Document Type : Research Paper


Electrical Engineering Dep., University of Technology-Iraq, Alsina’a street,10066 Baghdad, Iraq.


Pain is considered as an emotional experience and a restless feeling associated with tissue damage. When the interpretation begins in the brain, the sensation of pain occurs; a signal transmitted to the brain through the nerve fiber. Pain helps the body to stop further damage to the tissues. Since there are numerous ways to convey and feel pain, the perception of pain is special to all. Technology that promotes pain assessment is an urgent need to reduce restless feelings and suffering. This paper aims to demonstrate the issues and challenges facing the patient’s pain assessment based on facial expression. The design and implementation of an automatic pain recognition system and explain the various concepts relevant to it, such as the type of modalities, the procedure of collection and processing data sequentially to reach the classifier. Then presenting clarification for various signals as input data (facial expressions, body movement, and vocalization). This survey would positively help researchers to supplement their efforts towards the expansion of patients' pain assessment based on facial expression.


  • Automatic Pain Recognition (APR) reduces patient overcrowding in healthcare facilities. Especially during the time of epidemics, such as covid-19.
  • If the APR is not accepted by the physicians and the rest of the medical staff then this system will not give any chance to develop and obtain experimental results in real life.
  • Facial expression presented higher acceptability than other indicators of standing alone as an input signal for the automatic pain recognition system.
  • More efforts must be made to collect the data and make it available.


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