Deficits in sentence expression in amyotrophic lateral sclerosis

Area of Science:

• Neuroscience
• Linguistics
• Neurology

Background:

• Quantitative speech production studies in amyotrophic lateral sclerosis (ALS) are infrequent.
• Understanding language deficits independent of motor impairment in ALS is crucial.

Purpose of the Study:

• To investigate linguistic and motor factors in impaired sentence expression in ALS.
• To correlate speech deficits with gray matter (GM) and white matter (WM) abnormalities using MRI.

Main Methods:

• Analysis of semi-structured speech samples from 26 ALS patients and 19 healthy controls.
• Assessment of motor and language deficits, including speech rate, articulation, and grammaticality.
• Regression analyses linking grammaticality to GM atrophy and WM fractional anisotropy (FA).

Main Results:

• ALS patients exhibited deficits in speech quantity, rate, articulation, and grammaticality.
• Speech rate and articulation errors correlated with motor impairment.
• Grammatical difficulty was independent of motor deficits, even in subgroups without dysarthria or executive dysfunction.
• Grammatical expression deficits were associated with GM atrophy in left frontal/temporal regions and reduced FA in specific WM tracts.

Conclusions:

• ALS patients present with multifaceted sentence expression impairments.
• A distinct grammatical deficit exists in ALS, separate from motor neuron degeneration.
• Impaired grammar in ALS is linked to neural degeneration within a specific brain network involved in syntax.