How long should you observe arm movement during drift testing?

• A. Approximately 30 seconds.
• B. Approximately 5 seconds.
• C. Approximately 2 minutes.
• D. Approximately 90 seconds.

Answer: (C)

In drift testing, you’re checking for a persistent loss of the ability to hold the arm in position, not just a quick wobble. You need enough time to reveal any gradual or fatigable drift that might develop as the patient maintains the position. About two minutes provides a solid window to observe for subtle or evolving drift and to confirm that any downward movement isn’t just a momentary slip. Shorter durations, like a few seconds, can miss drift that develops slowly, while much longer times don’t add diagnostic value and can fatigue the patient. So, roughly two minutes is the best balance for reliable detection.