Transcranial Direct Current Stimulation Combined Sensory Modulation Intervention in Chronic Stroke Patients

Summary

Background and purpose:

About 30% of people with stroke suffered from severe long-term upper extremity （UE） motor impairment. Severe UE impairment, especially dysfunction of hand, can greatly impact stroke patients' daily living independence and quality of life. However, treatment effect of current interventions is still limited. Nick Ward and Leonardo Cohen suggested 5 intervention strategies for stroke motor recovery: （1） reduction of somatosensory input from the intact; （2） increase in somatosensory input from the paretic; （3） anesthesia of a body part proximal to the paretic hand; （4） activity within the affected motor cortex may be up-regulated; （5） activity within the intact motor cortex may be down-regulated. Recent studies have shown each strategy to be effective in stroke patients with mild or moderate UE impairment. However, evidence for people with severe UE impairment after stroke remains unclear. Since research has found a greater effect for combined strategies than a single strategy, this proposal develops a combined intervention with the above 5 strategies, named "transcranial direct current stimulation （tDCS） combined sensory modulation intervention". This intervention is expected to be most effective for people with severe UE impairment after stroke.

In addition, neuroimaging can provide in vivo information about the brain plasticity which underpinning the motor recovery after stroke. However, image indexes that can be used in stroke patients with severe UE impairment remained examined. Therefore, this proposal has 3 aims: （1） to examine the treatment effect of the "tDCS combined sensory modulation intervention" in stroke patients with severe UE impairment; （2） to examine the underline mechanism of the efficacy of "tDCS combined sensory modulation intervention" using neuroimaging technology.

Methods:

This study is a double-blinded randomized controlled trial which will recruit 60 people who have had stroke onset more than 6 months and have severe UE motor impairment. All participants will be randomly assigned into 2 groups. The experimental group will be given the "tDCS combined sensory modulation intervention", combining bilateral tDCS stimulation, anesthesia techniques and repetitive passive motor training. The control group is given sham tDCS, sham anesthesia and repetitive passive motor training. Each group will be evaluated for outcomes at 4 time points （i.e. baseline, post-intervention, 3 months and 6months post-intervention）. The immediate and long-term effect of the interventions will be examined.

Primary outcome indicators include upper extremity impairment measures. Secondary outcome measures include upper extremity function, activities of daily living function, functional Magnetic Resonance Imaging （fMRI）, and corticospinal tract structural integrity using diffusion spectrum imaging （DSI）. Fifteen subjects of each group will be assessed 2 times （i.e., prior to the intervention and after the intervention） for fMRI and DSI scan.

Anticipatory results and contributions:

The results of the studies are expected to present a potentially effective intervention for stroke patients with severe impaired UE motor. Imaging evidence of brain plasticity for this particular intervention is also provided. The results will contribute to our understanding of brain plasticity for UE motor recovery after stroke. Findings from this proposal may help researchers and clinicians choose or develop interventions that are optimal to their clients individually.

Conditions

• Stroke

Interventions

DEVICE

tDCS

Intelect mobile combination (Intelect, USA) is utilized as a direct current stimulator. The 25 cm2 electrodes on a sponge slice immersed in physiological salt solution are fixed on the left and right positions C3/ C4 of subject head (according to the international 10-20 system of electroencephalogram). During the treatment, 1.5 mA electric current is applied to stimulate the subjects in the experimental group for totally 30 minutes. At the start and the end of stimulation, the electric current will gradually increase from zero, or reduce to zero in 1 minute in order to avoid the possible appearance of slight flash effect of subject eyesight, which is caused by instantly turning on or turning off the electric current.

DRUG

Epidermis anesthesia

15 g of Emla 5% Cream(anesthetic) is applied to the ventral surface of the forearm of unaffected side with a distance of 10 mm from the wrist, and an area of 150 mm long x 50 mm wide. Furthermore, 10 g Emla 5% Cream(anesthetic) is applied to the ventral surface of the upper arm of affected side with a distance of 10 mm from the wrist, and an area of 100 mm long x 50 mm wide.

DRUG

sham anesthesia

15 g of 5% body Cream is applied to the ventral surface of the forearm of unaffected side with a distance of 10 mm from the wrist, and an area of 150 mm long x 50 mm wide. 10 g body Cream is applied to the ventral surface of the upper arm of affected side with a distance of 10 mm from the wrist, and an area of 100 mm long x 50 mm wide.

OTHER

Repeated passive movement

Repeated passive wrist extension training: Patients' wrist joint are passively moved by a trained occupational therapist (joint moving angle = 0- 60 degree), frequency 1 Hz, maintain for 20 minutes. Finger passive flexion and extension training: Patients' fingers joint are passively moved by a trained occupational therapist, frequency 1 Hz, maintain for 10 minutes.

DEVICE

sham tDCS

The equipment of sham stimulation in the control group is exactly the same as the equipment in the experiment group. However, the only difference is that 30 seconds after the start of electric current, the experimenter turns off the powder under subject ignorance situation. The stimulation just gives patients weak sense of electric current, in order to blind them for which group they are in.

Sponsors & Collaborators

• National Science and Technology Council, Taiwan

  collaborator OTHER_GOV

• National Taiwan University Hospital

  lead OTHER

Principal Investigators

• Jiann-Shing Jeng, Doctor · Department of Neurology, National Taiwan University Hospital

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

TRIPLE

Model

PARALLEL

Eligibility

Min Age

40 Years

Max Age

80 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2013-01-31

Primary Completion

2015-06-30

Completion

2015-06-30

Countries

• Taiwan