Dementia types

Clinical features of common forms of dementia


Alzheimer's diseaseVascular dementiaLewy body dementia
historyGradual onset cognitive decline.Stepwise onset of cognitive decline. Early gait disturbance. Emotional lability. History of artherosclerosis.Progressive cognitive decline. Fluctuations in conscious level (staring into space), visual hallucinations, Parkinson's symptoms. Marked response to neuroleptic / antiemetic medication.
examinationmay have frontal lobe signs or apraxiamay have upper motor neurone signsParkinson's features
pathologyamyloid plaques - neurofibrillary tangles outside and around neuronessmall ischaemic strokesLewy bodies - abnormal cytoplasmic protein inclusions
Structural imagingCerebral atrophy on CT and MRI. Loss of hippocampal volume on T1-weighted MRI.Small vessel disease or stroke on CT or MRI.Cerebral atrophy on CT and MRI.
Functional imagingBilateral, bitemporal and biparietal reduced perfusion on SPECT scanning. Increased [11C]PIB uptake on PET scanning."Patchy" reduced perfusion.Reduced signal on SPECT imaging of the dopamine transporter using DaTSCAN.
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Alzheimer's disease is the commonest form of dementia with vascular dementia second commonest. Mixed dementia with features of Alzheimer's disease and vascular dementia is the third commonest form.

Stoessl AJ. Neuroimaging in the early diagnosis of neurodegenerative disease. Transl Neurodegener 2012;1(1):5.

Edison P, Archer HA, Gerhard A, Hinz R, Pavese N, Turkheimer FE, Hammers A, Tai YF, Fox N, Kennedy A, Rossor M, Brooks DJ. Microglia, amyloid, and cognition in Alzheimer's disease: An [11C](R)PK11195-PET and [11C]PIB-PET study. Neurobiol. Dis. 2008 Dec;32(3):412–419.


Cerebral lobe signs |