Summary
Highlights
The presenter demonstrates the setup, placing the EMG Channel 1 on the orbicularis oris and Channel 2 (stimulation electrode) on their forearm for visibility. They show how to capture the target EMG level by asking the patient to perform the desired action (e.g., swallow, squeeze lips) and then setting the trigger threshold to about 50% of the maximum captured activity. They then adjust stimulation parameters like ramp time (1 second), stimulation duration (3-4 seconds), and relaxed time (15 seconds).
The presenter starts the EMG-triggered stimulation. They demonstrate how squeezing their lips (simulating a swallow) triggers the stimulation to their forearm. The device provides feedback, and the arm visibly extends due to the stimulation. They also show how the 'relaxed time' prevents immediate re-stimulation after a trigger, allowing the patient to recover before the next attempt. The demonstration highlights the smooth transition from detection to stimulation.
The video concludes by emphasizing that while EMG-triggered stimulation can seem complex, it becomes straightforward with practice. The presenter encourages users to practice on themselves to gain an intuitive understanding of the process and its application to patients.
EMG triggered stimulation involves monitoring muscle activity on one channel and, when it reaches a certain level, delivering stimulation to that muscle or other muscles. This creates interesting clinical scenarios, especially for patients with paralysis or difficulty initiating movement. The stimulation can be delivered to the same channel being monitored or to other channels.
For the EMG setup, Channel 1 (blue channel) is always the monitoring and triggering channel. You need to set a target level for EMG activity that will trigger stimulation. This target should be low enough for easy triggering but high enough to minimize inadvertent triggers. Patients should not look at the screen during this process to avoid confusion.
For the stimulation setup, consider several parameters: duration (long enough to cover the activity like a swallow), intensity (strong enough to meaningfully assist contraction), ramp time (how quickly the stimulation reaches full intensity, often short for swallowing), and a recovery time (a period after stimulation when the device won't trigger, allowing for patient rest or other actions). Frequency and phase duration should follow established protocols.
One clinical example is assisting hyolaryngeal approximation during swallowing. The EMG channel is placed under the chin (submandibular triangle) to detect swallow initiation. The stimulation channel is placed over the thyrohyoid muscle. When the patient attempts to swallow, the EMG triggers stimulation to the thyrohyoid, assisting with the movement. A very short ramp time is crucial here for proper timing.
Another example is for mouth closure in stroke patients with unilateral weakness. The EMG channel is placed on the orbicularis oris muscle of the 'good' side to detect mouth closure. The stimulation channel is placed on the impaired side, similar to a cranial nerve 7 placement, to facilitate the buccinator and orbicularis oris. The video also discusses using the EMG channel to indicate swallow beginning and stimulating various VitalStim positions to assist an effortful swallow.