The feasibility of improving discourse in people with aphasia through AAC: Clinical and functional MRI correlates

Abstract

Aims: The purpose of this study is twofold: (1) to examine the feasibility of providing high-tech augmentative and alternative communication (AAC) treatment to people with chronic aphasia, with the goal of evoking changes in spoken language; and (2) to identify evidence of AAC-induced changes in brain activation.

Method & procedures: We employed a pre- post-treatment design with a control (usual care) group to observe the impact of an AAC treatment on aphasia severity and spoken discourse. Further, we used functional magnetic resonance imaging (fMRI) to examine associated neural reorganization.

Outcomes & results: Compared to the usual care group, the AAC intervention trended toward larger treatment effects and resulted in a higher number of responders on behavioral outcomes. Both groups demonstrated a trend toward greater leftward lateralization of language functions via fMRI. Secondary analyses of responders to treatment revealed increased activation in visual processing regions, primarily for the AAC group.

Conclusions: This study provides preliminary guidance regarding how to implement AAC treatment in a manner that simultaneously facilitates language recovery across a variety of aphasia types and severity levels while compensating for residual deficits in people with chronic aphasia. Further, this work motivates continued efforts to unveil the role of AAC-based interventions in the aphasia recovery process and provides insight regarding the neurobiological mechanisms supporting AAC-induced language changes.

Keywords: Aphasia; Augmentative and Alternative Communication; Cortical Plasticity; Neuroimaging; fMRI.

Conflict of interest statement

Disclosure The authors have no conflict of interest to disclose.

Figures

Figure 1.

A depiction of the manual lesion delineation for each participant and summary of aphasia type and severity (via the Western Aphasia Battery-Revised Aphasia Quotient (WAB-R AQ) (Kertesz, 2006) at enrollment.

Figure 2.

This figure depicts the interface used during the narrative retell session and during the AAC treatment. Above, all elements of the system are displayed. For the purposes of this study, we removed the episodic navigation ring (which allows the person to talk about different topics). © 2015 DynaVox Mayer-Johnson. All rights reserved.

Figure 3.

Depiction of study tasks and sequence.

Figure 4.

(A) Anatomical regions of interest (ROI) used to calculate change in lateralization index (LI) and activation intensity (mean z-score) for the anterior and posterior language areas: blue = inferior frontal gyrus, middle frontal gyrus, and anterior insula, turquoise = superior temporal gyrus, middle temporal gyrus, supramarginal gyrus, and angular gyrus. (B) The anatomical ROIs used to calculate the change in z-score for three visual areas: turquoise = fusiform gyrus, red = inferior lateral occipital gyrus, blue = occipital pole.

Figure 5.

Pre- to post-treatment change in the anterior and posterior language lateralization indices for the AAC and the usual care groups. LI values 0.1 indicate left-lateralization; whereas values between −0.1

Figure 6.

Mean pre- to post-treatment change in activation intensity (change in mean z-score) on the verb generation task (overt verb generation > overt repetition), for three ROIs (bilateral) as defined by the Harvard-Oxford atlas. Error bars represent standard errors. Cohen’s d reflects the between group effect on change (small effect = 0.2, medium effect = 0.5, large effect = 0.8).