Major neurocognitive disorder followıng isolated hippocampal ischemıc lesions.

BACKGROUND AND PURPOSE: Major cognitive disorder (MND) following vascular events is known as second causes of dementia after Alzheimer's disease (AD). Acute onset MND due to isolated hippocampal infarction has not been recognized as a specific subtype of vascular dementia, and there is no validated criteria for the identification of such cases, either clinically or radiologically.

RESULTS: Among 7200 patients with first-ever ischemic stroke, 22 patients (0.3%) showed acute isolated ischemic lesions in the hippocampus. Four of them presented acute MND characterized by confusion at the beginning of stroke and thereafter they developed typical clinical characteristics of MND. These cases allowed us to delineate a specific type of dementia characterized by confusion at stroke onset, dull and aimless appearance, verbal and visual immediate or delayed memory deficits, dysexecutive syndrome. Major cognitive disorder was developed due to anterior involvement of the hippocampus with little interindividual variation. Stroke mechanism was artery-to-artery embolism or cardioembolism which can explain isolated infarcts of the hippocampus.

CONCLUSIONS: Hippocampal MND generally occurred in acute bilateral isolated hippocampal infarcts. The clinical characteristic of MND may be secondary to lesions of the body of the hippocampus and interruption of the hippocampo-temporal pathways and cortical projections.