Effects of Transcranial Direct Current Stimulation (tDCS) Over the Frontal Polar Area on Motor and Executive Functions in Parkinson's Disease; A Pilot Study.

Koji Ishikuro,Nobuhiro Dougu,Yuji Nakatsuji,Isao Matsushita,Satoshi Kuroda,Mamoru Yamamoto,Hiroshi Nishimaru,Takamasa Nukui,Hisao Nishijo,Mariana F P Araujo

doi:10.3389/fnagi.2018.00231

Koji Ishikuro, Nobuhiro Dougu + Show 8 more

Open Access

https://doi.org/10.3389/fnagi.2018.00231

Copy DOI

Abstract

Parkinson’s disease (PD) is a neurodegenerative disorder with motor and non-motor symptoms due to degeneration of dopaminergic neurons. The current pharmacological treatments induce complications associated with long-term use. However, current stimulation techniques for PD treatment, such as deep brain stimulation (DBS), are too invasive. In this context, non-invasive brain stimulation including transcranial direct current stimulation (tDCS) may be a safe and effective alternative treatment for PD. We previously reported that anodal tDCS over the frontal polar area (FPA) improved motor functions in heathy subjects. Therefore, in the present study, effects of tDCS over the FPA on motor and cognitive functions of PD patients were analyzed. Nine PD patients (3 men and 6 women) participated in this cross over study with three tDCS protocols; anodal, cathodal or sham tDCS over the FPA. Each tDCS protocol was applied for 1 week (5 times/week). Before and after each protocol, motor and cognitive functions of the patients were assessed using Unified PD Rating Scale [UPDRS (part III: motor examination)], Fugl Meyer Assessment set (FMA), Simple Test for Evaluating hand Function (STEF) and Trail Making Test A (TMT-A). The results indicated that anodal stimulation significantly decreased scores of motor disability in UPDRS-III compared with sham and cathodal stimulation, and significantly increased scores of motor functions in FMA compared with sham stimulation. Furthermore, anodal stimulation significantly decreased time to complete a motor task requiring high dexterity in STEF compared with those requiring low and medium levels of dexterity. In addition, anodal stimulation significantly decreased time to complete the TMT-A task, which requires executive functions, compared with sham stimulation. To the best of our knowledge, this is the first clinical research reporting that tDCS over the FPA successfully improved the motor and non-motor functions in PD patients. These findings suggest that tDCS over the FPA might be a useful alternative for the treatment of PD patients.

Highlights

Parkinson’s disease (PD) is characterized by a progressive loss of dopaminergic neurons in the substantia nigra pars compacta (SNc) and/or ventral tegmental area (VTA; Alberico et al, 2015) with an increased risk of PD in the aging population (Abdullah et al, 2015)
We previously reported that in heathy subjects, hemodynamic activity of the anterior dorsomedial prefrontal cortex, which corresponds to the frontal polar area (FPA), is correlated to the performance improvement rate in a motor task requiring high hand dexterity, and that anodal transcranial direct current stimulation (tDCS) of the FPA improves the performance in this task (Ishikuro et al, 2014)
We investigated whether tDCS over the FPA improved motor (UPDRS-III, Fugl Meyer Assessment set (FMA) and Simple Test for Evaluating hand Function (STEF)) and non-motor (TMT-A) functions in PD patients

Summary

Introduction

Parkinson’s disease (PD) is characterized by a progressive loss of dopaminergic neurons in the substantia nigra pars compacta (SNc) and/or ventral tegmental area (VTA; Alberico et al, 2015) with an increased risk of PD in the aging population (Abdullah et al, 2015). Basic medical treatment of PD is pharmacotherapy (especially levodopa), with long term treatment most patients gradually develop motor fluctuation and dyskinesia that may be more debilitating than the PD symptoms (Hauser, 2009). In this context, deep brain stimulation (DBS) techniques have been established as an alternative to treat PD and are reported to be effective to ameliorate motor and non-motor dysfunctions (Wichmann and DeLong, 2006). The high risk and cost associated with invasive neurosurgical procedures remains a major problem to be solved (Benabid et al, 2009)

Methods

Results

Conclusion