Pattern of vascular dementia in India: study of clinical features, imaging, and vascular mechanisms from a hospital dementia registry.
Vascular dementia (VaD) is heterogeneous in its clinical, imaging, and etiological characteristics. Although VaD is common in India, its pattern is not completely known. In a hospital-based cohort, we aimed to characterize VaD by its subtypes and study patterns of risk factors and clinical, and neuropsychological profiles. Vascular mechanisms, known to have racial and genetic variations were identified. NINDS-AIREN criteria were used to diagnose VaD. Patients were subtyped into subcortical, cortical, cortical-subcortical, and strategic infarct dementia. Vascular mechanisms were detected by vascular imaging, cardiac evaluation, and laboratory tests. In the 42 consecutive patients with VaD, subcortical dementia was the most common type (52.4%), followed by cortical-subcortical (26.2%), strategic infarcts in (14.3%), and cortical dementia (7.1%). Stroke (81%), hypertension (71.4%), and diabetes (35.7%) were important risk factors. Small artery disease was the underlying vascular mechanism in 42.9%; intracranial large artery disease, in 16.7%; extracranial disease, in 2.3%; cardioembolism, in 2.3%; multiple mechanisms, in 19%; and unknown, in 16.7%. Subtypes were similar in risk factor profile and neuropsychological features but differed in clinical characteristics and vascular mechanisms. Gait disorder (59.1% vs. 0%) and urinary symptoms (77.3% vs. 16.7%) were more common in subcortical dementia than in strategic infarct dementia (P < .05). Small artery disease was most common in subcortical dementia (72.7%). Intracranial large artery disease was associated with all subtypes. The pattern of VaD demonstrated in our study is a reflection of mechanisms of cerebrovascular disease in India. Outcome depends on underlying mechanisms and thus is likely to differ from that in other ethnic populations.