Efficacy of Temporal Interference-based Deep Brain Stimulation Combined With Conventional Rehabilitation Training for Lower Limb Motor Dysfunction After Stroke

The routine rehabilitation strictly follows the standard treatment protocols (SOC) recommended by domestic and international guidelines such as the "Chinese Guidelines for Stroke Rehabilitation Therapy", including secondary prevention with medication, task-oriented lower limb muscle strength training, balance training, gait correction training, and physical factor therapy. This is carried out by rehabilitation therapists according to the hospital's routine procedures, 5 times a week, each session lasting approximately 60 minutes, for a total of 3 weeks. The TI stimulation is a sham stimulation. Specifically, the electrode application, positioning, and equipment operation procedures are exactly the same as those in the true stimulation group. The current rises gradually from a 30-second slope to the preset intensity and then immediately returns to zero. Only the first 30 seconds produce a slight scalp sensation, and there is no effective modulated electric field thereafter.

The routine rehabilitation strictly follows the standard treatment protocols recommended by domestic and international guidelines such as "Chinese Guidelines for Stroke Rehabilitation Therapy", including secondary prevention with medication, task-oriented lower limb muscle strength training, balance training, gait correction training, and physical factor therapy. This is carried out by rehabilitation therapists according to the hospital's routine procedures, 5 times a week, each session lasting approximately 60 minutes, for a total of 3 weeks.

The electrode application, positioning, and equipment operation procedures are exactly the same as those in the true stimulation group. The current gradually increases from a 30-second ramp to the preset intensity and then immediately returns to zero. Only the first 30 seconds cause a slight sensation on the scalp, and no effective modulated electric field is generated thereafter. 20 minutes each time, 5 times a week, for a total of 3 weeks.

The conventional rehabilitation was the same as the sham stimulation group. On this basis, for the TI stimulation, the target area was selected as the affected side striatum (caudate nucleus), and a head model was constructed based on individualized cranial MRI (T1-weighted image). The NervioWeb and other online platforms were used to optimize the 8-12 electrode configuration scheme. Stimulation parameters: carrier frequency of 2 kHz and 2.020 kHz, generating a 20 Hz envelope; initial current intensity of 2 mA per electrode, gradually increasing to the tolerance limit (single electrode ≤ 5 mA, total current ≤ 10 mA); 20 minutes each time, 5 times a week, for a total of 3 weeks.

The routine rehabilitation strictly follows the standard treatment protocols recommended by domestic and international guidelines such as "Chinese Guidelines for Stroke Rehabilitation Therapy", including secondary prevention with medication, task-oriented lower limb muscle strength training, balance training, gait correction training, and physical factor therapy. This is carried out by rehabilitation therapists according to the hospital's routine procedures, 5 times a week, each session lasting approximately 60 minutes, for a total of 3 weeks.

The stimulation target selected by TI was the contralateral striatum (caudate nucleus), and a head model was constructed based on individualized cranial MRI (T1-weighted image). The 8-12 electrode configuration scheme was optimized using online platforms such as NervioWeb. Stimulation parameters: carrier frequency of 2 kHz and 2.020 kHz, generating a 20 Hz envelope; initial current intensity of 2 mA per electrode, gradually increasing to the tolerated upper limit (single electrode ≤ 5 mA, total current ≤ 10 mA); 20 minutes each time, 5 times a week, for a total of 3 weeks.

The Fugl-Meyer Assessment Lower Extremity component (FMA-LE) is a standardized tool for the assessment of lower limb motor function in patients after stroke. It contains 17 items and is divided into two subscales: lower limb motor and coordination/speed . Higher scores indicate better function. For each item, a score of 0 indicates unable to complete/no function, a score of 1 indicates partially completed/partially functional, and a score of 2 indicates fully completed/normal function.

Holden functional classification of walking scale is a classic observational scale to assess the walking independence of patients

For the balance function of the lower limbs, the Berg balance Scale was used. The scale contains 14 items covering tasks of varying difficulty ranging from balance in a sitting position to standing on one leg. Each item was scored on a 5-point scale from 0 to 4, with a total score ranging from 0 to 56. Higher scores indicate better balance.

The Modified Barthel Index (MBI) was used to evaluate the activities of daily living of patients

TMS was used to detect the latency and amplitude of MEP of tibial anterior muscle and quadriceps femoris muscle on the affected and healthy sides, and to evaluate the cortical excitability of M1 area and the conduction function (conduction velocity and integrity) of corticospinal tract.

Functional near-infrared spectroscopy (NIRS) was used to evaluate the brain function of the subjects in the resting state and task state (ankle dorsiflexion task), and to monitor the activation patterns of motor-related brain areas (such as primary motor cortex and supplementary motor area). The changes of functional connectivity of brain functional network were analyzed.