What is Dementia?
Dementia is a form of organic brain disorder associated with progressive neurodegeneration with resultant changes in cognition, memory, language and rational thinking. Changes in social skills, behavior, emotion and personality may also occur. Although dementia is more common in those over the age of 65 years, it is not confined to this age group.
Many terms have been used for dementia occurring before the age of 65 years. Presenile dementia is no longer used in the current literature. In DSM-IV-TR, dementia of onset before the age of 65 years is termed early-onset dementia. However, the term early-onset dementia may easily be taken to mean the early stages of dementia or mild cognitive impairment. Therefore, the terms “Young- onset Dementia” or “Younger-onset Dementia” have been widely adopted in the literature.
A clinical diagnosis of dementia is made on the basis of a comprehensive clinical history (including collateral history from the family members and close friends), mental state assessment (observation of a patient’s behavior and emotion) and neurological examination (for example, testing reflexes, muscle strength, eye movements). Testing of memory, language and other cognitive functions are conducted.
Computerized tomography (CT) uses X-Rays, while magnetic resonance imaging (MRI) uses magnetic fields to provide an image of the brain structure i.e. what the brain looks like. These scans can identify any areas of stroke, white matter disease or brain atrophy (Fig. 1). Specialized dementia protocols for MRI of the brain are required in order to obtain useful neuro-imaging information to aid dementia diagnosis.
Blood investigations are essential to look for medical conditions that may explain and/ or contribute to symptoms. These may include tests of thyroid, kidney and liver function, levels of calcium, phosphate and vitamin B12, as well as the presence of syphilis and HIV, depending on the findings of the medical specialist’s assessment.
Written by Dr. Chee Kok Yoon