Transcranial Direct Current Stimulation Over Prefrontal Areas Improves Psychomotor Inhibition State in Patients With Traumatic Brain Injury: A Pilot Study.

Nan Li,Dongyu Wu,Jun Hou,Yuanyuan Li,Guoping Duan,Xu Zhang,Baohu Liu

doi:10.3389/fnins.2020.00386

Abstract

ObjectivesMany post-traumatic patients with minimally conscious state are complicated by psychomotor inhibition state (PIS), which impedes further rehabilitation. The treatment of PIS is not satisfactory. This pilot study aimed to investigate effects of anodal transcranial direct current stimulation (A-tDCS) on PIS in post-traumatic patients and examine the altered cortical activation after tDCS using non-linear electroencephalogram (EEG).MethodsThe study included 10 patients with post-traumatic PIS. An A–B design was used. The patients received 4 weeks of sham tDCS during Phase A, and they received A-tDCS over the prefrontal area and left dorsolateral prefrontal cortex (DLPFC) for 4 weeks (40 sessions) during Phase B. Conventional treatments were administered throughout both phases. JFK Coma Recovery Scale-Revised (CRS-R), apathy evaluation scale (AES), and the EEG non-linear indices of approximate entropy (ApEn) and cross approximate entropy (C-ApEn) were measured before Phase A, before Phase B, and after Phase B.ResultsAfter A-tDCS treatment, CRS-R and AES were improved significantly. ApEn and C-ApEn results showed that the local cortical connection of bilateral sensorimotor areas with their peripheral areas could be activated by affected painful stimuli, while bilateral cerebral hemispheres could be activated by the unaffected painful-stimuli condition. Linear regression analysis revealed that the affected sensorimotor cortex excitability and unaffected local and distant cortical networks connecting the sensorimotor area to the prefrontal area play a major role in AES improvement.ConclusionA-tDCS over the prefrontal area and left DLPFC improves PIS. The recovery might be related to increased excitability in local and distant cortical networks connecting the sensorimotor area to the prefrontal area. Thus, tDCS may be an alternative treatment for post-traumatic PIS.

Highlights

The disorders of consciousness (DoCs) are common in patients with severe traumatic brain injury (TBI)
Electroencephalogram approximate entropy (ApEn) difference between painful-stimuli and eyes-closed conditions before and after the treatments are listed in Table 3 (Figures 3, 4)
After Phase B, no significant difference was observed in either of the electrodes under affected painful stimuli; the ApEn indices were significantly higher in PA and MTA under unaffected painful stimuli

Summary

Introduction

The disorders of consciousness (DoCs) are common in patients with severe traumatic brain injury (TBI). Such patients usually experience coma, unresponsive wakefulness state (UWS), and minimally conscious state (MCS). Many MCS patients, who have given great hope to the doctors and their families, entered into a psychomotor inhibition state (PIS), which is manifested as apathy, lack of desire for active communication, no appetite for food, and lack of motive for purposeful activities. The results of a prospective multicenter study showed excessive behavioral disorders in less than 3 months of trauma, while the incidence of deficient behavior disorder is higher in the chronic course (Nygren DeBoussard et al, 2017)

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