented after the age of 65, whereas presenile dementia applies to patients who become demented prior to that age. Late onset AD (LOAD) also known as senile dementia Alzheimers type (SDAT) is the predominant cause of senile dementia. Early onset AD (EOAD) is the most frequent cause of presenile dementia, but HD, Picks disease and Creutzfeldt-Jakob disease though not as frequent are also important causes in presenile dementia.The second dimension, cortical level, differentiates between cortical and subcortical dementia. Corticaldementia is used to describe dementia which results from brain lesions at the cortical level, whereassubcortical dementia describes dementia resulting from subcortical brain lesions. AD and Picks disease arethe best known examples of cortical dementia; whereas HD, Parkinsons disease (PD), and progressivesupranuclear palsy (PSP) are good examples of subcortical dementia (Mayke, 1994). Dementia with bothcortical and subcortical features is also possible, in that case the term mixed dementia is used. MID is acommon example of mixed dementia. Historical developments in dementia Pre-Modern Developments The use of the term dementia dates back to Roman times. The Latin word demens did not originallyhave the specific connotation that it does today. It meant being out of ones mind and, as such, was ageneral term for insanity (Pitt, 1987). It was the encylopedist Celsus who first used the worddementia in his De re medicina, published around AD 30. A century later the Cappadocian physicianAretaeus first described senile dementia with the word dotage (i.e. , The dotage which is the calamity of oldagedotage commencing with old age never intermits, but accompanies the patient until death. ).Curiously, dementia was mentioned in most systems of psychiatric classification throughout pre-moderntimes, though the precise meaning of the word is often unclear (Pitt, 1987).Nineteenth Century It can be argued that the origins of the scientific study of dementia date back to the early nineteenth century. The initial steps were undertaken by the great French psychiatrist Pinel at the beginning of that century. Pinels observations led him to the conclusion that the term dementia should be applied in relation to theprogressive mental changes seen in some idiots (Pitt,3). Furthermore, Pinel thought that dementiawas a distinct abnormal entity, and thus he used the term dementia to designate one of the five classes ofmental derangement. However, by applying the term dementia to idiots, Pinel failed to differentiatebetween dementia and mental subnormality. This was accomplished by Pinels student Esquirol in his 1838 textbook Mental maladies-A treatise on insanity. Esquirol summed up the difference between the dementedand the mentally handicapped in the following epigram: The dement is a man deprived of the possessionshe once enjoyed, he is a rich man who has become poor. But the defective has been penniless and wretchedall his life (Mahendra, 10). Furthermore, Esquirol was also instrumental in the popularization of the termsenile dementia. Remarkably, his description of senile dementia is very similar to our present day definition. Interestingly, in 1845 Griesinger proposed that senile dementia was due to a disease of the cerebralarteries, a faulty view which persisted until Alzheimers time. Much of todays basic knowledge about dementia was accumulated throughout the second half of the nineteenth century, and the first decade of the twentieth century. 1872 saw Huntington present a papercalled On chorea, in which he discussed a typical case of what is now known as Huntingtons disease.Twenty years later in 1892 two significant events occurred. First Pick in a paper called On the relationbetween aphasia and senile brain atrophy described the case of August H. a 71 year old patient with seniledementia. Although the case is not typical of our present day conception of the disease Pick was givencredit for discovering a new disease. The other more significant event in 1892 was Blocq and Marienscosdescription of scattered silver staining plaques in the cortex of senile patients. These plaques weresubsequently named senile plaques (SP) by Simchowitz in 1911.The year 1894 saw Alzheimers first major contribution , a differentiation between senile and vascular(arteriosclerotic)dementia. Alzheimer described the specific changes observed in arteriosclerotic atrophy ofthe brain, which resemble what we might call vascular dementia. In 1898 another milestone occurred whenBinswanger introduced the term presenile dementia. Thus by the twentieth century significant changes weretaking place in our understanding of dementia. The nineteenth century