To estimate the proportion of  vascular dementia  (VAD) among dementia subtypes in a memory clinic.

To estimate the proportion of vascular cognitive impairment (VCI) among patients with mild cognitive impairment (MCI). 

Prevalence of stroke and vascular risk factors is extremely high in India. Incidence of stroke in India has increased two fold in India (105-152/100,000 person years) while it has almost halved in high income countries.  In community studies, VAD  was less prevalent compared to Alzheimer’s disease (AD). We investigated how common was VAD  and VCI in a memory clinic at a private hospital, where one of the commonest clinical problem is stroke. 

A prospective study of  MCI and dementia was carried out from memory clinic over six years using a standard protocol. All patients underwent clinical evaluation, neuropsychology testing and neuroimaging.  The diagnosis of  dementia subtypes, MCI, VAD and VCI was based on standard criteria.

VAD was seen in 118 (13.7%) patients of a total of 861 patients (degenerative and vascular).  Commonest dementia subtypes were AD (44.7%) and Frontotemporal dementia (22.5%).   Of the 127 patients with MCI, 21.3% had VCI. During the same period approximately 19876  stroke patients were seen in the hospital, so VAD accounted for <1%.

VAD is uncommon in the memory clinic in spite of the high prevalence of stroke in India.  Surprisingly, VCI was not uncommon. There may be several reasons including the lack of referrals to the memory clinic, evaluation by general neurologist and the qualitative nature of cognitive impairment.   It may also suggest that many patients with VCI may not progress to VAD and the relationship of cognitive impairment to stroke may not be straightforward.  Our results are particularly relevant  in the current scenario with emphasis on preventing and slowing AD by targeting the vascular component.