The app measures the Angle of Trunk Rotation (ATR) — the same method clinicians use with a handheld scoliometer to screen and monitor scoliosis. Below is the peer-reviewed research behind this approach, presented honestly: what the evidence shows, and where its limits are.
Four decades of research validate the scoliometer / ATR method, and more than a dozen studies confirm that smartphones reproduce it accurately.
A scoliometer — physical or smartphone — is a screening and monitoring aid, not a diagnostic device, and not a replacement for clinical assessment or X-ray when those are indicated. The studies below validate the underlying method: smartphone-based scoliometry and ATR measurement.
Validation of a scoliometer smartphone app to assess scoliosis
The first study to formally validate a smartphone scoliometer app against the physical device, establishing smartphone scoliometry as a valid, low-cost alternative.
The smartphone as a tool to screen for scoliosis, applicable by everyone
In 50 adolescents, a smartphone app used by both a surgeon and a parent reached correlations of 0.97 and 0.92 against the scoliometer, with all ICCs above 0.92.
Validity and reliability of the iPhone to measure rib hump in scoliosis
In 34 patients, a smartphone app agreed with the physical scoliometer to within 0.4° (ICC 0.947).
Inter- and intraobserver reliability of axial trunk rotation: manual vs smartphone-aided tools
Smartphone-aided ATR matched the manual scoliometer for both intra- and inter-observer reliability.
Evaluation of a smartphone-based apparatus for early detection of spinal deformities
A parent presenting with the patient was able to take reliable measurements (ICC 0.91).
Validity and reliability testing of the Scoliometer
Established high reproducibility (r = 0.86–0.97); the authors noted readings alone are not sufficient for diagnosis.
Scoliometer measurements of patients with idiopathic scoliosis
Excellent reliability, good correlation with radiographic Cobb angle (r = 0.7), and 87% sensitivity at a 5° threshold.
Defining the trunk-rotation screening threshold
Bunnell’s work established the 5–7° ATR referral thresholds still used today.
Deep learning model to classify and monitor idiopathic scoliosis using a single smartphone photograph
Across 2,158 patients, an AI model reading one back photo matched or exceeded spine surgeons for flagging severity and progression risk — without radiation.
Smartphone-based surface topography app accurately detects clinically significant scoliosis
Validated against X-ray, detecting curves ≥20° with excellent reliability (inter-rater ICC 0.947) as an alternative to the scoliometer.
A new clinical tool for scoliosis risk analysis: Scoliosis Tele-Screening Test
A parent-administered remote test in 865 children was 94.97% accurate, 83.51% sensitive and 98.87% specific.
Scoliosis management through apps and software tools
A peer-reviewed review concluding app-based tools enable self-monitoring and remote progression tracking.
Clinicians trust evidence pages that acknowledge limitations.
3D topographic acquisitions to predict spinal curvature in AIS: a prospective validation study
A surface-topography app showed only moderate-to-poor agreement with X-ray for curve magnitude — useful for screening, but not yet a replacement for radiographs and in-person evaluation.
Research summaries on this page are drawn from peer-reviewed literature indexed in PubMed and are provided for educational purposes. Individual studies evaluated various apps and devices, not necessarily this specific app unless stated. Last reviewed June 2026 by Dr Kevin Lau, D.C.