Acute Effects of Smartphone-Delivered Local Vibration at Three Frequencies on Hand Grip Strength, Two-Point Discrimination, Pressure Pain Threshold, and Reaction Time in Healthy Young Adults: A Randomized Crossover Study
试验速览
- 阶段
- 不适用
- 状态
- 尚未招募
- 发起方
- 入组人数
- 20
- 试验地点
- 1
- 主要终点
- Change in Hand Grip Strength
研究概览
简要总结
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.
详细描述
BACKGROUND:
Local vibration (LV) has been investigated in physiotherapy and rehabilitation for modulating muscle activation, performance, and pain perception. Neurophysiological effects are mediated through tonic vibration reflex and enhanced sensory afferent input. LV offers a more targeted and portable approach compared to whole-body vibration (WBV). Short-duration LV applications have been shown to produce acute changes in muscle strength, tactile perception, reaction time, and pain threshold.
The hand region, with its high mechanoreceptor density and extensive cortical representation, provides a sensitive model for mechanical stimulation. Smartphones, through programmable haptic motors, can generate controlled vibration outputs and have been used in rehabilitation for vibrotactile feedback applications. However, studies combining assessment of grip strength, two-point discrimination, pressure pain threshold, and reaction time following mobile phone vibration on the hand are limited.
The frequency range (80-220 Hz) was selected to cover the optimal sensitivity band of Pacinian corpuscles (approximately 100-300 Hz), with 80 Hz being commonly used in LV literature. Three frequency levels (80, 150, 220 Hz) systematically represent the lower, middle, and upper portions of the range to explore a potential dose-response relationship.
STUDY DESIGN:
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Crossover
- 主要目的
- Basic Science
- 盲法
- None
盲法说明
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.
入排标准
- 年龄范围
- 18 Years 至 25 Years（Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Healthy university students aged 18-25 years
- •Willing to participate and provide written informed consent
- •Able to attend three separate measurement sessions
排除标准
- •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
研究组 & 干预措施
80 Hz Local Vibration
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.
干预措施: Smartphone Local Vibration at 80 Hz (Device)
150 Hz Local Vibration
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.
干预措施: Smartphone Local Vibration at 150 Hz (Device)
220 Hz Local Vibration
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.
干预措施: Smartphone Local Vibration at 220 Hz (Device)
结局指标
主要结局
Change in Hand Grip Strength
时间窗: Immediately before and immediately after vibration application at each session (3 sessions, minimum 48 hours apart)
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).
次要结局
- 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))
研究者
Ali Ömer Acar
Lecturer, Department of Physiotherapy and Rehabilitation
Acibadem University