JMIR Publications

ABSTRACT

Background:

Developing new clinical measures for degenerative cervical myelopathy (DCM) is an AO Spine RECODE-DCM Research priority. Difficulties detecting DCM, and change in DCM, cause diagnostic and treatment delays in clinical settings and heightened costs in clinical trials due to elevated recruitment targets. Digital outcome measures can tackle these challenges due to their ability to measure disease remotely, repeatedly, and more economically.

Objective:

To assess the validity of MoveMed, a battery of performance outcome measures performed using a mobile phone application, in the measurement of DCM.

Methods:

Design: Prospective observational study. Setting: Decentralised secondary care in England, United Kingdom. Participants: 27 adults aged 60 (SD: 11) who live with DCM and possess an approved smartphone. Primary and secondary outcome measures: Criteria from the Consensus-based Standards for the selection of health Measurement Instruments (COSMIN) manual were used to assess validity and risk of bias. Briefly, each MoveMed outcome was compared to two patient-reported comparators, and a priori hypotheses of convergence/divergence were tested against consensus thresholds. The primary outcome was the correlation coefficient between the MoveMed outcome and the patient-reported comparators. The secondary outcome was the percent of correlations in correspondence with a priori hypotheses. The comparators were the patient-derived modified Japanese Orthopaedic Association (P-mJOA) score and the World Health Organization Quality of Life Brief Version (WHOQOL-Bref) questionnaire. Thresholds for convergence/divergence were ≥0.3/<0.3, and >0/<0 for directionality.

Results:

Results:

As expected, MoveMed’s tests of neuromuscular function correlated most with questionnaires of neuromuscular function (≥0.3) and least with questionnaires of quality of life (<0.3). Furthermore, directly related constructs correlated positively to each other (>0), while inversely related constructs correlated negatively (<0). Over 70% and 50% of correlations (unidimensional and multidimensional, respectively) were in accordance with hypotheses. No risk of bias factors from the COSMIN Risk of Bias checklist were recorded. Overall, this was equivalent to ‘very good’ quality evidence of sufficient construct validity in DCM.

Conclusions:

Conclusions:

Criteria from COSMIN provide ‘very good’ quality evidence of the validity of the MoveMed tests in an adult population living with DCM.