Suppressing Functional Electrical Stimulation Artifact from Facial Surface EMG Measurements
Research output: Other conference contribution › Paper, poster or abstract › Scientific
|Publication status||Published - 25 Nov 2016|
|Event||BioMediTech Research Day 2016 - Tampere, Finland|
Duration: 25 Nov 2016 → …
|Conference||BioMediTech Research Day 2016|
|Period||25/11/16 → …|
Facial EMG signals typically have amplitudes up to a few hundreds of microvolts. The activation of facial muscles with functional electrical stimulation may require stimulation voltages that are more than 10^6 times larger. When electrical stimulation is fed to the paralysed one side of the face, the introduced voltage will also couple to the EMG measurements on the healthy side. This coupling is called the stimulation artifact. In the worst case, the EMG measurement inputs will saturate leaving it impossible to correctly detect facial muscle activations and their activation intensities. Additionally, the stimulation artifact may be erroneously detected as a muscle activation.
The presented methods for suppressing the stimulation artifact from EMG measurements include filtering implemented in the hardware and software, manipulating the stimulation waveform to help removing it with filtering, and sample-and-hold functionality implemented in the hardware of the EMG signal measurement chain to prevent amplifier saturation and to allow faster recovery from the artifacts. The methods are demonstrated with experimental results.