Acute Effects of Smartphone-Delivered Local Vibration on Hand Sensorimotor Performance
Trial statusNot yet recruiting
Trial phaseNot applicable
Trial typeInterventional
Biological sexAll
Age18-25
SponsorAcibadem University
About this trial
This study investigates the acute effects of smartphone-delivered local vibration on hand sensorimotor performance in healthy young adults. Using a custom-developed iPhone application, three vibration frequencies (80 Hz, 150 Hz, and 220 Hz) are applied to the dominant hand in a randomized crossover design with a minimum 48-hour washout between sessions.
The primary aim is to evaluate frequency-dependent dose-response effects on hand grip strength. Secondary aims include assessment of two-point discrimination (tactile spatial acuity), pressure pain threshold, and hand reaction time before and immediately after each vibration condition.
The study seeks to generate evidence on optimal application parameters for smartphone vibration as an accessible and portable local vibration source in clinical and educational settings.
Eligibility criteria
This trial accepts healthy volunteersQualifiers
Healthy university students aged 18-25 years
Willing to participate and provide written informed consent
Able to attend three separate measurement sessions
Disqualifiers
Surgical intervention on the hand or wrist within the past 6 months
Serious upper extremity injury or trauma within the past 6 months
Diagnosis of carpal tunnel syndrome or peripheral nerve entrapment
Numbness, paresthesia, or sensory impairment in the hand or wrist
Trial design
Design model
Crossover
Treatments tested in this trial
Smartphone Local Vibration at 80 Hz
DeviceLocal vibration delivered via a custom-developed iPhone application using the device haptic motor at 80 Hz. Participant seated with back support, shoulder neutral, elbow 90 degrees flexion, forearm neutral on table support, wrist relaxed. Phone held naturally in dominant hand palm. Five repetitions of 45 seconds vibration + 15 seconds rest. Participants instructed not to consciously squeeze during application.
Smartphone Local Vibration at 150 Hz
DeviceLocal vibration delivered via a custom-developed iPhone application using the device haptic motor at 150 Hz. Same positioning and protocol as 80 Hz condition. Five repetitions of 45 seconds vibration + 15 seconds rest.
Smartphone Local Vibration at 220 Hz
DeviceLocal vibration delivered via a custom-developed iPhone application using the device haptic motor at 220 Hz. Same positioning and protocol as 80 Hz condition. Five repetitions of 45 seconds vibration + 15 seconds rest.
Treatment groups
20 Participants
are divided into 3 treatment groupsGroup A: 80 Hz Local VibrationExperimental treatment 1 intervention
Group B: 150 Hz Local VibrationExperimental treatment 1 intervention
Group C: 220 Hz Local VibrationExperimental treatment 1 intervention
Trial outcomes
Primary outcomes
1
Change in Hand Grip Strength
Hand grip strength measured with Jamar hydraulic dynamometer (kg) using ASHT-recommended positioning. Three trials per measurement; mean of three trials used. Pre-post difference assessed at each frequency condition (80 Hz, 150 Hz, 220 Hz).
Time frame
Immediately before and immediately after vibration application at each session (3 sessions, minimum 48 hours apart)Secondary outcomes
1
Change in Two-Point Discrimination (2PD)
Tactile spatial acuity measured with Baseline Two-Point Discriminator on dominant hand third finger distal pulp (mm). Smallest distance correctly identified in at least 2 of 3 trials recorded as threshold. Lower values indicate better tactile discrimination.
Time frame
Immediately before and immediately after vibration application at each session (3 sessions, minimum 48 hours apart)2
Change in Pressure Pain Threshold (PPT)
Pressure pain threshold measured with pressure algometer on dominant hand thenar eminence (kg/cm2). Probe approximately 1 cm2, application rate approximately 1 kg/s. Mean of three trials used. Higher values indicate higher pain tolerance.
Time frame
Immediately before and immediately after vibration application at each session (3 sessions, minimum 48 hours apart)3
Change in Hand Reaction Time
Visual stimulus-motor response time assessed with Nelson Hand Reaction Time Test (ms). Five valid trials after 3 practice trials; best and worst excluded, mean of remaining three used. Reaction time calculated via free-fall formula. Lower values indicate faster reaction.
Time frame
Immediately before and immediately after vibration application at each session (3 sessions, minimum 48 hours apart)Sponsors and contacts
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Source ClinicalTrials.gov
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