The status of olfactory function and the striatal dopaminergic system in drug-induced parkinsonism.
Olfactory impairment has been reported in drug-induced parkinsonism (DIP), but the relationship between dopaminergic dysfunction and smell deficits in DIP patients has not been characterized. To this end, we studied 16 DIP patients and 13 patients affected by Parkinson's disease (PD) using the "Sniffin' Sticks" test and [(123)I] FP-CIT SPECT (single-photon emission computed tomography). DIP patients were divided based on normal (n = 9) and abnormal (n = 7) putamen dopamine transporter binding. Nineteen healthy age- and sex-matched subjects served as controls of smell function. Patients with DIP and pathological putamen uptake had abnormal olfactory function. In this group of patients, olfactory TDI scores (odor threshold, discrimination and identification) correlated significantly with putamen uptake values, as observed in PD patients. By contrast, DIP patients with normal putamen uptake showed odor functions-with the exception of the threshold subtest-similar to control subjects. In this group of patients, no significant correlation was observed between olfactory TDI scores and putamen uptake values. The results of our study suggest that the presence of smell deficits in DIP patients might be more associated with dopaminergic loss rather than with a drug-mediated dopamine receptor blockade. These preliminary results might have prognostic and therapeutic implications, as abnormalities in these individuals may be suggestive of an underlying PD-like neurodegenerative process.
Bovi
Tommaso
T
Dipartimento di Scienze Neurologiche e della Visione, Università di Verona, Verona, Italy. doctorbox@hotmail.it
Antonini
Angelo
A
Ottaviani
Sarah
S
Antonioli
Angela
A
Cecchini
Maria Paola
MP
Di Francesco
Vincenzo
V
Bassetto
Maria Antonietta
MA
Zamboni
Mauro
M
Fiaschi
Antonio
A
Moretto
Giuseppe
G
Sbarbati
Andrea
A
Osculati
Francesco
F
Tinazzi
Michele
M
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000978:Antiparkinson Agents / Q000009:adverse effects; D003342:Corpus Striatum / Q000000981:diagnostic imaging / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D000857:Olfaction Disorders / Q000000981:diagnostic imaging / Q000209:etiology / Q000378:metabolism*; D010300:Parkinson Disease / Q000150:complications / Q000378:metabolism / Q000503:physiopathology; D010302:Parkinson Disease, Secondary / Q000150:complications / Q000378:metabolism* / Q000503:physiopathology; D015899:Tomography, Emission-Computed, Single-Photon
D000978:Antiparkinson Agents; D004298:Dopamine