Psychiatric Aspects of Dementia Research Paper

1. Definition Of Dementia

In history, the term dementia has been subject to several changes in meaning. Today, it is defined as acquired, severe loss of mental functions due to structural brain diseases.

In dementia, the information processing capacity has deteriorated to a critical degree. Deficits are found predominantly in cognitive, but also in emotional and intentional domains. By definition, these deficits severely compromise the social and cultural activities of a person. There must be a loss of mental functions which had been acquired before (i.e., the long-standing cognitive deficiencies in mental retardation are excluded). The underlying pathology is a destruction or degeneration of brain structures, therefore dementia may not be caused by functional organic disorders such as psychoses or transient brain dysfunction like in delirium. Psychiatry is concerned primarily with the detection and diagnosis of dementia syndromes, and concerned secondly with the identification and treatment of certain dementia diseases. Dementia syndromes and dementia diseases have to be differentiated (Wells and Whitehouse 1996).

1.1 Dementia Syndromes

Characteristic clinical profiles emerge, patterns of cognitive, affective, and intentional disturbances be-cause in dementia diseases, the destruction or degeneration takes place with a predominance of certain brain regions or brain systems; the disease does not impair all brain structures to the same extent.

1.1.1 Dementia Syndrome Of Alzheimer Type. What is the clinical presentation, the pattern of deficits which characterize the syndrome of a dementia patient who suffers from Alzheimer’s disease? This issue has been clarified in large longitudinal studies (e.g., Berg et al. 1990). A second question addresses the reasons for failures in activities of daily living and the need for care. The syndrome can be differentiated into cognitive signs and not primarily cognitive signs.

(a) Cognitive neuropsychological signs

(i) Amnestic signs. Early in the time course of the dementia syndrome, deficits in episodic memory are noticed (Brandt and Rich 1995). Recall of word lists, stories, second word of paired associates, or the reconstruction of figures-drawings, which were en- coded several minutes earlier, becomes increasingly impaired. The immediate recall of digits (digit span), however, remains typically unimpaired. The patients can immediately repeat a list of words but forget the words within several minutes, e.g., after a disruption by intermittent attention to other topics.

Furthermore, errors of orientation for time and space are hallmarks of this dementia syndrome. Demented persons get lost easily—at first in unfamiliar, and then even in familiar surroundings. The forgetting of data of major impact or the forgetting of actions with dangerous consequences affects activities of daily living. These deficits are characteristics of anterograde amnesia and are a consequence of mediotemporal brain damage, including the hippocampus and entorhinal cortex. Degeneration within the basal forebrain, however, may also explain a large part of the symptoms. Later retrograde amnesia starts and the recollection of data which were well known in former times becomes impaired. In later stages of the disease, demented persons cannot remember anything but episodes from the first decades of their life.

To summarize, a dementia syndrome in persons with Alzheimer’s disease presents initially with amnestic signs. Episodic memory and/orientation, with respect to time and place, deteriorate, and a retrograde amnesia occurs.

(ii) Language disturbance, aphasic signs. Word finding is impaired early in the time course of the dementia syndrome of Alzheimer’s type, but these and other signs of language impairment usually occurs later than memory impairment. Difficulties in word finding are the most important feature of this language disturbance. Word finding is clinically observed mostly in the communication situation and in fluency tests.

As demented persons become increasingly incapable of finding correct words, in later stages of the disease, not much content is communicated: a phenomenon which has been called empty speech. Phonematic paraphasias (errors in the phonematic composition of words) or disordered syntax, which characterize various forms of aphasia after cerebrovascular strokes, are, however, not considered prominent signs in this dementia syndrome.

A lowered performance in fluency tasks is often assessed in clinical diagnosis, for example, by asking the patient to name as many animals as possible. It has been argued that fluency is not only a language test, but also a test of retrieval from semantic memory, and it is known that effective retrieval depends on non-language functions. Patients with frontal lobe lesions cannot retrieve words in fluency tasks, presumably because of inefficient retrieval strategies and a defective suppression of overlearned alternative word-finding routines. Furthermore, demented persons cannot retrieve semantic features of perceived objects because of a disturbance in semantic memory (Martin and Fedio 1983).

Later in the time course, language comprehension difficulties additionally impair the communication with a demented person. In summary, there are important language problems in the dementia syndrome of Alzheimer’s type which are predominantly caused by deficits in word finding and language comprehension.

