Background: Primary lateral sclerosis (PLS) is an idiopathic upper motor neuron degenerative disorder. The aim of this study was to compare brain volumes in patients with PLS and controls and determine whether differences were due to loss of gray matter (GM), white matter (WM), or both.
Methods: T1-weighted images were acquired in patients with PLS and controls. Freesurfer was used for volumetric segmentation of whole brain, cortical GM, precentral and postcentral cortex, WM, corpus callosum, basal ganglia, thalamus, cerebellum, and CSF. Relationships were sought between disease severity, disease duration, age and brain volumes.
Results: Eleven patients with PLS and 10 age-matched healthy controls were included in this study. Compared to control subjects, patients with PLS had significantly smaller whole brain (p = 0.043), frontal lobe (p = 0.036), precentral cortex (p = 0.016), and corpus callosum (p = 0.036) volumes. There was a trend toward a smaller thalamus (p = 0.051). Disease severity correlated with ventricular CSF volume (rho = -0.604, p = 0.025) and precentral cortex volume loss (rho = 0.599, p = 0.026). Disease duration tended to correlate with a loss of WM (rho = -0.636, p = 0.063).
Conclusions: Our results suggest that there is focal atrophy in patients with primary lateral sclerosis compared with controls especially in the precentral cortex and the corpus callosum, specifically where there is transfer of motor fibers.