Objective: To detect the functional changes of primary olfactory cortex (POC) in the early-stage Parkinson’s disease (PD) using functional magnetic resonance imaging (fMRI).

Background: Olfactory dysfunction is prevalent in PD, with deficits in odor detection, identification, and discrimination. The central olfactory system is highly affected by the PD pathology. Typical PD pathology, Lewy body deposition, initiates in the olfactory bulb and anterior olfactory nucleus. To date, the reports of neuroimaging of olfaction in PD have not demonstrated the functional changes in the POC. With our newly developed fMRI technique we are able to detect odor-induced POC activation, which can be separated from sniffing-related POC activation.

Methods: The POC activation of 27 early-stage idiopathic PD patients and 20 age-/gender-matched healthy controls was studied with an olfactory stimulation paradigm on a 3 T MRI system. The smell function of each subject was evaluated with University of Pennsylvania Smell Identification Test. All subjects gave written informed consent, which was approved by the local institutional review board.

Results: The psychophysical test shows significant smell function deficit in PD patients. Both odor-sniffing and odorless-sniffing induced significant POC activation in the PD subjects, however, compared to the healthy controls, the odor-induced POC activation were significantly reduced in the PD patients.

Conclusions: In early-stage PD patients, there is a significant POC dysfunction responding to the odor stimulation. The observed POC functional change is consistent with the impairment of smell identification function in these patients that detected by the psychophysical test. Conversely, the sniffing function of the POC was relatively intact in these early-stage patients, which suggests a bottom-up mechanism in the dysfunction of central olfactory structures in this disease.

« Back to 2016 International Congress

MDS Abstracts - https://www.mdsabstracts.org/abstract/detection-of-primary-olfactory-cortex-dysfunction-in-early-stage-parkinsons-disease/