view that there was only one mentaldisease-insanity-and that dementia was its terminal stage was dispelled by Kraepelin in the 6th edition of histextbook Psychiatrie, published in 1899 (Pitt, 4). Kraepelin separated dementia praecox (a concept heproposed in 1898 in relation to Schizophrenia) from the other dementias (paralytica and organic), and Seniledementia was included under another category called involution psychosis (Pitt, 4).Twentieth Century In 1907 Alzheimer published his landmark case A unique illness involving the cerebral cortex in which he described a fifty-five year old demented woman. The case was very unusual for two reasons its clinical course, and the discovery of a striking microscopic lesion in the womans brain (Beach, 1987). The clinicalcourse was unusual because of the young age of the patient and the rapidity of degeneration (the patient diedwithin four and a half years of symptom onset). At autopsy neuropathological findings were even moreunusual. One quarter to one third of cerebral cortical neurons had disappeared, and many of the remainingneurons contained thick, coiled masses of fibers within their cytoplasm (Beach, 1987). Alzheimer speculatedthat a chemical change had occurred in the neurofibrils. Thus Alzheimer described for the first timeneurofibrillary tangles (NFT), which togther with SP are considered to be the neuropathologocal halmarksof AD (See Appendix 1 for Alzheimers original drawing of NFT). Alzheimer concluded that hediscovered a unique entity separate from senile dementia as it was known at that time. However, it was notuntil 1910 when Kraepelin discussed the condition in the 8th edition of his textbook Psychiatrie that ADgained official recognition. The second decade of the twentieth century witnessed the end of the golden period in dementia research (this only lasted until the 1960s when a renaissance occurred). URen cites two reasons as the principalcauses (Pitt, 6). First the rise of Freuds Psychodynamic theory caused American psychiatry to swerve in thedirection of psychological explanations. Second Kraepelins descriptions and classifications seemed to leavelittle room for therapeutic efforts or optimism. Notwithstanding, several key contributions have been made in the Dark Ages of dementia research. In1920 Creutzfeldt, and in 1921 Jakob, described cases of dementia with pyramidal and extrapyramidal signs.Although it is now thought that only Jakobs case was typical of the disease the Creutzfeldt-Jakob disease(CJD) was given to the world. The year 1936 saw an important change with regards to the diagnosis of AD. Before 1936 it was common practice to provide a diagnosis based on both clinical and pathologicalcharacteristics. However, when it became clear that many non-demented people had some senile plaquesand neurofibrillary tangles, Jervis and Soltz advised that only clinical criteria would suffice for a diagnosis ofAD (Mahendra, 14). In 1948 Jervis published his landmark paper called Early senile dementia inMongoloid idiocy. Jervis described three individuals with Downs syndrome (DS), aged 37, 42 and 47years, each of whom had shown a profound emotional and intellectual deterioration in the last few years oflife. At autopsy, all were found to have SP and two also displayed NFT (Beach, 39). This was the firstdemonstration of NFT in DS and the first full clinical and pathological correlation supporting an Alzheimer- like syndrome in DS (Beach, 39). Research in dementia began to revive in the early sixties. New causes of the dementia syndrome have been recognized including, depression, which in the form of psuedodementia may mimic dementia (Kiloh,1961), progressive supranuclear palsy (Steele et al, 1964) and normal pressure hydrocephalus (Adams et al, 1965) , (cited in Pitt, 6). Prior to the 1960s dementia was still viewed as a chronic, irreversible anduntreatable condition (Mahendra, 14). Accordingly, in the 1960s, several writers in Europe called for arevision of the concept and emphasized that irreversibility should not be viewed as an essential feature ofdementia. Another important change that took place in the 1960s concerned epidemiology. Prior to thesixties arteriosclerosis was thought to be the predominant cause of dementia, whereas AD was thought to berare (Pitt, 12). However, arteriosclerosis was decisively challenged as the prime cause of dementia byseveral reports between 1960 and 1970 (i.e.,Tomlinson, Blessed, and Roth, 1968 and 1970). These reportsdemonstrated that arteriosclerosis was greatly overestimated as a cause of dementia, and that the majority ofpatients dying with dementia in fact showed the characteristic plaques and tangles of AD. Furthermore,Katzman, in 