Intramuscular electromyograms (EMG) are believed to provide several potential advantages over surface EMG for multifunctional myoelectric prosthesis control. One example is the ability to focally record from deep muscles of the forearm. However, intramuscular EMG has rarely been investigated due to the inability to obtain chronic recordings. New technology is emerging that may make chronic recording of intramuscular EMG clinically feasible. Additionally, while previous investigations of surface systems have either used electrodes targeted to specific muscles or in an untargeted array, no work has compared these two approaches. Untargeted electrodes would be preferable for both intramuscular and surface recordings because they are easier to implement. The classification accuracies of pattern recognition-based classifiers utilizing surface and intramuscular as well as targeted and untargeted electrodes were compared. A repeated-measures ANOVA analysis revealed that when additional EMG signal features were extracted, no statistical difference was observed in the classification accuracies between the electrode conditions across eleven subjects. It was concluded that untargeted surface electrodes provide the simplest and most cost-effective method of achieving high classification accuracies and any advantage gained by intramuscular electrodes for pattern recognition based classifiers would result from advantages in clinical implementation (i.e., faithfully providing the same recording site with daily donning and doffing of the prosthesis). During the investigation of the different electrode conditions it was discovered that a tradeoff exists when considering the delay created by multifunctional prosthesis controllers. Large controller delays will maximize the time used for EMG signal collection and analysis (and thus maximize classification accuracy); however, large delays can decrease responsiveness and degrade prosthesis performance. To elucidate an 'optimal controller delay,' twenty able-bodied subjects performed the Box and Blocks test using PHABS (Prosthetic Hand for Able Bodied Subjects). Tests were conducted with seven different controller delay levels ranging from nearly 0 to 300 ms and with two different artificial hand speeds. A repeated-measures ANOVA analysis and a linear mixed effects model found the optimal controller delay to be approximately 100 ms for both hand speeds. Finally, equations that related EMG analysis window parameters to the prosthesis controller delay were derived

Last modified

• 08/01/2018

Creator

• Todd Richard Farrell

DOI

• https://doi.org/10.21985/N2C13D

Subject

• Biomedical Engineering

Keyword

• prosthesis
• EMG
• electrode
• delay
• multifunctional
• intramuscular

Date created

• 07-17-2007

Resource type

• Dissertation

Rights statement

• In Copyright