Posterior Cortical Atrophy: Altered Language Processing System Connectivity and Its Implications on Language...

Area of Science:

• Neuroscience
• Cognitive Neurology

Background:

• Posterior cortical atrophy (PCA) primarily causes visual decline but can also feature significant language impairments.
• The precise nature of language processing disruptions in PCA remains incompletely understood.
• Existing research has touched upon language connectivity issues in PCA, necessitating further investigation.

Purpose of the Study:

• To investigate the functional connectivity of the language processing system in patients with posterior cortical atrophy (PCA).
• To compare language network connectivity between PCA patients and cognitively unimpaired (CU) individuals.
• To explore the relationship between language network connectivity, clinical language performance, and gray matter volumes in PCA.

Main Methods:

• Functional connectivity analysis of the language processing system (language, perceptual, motor, cognitive networks) in 37 PCA patients and 39 CU individuals.
• Linear regression was used to compare within- and between-network connectivity.
• Assessment of correlations between language network connectivity, clinical performance, and gray matter volumes.

Main Results:

• PCA patients exhibited reduced within-network connectivity in language and perceptual networks compared to CU individuals.
• Reduced between-network connectivity was observed in PCA patients.
• Regional connectivity breakdown within the language network was identified, notably affecting Broca-Wernicke, Wernicke-middle frontal gyrus, and Wernicke-frontal orbital gyrus connections, correlating with poorer sentence repetition.

Conclusions:

• The findings confirm a breakdown in language network connectivity in PCA, extending to the regional level within the language network.
• Reduced connectivity within the perceptual network and its association with language network disruptions suggest broader impacts on the language processing system in PCA.
• While overall language network connectivity did not correlate with clinical performance, specific regional breakdowns were linked to deficits in sentence repetition, highlighting targeted language processing impairments.