On Friday, we mainly looked at the materials that were sent to us on using a microphone and found that it was infeasible due to the ideal environment and expensive equipment required for the study that we looked at.
We then moved on and tried to detect swallowing using our EMG sensors. We tried two locations, below the chin as we had seen in another study and on the side of the face where we currently have our chewing EMG. For both locations we captured 1 minute of training data for both talking and swallowing. I drank about a little more than a gallon of water in the 2 minutes of capture for swallowing.
When we started looking at the chin electrode data things looked promising, because our training data was able to predict talking or swallowing with 85% accuracy. We soon learned that this was a fluke because our decision tree had been fit precisely to our training data and our testing data sets had an accuracy between 11% and 50%.
Detection of drinking on the side of the face was even worse our training set was only about 50% accurate.
After seeing these results we decided to search on line to see if anyone was able to detect swallowing using an EMG. It turned out again that this required an ideal situation. In this study, "oscilloscope traces were started at the examiner's order to swallow."
Basically what we have found is that the only way to detect swallowing is in an ideal environment where the user is only swallowing. The reasoning is that the muscles that one uses to swallow are used consistently when talking and doing other normal activities.
After 3 days of trying to get swallowing to work, we have decided to move on to packaging our product and making sure that the chewing mechanism works properly and that the user will get valuable feedback.