Dementia, Life Expectancy & Brainscreen
Konstantine K. Zakzanis, Ph.D., C.Psych
Dementia is an acquired syndrome of intellectual impairment produced by brain dysfunction (e.g., Alzheimer’s disease; AD). Its prevalence is rapidly increasing, and adequate care of the burgeoning population of demented individuals require a knowledgeable approach to diagnosis and management. Operationally, dementia can be defined as an acquired persistent impairment of intellectual function with compromise in at least three of the following spheres of mental activity: language, memory, visuospatial skills, emotion or personality, and cognition (abstraction, calculation, judgment, executive function and so forth). This definition is based on evaluation of disturbances that are readily testable using neuropsychological testing, such as that employed by Brainscreen.
Causes of dementia include but are not limited to:
Degenerative disorders: Alzheimer’s disease (AD); fronto-temporal dementias (FTD); dementia with Lewy bodies (DLB); Parkinson disease dementia; Huntington’s disease; progressive supranuclear palsy.
Vascular causes: multi-infarct dementia (MID); lacunar infarcts; Binswanger’s disease; cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL); vasculitis (eg, lupus erythematosus).
Trauma: major head injury; subdural haematoma; boxing.
Intracranial tumours: primary tumours; metastatic tumours.
Infection: bacterial (eg, Spirochetal spp. – causing Lyme disease and syphilis); fungal (eg, Cryptococcus); viral (eg, subacute sclerosing panencephalitis [SSPE]; progressive multifocal leukoencephalopathy; post-encephalitic HIV). Other infectious agents (eg, Creutzfeldt-Jakob disease [CJD], variant CJD [vCJD]; neurocysticercosis; tuberculosis).
Hydrostatic causes: hydrocephalus (obstructive or communicating); normal pressure hydrocephalus (NPH).
Toxic, endocrine and metabolic causes: heavy metals; drug intoxication; hypothyroidism; hypercalcaemia; B12 and folate deficiencies; hepatic and renal failure; paraneoplastic/limbic encephalitis; inherited metabolic disorders (eg, Wilson’s disease, leukodystrophies).
Anoxia: post-cardiac arrest; carbon monoxide poisoning
There are four main types of dementia:
• Alzheimer’s disease (60%; of cases)
• Vascular dementia (30–40%; including about 20% where dual pathology exists)
• Dementia with Lewy bodies (15% of cases)
• Fronto-temporal dementia (5%)
• Percentages total more than 100 because of variability in studies
Alzheimer’s disease is the most common type of dementia. In patients aged 65 years or older, who have some kind of cognitive decline, it accounts for over 50% of cases. Progression to full dementia may take several years following the signs of mild cognitive impairment (MCI) at the early stage of AD [Linn, 1995; Petersen, 1999].
How is Alzheimer’s disease characterized?
Alzheimer’s disease may be characterized by a diffuse pattern of cortical deficits including:
• Aphasia – loss or impairment of language caused by brain dysfunction
• Apraxia – inability to execute learned movements on command
• Agnosia – inability to recognize or associate meaning to a sensory perception
• Acalculia – inability to perform arithmetical calculations
• Agraphia – inability to write
• Alexia – inability to read
Some facts to consider about Alzheimer’s disease specifically:
- • Today, half a million Canadians have Alzheimer's disease or a related dementia. Approximately 71,000 of them are under age 65.
- • This means that 1 in 11 Canadians over the age of 65 currently has Alzheimer's disease or a related dementia.
- • This year alone, more than 103,000 Canadians will develop dementia. This is equivalent to one person every five minutes. By 2038, this will become one person every two minutes, or more than 257,000 people per year.
- • If nothing changes, the number of people living with Alzheimer's disease or a related dementia is expected to more than double, reaching 1.1 million Canadians within 25 years.
Alzheimer’s disease versus other dementia
- • Alzheimer's disease is the leading form of dementia. It currently represents 63% of all dementias. This will increase to 68% by year 2034, i.e. within a generation
- • Vascular dementia is the second most common form of dementia. It currently represents 20% of all dementias and will continue to do so within a generation.
Alzheimer’s disease – a gender specific illness?
- • Today, women represent 72% of all cases of Alzheimer’s disease. In the context of overall dementia, women represent 62% of cases.
- • In comparison, women represent 47% of vascular dementia cases.
Pressure on Families
- • The hours of care delivered by unpaid family members are expected to more than triple, increasing from 231 million hours in 2008, to 756 million hours by 2038.
Economic Burden of Dementia
- • Right now, dementia costs Canadians $15 billion a year, a figure expected to grow ten times to $153 billion by 2038.
