Interacoustics Eclipse Additional Information page 119

Eclipse Additional Information Page 109
4. EMG scaling
Many prefer to scale after recordings are completed. After the recording is complete, you can right click the
waveform and choose EMG Scaling.
Waveforms will then be scaled according to the average of the EMG values recorded throughout the collec-
tion. This will make individual recordings comparable, even though slightly different degrees of muscle tonus
may have been applied during the different recordings.
The mean rectified EMG, an average RMS EMG for each recording, is calculated from the pre-stimulus
EMG. To normalize the raw VEMP amplitudes, the recording is scaled by a factor. The factor depends on the
EMG size recorded from each pre-stimulus period. This is possible because the system is calculating the
RMS levels throughout the measurement, which is used in the EMG scaling to allow for more accurate com-
parison between the individual scaled right and left VEMP response.
HINT The display can be increased or decreased by using the arrows on the top left side of the recording
window or by using your keyboard arrows.
Example of EMG scaling
Before EMG scaling is applied After EMG scaling is applied