Cerebellar tDCS: A Novel Approach to Augment Language Treatment Post-stroke

Abstract

People with post-stroke aphasia may have some degree of chronic deficit for which current rehabilitative treatments are variably effective. Accumulating evidence suggests that transcranial direct current stimulation (tDCS) may be useful for enhancing the effects of behavioral aphasia treatment. However, it remains unclear which brain regions should be stimulated to optimize effects on language recovery. Here, we report on the therapeutic potential of right cerebellar tDCS in augmenting language recovery in SMY, who sustained bilateral MCA infarct resulting in aphasia and anarthria. We investigated the effects of 15 sessions of anodal cerebellar tDCS coupled with spelling therapy using a randomized, double-blind, sham controlled within-subject crossover trial. We also investigated changes in functional connectivity using resting state functional magnetic resonance imaging before and 2 months post-treatment. Both anodal and sham treatments resulted in improved spelling to dictation for trained and untrained words immediately after and 2 months post-treatment. However, there was greater improvement with tDCS than with sham, especially for untrained words. Further, generalization to written picture naming was only noted during tDCS but not with sham. The resting state functional connectivity data indicate that improvement in spelling was accompanied by an increase in cerebro-cerebellar network connectivity. These results highlight the therapeutic potential of right cerebellar tDCS to augment spelling therapy in an individual with large bilateral chronic strokes.

Impact of Combined Transcranial Direct Current Stimulation and Speech-language Therapy on Spontaneous Speech in Aphasia: A Randomized Controlled Double-blind Study

“…A recent systematic literature review including five meta-analyses and 48 studies found some evidence in the literature that tDCS could be effective for poststroke aphasia rehabilitation at the chronic stages, but there is still a lot of variability between studies (Biou et al, 2019). The nature of the task, the stimulation site, the intensity and duration of the stimulation greatly differed from one study to the other (Baker et al, 2010;Branscheidt et al, 2018;Cherney et al, 2013;Ewa et al, 2013;Jung et al, 2011;Lee et al, 2013;Manenti et al, 2015;Marangolo et al, 2014Marangolo et al, , 2017Sebastian et al, 2016;Vestito et al, 2014;Vines et al, 2011;Wu et al, 2015;You et al, 2011). Nevertheless, there is a consensus in the existing literature on the need of combining stimulation with speech-language therapy.…”

“…Indeed, 19 studies described the use of a stimulation at 1 mA and 22 at 2 mA. A stimulation intensity of 2 mA during 20 min repeated for 10 to 30 sessions has been a frequently used stimulation paradigm (Branscheidt et al, 2018;Marangolo et al, 2013b;Meinzer et al, 2016;Sebastian et al, 2016;Volpato et al, 2013;Wu et al, 2015). The electrode's placement differs from one study to another.…”

“…The share is larger for nouns naming because of its use when authors use standardized language evaluation batteries (Baker et al, 2010;Branscheidt et al, 2018;Campana et al, 2015;Cherney et al, 2013;Fiori et al, 2011;Flöel et al, 2011;Fridriksson et al, 2018;Galletta et al, 2015;Kang et al, 2011;Lee et al, 2011;Marangolo et al, 2013aMarangolo et al, , 2013bMarangolo et al, , 2014Marangolo et al, , 2016Marangolo et al, , 2017Marangolo et al, , 2018Meinzer et al, 2016;Monti et al, 2008;Pestalozzi et al, 2018;Polanowska et al, 2013;Sandars et al, 2017;Santos et al, 2013Santos et al, , 2017Shah-Basak et al, 2015;Spielmann et al, 2018;Vestito et al, 2014;Vines et al, 2011;Volpato et al, 2013;You et al, 2011). Furthermore, generalization has been measured in several studies: some of them assessed the transfer of competence on an untrained task (Lee et al, 2011;Marangolo et al, 2011Marangolo et al, , 2013aMarangolo et al, , 2013bMarangolo et al, , 2014Marangolo et al, , 2016Marangolo et al, , 2017Manenti et al, 2015;Sebastian et al, 2016;…”

Consensus Paper: Cerebellum and Emotion

“…By targeting the cerebellum, the same protocol can be used in different patient populations, leading to a better patient stratification. A recent study by Sebastian et al [38] showed that cerebellar stimulation indeed improves cognitive functions after stroke. The authors applied tDCS over the right cerebellar hemisphere in order to enhance the effects of behavioral aphasia therapy (spelling to dictation) in a patient who suffered anarthria and aphasia after a large bilateral stroke.…”

Non-invasive Stimulation of the Cerebellum in Health and Disease

“…As detailed above, cerebellar stimulation can modulate a wide range of behaviours in healthy subjects, and so has the potential to influence symptoms suffered by stroke patients. Certainly, a few small scale studies have shown success in improving post-stroke symptoms, such as greater recovery of language and spelling abilities with multiple sessions of cerebellar tDCS combined with spelling therapy compared to therapy alone [77].…”