Testing the therapeutic effects of transcranial direct current stimulation (tDCS) in semantic dementia: a double blind, sham controlled, randomized clinical trial

• Published in: Current controlled trials in cardiovascular medicine Vol. 20; no. 1; p. 632
• Main Authors: Sanches, Clara, Levy, Richard, Benisty, Sarah, Volpe-Gillot, Lisette, Habert, Marie-Odile, Kas, Aurelie, Ströer, Sébastian, Pyatigorskaya, Nadya, Kaglik, Anna, Bourbon, Angelina, Dubois, Bruno, Migliaccio, Raffaella, Valero-Cabré, Antoni, Teichmann, Marc
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 20.11.2019; BioMed Central; BMC
• Subjects: Alzheimer's disease; Aphasia; Bioengineering; Biological markers; Brain; Brain research; Clinical trials; Dementia; Diagnostic imaging; Disabilities; Double-Blind Method; Double-blind studies; Education; Electric currents; Electrodes; Electroencephalography; Executive Function; Frontotemporal Dementia - diagnostic imaging; Frontotemporal Dementia - physiopathology; Frontotemporal Dementia - psychology; Frontotemporal Dementia - therapy; Health aspects; Human health and pathology; Humans; Knowledge; Language; Language impairments; Life Sciences; Magnetic Resonance Imaging; Medical imaging; Medical research; Nervous system diseases; Neurodegenerative diseases; Neuroimaging; Neurons and Cognition; Non-invasive brain stimulation; Patients; Physiology; Positron emission tomography; Primary progressive aphasia; Research Design; Semantic dementia; Semantics; Study Protocol; Tomography; Transcranial direct current stimulation; Transcranial Direct Current Stimulation - methods; Transcranial magnetic stimulation; France; Non-invasive brain stimulation; Neurology; Semantic dementia; Language impairments; Neurodegenerative diseases; Primary progressive aphasia; Transcranial direct current stimulation
• ISSN: 1745-6215; 1745-6215
• DOI: 10.1186/s13063-019-3613-z

Semantic dementia is a neurodegenerative disease that primarily affects the left anterior temporal lobe, resulting in a gradual loss of conceptual knowledge. There is currently no validated treatment. Transcranial stimulation has provided evidence for long-lasting language effects presumably linked to stimulation-induced neuroplasticity in post-stroke aphasia. However, studies evaluating its effects in neurodegenerative diseases such as semantic dementia are still rare and evidence from double-blind, prospective, therapeutic trials is required. The primary objective of the present clinical trial (STIM-SD) is to evaluate the therapeutic efficacy of a multiday transcranial direct current stimulation (tDCS) regime on language impairment in patients with semantic dementia. The study also explores the time course of potential tDCS-driven improvements and uses imaging biomarkers that could reflect stimulation-induced neuroplasticity. This is a double-blind, sham-controlled, randomized study using transcranial Direct Current Stimulation (tDCS) applied daily for 10 days, and language/semantic and imaging assessments at four time points: baseline, 3 days, 2 weeks and 4 months after 10 stimulation sessions. Language/semantic assessments will be carried out at these same 4 time points. Fluorodeoxyglucose positron emission tomography (FDG-PET), resting-state functional magnetic resonance imaging (rs-fMRI), T1-weighted images and white matter diffusion tensor imaging (DTI) will be applied at baseline and at the 2-week time point. According to the principle of inter-hemispheric inhibition between left (language-related) and right homotopic regions we will use two stimulation modalities - left-anodal and right-cathodal tDCS over the anterior temporal lobes. Accordingly, the patient population (n = 60) will be subdivided into three subgroups: left-anodal tDCS (n = 20), right-cathodal tDCS (n = 20) and sham tDCS (n = 20). The stimulation will be sustained for 20 min at an intensity of 1.59 mA. It will be delivered through 25cm -round stimulation electrodes (current density of 0.06 mA/cm ) placed over the left and right anterior temporal lobes for anodal and cathodal stimulation, respectively. A group of healthy participants (n = 20) matched by age, gender and education will also be recruited and tested to provide normative values for the language/semantic tasks and imaging measures. The aim of this study is to assess the efficacy of tDCS for language/semantic disorders in semantic dementia. A potential treatment would be easily applicable, inexpensive, and renewable when therapeutic effects disappear due to disease progression. ClinicalTrials.gov NCT03481933. Registered on March 2018.