Patients affected by Parkinson's disease (PD) and Alzheimer's dementia (AD) manifest early and prominent olfactory dysfunction. Differently, patients with MPTP-induced parkinsonism, progressive supranuclear palsy and essential tremor have unaffected smell capabilities. The present pilot study was aimed at investigating olfactory performances in patients affected by dementia with Lewy bodies (DLB). The possibility to differentiate DLB from AD and other types of dementing disorders by psychophysiological testing is currently under investigation. Patients were diagnosed as affected by DLB according to the 1996 Newcastle clinical criteria. They showed an average score of 16.3 ±4.3 at MMSE. The Picture identification test (PIT), a 40-item forcedchoice test evaluating cognitive function, was previously applied to exclude patients not suitable for psychophysiological testing. Patients who scored well on PIT were administered the odor detection threshold test and the University of Pennsylvania Smell identification test (UPSIT). The odor detection threshold test (single staircase) provides a measure of the subject's ability to detect the lowest concentration of phenyl-ethyl-alcohol, an odorant selected to have minimal stimulatory activity on trigeminal free nerve endings. The UPSIT is a standardised and reliable microencapsulated odor test originally composed by 40 multiple-choice items. We have culturally adjusted and standardised this test to the Italian population by exclusion of 6 unfamiliar items. In comparison to age-matched controls, the DLB patients showed consistent and marked decrement of olfactory acuity and smell identification ability. As in the case of pure PD patients, olfactory test scores of DLB cases were independent of all other measures, including disease stage and duration. Further studies comparing the olfactory performances of DLB with AD patients might provide important clues on the differential diagnosis of these neurodegeneretive diseases.
|Number of pages||1|
|Journal||Italian Journal of Neurological Sciences|
|Publication status||Published - 1999|
ASJC Scopus subject areas
- Clinical Neurology