Overt naming fMRI pre- and post-TMS: Two nonfluent aphasia patients, with and without improved naming post-TMS

Abstract

Two chronic, nonfluent aphasia patients participated in overt naming fMRI scans, pre-and post-a series of repetitive transcranial magnetic stimulation (rTMS) treatments as part of a TMS study to improve naming. Each patient received ten, 1-Hz rTMS treatments to suppress a part of R pars triangularis. P1 was a 'good responder' with improved naming and phrase length; P2 was a 'poor responder' without improved naming.Pre-TMS (10 yr. poststroke), P1 had significant activation in R and L sensorimotor cortex, R IFG, and in both L and R SMA during overt naming fMRI (28% pictures named. At 3 mo. post-TMS (42% named), P1 showed continued activation in R and L sensorimotor cortex, R IFG, and in R and L SMA. At 16 mo. post-TMS (58% named), he also showed significant activation in R and L sensorimotor cortex mouth and R IFG. He now showed a significant increase in activation in the L SMA compared to pre-TMS and at 3 mo. post-TMS (p<.02; p<.05, respectively). At 16 mo. there was also greater activation in L than R SMA (p<.08). At 46 mo. post-TMS (42% named), this new LH pattern of activation continued. He improved on the Boston Naming Test from 11 pictures named pre-TMS, to scores ranging from 14-18 pictures, post-TMS (2 mo. to 43 mo. post-TMS). His longest phrase length (Cookie Theft picture) improved from 3 words pre-TMS, to 5-6 words post-TMS.Pre-TMS (1.5 yr. poststroke), P2 had significant activation in R IFG (3% pictures named). At 3 and 6 mo. post-TMS, there was no longer significant activation in R IFG, but significant activation was present in R sensorimotor cortex. On all three fMRI scans, P2 had significant activation in both the L and R SMA. There was no new, lasting perilesional LH activation across sessions for this patient. Over time, there was little or no change in his activation. His naming remained only at 1-2 pictures during all three fMRI scans. His BNT score and longest phrase length remained at 1 word, post-TMS.Lesion site may play a role in each patient's fMRI activation pattern and response to TMS treatment. P2, the poor responder, had an atypical frontal lesion in the L motor and premotor cortex that extended Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. The fMRI data of our patient who had good response following TMS support the notion that restoration of the LH language network is linked in part, to better recovery of naming and phrase length in nonfluent aphasia. NIH Public Access

Functional Reorganization of Right Prefrontal Cortex Underlies Sustained Naming Improvements in Chronic Aphasia via Repetitive Transcranial Magnetic Stimulation

“…Finally, it is important to note that our patients differed in their response to rTMS therapy, which may reflect differences in neuroplastic mechanisms of language recovery (Hamilton et al, 2011; Heiss and Thiel, 2006; Martin et al, 2009a; Shah-Basak et al, 2015; Torres et al, 2013). For instance, time since stroke and lesion distribution have been shown to affect neuroplastic changes in the cortical network underpinning language recovery (eg, Saur et al, 2006).…”

“…In the experimental condition, patients were presented with a black and white line drawing (taken from Snodgrass and Vanderwart, 1980) and instructed to name the picture aloud. In the control condition, patients were instructed to passively view one of six different black and white checkerboard patterns shown in random order (for details, see Martin et al, 2005, 2009a). Each trial lasted 6 seconds: 1 second for fixation (with a 120-msec audible beep) followed by 5 seconds of picture naming or pattern viewing.…”

“…There were two regressors of interest (timing parameters for picture naming and pattern viewing) and seven nuisance covariates (six head motion parameters and the intercept) for each run. Images were corrected for motion using a rigid-body six-parameter realignment algorithm, which included correction for jaw motion during speech, enabling the inclusion of fMRI volumes acquired during naming trials in statistical analyses (differing from Martin et al, 2005, 2009a; and Turkeltaub et al, 2012; but similar to Lee et al, 2017). The individual motion-corrected functional images were coregistered to the T1 structural images.…”

“…Few previous studies have followed up behavioral changes, and even fewer have followed up behavior-related neural changes for as long a time (6 months) as we report here. As an example, see Martin et al (2009a) for behavioral and accompanying neural changes pre- versus post-TMS in an individual who improved following therapy and one who did not.…”

Noninvasive Brain Stimulation for Treatment of Right- and Left-Handed Poststroke Aphasics

“…The effect of NIBS on the functional activation pattern was assessed by various studies applying functional imaging. With fMRI, it was possible to detect lasting changes in activation patterns following NIBS [42], whereas PET could be applied during NIBS to demonstrate the immediate modulation of network activity [43] as well as longer-lasting alterations related to recovery [29], thus lending direct support to the hypothesis of the relationship between activation shift and improvement of subacute poststroke aphasia.…”