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J Neurol Neurosurg Psychiatry. 2017 Jul;88(7):586-594. doi: 10.1136/jnnp-2016-314621. Epub 2017 Mar 4.

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

Author information

1
Department of Brain Repair and Rehabilitation, University College London, London, UK.
2
Wellcome Trust Centre for Neuroimaging, University College London, London, UK.
3
Department of Experimental Psychology, University of Oxford, Oxford, UK.
4
Institute of Cognitive Neuroscience, University College London, London, UK.
5
Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK.

Abstract

INTRODUCTION:

Aphasia is one of the most disabling sequelae after stroke, occurring in 25%-40% of stroke survivors. However, there remains a lack of good evidence for the efficacy or mechanisms of speech comprehension rehabilitation.

TRIAL DESIGN:

This within-subjects trial tested two concurrent interventions in 20 patients with chronic aphasia with speech comprehension impairment following left hemisphere stroke: (1) phonological training using 'Earobics' software and (2) a pharmacological intervention using donepezil, an acetylcholinesterase inhibitor. Donepezil was tested in a double-blind, placebo-controlled, cross-over design using block randomisation with bias minimisation.

METHODS:

The primary outcome measure was speech comprehension score on the comprehensive aphasia test. Magnetoencephalography (MEG) with an established index of auditory perception, the mismatch negativity response, tested whether the therapies altered effective connectivity at the lower (primary) or higher (secondary) level of the auditory network.

RESULTS:

Phonological training improved speech comprehension abilities and was particularly effective for patients with severe deficits. No major adverse effects of donepezil were observed, but it had an unpredicted negative effect on speech comprehension. The MEG analysis demonstrated that phonological training increased synaptic gain in the left superior temporal gyrus (STG). Patients with more severe speech comprehension impairments also showed strengthening of bidirectional connections between the left and right STG.

CONCLUSIONS:

Phonological training resulted in a small but significant improvement in speech comprehension, whereas donepezil had a negative effect. The connectivity results indicated that training reshaped higher order phonological representations in the left STG and (in more severe patients) induced stronger interhemispheric transfer of information between higher levels of auditory cortex.Clinical trial registrationThis trial was registered with EudraCT (2005-004215-30, https://eudract.ema.europa.eu/) and ISRCTN (68939136, http://www.isrctn.com/).

KEYWORDS:

Wernicke’s aphasia; magnetoencephalography; pharmacological trial; phonological training; speech comprehension

PMID:
28259857
PMCID:
PMC5659142
DOI:
10.1136/jnnp-2016-314621
[Indexed for MEDLINE]
Free PMC Article

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