1976 argued that because of similarity in the clinical picture and the identical nature of thehistopatholgy, distinctions between AD and senile dementia were arbitrary and no longer useful (Pitt, 12).Thus when it was understood that AD and senile dementia are similar, it was clear that AD is a commonillness.In the mid-1970s two important contributions were made. First, Butler in his 1975 book Why survive? Being old in America criticized the widespread notion that senility was a normal part of aging. Butlerargued that, senility, was a result of brain disease or depression and was potentially treatable. The extensionof this view was that senility was abnormal, and that its usual causes were diseases, not just aging(Pitt, 1987).Second, three different labs (Bowen et al, 1976; Davies Maloney, 1976; and Perry et al,reported low levels of choline acetyltransferase, the marker enzyme for acetylcholine 1977) (ACh), in thebrains of patients who died from AD. ACh deficiency has since been the target of most therapeutic efforts inAD (see treatment). Throughout the 1980s and 1990s two trends emerged. First, with regards to diagnosis, criteria have been made stricter. Classification systems like the Diagnostic and Statistical Manual have evolvedtowards a more precise and comprehensive definition of dementia. Moreover, neuoroimaging techniquesare becoming more and more standard, allowing in some cases for a more accurate diagnosis. Second,the past fifteen years have witnessed a substantial growth in genetically based research. For instance one of the genes involved in AD, the amyloid precursor protein (APP), has been localized to a specific segmentof chromosome 21 (see risk factors).Epidemiology Dementia is known as the quiet epidemic, but it affects a significant proportion of our population. In1989 the Canadian consensus conference on the assessment of dementia reported that Canada had about250,000 cases of dementia (which at the time comprised about 1% of the population), with 25,000 newcases occurring annually (Clarfield, 1989). Jorm et al. (1988) project that until the year 2025 Canada willexperience a growth in the prevalence of dementia, more rapid than the rise if the number of elderly agedover 65. The majority of dementia cases are attributable to AD, vascular dementias, or a combination ofthese (Table 1). In the past there were hopes that up to 40% of dementias had reversible causes. However, recent reports (Clarfield, 1988; Barry and Moskowitz, 1988) suggest that the true incidence of reversibledementias is at the most 11% and is probably far lower, with drugs, metabolic causes and depression accounting for about two thirds of the cases (Clarfield, 1989).Overall, there are no significant gender differences in prevalence and incidence rates for dementia as awhole. However, for AD, there is an increased prevalnce in females. Jorm et al. (1987) estimate a female tomale AD prevalence ratio of 1.6. Ethnically there seem to be important differences in both prevalence andsubtype of dementia. Prevalence wise, Heyman et al. (1991) found that out of a random sample of 411616% of African Americans had dementia compared to only 3.1% of Caucasians. The same study also found that mixed and MID were more likely to occur in African Americans (26% of dementias in African Americans compared to 14% in Caucasians). Moreover, in both Europe and North America most studiespoint to AD as the most common dementing illness; whereas in Asia (especially Japan) MID predominates(Morris, 1994). The observed high rate of stroke in Japan is consistent with a high MID rate. Possibly thehigher level of stress in Japan leads to more strokes and therefore a higher incidence of MID.Table 1. Etiology of Progressive Dementia and Approximate Incidencesenile dementia of the Alzheimer type50%Multi-infract dementia10-15%Mixed SDAT and MID 10-15%Alcoholic-nutritional dementia5-10%Normal pressure hydrocephalus 5%Miscellaneous: Huntingtons disease, neoplasms, chronicsubdural hematomas, Parkinsons disease,Cruetzfeldt-Jakob disease, AIDS, unknown cause5-20%Life Expectancy and Mortality Estimates The following summary is based on Terrys (1988) review of the Wang (1978) and Barclay et al. (1985) studies. The Wang study examined senile dementia (mean age of onset 71.3 years) and presenile dementia (mean age of onset 53.8 years) survival rates during the 1960s. Senile dementia patients survivedon the average 6.0 years, close to half of the expected survival rate (11.1 years) of similarly aged nondemented people. Presenile demented patients survived slightly longer an average of 6. 