Dementia in itself is not a disease but a syndrome where two or more cognitive functions are declined. Depending on the predominant symptom and pathology, they may be divided into different types. It is one of the most leading causes of disability in the elderly population. We spoke to Dr Ashish Gosar, Consultant Neurologist at Masina Hospital to know more about the types of Dementia and probably understand them better. He explained the three types of Dementia as below.
Alzheimer’s is the most common type of Dementia. It comprises 70 per cent of all Dementias. It was first reported by Dr Alois Alzheimer in 1907. Alzheimer’s disease can be sporadic or familial. Sporadic Alzheimer’s mostly occurs after the age of 65 and is the more common form of Alzheimer’s disease. Familial Alzheimer’s is a rare genetic condition and affects people usually in their 40s or 50s.
The most common presenting symptom of Alzheimer’s disease is lapses in memory and word-finding difficulty in day to day conversation. As the disease progresses, there are frequent memory lapses, especially of recent events. There is a loss of coordination in day to day conversation and a loss of enthusiasm in previously well-performed activities. It takes a longer time to do routine work. Forgetting familiar people’s name and faces. Deterioration of skilful executive work which was previously well performed.
With time, there is a progression of the disease and the person may require assistance for day to day activity and may completely become dependent. The cause of the disease is abnormal protein deposition (neurofibrillary tangles) predominantly in the temporal lobes. Diagnosis for it is mainly clinical. Good history and examination with neuropsychological testing and with a test for confirmation such as MRI/PET help to establish the diagnosis. There is no definite disease-modifying treatment for it but a group of drugs called cholinergic drugs help in improving symptoms to some extent. Apart from this, symptomatic treatment is given and with time the person continues to slowly deteriorate.
This is the second most common cause of dementia after Alzheimer’s disease. It commonly happens due to compromised circulation to the brain. This may happen due to secondary risk factors such as high blood pressure, smoking, diabetes, high cholesterol, cardiac issues and vascular risk factors.
Common symptoms include difficulty in walking, slowness and lethargy, emotional disturbance, loss of bladder control. Diagnosis for this is done by doing MRI and CT scan. The treatment involves management of the risk factors and symptomatic treatment.
Another common cause of dementia, Lewy Body disease may mimic Alzheimer’s disease. Patients commonly have difficulty in concentration and attention along with memory issues. The cardinal features include visual hallucinations and Parkinson’s symptoms such as tremors and stiffness. One other cardinal feature is inter and intraday fluctuations in mental state. The disease may be confirmed on MRI/PET scan and progresses more rapidly in comparison to Alzheimer’s disease.
Other common dementias include Fronto Temporal dementia which predominantly involves behavioural issues due to abnormal TAU protein deposition in the predominantly frontal and temporal lobe. Parkinson’s disease has clinical features more or less similar to dementia with Lewy body disease. Currently, disease-modifying treatment for various dementias is under clinical trial.
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