Reliability and validity of self-perception of posture during text typing on a mobile phone

Abstract

Introduction: There is a claim that the growing use of mobile phone in an inappropriate posture to text and read could be one of the reasons for the increasing prevalence of neck pain in the last decade. Nevertheless, it is not known if this new exposure should be faced as a public health concern. Before testing if there is an association between neck posture during smartphone use and neck pain, it is necessary to develop pragmatic tools appropriated to large sample epidemiologic studies. Objectives: To assess if the individual self-perception of the neck posture during mobile phone texting is reliable and in accordance to the physiotherapist’s opinion; To analyze the association between head posture during smartphone use and cervical pain in high school youth. Methods: This cross-sectional study enrolled a convenience sample composed of 113 high school students between 18 and 21 years old. The self-perception was assessed by illustrations in a questionnaire and was compared to an opinion of three experienced physiotherapists based on the photographic analysis. For test-retest reliability analysis (n = 113), self-perception was collected at two time points, with interval of seven days. Results: Showed that test-retest reliability of the self-perception was substantial (0.72, CI 95% 0.53-0.86). However, the accuracy of the self-perception when compared to the photograph analysis was low. The sensitivity was 0,88 (CI 95% 0,77- 0,95), the specificity was 0.24 (CI 95% 0,13-0,38). 76% of the participants with appropriate posture in the photograph analysis self-reported an inappropriate posture. Logistic regression analysis showed that cervical posture during self-perceived typing (OR = 1.59, 95% CI 0.60-4.17) or assessed by physiotherapists (OR = 0.59, 95% CI, 16-2,16) was not associated with neck pain. Conclusion: This study showed that the self-perception of the neck posture during mobile phone texting is reliable over time, however, it is not valid when compared to the physiotherapist’s opinion. The cervical posture, both self-perceived and evaluated by physiotherapists, does not seem to be associated with cervical pain.