9 years, against an expected survival of 22.3 years. The Barclay et al. Studies examined survival rates in AD and MID patientsin the 1980s. The mean survival rates for AD and multi-infarct dementia were 8.1 and 6.7 yearsrespectively. Interestingly, the survival rate of demented women on the whole is significantly higher than that of men. Terry (1988) suggests that the lower survival rate of demented men is due to a higher incidence of MID in men. Risk Factors Age Age is the biggest risk factor for developing dementia. According to a model proposed by Jorm et al.(1987) a doubling of the prevalence rate occurs every 5. 1 years. (1987) For the elderly population aged 65and above the prevalence of dementia is estimated at about 10%. Whereas in the very elderly it can reach upto 40% (Clarfield, 1989).Genetics Genetic factors are important in some dementing diseases. Biotechnology Essay and the mini-mental state exam of Folstein et al. The Blessed test is the most sensitive, and thus is used the most in very early cases. The mini-mental test is broader in that it also tests language,writing, and drawing. Both tests are inappropriate to use with mentally retarded individuals or those with apoor educational background. Also the tests should be adjusted for individuals who are not fluent in Englishor for those who have a different cultural background (Katzman et al. , 1988). Another useful brief item isthe dementia rating scale. It is utilized to estimate the severity of dementia. Neuropsychological Testing According to Morris (1994, P. 79) neuropsychological testing in demented patients serves threefunctions: (1) to provide objective documentation of impaired cognition and therefore support the clinicaldiagnosis of dementia (2) to assess cognitive changes longitudinally, and (3) to identify selective patterns ofcognitive deficits for correlation with neuroimaging and postmortem findings.The shortest battery for discriminating dementia patients from normals is the Iowa screening battery for mental decline. It consists of three neuropsychological tests, Temporal Orientation, Benton VisualRetention Test and the Controlled Oral Word Association Test. This battery is used to determine if furtherevaluation is necessary. If further evaluation is necessary usually the Consortium to Establish a Registry forAlzheimers disease (CERAD) battery is used. The battery consists of seven tests, some of which areslightly modified from their original form (Lezak, 1995). These tests include the Word List Memory Testand the Boston Naming Test, which test for memory and language respectively. The word List MemoryTest tests for memory by verifying how well a person can recall three lists of ten words. Whereas the Boston Naming Test tests for language by verifying how well the person can duplicate three lists of fivewords (Lezak, 1995). Sometimes it is useful to test for specific cognitive abilities. For instance theWechsler Memory Scale-Revised is often used to see if a memory impairment is present. Table 5 illustratessome of the more common neuropsychological tests utilized in the assessment of dementia.Table 5. Assessment of Neuropsychological Functions for Dementia Diagnosis Function(s) assessed Examples of useful clinical testsGlobal mental statusMini Mental State, Mattis Dementia Rating Scale, Information-Memory Concentration Test, Syndrome Kurtz Test Premorbid functioningNational Adult Reading Test, Wide-Range Achievement Test-Reading General intellectual functioningWechseler Adult Intelligence Scale-Revised, Ravens Progressive Matrices, Test of Nonverbal Intelligence MemoryWechsler Memory Scale Revised, Benton Visual Retention Test, Rey-Osterreith Complex Figure, Rey Auditory Verbal Learning Test, Selective Reminding Test, California Verbal Learning Test, Rivermade Behavioral Memory Test Language (naming and fluency)Boston Diagnostic Aphasia Examination, Western Aphasia Battery, Holland Communicative Abilities in Daily Living, Halstead-Wepman Aphasia Screening Test, Bost on Naming Test, Controlled Oral Word Association, Semantic Category Naming Problem solving (and executive functioning)Halstead-Reitan Category Test, Wisconsin Card Sorting Test, Trailmaking A ; B, Stroop Praxis and constructional abilityRosen Drawing Test, Rey-Osterreith Complex Figure (copy), Benton 3-Dimensional Blocks, Beery Test of Visual Motor Integration, WAIS-R Block Design, BDAE Stick Test MotorFinger Oscillation, Grooved and Purdue Pegboards, Diadokinesis Attention/concentration WAIS-R Digit Span, Reaction Time Tests, Cancellation Tasks, Syndrome Kurtz Test ______________________________________________________________________________________ Note: Reproduced from Morris, 1994, Handbook of Dementing Illnesses, New York: Marcel DekkerClinical Diagnosis