Psychometric Properties of the iHandy Level Smartphone Application for Measuring Lumbar Spine Range of Motion and Lordosis: A Systematic Review of the Literature

Abstract

Context: Advent of smartphones has brought a wide range of clinical measurement applications (apps) within the reach of most clinicians. The vast majority of smartphones have numerous built-in sensors such as magnetometers, accelerometers, and gyroscopes that make the phone capable of measuring joint range of motion (ROM) and detecting joint positions. The iHandy Level app is a free app which has a visual display alike with the digital inclinometer in regard to numeric size. Objective: The purpose of this systematic review was to evaluate available evidence in the literature to assess the psychometric properties (ie, reliability and validity) of the iHandy Level app in measuring lumbar spine ROM and lordosis. Methods: PubMed/MEDLINE, Scopus, Ovid, Google Scholar, and ScienceDirect were searched from inception to September 2018 for single-group repeated-measures studies reporting outcomes of lumbar spine ROM or lordosis in adult individuals without symptoms of low back pain (LBP) or patients with LBP. The quality of each included study was assessed using the Quality Appraisal of Reliability Studies checklist. Results: A total of 4 studies with 273 participants were included. Two studies focused on measuring active lumbar spine ROM, and 2 studies evaluated lumbar spine lordosis. Three studies included asymptomatic subjects, and one study recruited patients with LBP. The results showed that the iHandy Level app has sufficient psychometric properties for measuring standing thoraco-lumbo-sacral flexion, extension, lateral flexion, isolated lumbar spine flexion ROM, and lumbar spine lordosis in asymptomatic subjects. One study reported poor concurrent validity with a bubble inclinometer (r = .19–.53), poor intrarater reliability (intraclass correlation coefficient = .19–.39), and poor to good interrater reliability (intraclass correlation coefficient = .24–.72) for the measurement of active lumbar spine ROM using the iHandy Level app in patients with LBP. Conclusions: This review provided a valuable summary of the research to date examining the psychometric properties of the iHandy Level app for measuring lumbar spine ROM and lordosis.