Acute Effects of Smartphone-Delivered Local Vibration on Hand Sensorimotor Performance

NCT07521228 | Not Yet Recruiting

• 2 other identifiers: ACU-FTR-AOA52026-06/275
• Study Type: interventional
• Target: 20
• Locations: 1 country
• Sites: 1

Brief Summary

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.

Conditions

Healthy Volunteers; Vibration; Adverse Effect

Keywords

local vibration; smartphone vibration; haptic feedback; grip strength; two-point discrimination; pressure pain threshold; reaction time; sensorimotor performance; dose-response; crossover; hand function

Outcome Measures

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).

  Immediately before and immediately after vibration application at each session (3 sessions, minimum 48 hours apart)

Secondary Outcomes (3)

• Change in Two-Point Discrimination (2PD)

  Immediately before and immediately after vibration application at each session (3 sessions, minimum 48 hours apart)

• Change in Pressure Pain Threshold (PPT)

  Immediately before and immediately after vibration application at each session (3 sessions, minimum 48 hours apart)

• Change in Hand Reaction Time

  Immediately before and immediately after vibration application at each session (3 sessions, minimum 48 hours apart)

Study Arms (3)

80 Hz Local Vibration

EXPERIMENTAL

Smartphone-delivered local vibration at 80 Hz applied to the dominant hand. Stimulation protocol: 5 repetitions of 45 seconds vibration + 15 seconds rest (total approximately 5 minutes). Represents the lower end of the tested frequency range.

Device: Smartphone Local Vibration at 80 Hz

150 Hz Local Vibration

EXPERIMENTAL

Smartphone-delivered local vibration at 150 Hz applied to the dominant hand. Stimulation protocol: 5 repetitions of 45 seconds vibration + 15 seconds rest (total approximately 5 minutes). Represents the middle of the tested frequency range.

Device: Smartphone Local Vibration at 150 Hz

220 Hz Local Vibration

EXPERIMENTAL

Smartphone-delivered local vibration at 220 Hz applied to the dominant hand. Stimulation protocol: 5 repetitions of 45 seconds vibration + 15 seconds rest (total approximately 5 minutes). Represents the upper end of the tested frequency range.

Device: Smartphone Local Vibration at 220 Hz

Interventions

Smartphone Local Vibration at 80 Hz DEVICE

Local 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.

80 Hz Local Vibration

Smartphone Local Vibration at 150 Hz DEVICE

Local 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.

150 Hz Local Vibration

Smartphone Local Vibration at 220 Hz DEVICE

Local 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.

220 Hz Local Vibration

Eligibility Criteria

• Age: 18 Years - 25 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Healthy university students aged 18-25 years
• Willing to participate and provide written informed consent
• Able to attend three separate measurement sessions

You may not qualify if:

• 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
• History of neurological disease (e.g., stroke, multiple sclerosis, peripheral neuropathy)
• Active pain, infection, open wound, or dermatological condition at the measurement site
• Reported hypersensitivity or intolerance to vibration
• Pregnancy

Sponsors & Collaborators

• Acibadem University: lead

Study Sites (1)

Acibadem Mehmet Ali Aydinlar University, Department of Physiotherapy and Rehabilitation

Istanbul, Turkey (Türkiye)

Location

Study Officials

• Ali Omer Acar

  Acibadem Mehmet Ali Aydinlar University, Faculty of Health Sciences, Department of Physiotherapy and Rehabilitation

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Ali Omer Acar

CONTACT

+905378262790; aliomer.acar@acibadem.edu.tr

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Masking Details: Open label. Participants hold the vibrating phone and can perceive the stimulation. The same assessor administers all conditions and measurements. Blinding to vibration frequency is not feasible given the perceptible differences in vibration characteristics.
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Lecturer, Department of Physiotherapy and Rehabilitation

Model Details: Randomized crossover with three conditions. Each participant receives all three vibration frequencies (80 Hz, 150 Hz, 220 Hz) in separate sessions on different days, with a minimum 48-hour washout between sessions. Application order is counterbalanced across the 6 possible sequences (3! = 6) using randomization.

Study Record Dates

• First Submitted: April 3, 2026
• First Posted: April 9, 2026
• Study Start: April 1, 2026
• Primary Completion (Estimated): July 1, 2026
• Study Completion (Estimated): November 1, 2026
• Last Updated: April 9, 2026

Record last verified: 2026-04

Locations

TU (1)