and Related Problems A definitive diagnosis of AD and many other dementing diseases can only be made either throughcerebral biopsy, the surgical removal of a small piece of the cerebral cortex, or when the patient dies and ana utopsy is performed. The two most widely used criteria for the diagnosis of dementia are the Diagnosticand Statistical Manual Third Edition-Revised (DSM-IIIR) and the National Institute of Neurological andCommunicative Disorders and Stroke/Alzheimers Disease and Related Disorders Association(NINCDS/ADRDA). DSM-IIIR is more often used for research purposes and the NINCDS/ADRDA forclinical purposes. There are several problems in diagnosing dementia, most notably differentiating dementia from normalaging and from depression. In general, the cerebral processing resources needed for attention demandingtasks and secondary memory functions are adversely affected by age (Morris, 1994). Clinically, these impairments result in limited attentional capacity and diminished speed of information processing and retrieval. But unlike in dementia these symptoms are largely nonprogressive, and do not interferesubstantially with everyday life (Morris, 1994). In patients with mild cognitive changes it is almostimpossible to make an exact diagnosis even with the best neuropsychological tests. Only the likelihood ofdeveloping dementia can be estimated. There can be a great deal of symptom overlap between dementia and depression especially in the earlystages of dementia. Depression presenting as dementia is often called pseudodementia. The termpseudodementia implies that the dementia is reversible, and is not caused by an organic disorder but ratherit is caused by a psychiatric disorder (Clarfield, 1989). Currently there are no definitive tests to differentiatebetween dementia and depression.Clinical Subgroups of Alzheimers Disease Blenow, Wallin ; Gttfries (1994) have proposed a model for clinical subgroups in AD based upondifferential clinical symptomatology and neuropathology. Their findings indicate that there are two distinctsubtypes which they have termed Alzheimers disease type I and type II. Alzheimers disease type I ischaracterized by dominant temporoparietal symptoms, low frequency of vascular factors, normal blood-brainbarrier function, low frequency of CT indicated leukoaraiosis (white matter lesions), and relatively youngerage of onset. These characteristics correspond to the classic description of AD. Therefore AD type I appears to constitute classical or pure AD (Blenow et al. , 1994).Alzheimers disease type II is characterized by general cognitive symptoms, absence of or mild temporo- parietal symptoms, high frequency of confusional symptoms, relatively high frequency of vascular factors,mildly impaired blood-brain barrier function, high frequency of CT indicated leukoaraiosis, and relatively late age of onset. These characteristics suggest that vascular changes are responsible for the production ofdementia symptoms in AD type II (Blenow et al. , 1994). Markers Markers Reflecting Brain Changes Markers which belong to this category utilize cerebral spinal fluid (CSF) changes to reflect alteredneurotransmitter levels or abnormal proteins (Katzman et al. , 1988). The enzyme Acetylcholinesterase(which regulates the neurotransmitter Achetylocholine, see treatment) is known to be decreased in thecerebral cortex of demented patients. Several investigators have found it decreased in the CSF, while othershave failed to confirm this. According to Thal (1985) the apparentdecrease in some studies may be a dilutional effect secondary to ventricular enlargement. SimilarlySomatosatin and Norepinephrine are also reduced in the cerebral cortex of demented patients. However, inthe CSF Somatosatin is only decreased in some patients, whereas Norepinephrine is actually increased in theCSF. A good area for future research is to investigate whether any of the abnormal proteins associated withAD can be found in the CSF (Katzman et al. , 1988).Peripheral Markers Peripheral markers are markers which reflect changes in the skin or blood cells (Katzman et al. , 1988). Most of the findings in this category are either inconclusive or have not been replicated. For instanceDiamond et al. (1983) have found that the sodium-lithium counter- transport rates in red blood cells were elevated in AD patients, but this finding has not been replicated. Olfactory deficit Markers Several investigators have found that AD patients have olfactory recognition and threshold deficits.Peabody and Tinklenberg (1985) have found that 8 out of 18 AD patientshad these deficits compared to only 1 out of 26 normals. Katzman et al. (1988) discuss increased