Effects of smartphone overuse on hand function, pinch strength, and the median nerve

Muscle Nerve. 2015 Aug;52(2):183-8. doi: 10.1002/mus.24695. Epub 2015 Jun 3.

Abstract

Introduction: In this study we investigated the flexor pollicis longus (FPL) tendon and median nerve in smartphone users by ultrasonography to assess the effects of smartphone addiction on the clinical and functional status of the hands.

Methods: One hundred two students were divided into 3 groups: non-users, and high or low smartphone users. Smartphone Addiction Scale (SAS) scores and grip and pinch strengths were recorded. Pain in thumb movement and rest and hand function were evaluated on the visual analog scale (VAS) and the Duruöz Hand Index (DHI), respectively. The cross-sectional areas (CSAs) of the median nerve and the FPL tendon were calculated bilaterally using ultrasonography.

Results: Significantly higher median nerve CSAs were observed in the dominant hands of the high smartphone users than in the non-dominant hands (P<0.001). SAS scores correlated with VAS pain for movement and rest, DHI scores, and pinch strength (P<0.05; r=0.345, 0.272, 0.245, and 0.281, respectively).

Conclusions: Smartphone overuse enlarges the median nerve, causes pain in the thumb, and decreases pinch strength and hand functions.

Keywords: flexor pollicis longus; median nerve; repetitive wrist movement; smartphone addiction; ultrasonography.

MeSH terms

  • Adolescent
  • Cell Phone*
  • Cross-Sectional Studies
  • Cumulative Trauma Disorders / diagnostic imaging*
  • Cumulative Trauma Disorders / epidemiology
  • Cumulative Trauma Disorders / etiology
  • Female
  • Hand / diagnostic imaging*
  • Hand / physiology
  • Humans
  • Male
  • Median Nerve / diagnostic imaging*
  • Median Nerve / physiology
  • Pinch Strength* / physiology
  • Self Report / standards
  • Single-Blind Method
  • Turkey / epidemiology
  • Ultrasonography
  • Young Adult