Report by Jill McLean, Queensland University of Technology.
One of the most substantial current changes in dementia diagnosis is the updating of diagnostic criteria in the common DSM diagnostic manual. The forthcoming DSM-V will list dementia as a “Major Neurocognitive Disorder” with new criteria including:
- pre clinical markers
- mild changes to memory and thinking
- dementia due to Alzheimer’s disease, which impact on daily life.
- the likelihood of being diagnosed with dementia increases with age.
As interventions after cognitive symptoms develop may be too late, earlier and more accurate diagnosis resulting in earlier and more effective treatment/s continue to be a quest of dementia researchers. More recently demonstrated biomarkers are higher levels of amyloid protein and reduced levels of tau and phosphoro-tau in the cerebrospinal fluid, and MRI, SPECT and PET scans findings.
Issues around testing people for these biomarkers include:
- technically, how reliable are the tests?
- is it ethical to give a diagnosis without surety?
- what is the point of diagnosis without available disease modifying treatment?
- would a person want to know?
- the high cost of the tests.
Unfortunately, experimental disease-modifying drugs for dementia have not proven successful. Pharmacological treatments such as acetyl cholinesterase inhibitors and memantine may alleviate the progression of cognitive and functional symptoms but their effects are modest.
Behavioural disturbances are more distressing to family carers than cognitive and functional decline. Drugs have had limited success in dealing with these and are associated with adverse effects. Non-pharmacological interventions are equally if not more effective for behavioural disturbances. For example, the SMILE cluster randomised controlled trial of Laughter Bosses and Elder Clowns interventions in residential care facilities demonstrated significantly decreased agitation and depression in people with dementia, increased resident engagement and improved quality of life.
Prevention remains important. Small but significant correlations have been found between Alzheimer’s disease and type 2 diabetes mellitus, mid-life obesity, hypertension and hypercholesterolaemia, depression, physical inactivity and smoking. A diet that includes fish, vegetables and fruit has been linked with lower dementia risk and slower rates of cognitive decline.
Currently there are 3,154 centenarians in Australia, the fastest growing age group. Models of successful ageing and factors that contribute to longevity continue to be a focus of researchers. Support for dementia research, which is underfunded in Australia compared to other major conditions, is needed across all domains of cause, cure and care.