Multifocal Transcranial Direct Current Stimulation in Primary Progressive Aphasia Does Not Provide a Clinical Benefit Over Speech Therapy

Article type: Research Article

Authors: Borrego-Écija, Sergi^{a; 1} | Montagut, Nuria^{a; 1} | Martín-Trias, Pablo^b | Vaqué-Alcázar, Lídia^b | Illán-Gala, Ignacio^c | Balasa, Mircea^a | Lladó, Albert^a | Casanova-Mollà, Jordi^d | Bargalló, Nuria^e | Valls-Solé, Josep^d | Lleó, Alberto^c | Bartrés-Faz, David^b | Sánchez-Valle, Raquel^{a; *}

Affiliations: [a] Alzheimer’s disease and other cognitive disorders Unit. Neurology Service, Hospital Clinic de Barcelona, Institutd’Investigació Biomèdica August Pi i Sunyer, Institute of Neuroscience, University of Barcelona, Barcelona, Spain | [b] Medical Psychology Unit, Department of Medicine, Faculty of Medicine and Health Sciences, Insitute of Neurosciences, University of Barcelona; Institut d’Investigació Biomèdica August Pi i Sunyer, Barcelona, Spain | [c] Memory Unit, Service of Neurology, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain. Centro de Investigación en Red en enfermedadesneurogenerativas (CIBERNED), Madrid, Spain | [d] Clinical Neurophysiology Unit, Institutd’Investigació Biomèdica August Pi i Sunyer, NeurologyService, Hospital Clinic de Barcelona, Barcelona, Spain | [e] Radiology Service, Hospital Clínic de Barcelona, Barcelona, Spain

Correspondence: [*] Correspondence to: Raquel Sanchez-Valle, Alzheimer’s disease and other cognitive disorders unit, Hospital Clinic, Institut d’Investigacions Biomèdiques August Pi I Sunyer (IDIBAPS), University of Barcelona, Villarroel, 170 08036, Barcelona, Spain. Tel.: +34932275785; E-mail: rsanchez@clinic.cat.

Note: [1] These authors contributed equally to this work.

Abstract: Background:Primary progressive aphasia (PPA) is a group of neurodegenerative disorders including Alzheimer’s disease and frontotemporal dementia characterized by language deterioration. Transcranial direct current stimulation (tDCS) is a non-invasive intervention for brain dysfunction. Objective:To evaluate the tolerability and efficacy of tDCS combined with speech therapy in the three variants of PPA. We evaluate changes in fMRI activity in a subset of patients. Methods:Double-blinded, randomized, cross-over, and sham-controlled tDCS study. 15 patients with PPA were included. Each patient underwent two interventions: a) speech therapy + active tDCS and b) speech therapy + sham tDCS stimulation. A multifocal strategy with anodes placed in the left frontal and parietal regions was used to stimulate the entire language network. Efficacy was evaluated by comparing the results of two independent sets of neuropsychological assessments administered at baseline, immediately after the intervention, and at 1 month and 3 months after the intervention. In a subsample, fMRI scanning was performed before and after each intervention. Results:The interventions were well tolerated. Participants in both arms showed clinical improvement, but no differences were found between active and sham tDCS interventions in any of the evaluations. There were trends toward better outcomes in the active tDCS group for semantic association and reading skills. fMRI identified an activity increase in the right frontal medial cortex and the bilateral paracingulate gyrus after the active tDCS intervention. Conclusion:We did not find differences between active and sham tDCS stimulation in clinical scores of language function in PPA patients.

Keywords: Alzheimer’s disease, brain stimulation, frontotemporal dementia, primary progressive aphasia, speech therapy, transcranial direct current stimulation

DOI: 10.3233/JAD-230069

Journal: Journal of Alzheimer's Disease, vol. 93, no. 3, pp. 1169-1180, 2023