Assessment of Asymmetry in Thalamic Nuclei volume in Nigerian Parkinson's Disease Patients

Abstract

Background and aim: Emerging evidence suggests that asymmetrical alterations in thalamic gray matter may represent a key neuroanatomical feature of Parkinson’s disease (PD). However, the expression of these structural changes remains underexplored within African populations. This study examines thalamic asymmetry in a Nigerian cohort of PD patients, aiming to elucidate population-specific patterns of neurodegeneration and their relationship to sociodemographic variables.

Methodology: Twenty-two individuals diagnosed with PD and thirty-four age-matched healthy controls were recruited. Participant demographics, including age, socioeconomic status (SES), and educational attainment, were documented in accordance with Committee on Best Practice in Data Analysis and Sharing (COBIDAS) guidelines. High-resolution T1-weighted MRI scans were acquired using a 1.5T system and processed via FSL_Anat, with thalamic nuclei segmented and volumetrically assessed using FreeSurfer version 7.3.2. Group comparisons were conducted using independent t-tests, while correlational analyses assessed associations between thalamic volumes and age, SES, and education levels.

Results: The present study shows symmetry in the Thalamic nuclei of Parkinson's Disease patients as no significant differences were observed between the left and right thalamic nuclei (P>0.05). There was also interhemispheric symmetry of the thalamic nuclei observed in the control subjects except in the Pc nuclei (p=0.0094).The correlation analysis analysing association between the thalamic nuclei volume and the demographics of the data subjects showed significant asymmetry in the Ventral Anterior magnocellular (VAmc) nucleus of the thalamus among Parkinson's disease (PD) patients, with a p-value of 0.038, indicating a notable lateralization in this motor-related subregion. Additionally, we observed that female patients exhibited reduced VAmc asymmetry compared to males (p = 0.012), highlighting a sex-specific pattern in thalamic structural alterations associated with PD.

Conclusion: These findings advance our understanding of PD-associated thalamic reorganization within an understudied population and underscore the relevance of sociodemographic factors in shaping subcortical brain morphology.