Increased Recruitment of Domain-General Neural Networks in Language Processing Following Intensive Language-Action Therapy: fMRI Evidence From People With Chronic Aphasia.

Felix R Dreyer,Benjamin Stahl,Verena Arndt,Verena Büscher,Guglielmo Lucchese,Lea Doppelbauer,Bettina Mohr,Olaf Hauk,Friedemann Pulvermüller

doi:10.1044/2020_ajslp-19-00150

Abstract

PurposeThis study aimed to provide novel insights into the neural correlates of language improvement following intensive language-action therapy (ILAT; also known as constraint-induced aphasia therapy).MethodSixteen people with chronic aphasia underwent clinical aphasia assessment (Aachen Aphasia Test [AAT]), as well as functional magnetic resonance imaging (fMRI), both administered before (T1) and after ILAT (T2). The fMRI task included passive reading of single written words, with hashmark strings as visual baseline.ResultsBehavioral results indicated significant improvements of AAT scores across therapy, and fMRI results showed T2−T1 blood oxygenation-level-dependent (BOLD) signal change in the left precuneus to be modulated by the degree of AAT score increase. Subsequent region-of-interest analysis of this precuneus cluster confirmed a positive correlation of T2−T1 BOLD signal change and improvement on the clinical aphasia test. Similarly, the entire default mode network revealed a positive correlation between T2−T1 BOLD signal change and clinical language improvement.ConclusionThese results are consistent with a more efficient recruitment of domain-general neural networks in language processing, including those involved in attentional control, following aphasia therapy with ILAT.

Highlights

Intensive language-action therapy (ILAT), a type of therapy known as “constraint-induced aphasia therapy” or “constraint-induced language therapy,” has been shown clinically to be an effective method for aphasia therapy at the chronic stage in a number of randomized controlled trials (RCTs; Berthier et al, 2009; Heikkinen et al, 2019; Kurland et al, 2016; Pulvermüller et al, 2001; Stahl et al, 2018; Stahl et al, 2016; Szaflarski et al, 2015)
Whole-brain analysis of the regressor effect of the Aphasia Test (AAT) T-score T2–T1 change on the T2–T1 signal difference for the contrast of words versus visual baseline revealed a significant cluster in the left precuneus (MNI xyz = −10, −48, 40), thresholded at p < .005 and a minimum cluster size of k > 100
This study investigated the relationship between changes in neurometabolic activity and clinical language performance over a short interval of intensive speech-language therapy with ILAT in a cohort of 16 people with chronic poststroke aphasia

Summary

Introduction

Intensive language-action therapy (ILAT), a type of therapy known as “constraint-induced aphasia therapy” or “constraint-induced language therapy,” has been shown clinically to be an effective method for aphasia therapy at the chronic stage in a number of randomized controlled trials (RCTs; Berthier et al, 2009; Heikkinen et al, 2019; Kurland et al, 2016; Pulvermüller et al, 2001; Stahl et al, 2018; Stahl et al, 2016; Szaflarski et al, 2015). Recent evidence suggests that a moderately intensive delivery of at least 6 hr/week is important for its success, whereas further

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