Anterior temporal lobe connectivity correlates with functional outcome after aphasic stroke

Area of Science:

• Neuroscience
• Neurolinguistics
• Cognitive Psychology

Background:

• Language deficits after stroke are often attributed to local brain damage.
• However, disrupted communication between brain regions may also contribute significantly.
• Previous functional imaging studies have primarily focused on local cortical function.

Purpose of the Study:

• To investigate the relationship between language comprehension and functional connectivity in a key speech-processing area.
• To compare functional connectivity during speech comprehension in healthy individuals and stroke patients with aphasia.
• To identify how altered connectivity in the left anterolateral superior temporal cortex relates to language deficits.

Main Methods:

• Used positron emission tomography (PET) functional imaging.
• Compared functional connectivity of the left anterolateral superior temporal cortex in normal subjects and chronic aphasic stroke patients during narrative speech comprehension.
• Correlated language comprehension deficits with connectivity patterns and local activation.

Main Results:

• Normal speech comprehension involves connectivity between left anterolateral superior temporal cortex and other brain regions, including the right homolog.
• Aphasic patients showed disrupted left-right anterolateral superior temporal cortex connectivity.
• Auditory comprehension deficits correlated with the degree of this connectivity disruption and local activation.

Conclusions:

• Functional connectivity between left and right anterolateral superior temporal cortices is a key marker for receptive language outcome after stroke.
• Altered local and pathway-level function contribute to language system reorganization post-stroke.
• Preserved intertemporal connectivity may indicate compensatory mechanisms, potentially involving the left inferior frontal gyrus.