In EMG biofeedback, what does setting the sensitivity low do to the amplitude of signals from hypertonic muscles?

In EMG biofeedback, what does setting the sensitivity low do to the amplitude of signals from hypertonic muscles?

• A. Increases amplitude of hypertonic muscle signals
• B. Has no effect on amplitude
• C. Eliminates all signals
• D. Decreases amplitude of hypertonic muscle signals

Answer: (D)

Sensitivity in EMG biofeedback is the gain applied to the raw muscle electrical signal. When you set the sensitivity to a low level, the system amplifies the EMG signal less, so the displayed amplitude shrinks. Hypertonic muscles tend to produce stronger signals, but lowering sensitivity reduces the displayed output for those signals as well. So the amplitude shown for hypertonic muscle activity decreases with low sensitivity. Raising sensitivity would increase the display amplitude, while this setting does not eliminate signals or leave them unchanged.

Sensitivity in EMG biofeedback is the gain applied to the raw muscle electrical signal. When you set the sensitivity to a low level, the system amplifies the EMG signal less, so the displayed amplitude shrinks. Hypertonic muscles tend to produce stronger signals, but lowering sensitivity reduces the displayed output for those signals as well. So the amplitude shown for hypertonic muscle activity decreases with low sensitivity. Raising sensitivity would increase the display amplitude, while this setting does not eliminate signals or leave them unchanged.