Diagnosis of Alzeimers Disease (AD) and Vascular Dementia(VD) in clinical practice
I have read the Rapid Response of Jonathan Golledge to the article by
Purandare and colleagues but I am not totally in agreement with him that we are
unable to differentiate VD and AD using clinical and imaging criteria.
Firstly, a good history can help us a lot in distinguishing between
AD and VD: a family history of cognitive decline is not uncommon with AD.
Abscence of cardio and cerebrovascular diseases differentiates AD from VD.
VD is common in patients with pre-existing cardiac and cerebrovascular
diseases e.g. Ichemic Heart Disease, Myocardial
Infarction,Hypertension,Transient Ischemic Attacks. A stepwise pattern of
cognitive decline is common in VD--periods of abrupt decline alternating
with "plateau" periods of minimal decline.
Secondly, Nocturnal confusion and wandering, relative preservation of
emotional responsiveness and personality until the later stages of the
disease and the presence of depression, emotional lability, incontinence
and somatic symptoms defferentiate VD from AD.(1)
Abscence of corticospinal tract and gait disorders distinguishes AD from
"Ischemic Scores" are also useful in the differential diagnosis
between AD and VD.
Thirdly, imaging studies (CT and MRI brain) also very helpful in
differential diagnosis between AD and VD.
CT brain showes cortical atrophy in AD and periventricular ischemia and
multiple small old infarct in VD.
Signal abnormalities on intermediate T2weighted scans (MRI brain)in the
uncal-hippocampal or insular cortex are frequently and almost exclusively
common in Alzeimers disease. Other MRI findings e.g. basal ganglionic/
thalamic hyperintence foci,thromboembolic infarctions, confluent white
matter and irregular periventricular hyperintensities are more common in
And finally, good clinical history,clinical symptoms, imaging studies
help us to distinguish between two important type of dementia in clinical
1.Roman G C, Tatemichi T K, Erkinjuntti T et al. Vascular Dementia:
diagnostic criteria for reseach studies. Report of the NINDS-AIREN
international workshop. Neurology 1993; 43:250-260
2.Differential diagnosis between Alzeimers disease and Vascular
dementia:evaluation of common clinical method: Frkinjuntti T,Dept. of
Neurology, University of Helsinki, Finland.(Acta Neurol Scand. 1987
3.Schmidt R, Dept. of Neurology, Karl Frazens University Graz,Austria. Eur
Neurol 1992; 32(3): 162-9
Competing interests: No competing interests