Auditory training changes temporal lobe connectivity in 'Wernicke's aphasia': a randomised trial

Area of Science:

• Neuroscience
• Neurology
• Speech-Language Pathology

Background:

• Aphasia, a common post-stroke disability, significantly impairs speech comprehension.
• Effective rehabilitation strategies for post-stroke aphasia, particularly for comprehension deficits, are lacking.
• Understanding the neural mechanisms underlying speech comprehension recovery is crucial.

Purpose of the Study:

• To evaluate the efficacy of phonological training and donepezil on speech comprehension in chronic aphasia.
• To investigate the effects of these interventions on neural connectivity using magnetoencephalography (MEG).

Main Methods:

• A within-subjects trial involving 20 patients with chronic aphasia and comprehension deficits.
• Concurrent interventions: phonological training (Earobics software) and donepezil (acetylcholinesterase inhibitor).
• Double-blind, placebo-controlled, cross-over design for donepezil; MEG with mismatch negativity response to assess neural connectivity.

Main Results:

• Phonological training significantly improved speech comprehension, especially in severe cases.
• Donepezil showed an unexpected negative effect on speech comprehension.
• MEG revealed phonological training increased synaptic gain in the left superior temporal gyrus (STG) and strengthened interhemispheric connections in severe patients.

Conclusions:

• Phonological training offers a viable rehabilitation approach for improving speech comprehension in aphasia.
• Donepezil is not effective for improving speech comprehension and may be detrimental.
• Interventions can reshape neural networks, enhancing phonological representations and interhemispheric communication in the auditory cortex.