Terapia de Vibración Focal con Dispositivo Vestible sobre la Función de la Extremidad Superior en Personas con Esclerosis Múltiple: Un Estudio Piloto

Participants who will recieve the focal vibration therapy

The focal vibration intervention will be delivered using a modified MyoVolt wearable vibration therapy device. Each MyoVolt vibration device will be assigned to a single participant for individual use only and will be clearly labeled with a unique study ID. Devices will be distributed during the baseline training session and returned at the end of the study. To prevent unauthorized use:

• Participants will receive training on the appropriate use and safe handling of the device.
• Each device will be stored by the participant in their home in a designated area, along with written instructions and contact information in case of any issues.
• The device operates only via a linked smartphone app. This will restrict unauthorized users from easily accessing or operating the device.
• Participants will be instructed not to allow others to use the device and to report any device malfunction, loss, or suspected misuse immediately to the research team.

The Nine-Hole Peg Test (9HPT) assesses fine motor coordination and dexterity by timing how quickly participants can place and remove nine pegs from a pegboard using one hand.

AMSQ is a 31-item MS-specific patient-reported outcome measure assessing arm and hand function.

The Box and Block Test (BBT) measures gross motor function with high test-retest reliability by counting the number of blocks a participant can transfer over a partition from one compartment to another within 60 seconds.

Muscle strength will be evaluated using a handheld dynamometer. For grip strength assessment, participants will be seated with the shoulder adducted and neutrally rotated, the elbow flexed at 90 degrees, and the forearm and wrist in a neutral position. They will be instructed to squeeze the dynamometer with maximal effort for 3 seconds. Elbow flexion and extension strength will be assessed by applying the dynamometer to the distal part of the forearm as the participant resists the examiner's force for 3 seconds. The highest value from three trials in each arm and strength will be recorded and 60 seconds of recovery time will be applied between trials.

The Modified Ashworth Scale (MAS) is a widely used tool that assesses spasticity by measuring resistance during passive muscle stretching, graded on a scale from 0 (no increase in muscle tone) to 4 (rigid in flexion or extension) .

Subjective pain intensity will be measured by VAS on a scale from 0, indicating "no pain," to 10, indicating "worst possible pain". Participants will be asked about their neuropathic extremity pain in the UEx (manifesting as burning, tingling, and/or stabbing sensations), as well as pain caused by spasticity in the UEx (such as muscle stiffness or cramping). They will also be asked about instances where neuropathic pain occurs due to nonpainful stimulation such as light touch or non-extreme temperatures. Participants will rate their current UEx pain intensity, as well as the average level of UEx pain experienced over the past two weeks. Additionally, to evaluate how UEx pain has impacted their daily activities during the same period, participants will answer a modified question derived from the Chronic Pain Grade Scale.

MFIS is a validated self-report questionnaire designed to evaluate the perceived impact of fatigue in people with MS. The MFIS consists of 21 items, including 9 physical, 10 cognitive, and 2 psychosocial subscale items, and assesses fatigue experienced over the past 4 weeks.

Semi-structured interviews will be conducted with participants to explore their experiences with FVT after the post-intervention assessment and follow-up assessment. Each interview will be one-on-one, conducted by a single researcher. An open-ended interview guide will be developed to direct the conversation, covering domains of usability, acceptability, and perceived benefit of FVT.

Adherence to the 4-week FVT intervention will be tracked using multiple methods to ensure accuracy. Each participant will use the MyoVolt smartphone app, which automatically logs session attendance (date, time, intensity, and duration of each FVT session). The app data provides an objective record of when the device is activated. The MyoVolt app's built-in monitoring will serve as the primary source of adherence data. Participants will also fill out a simple daily adherence log immediately after each session. In this log, they will record the date and time of the session, the muscle sites stimulated (e.g., wrist extensors, biceps). This self-report acts as a cross-check against the app data and captures which muscle groups were targeted each day. Participants will be provided with a printed log template with spaces to fill in each field for every day of the 4-week intervention. This log will be collected at the post-intervention visit.

Retention will be assessed by recording which participants complete the intervention and all outcome assessments. A retention log will note the status of each participant (Completed, Dropped Early, Lost to Follow-Up) and the reasons for drop-out.

Participant safety will be closely monitored throughout the study. Adverse event documentation guidelines in the Agency for Healthcare Research and Quality manual were adopted. Participants will receive comprehensive information on adverse events and will be provided with diaries to record any occurrences, along with the contact information of the researcher. If an adverse event occurs, participants are instructed to immediately stop applying for FVT and contact the research team.