Category: Parkinson's Disease: Non-Motor Symptoms
Objective: To investigate difference in olfactory impairment between tremor dominant (TD) and akinetic rigid dominant (ARD) Parkinson’s disease patients.
Background: PD can be classified in different motor subtypes such as TD or ARD subtypes depending on the predominant symptoms (tremor or rigidity/bradykinesia). These PD subtypes can reflect different pathophysiologies, while slower disease progression and cognitive decline have been observed in TD patients compared to those with ARD subtype. Olfactory impairment has been well described in PD patients, although the definite correlation with different subtypes of PD is not clear.
Method: Sixty-Two PD patients, 20 with TD subtype and 42 with ARD subtype, were enrolled. Patients were divided into ARD and TD subtypes calculating tremor/rigidity ratio, through UPDRS III scores. Olfactory function was evaluated using Sniffin’ Sticks Extended test (SSET), assessing the following olfaction parameters: odor threshold (OT), odor discrimination (OD) and odor identification (OI). The total score (Threshold–Discrimination–Identification: TDI) was calculated. Patients with cognitive impairment were excluded from testing. Pearson’s correlation between tremor/rigidity ratio and olfaction parameters was analyzed. Moreover, a multivariate linear regression analysis was performed.
Results: OT, OD and TDI scores were significantly lower in the ARD subtype than in the TD group [respectively 1.9±1,4 vs 3.3±2.7 (p=0.008); 7.0±3.1 vs 8.6±2.2 (p=0.042); 16.0±6.5 vs 20.3±6.1 (p=0.017) ], while OI scores were not significantly different. Pearson’s correlation between tremor/rigidity ratio and OT was significant (r=0.462, p<0.001). Also Pearson’s correlation between tremor/rigidity ratio and TDI score was significant (r=0.335, p<0.008). On multivariate linear regression analysis the tremor/rigidity ratio was a significant predictor of OT (p=0.01) and TDI (p=0.02).
Conclusion: Conclusions: These findings show a more evident olfactory disfunction in PD patients with ARD subtype. This evidence supports the biological relevance of clinical subtypes in PD patients suggesting the idea of a different pathophysiological process between these different clinical forms.
To cite this abstract in AMA style:
P. Solla, C. Masala, P. Raffaella, S. Dagostino, T. Ercoli, G. Defazio. Difference in olfactory impairment between tremor dominant and akinetic rigid dominant Parkinson’s disease patients [abstract]. Mov Disord. 2020; 35 (suppl 1). https://www.mdsabstracts.org/abstract/difference-in-olfactory-impairment-between-tremor-dominant-and-akinetic-rigid-dominant-parkinsons-disease-patients/. Accessed June 15, 2025.« Back to MDS Virtual Congress 2020
MDS Abstracts - https://www.mdsabstracts.org/abstract/difference-in-olfactory-impairment-between-tremor-dominant-and-akinetic-rigid-dominant-parkinsons-disease-patients/