The aim of this clinical trial is to determine if trans-auricular vagus nerve stimulation (taVNS) is effective in improving upper extremity function in stroke survivors. The primary objectives include: Investigating whether taVNS improves motor function in stroke survivors. The secondary objectives include: Assessing any potential side effects associated with the method. Investigating taVNS effects on daily routine functions and spasticity Researchers will conduct a comparative analysis between taVNS and a sham procedure (which mimics the stimulation without any actual effect) to assess its effectiveness. Participants in the trial will: Undergo taVNS combined with physical therapy or a sham procedure with physical therapy daily over a two-week period.
None
Patients with any contraindication to taVNS, peripheral upper extremity injuries, use of medication affecting cortical excitability in the past 3 months, use of botulinum toxin in the past 3 months, presence of any other neurological disorder, or significant cognitive deficits.
Parallel
Active taVNS
DeviceProtocol uses a 25 Hz frequency with 500 μs pulse width in biphasic configuration, operating at a 1:1 duty cycle with current intensity set to the maximum tolerable level without inducing pain. The total stimulation duration is 60 minutes. The stimulation is combined with physical therapy focused on upper extremity function.
Sham taVNS
DevicePhysical therapy focused on upper extremity function with masking for transcutaneous vagus nerve stimulation
Upper extremity Motor Function (Fugl-Meyer Assessment - Upper Extremity)
The Fugl-Meyer Assessment for Upper Extremity (FMA-UE) will be used to evaluate motor impairment and recovery of the paretic upper extremity. It consists of items from sections III and IV, assessing motor function, coordination, and speed, with a maximum score of 66 points. Higher scores indicate lower motor impairment. A minimal clinically important difference (mCID) is defined as a change (Δ) of 5 or more points between baseline and post-intervention scores.
Manual Dexterity (Box and Block Test)
The Box and Block Test (BBT) will assess manual dexterity of the paretic upper extremity. It counts the number of wooden blocks (2.5 x 2.5 x 2.5 cm) transferred from one compartment to another over a central divider within one minute. The minimal detectable change (MDC) is defined as a difference of 5 blocks per minute.
Independence (Functional Independence Measure)
The Functional Independence Measure (FIM) assesses the level of independence through motor and cognitive subscales. Each item is scored from 1 to 7. Total score classifications: complete dependence (18-45), moderate independence (46-99), and complete independence (100-126). The MDC is defined as 17 points for the motor section, 3 points for the cognitive section, and 22 points for the total score.
Spasticity (Modified Ashworth Scale)
The Modified Ashworth Scale (MAS) will assess spasticity in finger, wrist, elbow, and shoulder flexors of the paretic upper extremity. It uses a 6-point scale (0 to 5) to quantify muscle tone. The minimal clinically important difference (mCID) is defined as a reduction of at least one point in spasticity score.
Health-Related Quality of Life (Stroke-Specific Quality of Life Scale)
The Stroke-Specific Quality of Life Scale (SS-QOL) assesses stroke-related quality of life across 12 domains, using 49 items. Scores range from 49 to 245, with higher scores indicating better quality of life. The MDC is 4.7 points for the total score, 2.1 for the physical subscore, and 2.8 for the psychosocial subscore.
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Universidade Federal de Pernambuco
Lead sponsor
Fundação de Amparo à Ciência e Tecnologia de Pernambuco
Collaborator
Conselho Nacional de Desenvolvimento Científico e Tecnológico
Collaborator
