Dementia is a term that describes a wide range of symptoms associated with a decline in memory severe enough to reduce a person’s ability to perform daily activities. Alzheimer’s disease accounts for 60 to 80 percent of all cases. The second most common type is the overall cognitive decline following a ‘Stroke’, and this is termed as the vascular dementia. There are quite a few medically reversible dementias which occur secondary to vitamin deficiencies and thyroid disorders.

Memory deficit is the cardinal feature of dementia, however, this definition requires impairment in one more domain namely language, perception, visuospatial function, calculation, judgement, abstraction and problem-solving skills. This disorder affects 3 – 11% of adults > 65 years age, with a greater presence among institutionalised residents ! The risk factors includes advancing age, family history of dementia and the presence of apolipoprotein E-4 allele.

There are a substantial subset of patients who have underlying reversible causes for dementia. A few of them do get misdiagnosed as depressive illness or ignored and attributed to advancing age ! Chronic subdural haematomas, normal pressure hydrocephalus, frontal lobe tumours (low grade astrocytoma), gliomatosis cerebri, metastatic brain tumours, lymphoma (brain) and benign cranial tumours like basifrontal Meningioma can lead to memory and cognitive decline. In these patients, dementia may be the first warning symptom without any other feature of raised intracranial pressure. Cases related to head trauma, encephalomenigitis (brain fever), stroke (occlusive & hemorrhagic) also present with a general decline in cognition and are correctable to a great extent (long duration of treatment required) if presented to the clinician early !