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 of smell in patients suffering from Alzheimer's disease (AD). They have both raised olfactory thresholds and impaired odour identification. The situation 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 normal elderly.

METHODS

We investigated three matched subject groups: 13 people having a Cambridge 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. The subjects were then tested with the UPSIT in their own home by an independent blind researcher to see if the test could distinguish the different diagnostic groups in this setting.

RESULTS

The median UPSIT score was 30 (out of a maximum of 40) for controls, 12 for the vascular group and 15 for the AD group. The difference was significant (p = 0.05) between both demented groups and the normal controls. Similarly there was a significant difference in the UPSIT score between the AD group and controls (p = 0.001) and between the vascular dementia group and controls (p = 0.001), but there was no significant difference between the AD group and the vascular dementia group. The UPSIT score correlated strongly 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 olfactory impairment to those with AD. The UPSIT successfully differentiated between dementia patients and normal elderly British subjects tested in their own homes. The UPSIT did not differentiate between those with AD and vascular dementia.