Intra- and inter-examiner reliability of the head postural assessment by computerized photogrammetry

Scientific articles about reliability of photogrammetry for cervical spine posture evaluation are infrequent. The aim of the present investigation is to verify intra- and inter-examiner reliability of computerized photogrammetry method for head postural evaluation in lateral view. Twenty-five young women between 20 and 30 years old were positioned seated in an upright position and photographed in lateral view. The photographs were imported to Corel Draw X13 program for postural evaluation by computerized photogrammetry. The reliability of intra- and inter-examiner analyses were performed for the angles: condyle-acromion (ACA), menton-sternum (AME) and Frankfurt (AF). The photogrammetry was performed by two examiners: EA and EB. The EA performed analysis of the photos of participants twice (A1 and A2) for the same angles in a range of three months to assess intra-examiner reliability. The EB performed the photogrammetry for the same angles (B1) for comparison with the data from EA (inter-examiner analysis). Excellent correlation in the intra-examiner analysis (A1 and A2) was found for the angles: ACA and AME, both with a 1.0 interclass correlation coefficient (ICC); for the AF angle, it was found ICC=0.78. For the ICC inter-examiner between A1 and B1, it was observed: ACA (ICC=0.24), AME (ICC=0.26), and AF (ICC=0.00). For the comparison between A2 and B1 the ICC values were: 0.23; 0.27; and 0.00, respectively for ACA, AME and AF, classified as weak correlations. The photogrammetry is reliable when performed by the same examiner. The inter-examiner assess showed low reliability, what could have been compromised by the reduced experience of the EB in applying the method.