Design and manufacture of a forearm prosthesis by plastic 3D impression for a patient with transradial amputation applied for strum of a guitar

At the present, the development of prostheses has been extremely wide and focused on restoring the patient to their daily activities. Nevertheless, not much has been done to restore the capability of playing musical instruments, perhaps due to the complexity and sensibility needed to perform certain movements. For example, the fingering movements on a guitar or a piano, are random and require of different amounts of force to be applied to the instrument. Furthermore, the playing of an instrument is accomplished by muscular memory. Nowadays, in order to emulate such movements, the application of robotically programmed prostheses has improved. Nevertheless, this is not a good option for musicians, as this solution do not offer the sensation of actually playing the instrument. One of the options to achieve the mentioned aim, would be the development of mechanical prostheses that apply myoelectric technology, however these devises do not possess sufficient sensibility to perform the movements needed to play an instrument. In this research, a mechanical design to be manufactured using 3D impression of a forearm prosthesis for a transradial amputated patient that is able to be used to play the guitar, is presented. The prosthesis is capable to provide the service for basic rehabilitation or train a recently amputated patient recently amputated. The proposed prosthesis was manufactured by the use of a plastic 3D impression machine using ABS-P400 strings. The prosthesis consists of two parts; the first one is the main socket that is attached to the forearm while the second part, that supports the nib guitar. The mechanical design of the prosthesis was based on data obtained by videometry of a musician developing the basic strum on a guitar. With these data was possible to define the basic strum technique, the movements that are involved (displacements, speed, acceleration, forces, etc.) and the joints involved in the strum of a guitar. The obtained results are very encouraging, since the prosthesis can be applied to restore the musician ability to perform the basic tasks to execute on his instrument, as well as, rehabilitation activities. This first proposal could be optimized to produce a final product with higher quality and with a wider area of applicability.