carbondioxide production, increased superoxide dismutase, and decreased calcium uptake as possible causes forthese deficits in AD patients.Pharmacological TreatmentCholinergic Drugs There is no known cure for AD or many other dementing diseases. Several medications are available but their effectiveness is limited. The most promising group of drugs work by potentiating the cholinergicsystems in the brain. During the 1970s several studies have shown that demented patients have low levels of the neurotransmitter Acetylocholine (ACh). This has led to the development of the cholinergic hypothesisfor dementia. It has since been established that the enzyme from which ACh is synthesized, CholineAcetyltransfearse (ChAT), is severely decreased in AD patients.There are three mechanisms by which these drugs work (1) precursor loading , (2) preventing thebreakdown of ACh , and (3) the direct stimulation of the postsynaptic receptors. Precursor loading in AD is similar to Parkinsons disease (PD). The difference is that instead of using the precursor L-dopa for dopamine in PD, the precursors choline and lecithin are used in AD to synthesize ACh. Generally this treatment when used alone fails to improve cognitive performance (Schneider, 1994). Preventing the breakdown of ACh involves inhibiting the enzyme Acetylocholinesterase (AChE). Theprincipal drugs which utilize this mechanism are Physostigmine, Tacrine, and Valancrine. The problem with Physostigmine is that the duration of its therapeutic effect is very short, usually about one to two hours,whereas Tacrine and Valancrine have serious side effects (Schneider, 1994). A second generation ofcholinesterase inhibitors which are longer acting and more selective are currently being developed, and the initial results are encouraging. In AD the postsynaptic M-1 cholinergic receptors are relatively intact. It is the presynaptic M-2cholinergic receptors which regulate ACh release that are damaged. Therefore, it makes sense to try todirectly stimulate the postsynaptic receptors (Schneider, 1994). These cholinergic agonists includeBethanechol, Oxotremorine, Pilocrapine, RS-86, and Arecholine. When these drugs are given orally theyare not very effective. They are more effective when administered through an implant of anintracereroventricular pump. But the risks of such an implant are not insignificant. For instance in one trialout of 68 implants 16 resulted in surgical complications, including one death, two hemorrhages, and sevenseizures (Schneider, 1994). Other Drugs There are several other drugs used in the treatment of dementia, although their therapeutic mechanismsare not understood very well. Hydergine is the longest used and most extensively studied antidementia drug.Hydergine is an ergoloid derivative which effects the alpha-adrenergic, dopaminergic, and sertoninergicreceptors. There have been conflicting reports about its efficacy, but overall it seems that it is only slightlybetter than a placebo in relieving symptoms (Schneider, 1994).Nootropics are a group of drugs derived from the neurotransmitter GABA. But instead of having GABAeffects they have a neuroprotective effect on the central nervous system, and they may stimulate centralcholinergic activity. Still, the specific mechanism of action relevant for dementia has not been established for these drugs. Overall results with Nootropics such as Piracetam, and Oxiracetam have not been veryencouraging (Schneider, 1994). Summary As the human race marches forward into the new millennia, one of the challenges that will remained to be solved is the dementia epidemic. The continuous increase in life span means that the number of peoplewhich are afflicted with dementia will continue to grow. Notwithstanding, we have come along way in ourunderstanding of the dementia syndrome since the days of Pinel or even since the days of Alzheimer. We now know that dementia (senility) is not the natural outcome of aging, rather it is the result of a varietyof possible abnormal brain processes. For instance in AD (the most important dementing disease) theformation of SP and NFT in the brain have been proven to be the main causal factors of the disease. Furthermore, in AD these processes have been shown to occur mainly in the cerebral cortex, and inparticularly in the temporal lobes.The effects of these brain lesions are mainly manifested in various cognitive and behavioral impairments.With regards to cognition, memory and language dysfunction are the most commonly encountered deficits in AD. In fact memory impairment is so crucial, that a diagnosis of AD will almost never be made unless it is present. With respect to behavior, anxiety disturbances tend