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

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.

Motor Imagery Training With Neurofeedback From the Frontal Pole Facilitated Sensorimotor Cortical Activity and Improved Hand Dexterity

“…These findings suggest that the activation of the aPFC is associated with improvement in hand motor functions. Consistent with this idea, our previous studies reported that Oxy-Hb gain in the aPFC positively correlated with performance gain during repeated training in a task similar to the Purdue Pegboard test, and that anodal stimulation of the aPFC by transcranial direct current stimulation (tDCS) increased performance in a motor rehabilitation task similar to the Purdue Pegboard test in healthy adults as well as in patients with Parkinson's disease (Ishikuro et al, 2014(Ishikuro et al, , 2018. Furthermore, activity in the aPFC was reported to correlate with shoulder function after surgery due to shoulder dislocation (Zanchi et al, 2017).…”

“…However, patients with stroke as well as chronic neurological disorders such as Parkinson's disease and Alzheimer's disease are expected to undergo the neurofeedback training, and would be older than the present subjects. A previous study reported that aPFC stimulation by tDCS ameliorated hand dexterity in elder patients with Parkinson's disease (Ishikuro et al, 2018), suggesting that the neurofeedback training to increase aPFC activity might be effective in elder patients. Third, we analyzed relationships between dexterity and hemodynamic activity in the left somatosensory motor-related area, since only this area was activated during the Purdue Pegboard test in the post-assessment session.…”

“…We previously reported that hemodynamic activity in the anterior part of the prefrontal cortex (aPFC), which corresponds to the frontal pole (Brodmann area 10), was increased during motor learning in a motor rehabilitation task of hand dexterity, and correlated with the performance improvement rate in healthy subjects (Ishikuro et al, 2014). Furthermore, anodal stimulation of the aPFC improved hand dexterity in the same motor rehabilitation task in both healthy adults and patients with Parkinson's disease (Ishikuro et al, 2014(Ishikuro et al, , 2018. These previous results suggest that the aPFC facilitates motor skill learning, and further suggest that training with neurofeedback from the aPFC might be useful for motor rehabilitation of the hand.…”

Non-invasive Transcranial Electrical Stimulation in Movement Disorders

“…Broeder et al (2019) noted an increase in writing amplitude with anodal tDCS to M1 (1 mA, 20 min). Fregni et al (2006) also noted some benefit in Purdue pegboard task with anodal tDCS to M1 (1 mA, 20 min), but other studies found no significant benefit in dexterity tasks with single-or multi-session tDCS to the fronto-polar area (five sessions, 1 mA, 15 min) (Ishikuro et al, 2018) or DLPFC (10 sessions, 2 mA, 20 min) (Doruk et al, 2014).…”

“…• Gait and balance (Benninger et al, 2010;Verheyden et al, 2013;Capecci et al, 2014;Kaski et al, 2014a;Mak and Yu, 2014;Manenti et al, 2014;Valentino et al, 2014;Costa-Ribeiro et al, 2016Schabrun et al, 2016;Swank et al, 2016;Fernandez-Lago et al, 2017;Lattari et al, 2017;Criminger et al, 2018;da Silva et al, 2018;Dagan et al, 2018;Harris et al, 2018;Yotnuengnit et al, 2018;Alizad et al, 2019;Putzolu et al, 2019) • Upper limb function (Fregni et al, 2006;Benninger et al, 2010;Doruk et al, 2014;Salimpour et al, 2015;Costa-Ribeiro et al, 2016;Ferrucci et al, 2016;Schabrun et al, 2016;Cosentino et al, 2017;Ishikuro et al, 2018;Broeder et al, 2019) • Cognition (Nitsche et al, 2005;Boggio et al, 2006;Biundo et al, 2015;Manenti et al, 2016;Elder et al, 2017;Lawrence et al, 2018;Adenzato et al, 2019) • Impulsive pathological gambling behavior (Benussi et al, 2017a) • Speech (Pereira et al, 2013) • Sleep (Hadoush et al, 2018) • Fatigue …”