3D back shape in healthy young adults: an inter-rater and intra-rater reliability study.
Whilst postural evaluation of spinal dysfunction is routine in physiotherapy practice, objective measurements are rarely undertaken due to the scarcity of reliable low cost assessment tools. Warren et al [12] found high intrarater reliability but inter-rater reliability has not as yet been evaluated. The purpose of this study was to assess both the intra-rater and inter-rater reliability of the Middlesbrough Integrated Digital Assessment system (MIDAS).


METHODS
A convenience sample of twenty-five healthy University of Teesside students was recruited for the study. One rater palpated fifteen key landmarks on each subjects back. Each of three raters took two measurements on each subject in a standardized upright posture. Rater order was randomized to minimize data recording bias. X (medio-lateral), Y (antero-posterior) and Z (height) landmark positions were recorded via a computer interface.


METHODS
Intraclass Correlation Coefficients (ICC 2,1) were used to analyse data using SPSS v13.


RESULTS
Both intra-rater agreement (mean ICCs - rater 1 r= 0.970, rater 2 r= 0.965 and rater 3 r= 0.965, p<0.001) and inter-rater agreement (mean ICCs r = 0.967, p<0.001 was very high between repeated measures and between markers. Error values for the z-axis (height) were lowest.


CONCLUSIONS
The system demonstrated both high inter-rater and intra-rater reliability. Before the system is used on a clinical population, data output needs to be converted from raw format to a clinically applicable format. Work is currently being undertaken to develop an interactive visual display and control for postural sway.
McAlpine
R T
RT
Darlington Memorial Hospital, Hollyhurst Road, Darlington, DL3 6HX, UK.
Bettany-Saltikov
J A
JA
Warren
J G
JG
D000328:Adult; D019317:Evidence-Based Medicine; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000295:instrumentation*; D017116:Low Back Pain; D008297:Male; D011187:Posture; D006113:United Kingdom