Define dementia
- Dementia is a syndrome evidenced by multiple acquired cognitive deficits that are due to direct physiological effect of a general medical condition, to the persisting effect of a substance or multiple aetiologies.
- Memory and one additional cognitive impairment, including aphasia, apraxia, agnosia and executive function are required to be affected according to common criteria in the DSM-IV
What is the prevalence of dementia ?
- In 2010, dementia was estimated to affect 35.7 million people worldwide
- Alzheimer’s disease is the most common form of dementia in people over the age of 65, yet Alzheimer’s disease is often accompanied by vascular disease or Lewy body symptoms. The latter two types can occur as a pure form.
define AD
Alzheimer’s disease is a neurodegenerative disease of the brain, characterised by a clinical dementia with prominent memory impairment and specific microscopic pathology including senile plaques and neurofibrillary tangles.
Over time, Alzhiemers disease produces neurochemical deficits and prominent brain atrophy. It has an insidious onset and gradual decline.
What is the prevalence of AD ?
- Either alone or in combination with other disorders, Alzheimer’s disease causes 75% of dementia cases.
- Alzheimer’s disease becomes more prevalent with age, although it is not a normal process of ageing.
What cognitive symptoms are associated with AD
In the early stages of AD, lapses in attention, concentration may be present, often with awareness of these symptoms. The most common and earliest symptom, is however memory loss. Semantic memory deficits, noted as word finding. Although working memory remains relatively intact in early AD, central executive function is impaired.
Attention, memory and executive function become severely impaired over the course fo the disease.
What is the diagnostic criteria of AD?
for alzheimer’s (major neurocognitive disorder in DSM5)to be present, it is required that the person has both:
- Presence of dementia
- Deficits in multiple cognitive areas (two or more)
- Gradual progression
- The ruling out of other causes
What are the behavioural symptoms associated with AD?
behavioural and psychiatric symptoms develop very early. Including:
- Apathy
- irritability
- Agitation
- Exacerbation of premorbid personality traits
Describe language in AD
- In mild cognitive impairment due to AD - language is often normal
- In very mild -mild alzheimer’s disease - problems with language attributable to the combination of anomia and semantic memory loss (can be tested with boston naming test).
Define vascular dementia
vascular dementia is a cognitive impairment that occurs when cognitive dysfunction is due to cerebrovascular disease (stroke).
Vascular dementia occurs when cerebrovascular disease causes both cognitive dysfunction and impairment is daily function.
What is the prevalence of VD?
Approximately 5-10% of patients with dementia have pure vascular dementia, another 10-15% patients of dementia have mixed dementia of cerebrovascular disease plus neurodegenerative disease.
What cognitive symptoms are associated with VD?
neuropsychological testing typically shows impairment in multiple domains, including attention, frontal/executive function, and speed of processing.
Memory impairments are usually secondary to attentional/ executive dysfunctions.
what is the diagnostic criteria of VD?
stepwise decline of cognitive function as a result of a stroke.
What behavioural symptoms are associated with VD?
depression is often present.
This is a type of dementia that occurs as a result of strokes.
The prototype for vascular dementia is acute onset and stepwise decline, with focal neurological signs and symptoms.
describe language in VD?
word finding difficulties are common.
True aphasia is uncommon.
Define Lewy body dementia.
Lewy body dementia is a type of dementia caused by protien deposits in the neuronal cell bodies in the neocortex of the frontal lobes and basal ganglia. It distinguishable from other types of dementia by the presence of parkinsonisms, neuroleptic sensitivity, fluctuations of consciousness, and spontaneous hallucinations.
Although patients vary in specific combinations of signs and symptoms. In contrast to idiopathic Parkinson’s disease, parkinsonism in Lewy body dementia tends to occur in the absence of rest tremor, is more symmetrical, and does not respond as well to dophamagenic drugs.
what is the prevalence of Lewy body dementia?
- 10-15% of all dementia cases as pure form
- Accounts for up to 20% of all cases of dementia, either by itself or in combination with other disorders.
what is the diagnostic criteria for Lewy body dementia?
core features (Two of these core features should be present for a diagnosis of probable dementia with Lewy bodies):
- fluctuating cognition with pronounced variation in attention and alertness
- recurrent visual hallucinations (typically well formed and detailed)
- spontaneous features of parkinsonism.
There are also three suggestive features for diagnosis:
- an REM sleep behavior disorder
- severe neuroleptic sensitivity
- low dopamine transporter uptake in the basal ganglia demonstrated by SPECT or PET imaging.
what are the behavioural symptoms of Lewy body dementia?
- changes in behaviour include visual hallucinations and fluctuations in attention and alertness
Define frontotemporal dementia
Frontotemporal dementia is progressive neurodegenerative disorder characterized by atrophy of the frontal and temporal lobes of the brain without senaile plaques, neurofibrillary tangles or Lewy bodies, but there may be presence of Pick bodies or Tau abnormalities. Also known as Picks disease. The conditions associated with frontotemporal lobar degeneration are characterised by prominent personality and behavioral symptoms that proceed memory loss. The specific presentation depends on the location, distribution, and severity of the pathology.
What are the variants of frontotemporal dementia.
- Behavioural variant (frontal lobe variant)
- Primary progressive aphasia:
- Semantic variant PPA
- Non-fluent/ agrammatic PPA
- Logopenic PPA
what is the prevalence of frontotemporal dementia.
second most common dementia in the under 65 group. found in 5-10% of all dementia cases. Up to 10-15% of those with frontotemporal dementia also show signs of motor neurone disease.
what are the cognitive and behavioural symptoms in FTD?
- prominent personality and behavioural changes that proceed memory impairment.
- Changes may be seen in
- social behaviours (e.g. compulsive lying)
- personality (e.g. self-centeredness, excessive sentimentality, and inappropriate jocularity)
- mood (e.g depression and anxiety)
- executive function (loss of insight, disinhibition, and impulsivity)
- other cognitive abilities (e.g. memory) - these remain intact initially
- The presence of greater executive function deficits than memory deficits help to differentiate FTD with AD.
What is primary progressive aphasia?
PPA is a clinical syndrome characterized by a progressive language dysfunction. There are three variants:
- Logopenic variant (most commonly associated with AD)
- Semantic variant (also called semantic dementia and is most commonly associated with FTD)
- non-fluent/agrammatic variant (most commonly associated with tau pathology)
Primary progressive apraxia of speech is an impairment in the production of speech sounds in the absence of a language impairment
what cognitive and behavioural symptoms are associated with logopenic variant of PPA?
Hesitant speech Difficulty naming and finding words Phonological and repetition errors No loss of comprehension and preserved grammar
