Patterns of olfactory dysfunctions in patients with Parkinson disease

Abstract

Background Olfactory dysfunction (OD) is a well-established nonmotor manifestations (NMM) of Parkinson disease (PD) which needs objective assessment for better understanding of the disease pathogenesis. The aim of this work was quantitative and qualitative assessment of olfactory performance in newly diagnosed PD patients. Methods This study was performed on 32 recently diagnosed PD patients and 24 healthy controls subjects (HCS) submitted to unified Parkinson’s disease rating scale–III (UPDRS–III), extended n-butanol Sniffin’ Sticks test (SST) and olfactory bulbs volumetry (OBV). Results There were significant decreases in SST threshold, discrimination, identification, and TDI variables as well as OBV in PD patients compared to HCS. The olfactory performance was negatively correlated with disease duration but had no relation with PD severity as well as motor subtype. Conclusion OD is highly prevalent during the early stages of PD which is both measurable and specific with identification and discrimination impairments to certain odors which makes smell performance testing an important step in PD patients’ evaluation.

Olfactory Impairment in Parkinson's Disease:Olfactory Impairment in Parkinson's Disease: Its Frequency and Correlation to Clinical severity in Sudanese Patients,Wad-Medani Teaching Hospital, 2022

“…Males were 32(52.46%) and females were 29(47.54%); with a male to female ratio of 1. [8] and this may explain the difference between the awareness of the patients to their olfaction and the actual state of Smelling ,because with the use of the standard psychophysical tests in this study almost all the Egyptian PD were found to be hyposmic . Similar results were obtained by Binyam et al on 123 PD patients, their age was also Similar to our cohort (mean age in the Ethiopian study was 62.9 years) showed that olfactory dysfunction was found in about 25.2% of Ethiopian patients with PD, this study had used the NMS questionnaire for data collection [9], the Ethiopian study had estimated the frequency of hyposmia near to our Sudanese Patients and this may be due to similarities in both genetic and environmental factors or due to subjective assessment of hyposmia using the NMS questionnaire in the Ethiopian cohort.…”

Disease progression modelling reveals heterogeneity in trajectories of Lewy-type α-synuclein pathology

“…A possible explanation for worse smell impairment in the S3 subtype that has been proposed before in light of the brain- vs body-first hypothesis, is that patients with the hypothesized brain-first LB type might show initial asymmetrical olfactory pathology, resulting in initially undetectable smell dysfunction, since the unaffected nostril might be able to compensate for this smell deficit 50,55 . Alternatively, it is possible that the lower smell test performance is a result of the higher proportion of clinicopathologically defined PD cases in the S3 subtype, with several studies estimating the presence of smell impairments in more than 90% of patients with PD 56,57 . This would also potentially explain the worse motor symptoms observed in this subtype.…”

Anosmia in Parkinson’s Disease in Pakistan: A Matched Case – Control Study

“…20 Olfactory dysfunction is a well-established NMS of Parkinson's disease. 11 Identification of Odor is an easy, however, valuable instrument that helps in differentiating Parkinson's disease from other parkinsonism causes. Though smells are based on cultural differences, thus test methods have to be modified to regional circumstances as well as habits in which they are envisioned for utilize.…”

“…10 Olfactory dysfunction is a well-established NMS of Parkinson's disease. 11 It is the dysfunction that could be from a mildly reduced sense of the smell (hyposmia) to entire smell loss (anosmia). 12 Anosmia is commonly observed in the PD, 13 although it is also quite common in older age 14 and mostly takes place early during the period of the disease.…”