Effect of Combining Central and Peripheral Cutaneous Electrical Stimulation on Lower Limb Motor Function in People With Stroke

A Randomized Controlled Trial of Anodal Transcranial Direct Current Stimulation and Transcutaneous Electrical Nerve Stimulation for Improving Lower Limb Function in Stroke Patients

This study aims to evaluate the effectiveness of transcranial direct current stimulation (tDCS) and transcutaneous electrical nerve stimulation (TENS) in augmenting the efficacy of the lower limb task-oriented training in people with stroke. It is hypothesize that lower limb motor function can be best improved by combining anodal tDCS with TENS, when compared with sham-tDCS with TENS, anodal tDCS with placebo-TENS, or control training at improving ankle muscle strength, motor control of lower limbs, walking performance, functional mobility and community integration in people with stroke.

The application of transcutaneous electrical nerve stimulation (TENS) over a paretic lower limb could augment the effects of task-oriented exercise therapy on lower limb motor function in people with stroke, possibly through increased excitability of sensorimotor cortex.

In transcranial direct current stimulation (tDCS), a weak electrical current is applied through electrodes placed on the scalp to modulate cortical excitability and neural activity in targeted brain regions. Anodal tDCS, specifically, involves positioning the positively charged electrode over the targeted cortical area, which facilitates neuronal depolarization and increases cortical excitability in the underlying brain tissue. The enhanced neural excitability induced by anodal tDCS could promote neuroplasticity and optimize motor learning processes, potentially through the modulation of N-methyl-D-aspartic acid (NMDA) receptor -dependent mechanisms and alterations in GABAergic activity, leading to improved motor function and rehabilitation outcomes in various neurological conditions.

The next question concerns whether anodal tDCS could be combined with TENS and whether their synergetic effects could maximise the motor output of paretic limbs in people with stroke.

Inclusion Criteria:

1. are between 50 and 85 years of age;
2. have had a single stroke more than 6 months and less than 15 years;
3. have at least 5 degrees of active ankle dorsiflexion in the antigravity position;
4. are able to walk 10 m independently, with or without a walking aid;
5. are able to score 6 or higher out of 10 on the abbreviated mental test;
6. have no skin allergies (e.g. redness or itchiness after application of the electrical stimulation pads) to electrical stimulation or electrodes;
7. are able to follow instructions and give informed consent.

Exclusion Criteria:

1. have any additional medical, cardiovascular or orthopedic conditions that would hinder their treatment or assessment;
2. have a cardiac pacemaker;
3. have aphasia or cognitive difficulties that may interfere with their comprehension of instructions;
4. have had one or more epileptic seizures within the year prior to the date of inclusion in the study;
5. have an intracerebral metal clip;
6. have a major somatosensory deficit
7. have any contraindication to tDCS;
8. are currently involved in drug studies or other clinical trials.