Validity, intratester and intertester reliability of a noninvasive quantitative forward head posture assessment method

Head Posture assessment is highly recommended in patients with neck pain in order to better diagnosis, planning the treatment strategies and monitoring progress. Considering the consequences of the radiation exposure associated with the repeated radiographic assessments of spinal curvature, attempts are continuously being made to develop skin-surface methods which often use non-commodious or unavailable devices, or non-comparable qualitative measurements, or they use photographic images which are not appropriate for women in Iranian culture. Therefore the aim of this study was to evaluate the validity and reliability of a non-invasive quantitative forward head posture assessment method which is easy, commodious and can be used for every group of subjects. Craniovertebral angle of 12 patients who were referred to a radiology laboratory was calculated from lateral cervical radiography image by a radiology specialist and were used as the reference value for each patient. Five minutes after the radiographic measurement, the patients were asked to stand with their back faced to wall. Then two testers measured the craniovertebral angle with the double square ruler for three times and the mean value of these craniovertebral angles were compared with the radiographic measurement for evaluating the validity. For evaluation of the intertester and intratester reliability, the craniovertebral angle of fifteen subjects (independent from those who were chosen in evaluating the validity) were measured three times (5 and 10 minutes after the first measurement for evaluating the intratester reliability) by each tester and the mean value of these three angles were used to evaluating the intertester reliability. The results presented the high validity for this method in relation to the radiographic image (r=0.857 and r=0.837), high intratester (r=0.895 and r=0.871 for measurements after 5 minutes and r=0.885 and 0.847 for measurements after 10 minutes) and high intertester reliability (r=0.933) between two testers. The results of this study showed that this quantitative method was highly valid and reliable. This newly developed method is easy, commodious and available and can be used in both sexes and we suggest this method as a proper alternative for measuring the craniovertebral angle for diagnosis, planning the treatment strategies and monitoring the progress of the rehabilitation program for the patients with forward head posture.