Dementia affects 1 to 6 per cent of the population over 65 years of age and 10 to 20 per cent of those above 80. The crucial aspect is to detect early symptoms in order to check its progress. Despite the enormity of the problem, imaging is still not a tool that has been able to deliver results.
This is because there is very little radiological difference between the brain of an elderly person and that of a patient who has some cognitive dysfunction that might ultimately lead to dementia, says Dr Deepak Patkar. But newer imaging modalities like SPECT and PET have been able to catch some aspects of the onset of dementia. Functional imaging would play a major role in this area, Dr Patkar said. He admitted that there is considerable overlap between Alzheimer’s Disease (AD) patients with mild cognitive impairment (MCI). However, 12 per cent of MCI patients finally land up with AD and imaging has a major role to play in checking this progression.
Ever since 1907 when Alois Alzheimer reported pathological factors in the brain that lead to dementia, there have been major milestones in studying the disease. Earlier it was thought that cognitive dysfunction or behavioural disorders in the aged was due to unknown forces. Things have changed today.
The areas of the brain that get affected due to dementia or AD are known today. The focus has been on the limbic system where temporary information is stored and the cortex where information on a permanent nature gets recorded.
While dementia and aging was earlier thought to be inseparable partners, the fact today is that the focus is on aging successfully. The causes of dementia are classified as primary, vascular, NPH, infection, dietary and toxic and other factors. The risk factors include age, sex (women are more prone than men) and family history.
The types of AD include sporadic, which is the cause of 75 per cent of the population of over 65. Next is familial and those with chromosomal disorders where the onset can be as early as in the 30’s. Infections can also lead to dementia. Creutzfeld Jakob’s disease (CJD) and HIV. It is now well documented that CJD was due to a tribal custom in Africa of eating the organs of the dead. But there have been sporadic cases where the causes need not be cannibalism alone. In HIV cases with drugs prolonging the survival, the incidence of dementia is likely to go up.
Speaking on future developments, Dr Patkar said MRI in cognitive stress test would play a major role and tactography, where the communication fibres of the brain can be studied in detail, would give better insights into the progression of dementia. New PET tracers too would be able to map the areas of the brain in finer details