Olfactory identification is impaired in clinic-based patients with vascular dementia and senile dementia of Alzheimer type

Aims It is now well established that there are abnormalities in the sense o f smell in patients suffering from Alzheimer's disease (AD). They have both raised olfactory thresholds and impaired odour identification. The situati on in vascular dementia is unclear. We used the University of Pennsylvania Smell Identification Test (UPSIT), a 40-item, forced choice, cued, 'scratch -and-sniff' test, to examine olfactory identification in vascular dementia and to determine whether it would differentiate the disorder from AD and no rmal elderly. Methods We investigated three matched subject groups: 13 people having a Ca mbridge Examination for Mental Disorders in the Elderly (CAMDEX) diagnosis of definite senile dementia of Alzheimer type, 13 having a CAMDEX diagnosis of definite vascular dementia and 13 non-cognitively impaired controls. Th e subjects were then tested with the UPSIT in their own home by an independ ent blind researcher to see if the test could distinguish the different dia gnostic groups in this setting. Results The median UPSIT score was 30 tout of a maximum of 40) for controls , 12 for the vascular group and 15 for the AD group. The difference was sig nificant (p = 0.05) between both demented groups and the normal controls. S imilarly there was a significant difference in the UPSIT score between the AD group and controls (p = 0.001) and between the vascular dementia group a nd controls (p = 0.001), but there was no significant difference between th e AD group and the vascular dementia group. The UPSIT score correlated stro ngly with the degree of cognitive impairment as measured by the CAMCOG (r(s )=0.683, p=0.01) Conclusions Patients with vascular dementia had a similar degree of olfacto ry impairment to those with AD. The UPSIT successfully differentiated betwe en dementia patients and normal elderly British subjects tested in their ow n homes. The UPSIT did not differentiate between those with AD and vascular dementia. Copyright (C) 2001 John Wiley & Sons, Ltd.