Subcortical structure volumes and correlation to clinical variables in Parkinson's disease

MRI studies in Parkinson's Disease have shown volumetric reductions of subcortical structures such as the thalamus, putamen, globus pallidus, and caudate nucleus. However, there are no studies which look at the relationship between subcortical structure volumes and clinical variables, such as age and motor severity scores.

Brain MRI scans of 47 consecutive PD patients undergoing deep brain stimulation was acquired. Volumetric data of the thalamus, putamen, caudate nucleus, and globus pallidus were extracted and corrected for total intracranial volume. Pearson correlation coefficient (PCC) and general linear modeling (GLM) were then applied to the volumetric and the clinical variable data to explore the relationships between the two.

PCC showed a positive correlation between volumes of the left and right thalamus and left and right putamen with increasing duration of disease. GLM demonstrated that duration of symptoms was a significant factor relating to larger left thalamic volume. Male gender was also a significant factor associated with smaller left and right thalamic and right putaminal volumes.

There is a correlation between the volume subcortical structures and clinical variables, particularly the disease duration, in PD. This may not only help understanding the disease process but also patient selection for invasive and noninvasive therapies.