(iii) Apraxia signs. Persons with the dementia syndrome of Alzheimer’s type show errors in performing purposive movements. These errors occur al-though there are no obvious motor problems, such as weakness of the limb or sensoric deficits in guiding movements. It is thought that the central control of movements is defective. Apraxia in the narrow sense describes errors in specific action sequences, for example, using tools. Clinically, errors in dressing properly are encountered. Tests of apraxia include the call for imitation of limb movements or gestures.

In diagnostic schedules for dementia, constructional apraxia is tested quite often. This apraxia comprises deficits not only of the execution of movement schemata, but also of the integration of visuospatial information into appropriate action (Heilman and Rothi 1997). Copying visual designs or drawings of well-known objects, such as a clock, are defective and are performed laboriously and slowly. In addition, many demented subjects show an apractic type of writing disorder, where the action sequences of writing the individual letters can no longer be carried out correctly.

To summarize, subjects with Alzheimer’s dementia show errors in performing motor tasks without weak-ness or paresis of the limbs, resembling central motor control deficits. Later in the time course of the disease, the impairments lead to incapability to perform any practical task in the household or in self-care.

(iv) Disorders of judgement. Judgement errors and inadequate evaluation are especially relevant for the every day functioning of demented persons and with respect to legal responsibility. In the narrow definition, erroneous or inadequate judgements, with full under-standing and appreciation of the problem, can be related to the decision process in itself. This specificity is difficult to ascertain in clinical neuropsychological investigation. Therefore, more generally, inadequate judgements about the own person and the disease are considered for diagnostic evaluation.

Self-related judgements: demented persons often cannot correctly evaluate the cognitive deficits they suffer from. Some patients describe grossly inadequate future plans. At times, not only disorder of judgement, but also the psychopathological phenomenon of denial has to be considered in such situations.

Formal assessment of logical decisions, as part of the capacity for adequate judgment, is done usually by intelligence tests which, demand, for example, the understanding of a logical rule within the sequence of symbols, and finding incorrect items.

In summary, inadequate or wrong judgements in self-related or logical problems are found commonly in the dementia syndrome of Alzheimer Type and may lead to legal consequences or intensify the demand of care for the patient.

(v) Other cognitive neuropsychological signs. Demented persons with Alzheimer’s diseases often show deficits in executive functions. The term ‘executive functions’ denotes the planning and the execution of goal directed activities, including preparations and the monitoring of already reached partial goals. Some researchers also included self-regulation and volitional processes in the domain of executive functions. Brain structures for executive functions are at least in part localized in the dorsolateral prefrontal lobe.

Mental calculations are often tested in the clinical diagnosis of a dementia syndrome. They do not, however, test calculation function only. For these tasks, the attentional demands, and additionally, in serial calculations, the demands on working memory are high. Therefore, the reason for individual test deficits is difficult to attribute precisely.

Agnosia is mentioned in some of the dementia criteria. The classical form of object agnosia, however, is very rare. In object agnosia, the patient perceives an object—and is even able to copy the form—but is not able to grasp its meaning, to name it, or describe it’s attributes or functions. Demented persons often fail to identify faces of well-known friends or relatives in later stages of the disease, but memory problems contribute to this deficit. More often, however, a perceptual deficit concerning visuospatial features of figural information can be documented by neuropsychological tests. Furthermore, the appreciation of the relation of many objects within a complex pictorial scene is often disturbed in dementia.

In addition to cognitive deficits, there are other dimensions of the dementia syndrome of Alzheimer’s type.

(b) Noncognitive part of dementia syndrome of Alzheimer’s type

Patients with a dementia syndrome of Alzheimer type suffer from affective symptoms or delusions. Noncognitive signs of dementia are traditionally described by psychopathology. They are not specific for dementia. Several of these signs are commonly observed in other psychiatric diseases, for example, anxiety or restlessness. Although these signs are not as relevant for diagnosis as cognitive deficits, they present major problems for the caregivers (Cummings et al. 1996) and are often the reason for institutionalization of demented patients.

(i) Signs in the affective domain. Early in the development of the dementia syndrome depression is observed. Later, affect control becomes impaired. Patients may cry after minor adverse events or be aggressive or inadequately cheerful. Often the emotional state lasts often only for a short period of time. The perceived emotional experience may not be as dramatic as the affective expression suggests. This phenomenon has been termed affective lability.

