Brain Reorganization in the Recovery of Aphasic Word Production Academic research paper on "Clinical medicine"

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Procedia - Social and Behavioral Sciences 61 (2012) 125 - 126

Academy of Aphasia 2012

Brain Reorganization in the Recovery of Aphasie Word Production

Abel S.a>*, Weiller C.b, Huber W.a, Specht K.c

a Department of Neurology, JARA Brain, RWTH Aachen University b Neurocenter, Freiburg University c Department of Biological and Medical Psychology, University of Bergen

Introduction

Both hemispheres appear to be engaged in word production of healthy participants (Abel et al., 2011) and recovery of word production deficits (Crosson et al., 2007). However, the interplay of factors influencing aphasia recovery and associated patterns of brain reorganization still remains unresolved (Crinion & Leff, 2007).

We applied intensive lexical training, which was evaluated with functional magnetic resonance imaging (fMRI), to 15 patients with aphasie word retrieval deficits. We aimed to illuminate brain reorganization of (i) recovered word production before training, (ii) recovery due to training, and (iii) activations in comparison to healthy controls.

Methods

Patients were recruited from the Aachen aphasia ward (EK 124/05). Inclusion criteria contained naming disorders in the chronic phase (>4 months) after stroke. Exclusion criteria were the presence of severe motor speech disorders or contraindications for fMRI-examinations.

Selected patients suffered infarctions of left middle (N=12) and additionally left anterior (N=2) cerebral arteries {Figure), or right ACM (N= 1). The experiment included testing of confrontation naming on a laptop (Tl) and on a 3T Philips MRI-scanner before (T2) and after (T3) the four-week therapy. Since overt responses were registered and classified according to a 4-scale naming score, 60 items with low performance were individually chosen for therapy, leaving 30 matched control and 42 untrained items. 15 matched healthy participants performed the fMRI-experiment twice in a similar time interval.

Results

Regarding performance in the fMRI scanner, 13/15 patients showed significant improvements for trained items, 6 with generalization to control items (/?<.05, Wilcoxon, T2-T3). Grouping patients with left-hemisphere lesions (N= 14; all 132 items; ¿-tests, uncorrected/K.001, >5 voxels) we found:

• (i) Highest activation peaks in the left hemisphere widely extending to the right for recovered word production before training (Figure).

• (ii) Activation decrease due to training (T3-T2) involving right anterior cerebellum (42 vox.).

• (iii) More activation at T2 for controls in the left-hemisphere naming network impaired in patients (peak: left superior temporal gyrus: 371 vox.). Due to training, there was stronger decrease for patients in left

* Corresponding author. Tel.: 0049-(0)241-80 88968 . E-mail address: steffie.abel@gmx.de .

© 2012 Published by Elsevier Ltd. Selection and/or peer-review under responsibility ofThe mcademy of Aphasia

1877-0428 © 2012 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of The Academy of Aphasia doi:10.1016/j.sbspro.2012.10.110

Abel S. et al. / Procedia - Social and Behavioral Sciences 61 (2012) 125 - 126

anterior cingulate gyrus (21 vox.)

Conclusions

Despite improvements in the majority of patients, effects of training on brain organization patterns were surprisingly low and quite similar to healthy controls. Amongst others, we attribute this finding to a high variance in our patient group - illustrating the need for in-depth patient analyses (see also Crinion et al., 2007). Thus, we will further present the data as case series and analyse the entire dataset with independent component analyses.

References

Abel, S., Hubeç W., Weiller, C., et al. (2011). The influence ofhandedness on hemispheric interaction during word production. Brain Connectivity, 1, 219-231.

Crinion, J., & Leff, A. (2007). Recovery and treatment of aphasia after stroke. Current Opinion in Neurobiology, 20, 667-673.

Crosson, B., McGregor K., Gopinath, K. S., et al. (2007). Functional MRI of language in aphasia. Psychological Review, 17,157-1.

Patient lesion map and naming network

+ -item Left side: Lesion overlay for all

^ 14 patients with left-

hemisphere stroke

Beiow: Compensatory activation for recovered word production before training in the same 14 chronic patients