''The Agreement Between Face-to-face and Tele-assessment of Fullerton Advanced Balance (FAB) Scale in Older People''

Research Design:

This is an observational, cross-sectional methodological study examining the measurement consistency and reliability between tele-assessment and face-to-face applications of the Fullerton Advanced Balance Scale (FAGBS). The study will use a randomized crossover design, with data collection planned between September and January 2026.

Sample:

Participants will be individuals aged 65 and older living in Istanbul and affiliated with institutions under the Darülaceze Presidency. Purposive sampling will be used, and recruitment will occur through the university's physical therapy unit, hospital waiting areas, neighborhood pharmacies, municipal senior centers, and social networks. Participation is voluntary.

The sample size was calculated using an ICC-based hypothesis testing approach (Walter et al., 1998) assuming an expected ICC of 0.90, a minimum acceptable ICC of 0.75, α = 0.05, and 90% power. A minimum of 44 participants is required; accounting for 15% attrition, the target sample size is 52.

Assessment Procedures:

All assessments will be performed by the same physical therapist following a standardized protocol. Face-to-face assessments will take place at the Department of Physical Therapy and Rehabilitation at Istanbul University-Cerrahpaşa or Darülaceze institutions. Tele-assessments will be conducted synchronously via Zoom or WhatsApp. Participants will be randomized to either face-to-face assessment followed by tele-assessment, or vice versa, with a 7-day interval between repeated tele-assessments.

Participants will receive instructions on device setup, camera positioning, and safety measures. A companion is recommended for safety, and sessions may be video recorded with consent. Assessments will be conducted in a quiet, well-lit area with a non-slip floor, and the camera positioned approximately 2-3 meters away to capture full-body movements. Participants without compatible devices will be provided with a computer and technical guidance. Assessments will be paused if fatigue, dizziness, or fall risk occurs. Physical performance tests are brief (~10 minutes), and a rest period of 1.5-2 hours will be scheduled between assessments, extendable if needed. Internet interruptions will be managed with reconnection attempts and rescheduling if necessary.

Statistical Analysis:

Data will be analyzed using SPSS 24.0. Reliability between tele-assessment and face-to-face FAGBS applications will be evaluated using the Intraclass Correlation Coefficient (ICC), including inter-observer reliability for tele-assessment. Measurement consistency will be assessed via Bland-Altman analysis. Standard Error of Measurement (SEM) and Minimal Detectable Change (MDC) will be calculated for measurement sensitivity. Concurrent validity between FAGBS and FES-I scores will be examined using Spearman's correlation. Participant satisfaction, completion rates, and Telehealth Usability Questionnaire results will be reported descriptively (mean, standard deviation, frequency, and percentage).

Inclusion criteria

• Being 65 years of age or older
• Able to walk independently, even if using an assistive device
• Having a Mini-Mental State Examination (MMSE) score of ≥ 24
• Having adequate vision and hearing (able to read and understand test instructions and information materials)
• Having the necessary technical equipment and a suitable environment to participate in video conference assessments
• Providing voluntary written informed consent

Exclusion criteria

• History of acute conditions in the past month that may temporarily affect balance (e.g., lower limb trauma, ankle sprain, acute vestibular problems)
• History of advanced neurological diseases such as Parkinson's disease, multiple sclerosis, or stroke sequelae
• Serious orthopedic problems limiting lower limb function (e.g., recent surgery, significant movement restriction)
• Systemic medical instability that may affect balance, such as uncontrolled diabetes or advanced heart failure
• Psychiatric disorders severe enough to significantly impair communication or the assessment process
• Insufficient technical equipment, environmental support, or social resources to participate in the tele-assessment process