The following document was written by Dr Alok Kumar Rana, MBBS; PG Diploma in Hospital Management, MRCPsych (UK) Specialty Registrar – Old Age Psychiatry, Herefordshire PCT NHS Trust, UK - Jan 2009.
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Dementia

Definition:

Dementia is a progressive and largely irreversible clinical syndrome that is characterised by a widespread impairment of mental function and can express as some or all of the following: memory loss, language impairment, disorientation, changes in personality, difficulties with activities of daily living, self-neglect, psychiatric symptoms (for example, apathy, depression or psychosis) and out-of-character behaviour (for example, aggression, sleep disturbance or disinhibited sexual behaviour).

Classification:

(i) Cortical and Subcortical dementia

A) Cortical: Alzeimer’s Disease (AD), Frontotemporal Dementia and Creutzfeldt-Jacob disease.

B) Subcortical: Parkinson’s disease, Huntington’s disease, Normal Pressure Hydrocephalus, Multiple sclerosis.

C) Mixed: Vascular dementia, Dementia with Lewy bodies (DLB), Corticobasal degeneration and Neyrosyphilis.

	Memory Impairment	Language	Mathematical Skills	Personality	Mood	Co-ordination	Cognitive & Motor Speed	Abnormal movements
Cortical Dementia	Severe, early	Dysphasia, early	Impaired early	Indifferent	Normal	Normal	Normal	Rare
Subcortical Dementia	Moderate	Normal	Preserved	Apathetic, inert	Flat, depressed	Impaired	Slowed	Common: choreiform or tremor

(ii) Presenile and Senile dementia

A) Presenile Dementia or early-onset dementia: dementia occurring in those under 65

B) Senile Dementia or Late-onset dementia: dementia occurring in those above 65.

Alzeimer’s Disease (AD)

AD is one cause of dementia and the core clinical symptom of AD is cognitive impairment. However, as noted above, AD is clinically heterogeneous and includes diverse non-cognitive symptoms and inevitable functional impairment. Cognitive decline is manifested as amnesia, aphasia, agnosia, and apraxia (the 4As).

• Amnesia: Memory loss in AD is early and inevitable. Characteristically, recent memories are lost before remote memories. However, there is considerable individual variation. With disease progression, even remote and emotionally charged memories are lost.



• Aphasia: Language problems are found in many patients at presentation, although the language deficits in AD are not as severe as those of the frontotemporal degenerations. Word-finding difficulties (nominal dysphasia) are the earliest phenomena observed and are accompanied by circumlocutions and other responses, for example repetitions and alternative wordings. As the disorder progresses, syntax is affected and speech becomes increasingly paraphasic. Although harder to assess, receptive aphasia, or comprehension of speech, is almost certainly affected.



• Agnosia: Patients with AD may have difficulty in recognizing as well as naming objects. This can have implications for care needs and safety if the unrecognized objects are important for daily functioning. One particular agnosia encountered in AD is the loss of recognition of one’s own face (autoprosopagnosia). This distressing symptom is the underlying cause of perhaps the only clinical sign in AD—the mirror sign.



• Apraxia: Difficulties with complex tasks that are not due to motor impairment become apparent in the moderate stages of AD. Typically, difficulties with dressing or tasks in the kitchen are noticed first, but these are inevitably preceded by loss of ability for more difficult tasks.



• Other cognitive impairments: There appear to be no cognitive functions that are truly preserved in AD. Visuospatial difficulties commonly occur in the middle stages of the disorder and may result in topographical disorientation, wandering, and becoming lost. Difficulties with calculation, attention, and cognitive planning all occur.



• Functional impairment: Although the cognitive decline in AD is the core symptom, it is the functional deterioration that has the most impact on the person themselves and it is the functional loss that necessitates most of the care needs of patients with AD, including nursing-home residency. Increasingly, abilities to function in ordinary life (activities of daily living (ADLs)) are lost, starting with the most subtle and easily avoided and progressing to the most basic and essential. ADLs are divided into those that relate to self-care and those that concern instrumental activities. Instrumental ADLs, those related to the use of objects or the outside world, are lost first and can be subtle.



• Neuropsychiatric symptoms:
  
  
  1. Mood: The relationship between AD and depression is complex. Depression is a risk factor for AD, depression can be confused with dementia (pseudo¬ dementia), depression occurs as part of dementia, and cognitive impairments are found in depression. A major depressive episode is found in approximately 10 per cent of patients, minor depressive episode in 25 per cent, some features of depression in 50 per cent, and an assessment of depression by a carer in up to 85 per cent.8–10 It is commonly believed that depression is more common in the early than in the later stages of AD, although this may reflect the difficulties of assessing depression in the more severely affected and least communicative patients. Elation, disinhibition, and hypomania all occur in AD but are relatively infrequent, elevated mood being found in only 3.5 per cent of patients by Burns et al.
  
