Development of quantitative evaluation indices for caregiver posture during feeding of infants with cleft lip and/or palate.

Infants with cleft lip and/or palate (CLP) often experience feeding difficulties. The Kumagai method, a bottle-feeding technique using a long nipple, is effective but requires expert instruction, limiting training opportunities for caregivers. This study developed quantitative indicators to evaluate caregiver posture, a key component of the Kumagai method, as a step towards a posture guidance system. The proposed indicators include a Partial Index, which evaluates individual joint angles to identify those needing correction, and an Overall Index, which assesses the similarity between a learner's posture and that of experts. A receiver operating characteristic (ROC)-based threshold determines when to end guidance. Experiments using feeding postures from five experts and 10 untrained individuals showed that the determined threshold distinguished appropriate and inappropriate postures with 80% accuracy. These findings demonstrate the potential of the proposed indicators as evaluation metrics, providing a foundation for developing an effective feeding posture guidance system for CLP feeding.