Abstract:Accurate and reliable pain assessment(PA) is crucial for formulating effective treatment plans. However, traditional methods of PA relied on patient self-reporting or pain rating scales with certain limitations. In recent years, the development of artificial intelligence(AI) technology has provided new perspectives for PA. This paper reviews the current state and future trends of AI applications in the field of PA, exploring the working principles of AI and its application in PA. This article first introduces the importance of PA and the shortcomings of existing methods, then discusses in-detail AI-based PA methods, including behavior-based methods and neurophysiology-based pain detection methods. The early machine learning algorithms such as support vector machines, decision trees, and random forests, as well as recently emerging deep learning techniques, including convolutional neural network(CNN) and recurrent neural network(RNN) were further analyzed. The advancement of these technologies has significantly improved the accuracy and reliability of PA. Finally, this article discusses the importance of explainability and ethical issues when AI is applied to pain research and management. The purpose of this paper is to provide readers with a comprehensive perspective on the application of AI in automatic PA and to explore potential research directions to advance the field further.