Frequently Asked Questions

Equipment Use

No. All Delsys EMG Systems are classified as medical devices, and as such must conform to rigorous medical standards. Delsys sensors are critical components of these EMG Systems. Separating the EMG sensor from the rest of the System constitutes a violation of the Quality Assurance procedures established to ensure that compliance is maintained. Safety requirements such as isolation voltages and leakage currents, as well as signal quality performance specifications cannot be guaranteed by Delsys when the sensors are operated in unknown environments, with untested systems.

Delsys EMG systems are not approved for use in MRI machines. MRI machines make use of very strong magnetic fields that may induce unwanted currents in metallic objects they traverse. The sensitive electronic components used in Delsys EMG systems will be highly susceptive to these magnetic fields. More importantly, these unwanted current could result in patient harm or equipment damage. In general, metallic objects inside the MRI chamber will cause distortions of the resulting images. All conductive materials will be subject to these deleterious effects, some more than others. Ferrous objects exasperate these difficulties since these will also generate real magnetic forces when subjected to magnetic fields. Any research that introduces metallic objects in the MRI chamber should discuss the application with the MRI manufacture, since subtle safety and performance matters must be considered.

Yes, many studies and applications have successfully employed Delsys EMG sensors and systems on animals. Be sure correctly identify appropriate muscle sites and remove all fur/hair prior to applying the sensors. Wipe the site carefully with isopropyl alcohol to remove all oils and dry dermis. Apply the sensor with the arrow on top parallel to the muscle fibers of interest, and use the Delsys Adhesive Interface to affix the sensor to the skin. In highly dynamic situation it may be necessary to wrap the EMG sensor with additional tape or elastic bandages.

Input Module CableThe most likely cause is a problem with the Input Module cable. Check the cable carefully, making certain that it is not damaged or excessively twisted. Additionally check the cable connectors to ensure that the contacts and connector shell are not damaged. If the connector is forced to mate upside-down, the shell will become damaged and protective fuses in the Main Amplifier will expire. In this case the cable will need replacement and the Bagnoli™ Main Amplifier will need to be returned to Delsys for repair. The bottom connector shows a deformed shell, indicated by the yellow arrows. This damage is attributed to a forced connection with upside-down orientation. Contrast this to the undamaged top connector shell.
Delsys devices are not designed to be used with stimulation devices.

The fundamental performance issue is the amplitude of the detected stimulus as recorded by the DE-2.1 sensor. An amplitude at the recording site that exceeds +/-5mV will saturate the system. This may cause the artifact tail to extend for some time before the amplifiers recover. If the latency of your evoked response is short, the information of interest may be masked in the artifact tail.

The sensors are powered with +/-5V. An input signal below this value may cause saturation but should not cause damage. Inputs above +/-5V should be presented with caution, as voltages exceeding this range may damage sensitive components.

The true amplitude of the detected artifact is generally unknown apriori, since the stimulus undergoes a transformation as it traverses the body as a volume-conducted wave. This artifact is often quite large and may mask the evoked signal of interest. Latency between artifact and evoked response is generally maximized so that the effect of the artifact tail on the signal is diminished.

All Delsys products that produce an analog signal output can be connected to any A/D card that can support +/-5V analog signals and is controlled by appropriate software.

However, when using Delsys software (EMGworks®), it is only possible to use the specific A/D cards that have been tested and approved. Please refer to the software section of our web site for a listing of current compatible A/D cards.

Click here for a listing of Delsys software comparable A/D cards.

There are three methods available for integrating additional external signals to Myomonitor recordings.

1) The preferred method is to use a Delsys Biosignal Sensor, than can connect directly to any available channel Myomonitor. Contact Delsys for custom modifications and/or custom sensors.

2) For situations where an external data acquisition system is available,the Myomonitor Analog Output System can be used to recreate the analog signals and connect these to the acquisition system. This option is typically chosen when the external system and software supports EMG signals, and other dedicated equipment such as motion capture cameras and force plates are needed in the setup.

3) For situations when an external data acquisition system is available, but it cannot support additional analog EMG signals, then the Myomonitor device can synchronize with this A/D card by use of input and output triggers.

Please refer to the technical note TN-301 for in-depth details on Myomonitor data integration and synchronization.

The most likely cause is a wrong power supply. It is important that you only use the power supply supplied with the Myomonitor, since any other power supply may damage the device. The Myomonitor power supply is manufactured by “Phihong” and is MODEL PSA31U-090. This number is clearly listed on the power supply label.

Depress and Hold the ‘ON/OFF’ button on the Myomonitor. While holding this button in a depressed state, use the stylus to depress the ‘RESET’ button for at least 2 seconds. Release the ‘RESET’ button, and continue to hold the ‘ON/OFF’ button until the crosshairs for a screen calibration appear. This will perform a complete reboot of the Myomonitor device.