Waveform symmetry refers to whether the waveform is balanced on both sides of the line.

• A. Based on the shape
• B. Are they the same on both sides of the line
• C. Amplitude relative to time
• D. Frequency content

Answer: (B)

Waveform symmetry is about balance around the baseline. It means the positive and negative portions of the waveform are mirror images about zero, so the areas under the curve on both sides are equal. When this balance exists, there is no net direct current component delivered over a cycle, which helps prevent electrode polarization and tissue damage. That idea is captured by describing whether the waveform is the same on both sides of the line.

In practice, symmetric (balanced) waveforms deliver equal positive and negative charge, which is desirable in many electrotherapy applications. The shape alone doesn’t guarantee balance, and the other concepts—how tall the peaks are over time or the signal’s frequency content—don’t describe whether the positive and negative halves are equal around zero.