#10 Electrophysiological Measurements – Objective v. Subjective

Standard EMG is not objective. In spite of the complex science surrounding 1944 EMG the examination it is entirely subjective:

1. The patient reports when increasing shocks become strong enough to cause a muscle twitch.

2. The examiner subjectively attempts to visualize the twitch.

3. The examiner subjectively judges the sound of the muscle’s electrical activity.

4. The examiner judges the shape of the oscilloscope’s waveform.

In contrast both F-NCS and F-EMG are objective:

1. The potentiometer records the electrical amplitude released by the nerve or the muscle contracts.

2. The voltage stimulus strength initiating both of these is an objective measurement.