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Advanced Neurology Brain regions in olfactory dysfunction in PD

structural findings in this study, we conclude that the significantly enhance sensitivity. The increased magnetic
structural connectivity between the entorhinal cortex and field strength improves the signal-to-noise ratio, leading
parahippocampal regions plays a crucial role in olfactory to greater image clarity and the ability to detect smaller
function. In PD patients, the reduction of volumes in these lesions. This could provide more in-depth results by
areas may have a more significant impact on the olfactory examining cortical thickness and comparing it with brain
dysfunction. volume.
Another factor that may influence a VBM study is 5. Conclusion
the type of treatment that can influence the morphologic
features of the VBM. For example, the study by Donzuso PD patients exhibited more severe olfactory dysfunction in
et al. investigated whether a neuroanatomical substrate the hippocampal regions compared to the HC group. This
46
might underlie the development of long-duration may be attributed to the initial pathological loss of GM in
responses using structural MRI and VBM analyses. both the right and left hippocampi.
Their study showed that some cortical structural changes Acknowledgments
may predispose individual patients to developing long-
duration responses to L-dopa. Based on the results of We extend our sincere gratitude to all those who assisted us
the present study, it can be concluded that the type of in conducting this research.
treatment, along with other factors, such as olfactory
dysfunction and the presence of cognitive impairment Funding
(mild/moderate/severe), may influence the morphologic The authors are grateful for the technical assistance and
features of the VBM. Furthermore, the brain regions financial support of Hamadan University of Medical
23
exhibiting reduced volume in PD patients undergoing Sciences (project code: 140203091653) and would like
L-dopa treatment, with or without olfactory dysfunction, to thank the Clinical Research Development Unit of
differ from those affected in PD patients with cognitive Hamadan University of Medical Sciences, Hamadan, Iran.
impairment. Future studies should focus on the effects of
medication on brain volumetric results in PD patients. Conflict of interest
Accounting for comorbid disorders, such as cognitive The authors declared that they have no competing interests.
impairment and olfactory dysfunction, may offer valuable
insights. Author contributions
Moreover, the interplay between pharmacotherapy Conceptualization: Naser Moradi
and neuroanatomical changes may be further Data curation: Naser Moradi, Siamak Shahidi, Bahareh
elucidated by investigating the underlying biological Zaker Harofteh, Ghodratollah Roshanaei
mechanisms influenced by L-dopa treatment. Research Formal analysis: Naser Moradi, Bahareh Zaker Harofteh,
indicates that neuroinflammation and dopaminergic Ghodratollah Roshanaei
signaling alterations can affect neuroplasticity and Investigation: Naser Moradi, Siamak Shahidi, Bahareh
neurodegeneration in PD. 47-49 Studies employing Zaker Harofteh, Mohammad Ahmadpanah, Sajjad
advanced imaging techniques, such as VBM and Farashi
diffusion tensor imaging, can offer critical insights into Methodology: Naser Moradi, Siamak Shahidi, Bahareh
how L-dopa influences brain volumetric outcomes in PD, Zaker Harofteh, Mohammad Ahmadpanah
particularly regarding its impact on neural structure and Writing – original draft: Naser Moradi
the association with cognitive and olfactory function. 50,51 Writing – review & editing: Naser Moradi
In addition, the incorporation of machine learning
algorithms in volumetric analysis could facilitate the Ethics approval and consent to participate
identification of subtle morphometric changes that Ethical approval was obtained from Hamadan University
traditional VBM may overlook. Such approaches could of Medical Sciences (ethical approval: IR.UMSHA.
enhance our understanding of the differential effects of REC.1401.1053). All participants in our study were adults,
treatment modalities on brain structure and function, and each provided written informed consent before
ultimately leading to more personalized therapeutic participation.
strategies for PD treatment.
Consent for publication
This study encountered limitations. The MRI scanning
was conducted at 1.5 Tesla. Acknowledging the limitations Written informed consent was obtained from all
of 1.5T MRI, higher-field strengths in 3T or 7T MRI can participants to publish their data.

Volume 4 Issue 3 (2025) 66 doi: 10.36922/AN025110024