  
  
  2. Psychosis: Psychotic symptoms occur in many patients. However, of those known to, largely, psychiatric services, between 10 and 50 per cent suffer from delusions and between 10 and 25 per cent experience hallucinations.
     
     
     
     1. Delusions are frequently paranoid and the most common delusion is one of theft. In the context of the confusion and amnesia of dementia, it is easy to appreciate how the experience of mislaying an object becomes translated into conviction of a theft. Other patients become convinced that someone, often a family member, is trying to harm them.
     
     
     
     2. Hallucinations are only somewhat less frequent than delusions—the median of one series of studies being 28 per cent. Visual hallucinations are reported more commonly than auditory ones, and other modalities are rare. Most studies of the non-cognitive symptomatology of AD precede the wide recognition and accepted criteria of dementia with Lewy bodies, one of the cardinal symptoms of which is visual hallucinations. It is probable that a large number of those AD patients experiencing visual hallucinations reported in the studies would now be classified as having dementia with Lewy bodies.
     
     
     
     3. Phenomena falling short of delusions or hallucinations, such as persecutory ideas or intrusive illusionary experiences, are common in AD as are misidentification syndromes. Capgras’ syndrome may occur, but frequently the symptom is less fully evolved with the patient mistaking one person for another. Failure to recognize one’s own face may be due to visuospatial difficulties or to a true misidentification syndrome—distinguishing between the two is difficult.
  
  
  
• Personality: Changes in personality are an almost inevitable concomitant of AD. Indeed, it is difficult to envisage how profound cognitive impairment resulting in the loss of recognition of loved ones, and an understanding of and ability to react with the outside world, could not result in a change in personality. Family members have described the loss of personality as a ‘living bereavement’—the person remains, but the person once known has gone. Personality change is most frequently one of loss of awareness and normal responsiveness to the environment.

Vascular Dementia:

• Vascular dementia is the second most frequent cause of dementia. Because vascular causes of cognitive impairment are common, may be preventable, and the patients could benefit from therapy, early detection and accurate diagnosis of vascular dementia is desirable.



• Vascular dementia is not only multi-infarct dementia, but is related to other other vascular mechanisms and pathological changes in the brain, and has other causes and clinical manifestations. Vascular dementia is not a disease, but a syndrome. The origin of this syndrome reflects complex interactions between vascular aetiologies (cerebrovascular disorders and vascular risk factors), changes in the brain (infarcts, white-matter lesions, atrophy), host factors (age, education), and cognition.



• Risk factors for vascular dementia can be divided into vascular factors (e.g. arterial hypertension, atrial fibrillation, myocardial infarction, coronary heart disease, diabetes, generalized atherosclerosis, lipid abnormalities, smoking), demographic factors (e.g age, education), genetic factors (e.g. family history, individual genetic features), and stroke-related factors (e.g. type of cerebrovascular disease, site and size of stroke). Hypoxic ischaemic events (cardiac arrhythmias, congestive heart failure, myocardial infarction, seizures, pneumonia) may be an important risk factor for incident dementia in patients with stroke



• Clinical Features: The ICD-10 criteria require unequal distribution of cognitive deficits, focal signs as evidence of focal brain damage, and significant cerebrovascular disease judged to be aetiologically related to the dementia. The criteria do not detail brain imaging requirements.



• Course: Traditionally, vascular dementia has been characterized by a relative abrupt onset (days to weeks), a stepwise deterioration (some recovery after worsening), and fluctuating course (e.g. differences between days) of cognitive functions.



• The mean duration of vascular dementia is around 5 years.2 In most studies survival is less than for the general population or those with Alzheimer’s disease



• Epidemiology: Vascular dementia is the second most common cause of dementia accounting for 10 to 50 per cent of cases, depending on the geographic location, patient population, and clinical methods used.1,2 The prevalence of vascular dementia is from 1.2 to 4.2 per cent of persons aged 65 years and older, and the incidence is 6 to 12 cases per 1000 persons aged over 70 years per year.2 The prevalence and the incidence of vascular dementia disease increases with increasing age, and men seem to have a higher prevalence of vascular dementia than women.

Frontotemporal Dementia:

• Dementia caused by a degenerative disease primarily affecting the frontal and temporal lobes called frontal-lobe dementia or frontotemporal dementia (FTD). This includes Pick’s disease (due to presence of pick cells and pick body in neurones) and frontal-lobe degeneration of non-Alzheimer type (FLD).



• The first clinical manifestations of FTD usually appear in the presenium, in some cases as early as 35 and seldom after 70 years of age.



