When does polarity matter?

• A. Monophasic for wound care
• B. Symmetrical biphasic current
• C. High voltage galvanic
• D. Pulsed biphasic

Answer: (D)

Polarity is about which electrode is positive and which is negative, and how that direction of current affects the tissue at the electrode-tissue interface. When a current has a directional, unbalanced flow—like monophasic or high-voltage galvanic (direct current)—polarity directly drives chemical and physiological effects in the tissue, such as ion migration and pH changes, and the healing response can depend on which pole is placed where. Symmetrical biphasic current, which reverses polarity within each cycle, tends to cancel net charge over time, so the long-term chemical effects are minimized and polarity is less critical for the overall outcome. In pulsed biphasic stimulation, the waveform is bidirectional and delivered in discrete pulses; however, the leading phase and its polarity still influence the immediate tissue response, nerve recruitment, and comfort during stimulation, even though the overall charge balance is maintained. That combination makes polarity considerations most relevant in pulsed biphasic therapy among the given options, which is why this choice is the best answer.