Neural changes after phonological treatment for anomia: An fMRI study

Abstract

Functional magnetic resonance imaging (fMRI) was used to investigate the neural processing characteristics associated with word retrieval abilities after a phonologically-based treatment for anomia in two stroke patients with aphasia. Neural activity associated with a phonological and a semantic task was compared before and after treatment with fMRI. In addition to the two patients who received treatment, two patients with aphasia who did not receive treatment and 10 healthy controls were also scanned twice. In the two patients who received treatment, both of whose naming improved after treatment, results showed that activation patterns changed after treatment on the semantic task in areas that would have been expected (e.g., left hemisphere frontal and temporal areas). For one control patient, there were no significant changes in brain activation at the second scan; a second control patient showed changes in brain activation at the second scan, on the semantic task, however, these changes were not accompanied with improved performance in naming. In addition, there appeared to be bilateral, or even more right than left hemisphere brain areas activated in this patient than in the treated patients. The healthy control group showed no changes in activation at the second scan. These findings are discussed with reference to the literature on the neural underpinnings of recovery after treatment for anomia in aphasia.

Fig. 1

Study timeline showing sequence of testing. Note. Ax = Second assessment and follow-up period. See p. 14 for explanation of differences in length of treatment for ATr1 and ATr2. ^aScan 2 for AUn2 occured before the end of this second assessment due to scheduled scanner maintenance.

Figure 2

Fig. 2a. Example of an experimental trial for the phonological task. Fig. 2b. Example of an experimental trial for the semantic task.

Figure 2

Fig. 2a. Example of an experimental trial for the phonological task. Fig. 2b. Example of an experimental trial for the semantic task.

Fig. 3

Healthy control subject activation during the phonological and semantic tasks. Activations denoted in yellow/red represent brain regions that positively correlate with the phonological task and negatively with the semantic task. Activations denoted in blue represent brain regions that positively correlate with the semantic task and negatively with the phonological task. The images show the active areas on a standard MRI scan in which the right side of the brain is shown on the right side of the image.

Fig. 4

Results of the analysis comparing activations in the phonological and semantic tasks for scans 1 and 2 for ATr1 with representative areas of activation on the semantic task.

Fig. 5

Results of the analysis comparing activations in the phonological and semantic tasks for scans 1 and 2 for ATr2 with representative areas of activation on the semantic task.

Fig. 6

Results of the analysis comparing activations in the phonological and semantic tasks for scans 1 and 2 for AUn1 with representative areas of activation on the semantic task.

Fig. 7

Results of the analysis comparing activations in the phonological and semantic tasks for scans 1 and 2 for AUn2 with representative areas of activation on the semantic task.