JOVE Video Publication
We have published a JOVE video article showing how to set up the EMG and perform TMS, but you may need JOVE journal access from your institution to view it. This is the most comprehensive video showing the TMS session from setup to completion with MEP interpretation. Please note some differences between this published video and the VERIFY TMS protocol:
- Five MEPs are not needed to classify someone as MEP+ for VERIFY as indicated in the published video.
- ECR electrodes are placed in a belly-tendon montage for VERIFY, not both over the muscle belly as in the published video.
Determining the Functional Status of the Corticospinal Tract Within One Week of Stroke
VERIFY Training Videos
Below are short videos showing how to set up the EMG recordings and position the TMS coil using a MEGA-TMS system. The videos feature Sian McGee who is an Occupational Therapist that uses TMS to determine MEP status as part of her routine clinical practice at Auckland City Hospital.
Please note that the disposable items needed for TMS such as the razors, alcohol wipes, and prep tape are not supplied with the MEGA-TMS machine and need to be purchased by each site. Only one pack of electrodes is supplied with the MEGA-TMS machine and further electrodes will also been to be purchased by each site. There is no mandatory brand of electrodes to use but we recommend using these 3M electrodes or something similar. It says they’re pediatric but they still work for TMS, and they work with the electrode cables that came with your MEGA-TMS machine. For stroke patients the costs for these items are covered in the per patient payments, while disposables for healthy volunteers are covered by the set up payment(s) that sites receive.
Bilateral Facilitation
This updated video shows how to ask the patient to perform bilateral facilitation and stimulate them during facilitation. The patient should be stimulated during bilateral facilitation if no MEPs are observed at 100% intensity while the participant is at rest. This voluntary activity may allow you to observe MEPs and classify the patient as MEP+.
Please note how the TMSO in the video is encouraging the patient during bilateral facilitation, and the TMSO is moving the coil around on the participant’s head during the 3 stimulations.
Skin Preparation
This 3 minute video shows the steps in locating the ECR muscle belly, preparing the skin, and applying the EMG electrodes. Note that you can use either skin preparation tape or an abrasive cream or gel to exfoliate the skin.
Ask the patient to extend their wrist with their fist closed if they are able. This can help identify the ECR muscle body and isolate it from the extensor digitorum muscle body. If the patient is unable to extend their wrist then the ECR muscle belly can be found by palpating the large brachioradialis muscle belly that runs along the radial (lateral) border of the forearm, and then rolling your fingers off to the extensors, which should lead to palpating the ECR muscle belly. The ECR muscle belly should be along an imaginary line running from the lateral epicondyle of the humerus to the styloid process of the radius.
The FDI muscle body is located slightly proximal to the webbed space between the thumb and index finger on the dorsal side of the hand and can be palpated by having the patient abduct their index finger if possible.
Taping Electrode
This 10 second video shows how to tape down the edge of the electrode over the FDI muscle belly, if it isn’t sticking well to the web of the thumb.
EMG Connections
This 2 minute video shows positioning of the ground strap and connecting of the EMG electrodes to the EMG system via the cables. Top tip: untangle the cables before you start preparing the patient.
Starting the Software
This 1’20’’ video shows starting the MEGA-TMS software, checking the EMG signals, and checking the electrode impedance.
Please note that for the MEGA-TMS system the button for checking electrode impendence is on the top left corner of the Focus EMG unit labelled “electrode test.”
Reducing Biological Noise due to Muscle Activation
This 30 second video shows repositioning of the arm to relax the ECR muscle and reduce biological noise due to muscle activation in the EMG trace. In this scenario, adding a pillow under the person’s arm helped them to relax their muscles. Other strategies include asking the patient to drop their shoulders, or let their hand and arm feel heavy and fully supported by the pillow.
Initial Coil Position
This 2’30’’ video shows how to use anatomical landmarks to position the center of the TMS coil over the primary motor cortex. Note that the center of the coil is marked with a small square on its upper surface. This should be positioned over the inter-aural line, approximately 2 inches lateral to the vertex.
Coil Positioning Tips
This 1’10” video shows how to avoid coil positions that are too anterior, medial, or posterior, and will miss the person’s primary motor cortex.
Finding MEPs
This 1’20” video shows how to move the coil in small steps to check different coil positions, then increasing the stimulus intensity if no MEPs are observed. Note that MEPs are easily observed on the laptop screen in the background once the intensity is increased to 40%.
Coil Orientation Tips
This 40 second video shows some of the common problems that can occur with the orientation of the coil. It’s important to keep a consistent coil position and orientation, with the center of the coil flat against the patient’s head.
Coil Angle Tips
This 20 second video shows how to hold the coil at the correct 30 to 45 degree angle.
MEGA-TMS Traces Viewing Options
The short video below summaries how changing the visualization of EMG traces in the MEGA-TMS software can assist with MEP status determination. Please note the closed captions were automatically generated and are highly inaccurate.