Specificity in Generalization Effects of Transcranial Direct Current Stimulation Over the Left Inferior Frontal Gyrus in Primary Progressive Aphasia

Wang, Zeyi; Ficek, Bronte; Webster, Kimberly; Herrmann, Olivia; Frangakis, Constantine; Desmond, John E.; Onyike, Chiadi U.; Caffo, Brian; Hillis, Argye E.; Tsapkini, Kyrana

doi:10.1016/j.neurom.2022.09.004

Cited by 7 publications

(7 citation statements)

References 102 publications

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“…It follows that active tDCS over hyperconnected areas may be beneficial. Unsurprisingly, in our previous clinical trial, patients with nfvPPA with the largest amount of atrophy in left IFG showed the largest benefits from IFG stimulation [32]. Therefore, active tDCS may be beneficial on compromised tissue (atrophied but still viable) when other network or compensatory brain areas remain intact.…”

Section: Discussionmentioning

confidence: 99%

“…In the present study we based our prediction methodology on generalization effects we previously found in semantic fluency [32] and not on the trained task, since trained tasks are always expected to show benefits and generalization of treatment to other tasks is the most desirable outcome in neurodegenerative disorders. Also, we have extensively reported on the results for the trained task, oral and written naming [4].…”

Section: Methodsmentioning

confidence: 99%

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Baseline functional connectivity predicts who will benefit from neuromodulation: evidence from primary progressive aphasia

Wang,

Gallegos,

Tippett

et al. 2024

Preprint

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Background: Identifying the characteristics of individuals who demonstrate response to an intervention allows us to predict who is most likely to benefit from certain interventions. Prediction is challenging in rare and heterogeneous diseases, such as primary progressive aphasia (PPA), that have varying clinical manifestations. We aimed to determine the characteristics of those who will benefit most from transcranial direct current stimulation (tDCS) of the left inferior frontal gyrus (IFG) using a novel heterogeneity and group identification analysis. Methods: We compared the predictive ability of demographic and clinical patient characteristics (e.g., PPA variant and disease progression, baseline language performance) vs. functional connectivity alone (from resting-state fMRI) in the same cohort. Results: Functional connectivity alone had the highest predictive value for outcomes, explaining 62% and 75% of tDCS effect of variance in generalization (semantic fluency) and in the trained outcome of the clinical trial (written naming), contrasted with <15% predicted by clinical characteristics, including baseline language performance. Patients with higher baseline functional connectivity between the left IFG (opercularis and triangularis), and between the middle temporal pole and posterior superior temporal gyrus, were most likely to benefit from tDCS. Conclusions: We show the importance of a baseline 7-minute functional connectivity scan in predicting tDCS outcomes, and point towards a precision medicine approach in neuromodulation studies. The study has important implications for clinical trials and practice, providing a statistical method that addresses heterogeneity in patient populations and allowing accurate prediction and enrollment of those who will most likely benefit from specific interventions.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Baseline functional connectivity predicts who will benefit from neuromodulation: evidence from primary progressive aphasia

Wang,

Gallegos,

Tippett

et al. 2024

Preprint

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“…Promising findings regarding anodal tDCS stimulating the left IFG with written word naming/spelling treatment versus sham have been demonstrated as well [17,[25][26][27][28][29][30]. More recently, Wang et al showed generalization effects of tDCS to the left IFG paired with lexical/semantic retrieval intervention for oral and written naming and semantic fluency [31].…”

Section: Introductionmentioning

confidence: 99%

Home-Based Transcranial Direct Current Stimulation in Primary Progressive Aphasia: A Pilot Study

Neophytou,

Williamson,

Herrmann

et al. 2024

Brain Sciences

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Background: This study aims to determine (a) if home-based anodal transcranial direct current stimulation (a-tDCS) delivered to the left supramarginal gyrus (SMG) coupled with verbal short-term memory/working memory (vSTM/WM) treatment (“RAM”, short for “Repeat After Me”) is more effective than sham-tDCS in improving vSTM/WM in patients with primary progressive aphasia (PPA), and (b) whether tDCS effects generalize to other language and cognitive abilities. Methods: Seven PPA participants received home-based a-tDCS and sham-tDCS coupled with RAM treatment in separate conditions in a double-blind design. The treatment task required participants to repeat word spans comprising semantically and phonologically unrelated words in the same and reverse order. The evaluation of treatment effects was carried out using the same tasks as in the treatment but with different items (near-transfer effects) and tasks that were not directly related to the treatment (far-transfer effects). Results: A-tDCS showed (a) a significant effect in improving vSTM abilities, measured by word span backward, and (b) a generalization of this effect to other language abilities, namely, spelling (both real words and pseudowords) and learning (retention and delayed recall). Conclusions: These preliminary results indicate that vSTM/WM intervention can improve performance in trained vSTM/WM tasks in patients with PPA, especially when augmented with home-based tDCS over the left SMG.

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“…Studies of tDCS in PPA by different groups have focused on the treatment of language deficits in this clinical syndrome and have shown significant augmentative tDCS effects in several language functions by stimulating left hemisphere language regions. 19 - 28 …”

Section: Introductionmentioning

confidence: 99%

Long-term, home-based transcranial direct current stimulation coupled with computerized cognitive training in frontotemporal dementia: A case report

Tippett,

Neophytou,

Tao

et al. 2024

J Cent Nerv Syst Dis

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We present the case of a 62-year-old woman with probable behavioral variant of frontotemporal dementia (bvFTD) with cognitive/language deficits who demonstrated improved performance on cognitive/language testing and in functional tasks following long-term, home-based transcranial direct current stimulation (tDCS) coupled with computerized cognitive training (CCT). The patient underwent home-based tDCS (anode on the left prefrontal cortex and cathode on the right homologue) for 46 sessions over 10 weeks along with CCT. On post-treatment testing, the patient improved by 3 points on the Mini-Mental State Exam (MMSE) (23 to 26). She also showed improvement on several cognitive/language tasks, such as immediate recall of single words and word pairs, total accurate words in sentence repetition, delayed recall, semantic processing, and sentence level comprehension. There was no decline in several other cognitive and language tasks. Family members reported subjective improvements in expressiveness, communication, and interaction with others as well as increased attention to grooming and style which contrasted with her pre-treatment condition. This report suggests that home-based tDCS combined with CCT for an extended period may slow decline, and improve cognitive/language performance and everyday function in FTD.

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Specificity in Generalization Effects of Transcranial Direct Current Stimulation Over the Left Inferior Frontal Gyrus in Primary Progressive Aphasia

Cited by 7 publications

References 102 publications

Baseline functional connectivity predicts who will benefit from neuromodulation: evidence from primary progressive aphasia

Baseline functional connectivity predicts who will benefit from neuromodulation: evidence from primary progressive aphasia

Home-Based Transcranial Direct Current Stimulation in Primary Progressive Aphasia: A Pilot Study

Long-term, home-based transcranial direct current stimulation coupled with computerized cognitive training in frontotemporal dementia: A case report

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