Clinical determinants of dementia and mild cognitive impairment following ischaemic stroke: the Sydney Stroke Study.
BACKGROUND
Dementia following stroke is common but its determinants are still incompletely understood.


METHODS
In the Sydney Stroke Study, we performed detailed neuropsychological and medical-psychiatric assessments on 169 patients aged 50-85 years, 3-6 months after a stroke, and 103 controls with a majority of both groups undergoing MRI brain scans. Stroke subjects were diagnosed as having vascular mild cognitive impairment (VaMCI) or vascular dementia (VaD) or no cognitive impairment by consensus. Demographic, functional, cerebrovascular risk factors and neuroimaging parameters were examined as determinants of dementia using planned logistic regression.


RESULTS
21.3% of subjects were diagnosed with VaD, with one case in those aged 50-59 years, 24% in those aged 60-69 years and 23% in those 70-79 years. There was no difference by sex. The prevalence of VaMCI was 36.7%. VaD subjects had lower premorbid intellectual functioning and had 0.9 years less education than controls. The VaD and VaMCI groups did not differ from the no cognitive impairment group on any specific cerebrovascular risk factor, however overall those with impairment had a greater number of risk factors. They did not differ consistently on depression severity, homocysteine levels and neuroimaging parameters (atrophy, infarct volume and number of infarcts) except for an excess of white matter lesions on MRI and greater number of infarcts in the VaD and VaMCI groups. On a series of logistic regression analyses, stroke volume and premorbid function were significant determinants of cognitive impairment in stroke patients.


CONCLUSIONS
Post-stroke dementia and MCI are common, especially in older individuals. Cerebrovascular risk factors are not independent risk factors for VaD, but stroke volume is a significant determinant of dementia. Premorbid functioning is a determinant of post- stroke impairment.
School of Psychiatry, University of New South Wales, Sydney, Australia. p.sachdev@unsw.edu.au
P S
PS
Sachdev
H
H
Brodaty
M J
MJ
Valenzuela
L
L
Lorentz
J C L
JC
Looi
K
K
Berman
A
A
Ross
W
W
Wen
A S
AS
Zagami
D000368:Aged; D001315:Australia / Q000453:epidemiology; D001921:Brain / Q000098:blood supply / Q000473:pathology; D002545:Brain Ischemia / Q000150:complications* / Q000453:epidemiology* / Q000473:pathology; D002391:Catchment Area, Health; D002560:Cerebrovascular Circulation / Q000502:physiology; D003072:Cognition Disorders / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology*; D003704:Dementia / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology*; D005260:Female; D006304:Health Status; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D015995:Prevalence; D012307:Risk Factors; D012720:Severity of Illness Index