Affective states like aggression may also be expressed as an increased intensity. Such behaviors may often present as behavior which cannot be tolerated and may lead to institutionalization.

(ii) Signs in the intentional and attentional domain. The cerebral information processing for motivation and attention is impaired in late stages of Alzheimer’s dementia. A state of ‘apathy’ is described quite often. A person, for example, sits in a chair for most of the time and does not move, and has no intention to start any action. Many of the noncognitive signs of the dementia syndrome are traditionally described as organic personality change. A further component of this is, as a consequence of frontal lobe disturbance, a disinhibition of action tendencies, which are usually supressed because of cultural constraints. In addition, paranoid delusional thinking and hallucinations occur quite often within the time course of a dementia syndrome of Alzheimer’s type. These also may induce aggressive behavior.

In summary, signs in multiple domains of brain functions are observed. The signs which characterize the dementia syndrome of Alzheimer’s type are predominantely from the cognitive domain. However, disorders in the emotional and intentional domains have some impact for the resulting individual syndrome and for caregivers and relatives. The primary sensory and motor functions, however, are relatively spared. Accordingly, the spread of the Alzheimer’s pathology in the brain does not include the primary sensory and motor areas.

1.1.2 Frontotemporal Dementia Syndrome. The dementia syndrome of frontotemporal type is less common than the dementia syndrome of Alzheimer’s type and should be described here in outline only (Brun et al. 1994). The major feature of this syndrome is a change in personality. Features of the dementia syndrome of Alzheimer’s type, like predominantly amnestic and apractic signs, or a decrease in intellectual functions, are not detectable at early stages of the frontotemporal dementia syndrome.

The personality change comprises changes in the way of experiencing certain situations, in the way of reacting in certain situations, or in the way a person was used to acts spontaneously.

(a) Lack of expected reactions or actions. The patient is aspontaneous and does not react as they did before the onset of the dementia syndrome. At times, a lack of drive is noted. As there is no emotional symptom of depressed mood and despair, this has been named pseudodepression.

(b) Disinhibition. A lack of control of intentions, especially with respect to social norms or cultural restraints, is observable.

(c) Perseveration and stereotyped Behavior. The patient reiterates actions and is inflexible in the way of reacting.

(d) Lack of insight and disorder of judgement, as described above (Sect. 1.1.1(a))

In addition to the psychopathological symptoms described above, formalized neuropsychological testing reveals deficits in planning, in shifting mental set, and in working memory. The frontotemporal dementia syndrome can be identified clinically only in early stages. In late stages, mostly an unspecific terminal dementia syndrome is clinically observed.

As for the dementia syndrome of Alzheimer’s type, also in frontotemporal dementia there is a heterogenous etiology with mostly genetically determined underlying diseases.

1.2 Dementia Diseases

Dementia has two sides—the individual pattern of neuropsychological or psychopathological impairments on the one side, and the damage or degeneration within the brain on the other side.

A dementia disease is a class of pathophysiological processes which result in structural brain changes that are underlying the clinical signs of the dementia syndromes (Wells and Whitehouse 1996, McHugh and Slavney 1998). There are many diseases of the brain which lead to a dementia syndrome.

1.2.1 Primary Dementia Diseases. Alzheimer’s dementia disease, Pick dementia disease, or Lewy body dementia are degenerative brain diseases which up to now inevitably lead to a progressive dementia syndrome. They cause no other symptoms except symptoms of the dementia syndromes.

1.2.2 Neurological Diseases With Associated Dementia Syndrome.

(a) In some diseases the dementia outcome is obligatory. In Huntington’s chorea, for example, a movement disorder precedes the progressive dementia syndrome, which regularly develops later in the time course of the disease.

(b) In other diseases, the dementia outcome is facultative. These diseases are not dementia diseases per se. Vascular dementia, which is the second most frequent cause of dementia cases, is in some of its variants not associated with a dementia syndrome. Prevention of subsequent strokes, furthermore, may stop the cerebrovascular disease and prevent the development of vascular dementia.

The brain behavior relationship is interindividually variable and even the distribution of pathological changes within one disease is varying. Because in many cases the dementia disease cannot be identified reliably before neuropathological post mortem examination, the clinical dementia syndrome guides the medical decisions about treatment and secondary prevention.

