Speech network regional involvement in bulbar ALS: a multimodal structural MRI study.

Area of Science:

• Neuroimaging
• Neurodegeneration
• Speech Network Anatomy

Background:

• Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease affecting motor neurons.
• Bulbar onset ALS presents with specific speech and swallowing difficulties.
• Understanding structural changes in the speech network is crucial for ALS patient care.

Purpose of the Study:

• To investigate gray matter (GM) and white matter (WM) alterations in speech network (SpN) regions in ALS patients.
• To correlate these structural changes with the severity of bulbar disease.
• To explore the relationship between neuroanatomy and clinical measures of disability.

Main Methods:

• T1 and Diffusion Tensor Imaging (DTI) were used for 19 ALS patients and 13 controls.
• Surface-based, volumetric, and DTI metrics were analyzed in 6 speech network regions of interest.
• Linear models assessed disease effects and brain-behavioral correlations.

Main Results:

• ALS patients exhibited structural changes in the right primary motor cortex (PMC) and left pars triangularis (parsT), transverse temporal (TT), and posterior superior temporal gyrus (pSTG).
• Bulbar motor dysfunction correlated with WM abnormalities in the right oral PMC and left pSTG, and GM changes in bilateral TT.
• Symptom progression rate predicted GM and WM changes in bilateral pars opercularis (Broca's area).

Conclusions:

• Degeneration in left-dominant speech network regions is associated with bulbar ALS severity.
• Changes in Broca's area are linked to the rate of disease progression.
• These findings aid in understanding bulbar ALS subtypes for improved clinical management and trial recruitment.