Vascular dementia is a condition that affects cognitive functions, such as memory, reasoning, planning, and judgement. This type of dementia occurs due to reduced blood supply to the brain, resulting in damage to brain tissue.
The research conducted by scientists at the University of Oxford, the results of which appeared in journal Circulation Research, represents a significant advancement in the battle against dementia. The findings could provide a crucial turning point in the efforts to combat the disease, said city doctors.
Dr Praveen Gupta, principal director, neurology, Fortis Gurgaon, distinguished between vascular and Alzheimer’s disease dementia, noting that while the end result was comparable, the underlying pathophysiology differed. “In Alzheimer’s, dementia occurs due to deposition of Amyloid beta plaques in the brain, which prevents connectivity of neurons causing cognitive or brain dysfunction,” he explained. “In vascular dementia, the damage to brain cells occurs due to the obstructions in blood vessels.” The underlying processes leading to these two types of dementia are distinct, despite their similar outcomes in terms of cognitive impairment.
According to a study titled ‘Vascular cognitive impairment in India’, the burden of vascular contribution to cognitive impairment and dementia is substantially high in India. There are approximately 5.3 million dementia patients in India and nearly 40% are estimated to be sufferers of vascular dementia.
Gupta said the Oxford studies provide promising early results that could pave the way for treatment. However, larger studies were needed to demonstrate the efficiency of sildenafil before it could be considered standard treatment.
Dr Manjari Tripathi, head of AIIMS’ neurology department, explained that the primary risk factors for vascular dementia included blood pressure, smoking, diabetes, hypertension, obesity, obstructive sleep apnea and atherosclerosis. She said that vascular dementia could manifest in different forms. One type is multi-infarct dementia (MID), which develops as a consequence of multiple small strokes that lead to brain damage. Another type is strategic infarct dementia, where a single infarct occurs in a crucial region of the brain, such as the anterior nucleus of the thalamus, resulting in dementia even with a solitary infarct.
“Strokes can affect individuals of all ages. The cognitive impairments resulting from a stroke, such as diminished reasoning, logical thinking, attention and judgment, are often more severe compared to those observed in Alzheimer’s dementia,” said Tripathi. “The onset of these cognitive deficits can be sudden and profound, regardless of the patient’s age. While Alzheimer’s dementia typically progresses gradually, the impact of a stroke on cognitive functions can be immediate and substantial.”
Agreeing that the Oxford research was groundbreaking in linking sildenafil with improvement in vascular dementia, Dr Rajeev Mehta, senior psychiatrist, Sir Ganga Ram Hospital, added, “It is important to note that in vascular dementia, memory deficiency or forgetfulness occurs in steps.”
However, further comprehensive multi-centric trials were needed to substantiate these findings, said Dr Jitendra Nagpal, chairman, Institute of Mental Health, Moolchand Hospital. That said, any benefit to chronic sufferers was a welcome step in cognitive recovery, he added.