• Onset: The mean age at onset in post-mortem-verified FLD cases is 56 ± 7.6 years with a mean duration of 8 ± 3.4 years (range 3–17 years).18 The mean age of onset in Pick’s disease is similar, 62 years, with a range of 45 to 80 years, and a mean survival of 9.8 years with a range of 4.8 to 21.2 years.20 This large variation of the duration of FLD and Pick’s disease is similar to that of early-onset Alzheimer’s disease, which is 10.6 ± 3 years, with a range of 5 to 16 years.



• Epidemiology: Pick’s disease is rare, with a prevalence of 1 to 2 per cent in post-mortem studies of dementia,17 compared to a prevalence of 7.5 per cent of FLD and 40 to 50 per cent of Alzheimer’s disease



• Clinical Features:
  
  
  1. The early stage of FLD and Pick’s disease is characterized by changes of personality and behaviour, affective symptoms, and a progressive reduction of expressive speech, revealing the dysfunction of frontotemporal brain structures. The changes of personality and behaviour are mainly non-specific and easily misinterpreted as expressions of non-organic mental disease such as mood disorder, hypochondriasis, schizophrenia, or other psychotic reaction.
  
  
  
  2. The early loss of personal and social awareness is seen as neglect of personal hygiene and grooming, and tactlessness and antisocial behaviour.
  
  
  
  3. The FTD patient becomes emotionally shallow and blunt, showing less concern about family and friends. The patient is described as egocentric, rigid, and lacking empathy.
  
  
  
  4. A striking feature of FTD is the stereotyped and perseverative behaviour seen as wandering, clapping, humming, dancing, and hoarding of objects, as well as complex rituals involving washing and dressing.
  
  
  
  5. The human counterpart of the ‘Klüver–Bucy syndrome’ with elements such as blunted affect, hyperorality, and unrestrained sexuality has been reported in FLD and in Pick’s disease.
  
  
  
  6. Core feature of FTD is progressive impairment of expressive speech described as ‘dissolution du langage’ or ‘Sprachverödung’.
  
  
• Course: The clinical onset is insidious with slow progression without ictal events. Therefore the duration of the disease may easily be underestimated.

Lewy body dementia:

• Lewy bodies are spherical neuronal inclusions, first described by the German neuropathologist ‘Friederich Lewy’. These are found in the cerebral cortex



• The spectrum of Lewy body disease: Three main clinicopathological syndromes have been described.
  
  
  1. Parkinson’s disease, an extrapyramidal movement disorder—associated with degeneration of subcortical neurones, particularly in substantia nigra.
  
  
  
  2. Dementia with Lewy bodies, a dementing disorder with prominent neuropsychiatric features—associated with degeneration of cortical neurones, particularly in frontal, anterior cingulate, insular, and temporal regions.
  
  
  
  3. Primary autonomic failure with syncope and orthostatic hypotension — associated with degeneration of sympathetic neurones in spinal cord.
  
  
• Clinical Features: Dementia is usually, but not always, the presenting feature; a minority of patients present with Parkinsonism alone, some with psychiatric disorder in the absence of dementia, and others with orthostatic hypotension, falls, or transient disturbances of consciousness. Fluctuation in cognitive performance and functional ability, which is based in variations in attention and level of consciousness, is the most characteristic feature of DLB It is usually evident on a day-to-day basis and often apparent within much shorter periods. The marked amplitude between best and worst performance distinguishes it from the minor day-to-day variations that commonly occur in dementia of any aetiology. Repeated visual hallucinations are present in about two-thirds of patients. They take the form of vivid, colourful, and sometimes fragmented figures of people and animals, which are usually described in great detail.



• Epidemiology: DLB accounts for just under 20 per cent of all cases of dementia referred for neuro¬pathological autopsy. The male-to-female ratio in these autopsy series is 1.5:1, but it is unclear to what extent this represents increased male susceptibility or reduced survival. Age at onset ranges from 50 to 83 years and an age at death of between 68 and 92 years.



• Course and prognosis: Progression is usually more rapid than in AD, typically 1 to 5 years from onset to an endstage of profound dementia and Parkinsonism. Men appear to have a worse prognosis than women. Even in the early stages, personal and social function and performance in daily living skills may be markedly impaired by a combination of cognitive, psychiatric, and neurological disability.

Author:
Dr Alok Kumar Rana, MBBS;
PG Diploma in Hospital Management,
MRCPsych (UK)
Specialty Registrar – Old Age Psychiatry,
Herefordshire PCT NHS Trust,
UK

References:

1. Oxford Textbook of Psychiatry, Publisher: Oxford University Press, Michael Gelder et al
2. Shorter Oxford Textbook of Psychiatry, Fifth Edition, Michael Gelder et al.
3. Concise Textbook of Psychiatry, Second Edition, Kaplan and Sadock
4. The ICD-10 Classification of Mental and Behavioural Disorders- WHO

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