Dementia - not just a memory thief
|Mother||: What are we doing tomorrow?|
|Son||: I mentioned that already this morning, do you not remember?|
|Mother||: Oh, did you?|
Dementia is diagnosed when a person’s thinking and memory capacity degrades to a point that it impacts daily living. The mind becomes perplexed, simple tasks become challenging and as there is increasing loss of function, the person is robbed of his or her independence and becomes socially isolated. As the brain shrinks, so does the world. In many cases, family members of these patients experience emotional pain and burn-out from caring for them as deterioration takes place over an extended period of time. Many resort to sending their loved ones to care facilities.
Worldwide, around 50 million people suffer from dementia. Every year, 10 million new cases are found.1 Locally in Singapore, a study led by the Institute of Mental Health in 2015 reported that 1 in 10 people aged 60 and above may have dementia.2 These numbers are expected to rise in years to come.
Alzheimer’s disease accounts for 50-70% of all dementia cases in the elderly population, implying age is the most well-known risk factor for dementia. Other causes include vascular dementia, frontotemporal lobe dementia and Lewy body (abnormal clumps of protein in nerve cells) dementia. It is common for people to have mixed dementia i.e a combination of two or more types.
However, dementia does not affect only the elderly. In younger patients affected by the disease, it is called young onset dementia (YOD). YOD refers to onset of dementia between 35 and 65 years old. The National Neuroscience Institute (NNI) Singapore has seen an alarming rate of younger people being diagnosed with this disease and numbers have been increasing through the years. In 2013, there were only 60 patients, in 2018, 228 patients and in 2019, there were 245 people diagnosed with YOD.3 NNI’s youngest patient with YOD was only 46 years of age.3 Whilst older people tend to present with forgetfulness, these younger patients present with more varied symptoms such as behaviour changes, difficulty with planning, sequencing and judgement.
Role of MRI
The role of imaging in dementia is not only to look for degenerative change such as in Alzheimer’s disease which manifests as brain shrinkage, but also to exclude surgical causes such as a brain tumour causing dementia symptoms. In addition, imaging can also be used to assess for early dementia or progression of disease.
An MRI brain tailored for dementia screening is about 20-30 minutes.
The main difference between a usual MRI brain scan versus an MRI brain scan for dementia is that in the latter, extra set of images are acquired in thin slices, to interrogate the hippocampus and medial aspect of the temporal lobe. The reason for evaluation of the hippocampi is because it is a part of the brain that is involved in many forms of dementia.
MRI is able to add value to the clinical assessment in a person suspected to have dementia, by contributing to scoring systems for the diagnosis and to stage severity of disease.
Life after diagnosis
There is no known cure for dementia. The role for early diagnosis is i) to enable early treatment to slow the progression of dementia and to better manage the effects of the disease and ii) to identify and control vascular risk factors like high blood pressure and diabetes which has been shown to be associated with dementia.4
Usually the patient with dementia will be under the care of a team, led by a geriatrician, neurologist and psychologist.
1 Dementia. World Health Organization. URL: https://www.who.int/news-room/fact-sheets/detail/dementia. Last accessed: 23 March 2021.
2 Dementia in Singapore. Alzheimer’s Disease Association.
URL: https://alz.org.sg/dementia/singapore. Last accessed: 23 March 2021.
3 Teo J. ‘More here diagnosed with young onset dementia, says NNI.’ The Straits Times Singapore. 21 June 2020. https://www.straitstimes.com/singapore/health/more-here-diagnosed-with-young-onset-dementia-says-nni. Last accessed: 23 March 2021.
4 van der Flier WM and Scheltens. Epidemiology and risk factors of dementia. Journal of Neurology, Neurosurgery & Psychiatry, vol 76 issue sppl 5.