Comparing the Effects of Motor Imagery and Transcranial Direct Current Stimulation (tDCS) Interventions Combined with Neuromuscular Training on Pain Intensity, Quadriceps Muscle Activity, Gait Pattern, and Range of Motion Using Machine Vision in Women with Knee Osteoarthritis

The aim of this study was to compare the effects of four weeks of motor imagery and transcranial direct current electrical stimulation combined with neuromuscular training on pain intensity and motor functions in women with knee osteoarthritis.

This study is a randomized clinical trial with control and parallel groups, with blinding of the assessor, on 48 women with unilateral knee osteoarthritis. Randomization is performed in a block design and the unit of randomization is the individual. This study is conducted in the second phase of the clinical trial.

The study will be conducted in the laboratory and corrective exercise center of Razi University, Kermanshah. After initial assessments, participants will be randomly assigned to study groups. The evaluator will not be aware of group allocation and all interventions will be administered by the principal investigator.

Participants were women aged 40 to 65 years with unilateral knee osteoarthritis, chronic pain of at least three months and pain intensity of at least three out of ten, with a confirmed diagnosis Exclusion criteria included knee surgery or replacement within the past six months, neurological or inflammatory diseases, pregnancy or lactation, use of medications affecting the central nervous system, metal implants, or a history of seizures.

Participants will be randomly assigned to three groups: The motor imagery plus neuromuscular training group, where motor imagery is performed before the training; The transcranial direct current electrical stimulation plus neuromuscular training group, where stimulation is applied before the training; The control group, which receives neuromuscular training only.

Pain intensity; quadriceps muscle activity; gait pattern; knee joint range of motion.

Participants will be allocated to study groups using block randomization. The unit of randomization in this study is the individual. To maintain a balanced number of participants in each study group and reduce the likelihood of group imbalance, block randomization with equal block sizes will be employed. The random sequence will be generated using Random Number Generator software based on a random number table. The randomization process will be conducted by an individual independent of the research team and assessors to prevent allocation bias.

To prevent any potential bias in the results, the study assessor will be blinded, and the assessor will be different from the individual responsible for delivering the interventions. The intervention procedures, including motor imagery, transcranial direct current stimulation (tDCS), and neuromuscular exercises, as well as the assessment methods and participants’ ethical and treatment rights, will be explained by the principal investigator.Random allocation will be performed using a random number table by an individual independent of the research team to prevent allocation bias. The randomization process will be carried out using Random Number Generator software, and each participant’s allocation code will be placed in opaque, numbered envelopes. The envelopes will be opened only at the time of participant entry, after assessments, and by a person other than the assessor to maintain assessor blinding (the assessor will remain unaware of participants’ group allocation and type of intervention).Preliminary screening will be conducted to confirm participants’ ability to participate in the study, and each participant will then be assigned to one of the three study groups. In this study, participants will be randomly assigned to three intervention groups. All interventions will be conducted by the principal investigator.

To protect participant confidentiality and comply with research ethical considerations, there is no plan to share individual participant data (IPD). Access to the raw data will be restricted to the principal investigators and will be used solely for the purposes of the present study.

Study protocol, statistical analysis plan, informed consent form, and final study report. These documents include the study methodology, interventions, statistical analysis procedures, ethical considerations, and final study results and do not contain identifiable participant information.

The documents will be available from the time of publication of the study results and for at least 5 years thereafter.

Researchers, faculty members, graduate students, and other applicants with legitimate scientific and research purposes.

The documents may be used solely for scientific, educational, and research purposes. Commercial use or any use inconsistent with research ethics is prohibited. Applicants must provide a written description of the intended use.

Applicants may submit their requests through correspondence with the principal investigator or the Faculty of Sport Sciences, Razi University.

Requests will be reviewed by the principal investigator. If approved, the requested documents will be provided within a maximum of 30 working days.

Individual participant data and raw datasets will not be shared. Participant confidentiality will be protected in accordance with research ethics principles.