Abstract Details

Title Neuroplastic Changes in Right Hemisphere Activation after Therapeutic rTMS in Chronic Non-Fluent Aphasia

Topic Behavioral Neurology

Presentation(s) P06 - (-)

Poster/Presentation
Number 058

Objective

Background BACKGROUND: The role of the right hemisphere in aphasia recovery after left hemisphere stroke is controversial. Most therapeutic studies of rTMS in aphasia involve inhibition of right hemisphere targets, guided by a model of interhemispheric inhibition that asserts that excessive right hemisphere activity interferes with the recovery of left perilesional language networks. By this account, recovery can be enhanced by inhibiting the right hemisphere with rTMS. However, this model does not accord with lesion studies and imaging evidence that suggest a beneficial role of the right hemisphere.

Design/Methods DESIGN/METHODS: Six patients with chronic non-fluent aphasia performed a picture naming task during 3T fMRI imaging. Scans consisted of 4 blocked runs (pictures vs. patterns), performed as part of a therapeutic rTMS treatment study. Subjects received inhibitory 1 Hz rTMS to individually-selected targets in the right inferior frontal gyrus (IFG) that had previously been shown to improve naming. Stimulation was administered for 20 minutes daily in 10 sessions over two weeks . Patients were scanned at study enrollment (baseline), twice on Day-1 of rTMS treatment (immediately before and after rTMS treatment), and 6 months after rTMS treatment.

Results RESULTS: 1) Group analysis revealed bilaterally reduced IFG activity immediately following rTMS. 2) Six months after stimulation, there were regions of increased activation in the left IFG and bilateral superior temporal gyri. 3) Individual analyses revealed increased right inferior frontal gyrus activity in 5 out of 6 subjects.

Conclusions CONCLUSIONS: The enduring benefits of therapeutic rTMS in chronic non-fluent aphasics are not likely due to persistent right hemisphere inhibition. They appear to be mediated by left perilesional activation, and in some patients, additional activation of homotopic right hemisphere areas.

Authors/Disclosures
PRESENTER	No disclosure on file
Peter Turkeltaub, MD, PhD (Georgetown University)	Dr. Turkeltaub has nothing to disclose.
Harry B. Coslett, MD, FAAN (Univ of Pennsylvania)	The institution of Dr. Coslett has received research support from NIDCD, NINDS, NIA. Dr. Coslett has received publishing royalties from a publication relating to health care.
	No disclosure on file
Roy H. Hamilton, MD, MS, FANA, FAAN	Dr. Hamilton has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Highland Instruments. Dr. Hamilton has received personal compensation in the range of $0-$499 for serving on a Scientific Advisory or Data Safety Monitoring board for Cognito Therapeutics. Dr. Hamilton has received personal compensation in the range of $10,000-$49,999 for serving as an officer or member of the Board of Directors for McKnight Brain Research Foundation. The institution of Dr. Hamilton has received research support from NIH. The institution of Dr. Hamilton has received research support from Department of Defense. The institution of Dr. Hamilton has received research support from Chan Zuckerberg Initiative.
	No disclosure on file

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