Effects of More-Affected vs. Less-Affected Motor Cortex tDCS in Parkinson’s Disease

Abstract

Objective: To evaluate therapeutic potential of different montages of transcranial direct current stimulation (tDCS) in Parkinson’s Disease (PD) patients with asymmetric motor symptoms.Materials and Methods: Fourteen patients with asymmetric PD underwent, while on treatment, seven separate sessions including electrophysiological and clinical evaluation at baseline and after anodal, cathodal and sham tDCS of the primary motor cortex (M1) of the two hemispheres. Changes in motor cortical excitability were evaluated by transcranial magnetic stimulation (TMS). Effects on motor symptoms were assessed by testing finger tapping (FT) and upper limb bradykinesia, and by using the Italian validated Movement Disorder Society revision of the Unified PD Rating Scale (MDS-UPDRS).Results: Only anodal tDCS of the more-affected M1 (contralateral to the more-affected body side) and cathodal tDCS of the less-affected M1 (contralateral to the less-affected body side) were able to induce significant changes in cortical excitability, i.e., facilitation and inhibition of the motor evoked potentials respectively. The motor performances of both hands significantly improved after anodal tDCS of the more-affected M1, as well as after cathodal tDCS of the less-affected one.Conclusion: Our findings support the potential usefulness of tDCS as add-on treatment for asymmetric PD, also providing interesting clues on the possible pathophysiological role played by an asymmetric activation of homologous motor cortical areas in PD.

Anodal transcranial direct current stimulation prevents methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced neurotoxicity by modulating autophagy in an in vivo mouse model of Parkinson’s disease

“…and Coesntino et al . showed that treatment with tDCS produced significant improvements in UPDRS-III scores in humans 17 , 30 . Furthermore, tDCS also had beneficial effects on cognitive function and freezing of gait 31 .…”

Invasive and Noninvasive Brain Stimulation in Parkinson's Disease: Clinical Effects and Future Perspectives

“…Although the results showed improved finger tapping rates when anodal tDCS was applied to the more affected M1 and when cathodal tDCS was applied to less affected M1, UPDRS part III scores was reduced after anodal tDCS was applied to the more affected M1, but did not change after cathodal tDCS was applied to the less affected M1. 116 Other studies combined tDCS with rehabilitation to treat gait disturbance in PD. One study showed improved gait and motor performance after tDCS to SMA combined with gait training.…”

Does transcranial direct current stimulation during writing alleviate upper limb freezing in people with Parkinson’s disease? A pilot study

“…Cosentino and colleagues pointed to different effects of tDCS when targeting the M1 of the most-or less-affected hemisphere in PD. They found that only anodal tDCS applied to the most-affected hemisphere resulted in increased cortical excitability together with improved motor performance (Cosentino et al, 2017). Moreover, pairing tDCS to training of gait resulted in significantly greater benefit than the effects of tDCS and training as single therapy (Kaski et al, 2014).…”

“…Several studies used tDCS as a single or adjuvant intervention in Parkinson rehabilitation (for reviews see Broeder et al, 2015;Elsner, Kugler, Pohl, & Mehrholz, 2016;Ferrucci, Mameli, Ruggiero, & Priori, 2016;Goodwill et al, 2017;Tahtis & Kaski, 2017). Improvements in upper limb performance of PD patients were found after anodal tDCS compared to sham when stimulation was applied to the primary motor cortex (M1) in rest (Benninger et al, 2010;Cosentino et al, 2017;Fregni et al, 2006) as well as during task performance (Salimpour, Mari, & Shadmehr, 2015). Moreover, changes in M1 excitability after repetitive TMS of the supplementary motor area (SMA) in rest were related to increased writing performance in PD (Randhawa, Farley, & Boyd, 2013).…”