1.2.3 Dementia Disease Etiology. Alzheimer’s disease is genetically heterogenous. Many different mutations on several genes are known to cause a presenile Alzheimer’s dementia. The same is true for frontotemporal dementia. Additionally, multiple causal factors are identified in senile dementia of Alzheimer’s type, and it is not known whether an interaction of several factors is responsible for senile dementia cases. In some dementia cases, etiologically distinct causes are known, like in dementia following traumatic brain lesion, or in a dementia patient with a series of strokes within strategic regions of the brain.

2. Diagnosis Of Alzheimer’s Dementia

The diagnosis of a dementia disease will be described for the most frequent dementia, Alzheimer’s.

(a) The confirmation of the disease can only be given by a neuropathological investigation of the brain after death. The microscopic analysis will reveal the amount and distribution of neuropathological features like neuritic plaques and neurofibrillary tangles.

(b) There is some uncertainty as to the clinical diagnosis of Alzheimer’s dementia. There are several lists of criteria proposed, e.g., by diagnostic systems, such as International Classification of Diseases (ICD) and by consensus committees (e.g., the classification of probable or possible Alzheimer’s dementia according to clinical criteria). However, the criterium lists differ considerably, and the criterium variance results in major differences in the estimated prevalence rates of population-based studies (Erkinjunnti et al. 1997).

Prospective studies of dementia syndromes im-proved the specificity of clinical diagnostic methods. However, at present technicians cannot distinguish between dementia diseases such as Lewy body dementia and Alzheimer’s dementia with sufficient reliability.

2.1 Problems Of Diagnosis Of Mild Dementia In Old Age

The factors mentioned add to the diagnostic un-certainty with respect to differential diagnosis. Most dementia cases are seen in old age. The differentiation from normal aging and organic psychiatric disorders, like mild cognitive impairment or amnestic syndrome, is for many cases not easy or, especially in early stages, not possible at all.

The early detection of dementia is difficult in old age, because age in itself is associated with some cognitive decline (Reischies 1998). Furthermore, mild cognitive deficits have to be differentiated from low talent domains of a person, and personality changes have to be diagnosed considering the premorbid personality.

2.2 Dementia Case

If the severity of the cognitive impairments of the dementia syndrome of Alzheimer’s type is sufficiently high, and the severity of impairment in everyday functioning is high as well, a dementia case can be diagnosed. For these decisions, cut-off values of assessment instruments have been applied (e.g., the Mini Mental State Examination and the Global Assessment of Functioning scale).

The diagnosis of a dementia case without specification of the kind of probable dementia disease is often a clinical reality. With the advent of better diagnostic methods, however, the diagnosis of the dementia disease may be made before a clinical dementia syndrome has developed.

3. Time Course Of Alzheimer’s Dementia

There is a characteristic time course of Alzheimer’s dementia over about 10 years. Interindividual variation of the time course with plateaus and progression phases are common.

Within a preclinical stage of Alzheimer’s disease, cognitive decline takes place which can be assessed by serial neuropsychological testing. Especially memory decline can be found. With memory deficits as the only clinical sign, no formal diagnosis of dementia can be made. The early phase of Alzheimer dementia thus represents an amnestic stage.

In the second stage, a clinical dementia syndrome of Alzheimer’s type is detectable, which exhibits more or less the complete features of the dementia syndrome, as described above. In this stage, there are disturbances in activities of daily living, but they may still be minor. In the stage of a severe dementia syndrome, memory loss, aphasia, apraxia, and the noncognitive symptoms have increased, and global functioning is deteriorated such that normal activities of daily living are critically compromised or no longer possible. Additionally, the noncognitive disorder disturbs the relation between the patient and the environment. Institutionalization is common.

The last stage is a terminal or vegetative stage, where no communication is possible, the patient is mostly bedridden, and has to be cared for completely.

4. Treatment, Professional Care, And Prevention

An increasing number of new drug treatments for Alzheimer’s dementia are being investigated. How-ever, at present only limited relief can be provided. At best, the time course can be stopped or retarded for a short time only. Training of activities of daily living, with the goal of adaption to the specific environment, can be quite successful in order to aid care of subjects with an advanced dementia syndrome.

Major efforts must be directed to prevention, detection of risk factors, and early detection of dementia syndromes. A certain success of prophylaxis by controlling risk factors for artherosclerosis has been documented in the field of vascular dementia.

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