Output details

Dynamic Facial Prosthetics for Sufferers of Facial Paralysis

Leading the Design for Health and Wellbeing research group, Breedon uses product design strategies to deploy Design expertise for innovative solutions related to smart materials and systems, integrating advanced design principles and materials to contribute to the health sector. The group’s novel design approach to medical ‘in vivo’ devices communicates the potential of smart materials for designers, technologists and other practitioners.

This article discusses the methods and materials used by the group in the design and fabrication of active artificial facial muscles to reanimate paralysed or atrophied muscles of sufferers of non-recoverable unilateral facial paralysis. The system senses motion of the contralateral healthy muscles and replicates it on the paralysed side of the patient’s face, via solid state and thin film actuators. The paper details achievements and future plans directly linked to Breedon’s other outputs that focus on fabricating actuation structures e.g. using auxetics. It addresses the strengths and shortcomings of various ‘smart’ materials whilst examining both design practice and design methods.

Following Breedon and Vloeberghs’ investigation of the use of Shape Memory Alloys as dynamic facial prosthetics for sufferers of facial paralysis this development of facial prosthetics focused on recreating a varying intensity smile, emphasising timing, displacement and the appearance of the characteristic smile wrinkles that appear around the nose and eyes.

After recording and analysing measurements of various subjects, an animatronic face was constructed with actuations being made to a silicone representation musculature, using multiple shape-memory alloy cascades. Alongside the prototype, a facial expression recognition software system was constructed to form the basis of automated calibration and reconfiguration for the artificial muscles following implantation, customised to a patient's unique physiognomy. This work has led to a more ambitious facial reanimation project with the Queen Victoria Hospital, West Sussex, and NIHR funding of £350k for treatment of stroke patients.