Economic Burden of Dementia (in future dollars)
- • 2008 - $15 billion
- • 2018 - $37 billion
- • 2028 - $75 billion
- • 2038 - $153 billion
Cumulative Consequences of Dementia over a 30-year period
Cumulative data represents the combined total of either the economic costs of dementia per year, or the number of people developing dementia per year, each year between 2008 and 2038. By 2038, the cumulative incidence of dementia will be more than 5.5 million people, with a cumulative economic cost of $872 billion (2008 dollars). Indeed, dementia disorders are today considered to be a major driver of costs in health care and social systems and worrying estimates of future dementia prevalence have been presented. It is of great interest for policy makers to have an estimate of dementia disorders' contribution to global social and health care costs, particularly in light of the demographic prognose
Vascular dementia is the second most common cause of dementia. It results from vascular or circulatory lesions or from diseases of the cerebral vasculature leading to ischaemia or infarction.
How is vascular dementia characterized?
Vascular dementia is characterized by three elements:
- • Presence of clinical dementia
- • Evidence of cerebrovascular disease
- • Exclusion of other conditions capable of producing dementia
Dementia with Lewy bodies
Dementia with Lewy bodies (DLB) is an increasingly recognized cause of dementia in elderly patients. The typical presenting features of DLB include fluctuating dementia with prominent deficits in attention, frontal executive tasks and visuospatial abilities. The cognitive profile of DLB contains both cortical and subcortical feature
Dementia of six months’ duration with:
- • Periods of confusion
- • Fluctuations in cognition (especially attention and alertness)
- • Visual hallucinations
- • Spontaneous extrapyramidal signs such as rigidity or slowing (mild parkinsonism)
- • Bradykinesia (paucity of movement)
- • Frequent or unexplained falls, syncope or transient loss of consciousness
- • Increased sensitivity to neuroleptics
- • Hallucinations in other modalities
- • Systematized delusions [Perry, 1990; McKeith IG, 1996]
Fronto-temporal dementia (FTD) – sometimes called Pick’s complex – is characterized by focal frontal atrophy with personality and behavioural disturbances, or temporal atrophy with either progressive aphasia or semantic dementia [Hodges, 1992; Neary, 1998]. Onset of FTD is observed in a younger age group than other dementias and diagnosis may be difficult in the early stages of disease. Routine neuropsychological assessment procedures such as the Mini-Mental State Examination (MMSE) are usually insensitive at detecting frontal abnormalities, therefore more extensive neuropsychological testing is required to establish frontal deficit in patients suspected with FTD. The clock drawing test may be helpful which Brainscreen includes.
What are the clinical features of fronto-temporal dementia?
Presenting features of FTD include:
- • Insidious onset and slow progression
- • Preservation of memory to late-stage disease making diagnosis difficult
- • Early and prominent personality changes (eg, apathy, irritability, jocularity, euphoria, loss of personal and social awareness)
- • Loss of tact and concern
- • Impaired judgement and insight
- • Mental rigidity and inflexibility
- • Hypochondriasis
- • Unrestrained exploration of objects and the environment (hypermetamorphosis)
- • Distractability and impulsivity, depression and anxiety
- • Language difficulties (eg, problems with word recall, circumlocution, word repetition – also known as gramophone syndrome)
- • Inertia
Other features (associated with Kluver-Bucy syndrome):
- • Emotional blunting
- • Hyperorality
- • Hypersexuality
More than 100 types of dementias have been documented and reviewed [Perry, 1990; Cummings, 1992; Pryse-Phillips W; Morris, 1994]. Apart from the four main types discussed above, other less common dementias result from:
- • Head injury and trauma
- • Brain tumours
- • Hydrostatic causes
- • Bacterial and viral infections
- • Anoxia
A number of potentially reversible causes of dementia include thyroid deficiency or excess, vitamin B12 deficiency, abnormal calcium levels and intracranial space-occupying lesions.
Mostly, patients themselves do not present to the clinician with dementia, owing to gradual onset and denial of the problem. It is usually the primary carers, caregivers, supporters, partners or family members who initiate the consultation [Brodaty, 1990]. In some circumstances, signs of dementia may occur following a major situational change which uncovers the patient’s cognitive impairment, such as a house move or change in career.
What are the typical presenting signs of dementia?
Other features (associated with Kluver-Bucy syndrome):
- • Memory impairment
- • Difficulties in finding words
- • Decline in managing finances or work performance
- • Personality or mood changes
- • Sudden withdrawal or uncharacteristic behaviour