Olfactory Dysfunction in Parkinson's Disease, Its Functional and Neuroanatomical Correlates

Area of Science:

• Neuroscience
• Neurology
• Pathophysiology

Background:

• Parkinson's disease (PD) is primarily known for motor symptoms, but non-motor symptoms (NMSs) like olfactory dysfunction (OD) are increasingly recognized.
• OD can precede motor symptom onset in PD, suggesting its potential as a prodromal marker.
• Understanding olfactory system alterations is crucial for comprehending PD's broader impact.

Purpose of the Study:

• To review the role of olfactory dysfunction in Parkinson's disease.
• To explore OD as a potential diagnostic marker and indicator of PD progression.
• To detail the functional, morphological, and histological changes in the olfactory system in PD.

Main Methods:

• Literature review focusing on Parkinson's disease and olfactory dysfunction.
• Analysis of the prevalence and diagnostic role of OD in PD.
• Examination of the pathophysiology of PD, including alpha-synuclein.
• Description of alterations in olfactory system structures and the cerebellum.

Main Results:

• Olfactory dysfunction is a prevalent NMS in Parkinson's disease, often appearing early.
• OD's presence and severity correlate with PD progression and may aid in diagnosis.
• Alterations are observed in various olfactory-related brain regions, including the olfactory epithelium, bulb, and cortex, as well as the cerebellum.

Conclusions:

• Olfactory dysfunction is a significant early indicator in Parkinson's disease.
• Investigating olfactory system changes provides insights into PD pathophysiology.
• OD assessment can contribute to early diagnosis and monitoring of Parkinson's disease progression.