In recent years, numerous technological products and devices have been developed in rehabilitation through advances in biomedical technology. These innovations support traditional rehabilitation services, offering more effective treatment methods and improving patients' adherence and participation. Increased compliance in treatment positively influences functional status, quality of life, and satisfaction. However, the diversity of biomedical products and the varying strength of their scientific foundations make it critical to evaluate them in terms of benefit, patient compliance, and usability. In physiotherapy and rehabilitation, objective tools for this purpose remain limited, which hinders accurate assessment of product effectiveness and the identification of improvements. Uncertainty regarding usability and ease of use may also result in inefficient utilization of resources.

Questionnaires provide cost-effective tools to capture users' opinions, reflecting strengths and weaknesses of a product without the need for measurement devices. The Usefulness, Satisfaction, and Ease of Use (USE) Questionnaire, developed by Arnold Lund in 2001, is a comprehensive 30-item scale scored on a 7-point Likert system. It evaluates usefulness, ease of use, ease of learning, and satisfaction, with items applicable across different products and services such as software, hardware, applications, or user support materials. Its multidimensional structure allows for the evaluation of usability in physiotherapy and rehabilitation technologies as well as in broader fields including robotics, social networking sites, diagnostic tools, and virtual reality.

Despite its wide use internationally, no validated Turkish version of the USE Questionnaire exists. Establishing a culturally adapted, valid, and reliable Turkish version will address this gap and provide clinicians and researchers with a standardized tool for usability assessment.

The aim of this study is to investigate the validity and reliability of the Turkish version of the USE Questionnaire.

This study will be carried out at Hacettepe University, Faculty of Physical Therapy and Rehabilitation, Spine Health Unit. Individuals who apply to the rehabilitation program and use biomedical devices will be included. Inclusion criteria are: presence of back or neck pain for at least three months, use of a supportive biomedical device in the rehabilitation program, literacy, age between 18-65 years, and voluntary participation with written informed consent. Exclusion criteria include malignancy, pregnancy, neurological or systemic disease causing functional loss, surgery within the last six months, acute infection, unhealed fracture, or withdrawal of consent at any stage.

The cross-cultural adaptation of the Usefulness, Satisfaction and Ease of Use (USE) Questionnaire will be conducted according to established guidelines. Permission has been obtained from the original author. Two bilingual translators (a physiotherapist with a PhD and a linguist from Hacettepe University School of Foreign Languages) will independently translate the questionnaire into Turkish. Their translations will be reviewed by an expert committee consisting of three health professionals and three linguists. Back-translation into English will be performed by two native English speakers. Following review and consensus, a pre-final Turkish version will be created. The pre-test phase will include 10 individuals with back or neck pain who used biomedical devices in rehabilitation. Comprehensibility, clarity, and time to complete the questionnaire will be evaluated. Items that are unclear will be revised or removed.

A total of 150-300 participants will be recruited, following the recommendation of 5-10 participants per item for validation studies. Data collection will include demographic information (age, sex, weight, height, occupation, education, diagnosis), the Turkish USE Questionnaire, Neck Disability Index, Oswestry Disability Index, Quebec User Evaluation of Satisfaction with Assistive Technology, and Numeric Pain Rating Scale. Device-related usefulness, learning, and ease of use will be evaluated using Visual Analog Scales. The USE Questionnaire will be administered twice, with a three-day interval, to assess test-retest reliability.

Statistical analyses will be performed using IBM SPSS. Construct validity will be examined using factor analysis and correlations with established scales. Internal consistency will be assessed by Cronbach's alpha coefficient, and test-retest reliability will be evaluated using intraclass correlation coefficients. These methodological steps will ensure the scientific rigor, validity, and reliability of the Turkish version of the USE Questionnaire. The adapted instrument is expected to provide a standardized and reliable tool to evaluate usability of biomedical devices and technologies in physiotherapy and rehabilitation settings, filling an important gap in the Turkish literature.

Inclusion Criteria:

1. Presence of back or neck pain lasting at least 3 months
2. Use of a supportive biomedical device in a rehabilitation program
3. Literacy
4. Age between 18 and 65
5. Willingness to participate in the study on a voluntary basis

Exclusion Criteria:

• 1. Malignant condition 2. Pregnancy 3. Loss of function due to neurological or systemic disease 4. Having undergone surgery in the last 6 months 5. Acute infection 6. Unhealed fracture 7. Withdrawal from any phase of the study 8. Light sensitivity

patients with low back pain and neck pain