Examining accuracy of and determining the best cutoff point for photographic-based postural angles to discriminate between slight and moderate-to-severe forward head posture

Purpose To evaluate the accuracy of and determine the best cutoff point for craniovertebral angle (CVA) and forward shoulder angle (FSA) in discriminating between two groups of individuals with different severities of forward head posture (FHP). Methods A sample of 90 subjects aged 20-50 who had different severities of FHP was recruited. Participants were categorized into two groups based on observational method, namely individuals with slight FHP and those with moderate-to-severe FHP. The CVA and FSA were assessed using the photographic device. The accuracy of these measures was determined by calculation of sensitivity, specificity, area under the receiver operating characteristic curve, likelihood ratio (LR), and predictive value (PV). Results Our results show that CVA has high sensitivity (0.93) and acceptable area under the curve (0.88) in discriminating between the two groups of FHP (P < .01), but FSA cannot discriminate between the two groups of FHP (P = .06). The LR and PV results show that the CVA has a low negative LR (0.13) and a large negative PV (0.93). The best cutoff point for CVA was determined at 45.5 degrees. Conclusion Overall, the results of the present study showed that CVA has a good accuracy in discriminating between two groups of individuals with slight and moderate-to-severe FHP. It can be valuable in correctly identifying the slight FHP and screening the moderate and severe grades of the FHP. Researchers and clinicians can also use the optimal cutoff point for the CVA obtained in this study to accurately quantify and classify the severity of the FHP.