to predominate in the earlier stages of AD,whereas aggression is encountered in the latter stages.Significant progress has also been made in the assessment of dementia. Standard interviewing methods are now used alongside brief mental status examinations. Although the mental status exams have a limited diagnostic usefulness (they are only used as initial screening devices), they are nevertheless importantbecause of their relative low cost and quick administration time. When further confirmation is required or more detail is desired neuropsychological testing is performed. Neuropsychological testing allows for the assessment of specific cognitive functions (i.e. memory, language, attention) thus discovering which brain areas are affected. This is useful because not only is it possible to judge if the person suffers from dementia, but with a high degree of accuracy it is possible to say which dementing disease is responsible.Notwithstanding, even the best neuropsychological tests may run into difficulties at times. For instance differentiating dementia from depression is extremely difficult since people who are depressed may display many of the clinical symptoms observed in dementia.As our understanding of dementia grows it is conceivable that an effective treatment will be found within the next century. Genetically several important breakthroughs have occurred recently in AD.Abnormalities in chromosomes 14 and 19 have been added to chromosome 21 as causal factors.Furthermore, investigators are now close to localizing the specific genes involved in these chromosomes (it is already known that in chromosome 21 the specific gene involved is the APP gene). With regards to pharmacological treatment the ACh hypothesis for dementia has led to the development of three groups of cholinergic drugs, some of which show great promise. Other drugs are also available but theireffectiveness is questionable.References Beach, Thomas G. (1987). The history of Alzheimers Disease: three debates. Journal of the History ofMedicine and Allied Sciences, 42, 327-349. Blenow, Kaj, Wallin, Anders ; Gottries, Carl-Gerhard. (1994). Clinical subgroups of AlzheimersDisease. In V. Olga, B. Emory and Thomas E. Oxman (Eds. ), Dementia: Presentations, DifferentialDiagnosis, and Nosology. Baltimore: The John Hopkins University Press. Carson, Robert C and Butcher, James N (1992). Abnormal psychology and modern life. New York:Harper Collins publishers Clarfield, A. Mark. (1989). Canadian consensus conference of the assessment of dementia. Montreal:the Canadian Consensus Conference on the Assessment of Dementia. Cummings, Jeffery L. (1988). Dementia of the Alzheimer type: challenges and definition and clinicaldiagnosis. In Harry A. Whitaker (Ed.), Neuropsychological studies of nonfocal brain damage. NewYork: Springer-Verlag New York Inc. Derix, Mayke M.A. (1994). Neuropsychological differentiation of dementia syndromes. Amsterdam:Swets Zeitlinger B.V., Lisse. Graves, Amy B. and Kukull, Walter A. (1994). The epidemiology of dementia. In John C. Morris (Ed.),Handbook of dementing illnesses. New York: Marcel Dekker Inc. Hart, Siobhan and Semple, James M (1990). Neuropsychology and the dementias. London: Taylor Francis Ltd. Katzman, Robert, Lasker, Bruce and Bernstein, Nancy. (1988) Advances in the diagnosis of dementia:accuracy of diagnosis and consequences of misdiagnosis of disorders causing dementia. In Robert D.Terry (Ed.), Aging and the brain. New York: Raven Press. Lezak, Muriel Deutsch. (1995). Neuropsychological assessment (Third edition). New York: OxfordUniversity Press. Mahendra, B. (1984). Dementia a survey of the syndrome of dementia. Lancaster: MTP Press Limited. Marco, L.A. (1995). Alzheimers dementia and related disorders: genetic and molecular pathology. InManfred Bergner and Sanford I. Finkel (Eds.), Treating Alzheimers and other dementias. New York:Springer Publishing. Mirra, Suzanne S., Gearing, Marla. (1994). The neuropathology of dementia. In John C. Morris (Ed.),Handbook of dementing illnesses. New York: Marcel Dekker Inc. Morris, John C. (1994). Evaluation of the demented patient. In John C. Morris (Ed.), Handbook ofdementing illnesses. New York: Marcel Dekker Inc. Plum, Fred. (1987). Dementia. In George Adelman (Ed.), Encyclopedia of Neuroscience (Volume 1). Boston: Birkhauser. Schmitt, Frederick A. and Sano, Mary C. (1994). Neuropsychological approaches to the study ofdementia. In John C. Morris (Ed.), Handbook of dementing illnesses. New York: Marcel Dekker Inc. Schneider, Lon S. (1994). Experimental pharmacotherapy of primary symptoms of dementia. In John C.Morris (Ed.), Handbook of dementing illnesses. New York: Marcel Dekker Inc.