Structural imaging differences and longitudinal changes in primary lateral sclerosis and amyotrophic lateral...

Area of Science:

• Neuroimaging
• Neurology
• Biomarkers

Background:

• Magnetic resonance imaging (MRI) measures are explored as objective markers for upper motor neuron loss in motor neuron disorders.
• Previous cross-sectional studies show imaging differences between healthy controls and patients with amyotrophic lateral sclerosis (ALS) or primary lateral sclerosis (PLS), correlating with disease severity.
• The longitudinal changes in these imaging measures and their comparability between ALS and PLS remain unclear.

Purpose of the Study:

• To investigate whether MRI measures change with disease progression in patients with ALS and PLS.
• To compare the pattern of imaging changes over time between ALS and PLS.
• To determine if imaging changes correlate with clinical disease progression.

Main Methods:

• A prospective cross-sectional study involving 23 ALS patients, 22 PLS patients, and 19 healthy controls.
• Clinical evaluations included neurological examination, ALS Functional Rating Scale-Revised (ALSFRS-R), finger tapping, gait, and timed speech.
• Imaging measures included cortical thickness, regional brain volumes, and diffusion tensor imaging (DTI) of the corticospinal tract and callosum. Longitudinal analysis was performed on a subset of patients.

Main Results:

• Both ALS and PLS groups showed cortical thinning, more extensive in motor regions in PLS patients cross-sectionally.
• Over time, cortical thinning and grey matter volume loss in the precentral gyri progressed in both patient groups.
• Clinical measures declined more in ALS than PLS patients. Changes in clinical measures correlated with changes in precentral cortical thickness and grey matter volume. Corticospinal tract cross-sectional area declined in ALS patients.

Conclusions:

• Structural imaging changes evolve with disease progression in motor neuron disorders.
• Cortical thinning and grey matter volume loss in the precentral gyri are potential imaging markers for disease progression, with changes potentially depending on disease duration and progression rate.
• Some diffusion changes occur early, while cortical thinning and volume loss appear later in the disease course.