Andreu Barrachina, L. . , Muñoz Marrón, E. . & Redolar Ripoll, D. .
Universitat Oberta de Catalunya
Electrical Stimulation techniques, including Transcranial Magnetic Stimulation (TMS), can be used to temporally facilitate or inhibit neural activity to examine intact systems, examine the presence of residual capacity in an injured system, or to accelerate natural recovery mechanisms. Several studies have showed that low frequency repetitive Transcranial Magnetic Stimulation (rTMS) can be used to produce changes in cortical excitability. When delivered to the same cortical region, slow (≤1Hz) rTMS appears to decrease excitability in the targeted cortical region of interest (ROI) that lasts beyond the duration of the train itself, leading to measurable behavioral effects. Coversely, rapid rTMS (>1Hz) increases cortical excitability. rTMS has been observed to affect language ranging from facilitation of naming to speech arrest depending on rTMS parameters and location of the coil.
In this work we present the application of TMS to improve language behavior in stroke patients. These patients have very often speech and language problems, which include hesitant, poorly articulated agrammatic speech with word-findings problems (non-fluent aphasia). Low frequency rTMS has been applied to improve picture naming in aphasia. The application of low frequency rTMS to a specific cortical ROI in the undamaged hemisphere suppress the inhibitory process of that ROI, permitting reactivation of some areas within the damaged hemisphere, promoting some functional recovery. This treatment has been applied either only a single session or several sessions over longer periods of time.
Results showed a site-specific effect of TMS for number of pictures named correctly, including a double dissociation within Broca’s area. Moreover, more treatment sessions produce better language recovery. This shows the capacity of TMS to modulate neural language networks and lexical-semantic function in patients with non-fluent aphasia.