Dementia should not be expected as a normal part of ageing, writes Louis Roller
“Last scene of all,
That ends this strange eventful history,
In second childishness and mere oblivion,
Sans teeth, sans eyes, sans taste, sans everything”
William Shakespeare, As you like it. (1599)
Dementia is a syndrome due to disease of the brain, usually of a chronic or progressive nature, in which there is disturbance of multiple higher cortical functions, including memory, thinking, orientation, comprehension, calculation, learning capacity, language and judgement.
Impairments of cognitive function are commonly accompanied, and occasionally preceded, by deterioration in emotional control, social behaviour or motivation.
This syndrome occurs in Alzheimer’s disease, in cerebrovascular disease and in other conditions primarily or secondarily affecting the brain.
Progressive dementias are most common among older people and many have concomitant physical illness or disability. Most people who reach advanced years do not develop dementia, and the expectation that senility is an inevitable part of the aging process is a misconception.
There are two broad categories of dementia that are generally recognised:
Primary dementias are those like Alzheimer’s in which the dementia itself is the major sign of some organic brain disease not directly related to any other organic illness.
Secondary dementias are those caused by, or closely related to, some other recognisable disease including AIDS, chronic subdural haematoma, multiple sclerosis, or one of numerous other identifiable mental conditions.
In Alzheimer’s disease, accumulation of beta-amyloid peptide appears to be central to the degenerative changes seen in the brain. It results in the destruction of cholinergic neurones and a fall in acetylcholine concentration.
The most important causes of dementia are degenerative including Alzheimer’s disease (50% to 70%), dementia of frontal type (up to 10%), dementia with Lewy bodies (up to 10%), vascular (10% to 20%), and alcohol (up to 5%).
Symptoms of Dementia
All dementias—whether primary or secondary, treatable or untreatable—share a few clinical characteristics in common. Loss of memory and inability to perform routine tasks—such as losing one’s way in the neighbourhood, difficulties in job performance, language problems—are particularly common.
The most recent memories are lost sooner than older ones, and new memories, perhaps of something that happened minutes earlier, are difficult to retain. In addition, behavioural changes (such as increased aggressiveness), often mild but sometimes dramatic, almost always accompany dementia.
As the disease progresses, patients lose the ability to function independently and becomes increasingly disoriented to time and place. Wandering may become a significant problem.
Grooming and dressing standards deteriorate rapidly, and basic social skills are lost. Patients often dress inappropriately for the season and may confuse underwear with outer garments.
Recent memory, retention and attention span deteriorate steadily. Language skills, particularly ability to name objects (anomia) or generate a word list decline until a patient can no longer use full sentences.
Evidence of memory difficulty remains the best single indicator of dementia and should always be evaluated by formal memory testing. However, memory problems may be due to factors other than dementia, and demonstrating failure in other areas of cognitive functioning (language, spatial ability, reasoning) is necessary to confirm the diagnosis of dementia.
A number of screening tests are available, but the minimental state examination (MMSE) is commonly used and recommended.
Non-cognitive disorders are very common and significant. They are referred to as Behavioural and Psychological Symptoms of Dementia (BPSD) as they are due to illness.
Among the most intrusive psychological symptoms are delusions, hallucinations, depression, sleeplessness and anxiety. Other behaviours include physical aggression, wandering and restlessness.
Moderately common BPSDs that are distressing include misidentification, agitation, culturally inappropriate behaviours, sexual disinhibition, pacing and screaming. BPSDs that are common and upsetting, but manageable and less likely to result in institutionalisation, include: crying, cursing, lack of drive, repetitive questioning and shadowing.
Consequently, health professionals dealing with patients with dementia must address not only memory but also non-cognitive issues that create major problems for patients, carers and the community at large.
Other causes of dementia-like symptoms include: metabolic disorders, dehydration, hyperthyroidism/hypothyroidism, hyponatraemia, hypercalacaemia, intracranial infection or disease, meningitis, neurosyphilis, normal-pressure hydrocephalus, subdural haematoma, toxoplasmosis, toxins, vitamin B12 deficiency, depression and psychosis.
Some medicines may cause or exacerbate delirium or dementia and include: antiarrhythmics, antibacterials (macrolides, fluoroquinolones), anticholinergics, antidepressants (with anticholinergic activity), antiepileptics, antiparkinsonism drugs (with anticholinergic activity), antipsychotics, antitubercular drugs, benzodiazepines, corticosteroids, digoxin, dopamine agonists, H2-antagonists, lithium, metoclopramide, opioid analgesics and propranolol.
There is a good role for pharmacists here, in that they can determine if any of the symptoms being displayed by the patient may have been induced or exacerbated by a particular medication.
None of the currently available drugs (donepezil, gallantamine, rivastigmine) prevents Alzheimer’s disease or modifies its pathology. At best they show modest efficacy in improving cognition and/or reducing the rate of cognitive and functional decline; their clinical usefulness and effect on quality of life remains uncertain.
The optimal duration of treatment with these drugs is unclear, but there is some evidence that patients may benefit from anticholinesterases for up to three years.
The use of mega-doses of vitamin E and omega-3-fatty acid fish oils have proved to be disappointing.
Pharmacists can assist relatives of persons displaying some of the above symptoms by suggesting, that as a starting point, the person should visit a GP and to take it from there.
Associate Professor Louis Roller, from the Faculty of Pharmacy and Pharmaceutical Sciences Monash University, was the 2014 recipient of the PSA Lifetime Achievement Award.