COMPARATIVE STUDY OF THE SPINAL KINEMATICS OF SMARTPHONE USERS WITH AND WITHOUT NECK- SHOULDER PAIN

T. Sun¹, S. Tsang¹, G. Szeto²

Background: In recent years, the use of mobile devices has become indispensable to our modern lifestyle, and relevant studies have shown that neck-shoulder pain is associated with the use of smartphone.

Purpose: This study compared examined the characteristic changes of spine kinematics and pain over the usage time, and these variables are compared between young adults with and without neck-shoulder pain when using touch-screen smartphones for game playing.

Methods: There were 24 subjects (12 males, 12 females) in the asymptomatic group and 21 subjects (9 males, 12 females) in the symptomatic group  (mean age: 21.25±0.85 years). Subjects signed the consent form and completed the questionnaire survey to evaluate their neck function and psychological status at baseline (Neck Disability Index, NDI; Tampa Scale for Kinesiophobia, TSK). Each subject used the iPhone6s for 20 mins to play a game while assuming each of three commonly adopted sitting positions. Position 1 (upright) refers to sitting with the smartphone held in mid-air without arm support. Position 2 (slouched) refers to sitting with wrists resting on thighs while holding the smartphone. Position 3 (forward leaning) refers to sitting with trunk lean forward and elbows resting on thighs while holding the smartphone.
The sagittal profile of the subject was captured on a video camera and the software Kinovea (version 8.15) was used to digitize the spinal angles of the cervical flexion and trunk flexion. The subjects were also asked to rate their pain scores with the numerical pain rating scale (NPRS, 0-10) before and after the game playing. The mixed model repeated measurement ANOVA(RMANOVA) was used to analyze the data by IBM SPSS statistical software 22.0.

Results: The symptomatic group had a mean NDI of 5.67 (±3.02) and NPRS of 4.81 (±1.60). Both groups gradually increased their spinal flexion angles in three positions, and there was a significant difference between the two groups in the extent of postural variations in spinal flexion angle in position 1 (upright) (P=0.006). There is a significant difference (P=0.026) between the two groups in the extent of postural variations of lower trunk flexion angle in Position 2 (slouched), and there is an interactive effect in the upper trunk flexion angle (P=0.02) and the lower trunk flexion angle (P=0.05) in Position 3 (forward leaning) between the group and time factors. The neck-shoulder pain in both groups increased significantly before and after 20 minutes (P<0.05) at each position，but there was no significant difference in NPRS of neck-shoulder pain between the two groups after 20 minutes (P>0.05).

Conclusion(s): The changes of spinal angles for those young adults with neck-shoulder pain when using the smartphone were significantly different from those who were symptom free. Pain intensity was found to have increased significantly after the 20-minute game playing for both groups.

Implications: This study has provided valuable insight into the postural control mechanisms in  using smartphone and how this is related to neck-shoulder pain. This information is useful for physiotherapists in managing patients with smartphone-related neck pain.

Funding, acknowledgements: No funding sources or conflicts of interest were reported for this study.

Keywords: Neck-shoulder pain, Smartphones, Spinal Kinematics

Topic: Musculoskeletal: spine

Did this work require ethics approval? Yes

Institution: The Hong Kong Polytechnic University

Committee: Department research committee

Ethics number: HSEARS20180528002