Cerebellar tract alterations in PLS and ALS

Area of Science:

• Neuroscience
• Neurology
• Neuroimaging

Background:

• Cerebellar neuropathology occurs in neurodegenerative diseases like amyotrophic lateral sclerosis (ALS), but its impact on cerebellar pathways is unclear.
• Understanding cerebellar tract integrity is crucial for differentiating neurodegenerative conditions.

Purpose of the Study:

• To investigate the integrity of cerebellar pathways, specifically the dentato-rubro-thalamo-cortical (DRTC) and spino-cerebellar (SC) tracts, in ALS and primary lateral sclerosis (PLS).
• To compare diffusion metrics in these tracts between ALS patients, PLS patients, and healthy controls.

Main Methods:

• Diffusion tensor imaging (DTI) was employed to assess the microstructural integrity of the DRTC and SC tracts.
• ALS patients (n=9) with an upper motor neuron (UMN)-predominant phenotype, PLS patients (n=10) with UMN-only involvement, and healthy controls (n=17) were included.

Main Results:

• Both ALS and PLS groups exhibited significant diffusion metric alterations in the DRTC, particularly near the motor cortex.
• PLS patients demonstrated independent diffusion abnormalities within the cerebellar regions of both DRTC and SC tracts.
• These findings suggest disruption of cerebellar tracts in PLS.

Conclusions:

• Cerebellar tract disruption is present in both ALS and PLS, but PLS shows unique cerebellar abnormalities.
• These distinct patterns indicate divergent pathogenesis between ALS and PLS.
• DTI is a valuable tool for characterizing white matter tract integrity in neurodegenerative diseases.