Association Between White Matter Microstructure and Verbal Fluency in Patients With Multiple Sclerosis

Area of Science:

• Neuroscience
• Cognitive Science
• Neurology

Background:

• Verbal fluency is crucial for communication, and deficits impact social functioning.
• Multiple sclerosis (MS) can cause cognitive impairments, including language deficits.
• Understanding language pathway contributions in MS is vital for targeted interventions.

Purpose of the Study:

• To investigate the roles of dorsal and ventral language pathways in verbal fluency among MS patients.
• To correlate diffusion MRI (dMRI) parameters with verbal fluency measures in MS.
• To examine the specific contributions of distinct white matter tracts to different types of verbal fluency.

Main Methods:

• Diffusion MRI (dMRI) was performed on 33 MS patients.
• Verbal fluency was assessed using both letter-based and category-based tasks.
• Diffusion parameters, including fractional anisotropy (FA), were calculated along individually identified dorsal and ventral language pathways and their homologs.

Main Results:

• Significant correlations were found between verbal fluency measures and mean FA in the left arcuate fasciculus (AFft), bilateral inferior fronto-occipital fasciculus (IFOF), and bilateral frontal aslant tract.
• Letter-based fluency correlated with FA in a segment of the left AFft (dorsal pathway).
• Category-based fluency correlated with FA in a segment of the right IFOF (ventral pathway).

Conclusions:

• The findings support a dual-stream model of language processing, associating the dorsal stream with letter-based fluency and the ventral stream with category-based fluency in MS.
• These associations may be specific to the clinical state of MS and warrant further investigation in the general population.