Targeted High-definition Transcranial Direct Current Stimulation (HD-tDCS) for Reducing Post-stroke Movement Impairments

Not Applicable

Completed

Interventions: Device: Transcranial direct current stimulation (high-definition)

Brief Summary: Stroke is the leading cause of serious, long-term disability. The emergence of abnormal muscle synergies following a stroke presents a major limitation to the recovery of independent function. Despite the development of many interventions for movement recovery post-stroke, rehabilitation treatments are minimally effective to the muscle synergy impairment. Previous studies have found that muscle synergy impairment is associated with the damage to the corticospinal tract and the maladaptive recruitment of the contralesional cortico-reticulospinal tract. The investigators hypothesize that facilitating the damaged cortico-spinal tract (via primary motor cortex) and/or inhibiting the contralesional cortico-reticulospinal tract (via dorsal premotor cortex) will reduce muscle synergy impairment. In this pilot project, the investigators propose to run a proof-of-concept pilot trial to evaluate the effect of the targeted high-definition transcranial direct current stimulation (HD-tDCS) on mitigating muscle synergy impairment.

Detailed Description: This randomized, double-blinded, sham-controlled cross-over study will include three stimulation conditions: 1) anodal stimulation over the ipsilesional primary motor cortex, 2) cathodal one over the contralesional premotor cortex, 3) sham stimulation in chronic hemiparetic stroke patients.

Stroke participants (\> 3 months after stroke) with moderate to severe motor impairments (Fugl-Meyer Motor Assessment - Upper Extremity score between 10-40, in absence of clinically defined sensory deficits) and an ischemic unilateral subcortical lesion will receive each type of stimulation for 20 minutes.

Their brain activity and behavior data will be collected for the outcome measures.

The patient time commitment in this study is approximately 7 weeks where subjects have 3 x 1-day intervention and measurements, with 2 weeks washout period in between.

The total number of potential enrolled subjects in this pilot study is 12.

Recruitment & Eligibility

Inclusion Criteria

Ischemic unilateral stroke lesion (confirmed by the most recent clinical or radiological reports) at least 3 months prior to participation in this project.
Paresis confined to one side, with moderate to severe motor impairment of the upper limb (Fugl-Meyer upper extremity scores of 10-40)
Capacity to provide informed consent

Exclusion Criteria

Muscle tone abnormalities and motor or sensory impairment in the unimpaired limb
Severe wasting or contracture or significant sensory deficits in the paretic upper limb
Severe cognitive or affective dysfunction that prevents normal communication and understanding of consent or instruction
Severe concurrent medical problems (e.g. cardiorespiratory impairment)
Using a pacemaker
Metal implants in the head
Known adverse reaction to TMS and tDCS
Pregnant

Arm && Interventions

Group	Intervention	Description
Cathodal, Sham, Anodal	Transcranial direct current stimulation (high-definition)	Treatment order 3: Cathodal, Sham, Anodal
Anodal, Sham, Cathodal	Transcranial direct current stimulation (high-definition)	Treatment order 6: Anodal, Sham, Cathodal
Sham, Anodal, Cathodal	Transcranial direct current stimulation (high-definition)	Treatment order 1: Sham, Anodal, Cathodal
Anodal, Cathodal, Sham	Transcranial direct current stimulation (high-definition)	Treatment order 2: Anodal, Cathodal, Sham
Sham, Cathodal, Anodal	Transcranial direct current stimulation (high-definition)	Treatment order 4: Sham, Cathodal, Anodal
Cathodal, Anodal, Sham	Transcranial direct current stimulation (high-definition)	Treatment order 5: Cathodal, Anodal, Sham

Primary Outcome Measures

Name	Time	Method
Fugl-Meyer Upper Extremity Assessment Part A	The FM-UE assessment is completed before and immediately after (within 30 min range) the intervention. The mean difference is then calculated (Post-Pre intenvention) and recorded for each treatment group (anodal, cathodal, and sham). .	The Fugl-Meyer Upper Extremity (FM-UE) subset is a component of the Fugl-Meyer Assessment (FM) assessing motor impairment in individuals with stroke or other arm impairments. The (FM-UE) subset focuses on evaluating motor impairment and recovery using movements assessing strength, coordination, sensation, and range of motion of the upper extremity. Each item in the FM-UE subset is scored on a scale from 0-2. These are added together, with higher scores indicating better motor function. The FM-UE subset has 33 items for a maximum possible (highest functioning) score of 66.

Secondary Outcome Measures

Name	Time	Method
Change in Onset Latency of Transcranial Magnetic Stimulation (TMS)-Evoke Motor-evoked Potentials (MEP)	The latency of TMS-evoke MEP assessment is completed before and immediately after (within 30 min range) the intervention. The mean difference is then calculated (Post-Pre intevention) and recorded for each treatment group (anodal, cathodal, and sham).	This is a neurophysiological measure that determines the use of ipsilesional corticospinal tract. The paired-pulse TMS was applied at the respective hotspot for the elbow flexor muscle at the paretic arm over the ipsilesional primary motor cortex. The center of the coil was positioned tangentially to the skull. The patient was considered MEP+ if MEPs of any amplitude are observed at a consistent latency on at least 5 out 10 trials. After determining the status of MEP, at least eight more pulses were applied. We calculated average latency across all positive trials to determine the latency of MEP.

Locations (1): University of Oklahoma Health Sciences Center
🇺🇸
Oklahoma City, Oklahoma, United States