Biofeedback for anismus: has placebo effect been overlooked?

Area of Science:

• Gastroenterology
• Physiology
• Clinical Medicine

Background:

• Anismus is a condition often treated with biofeedback, with prior studies suggesting its efficacy.
• However, the physiological underpinnings and the extent of placebo effect in anismus treatment remain unclear.

Purpose of the Study:

• To evaluate the physiological effects of biofeedback versus placebo in patients diagnosed with anismus.
• To correlate observed physiological changes with clinical symptom improvement.

Main Methods:

• Twelve anismus patients underwent assessment including symptom scales, anorectal manometry, and scintigraphy.
• They received 5 days of placebo treatment, followed by reassessment, then 5 days of biofeedback, followed by a final reassessment.

Main Results:

• Seven patients reported symptom improvement with placebo, and seven with biofeedback; three improved with both.
• Biofeedback uniquely improved anal pressure and electromyographic activity during defecation attempts.
• No correlation was found between symptom changes and physiological test results; rectal ejection fraction remained unchanged.

Conclusions:

• Clinical improvements in anismus may be partly attributed to placebo effects and observer bias.
• Observed physiological changes with biofeedback might not be captured by standard anorectal tests.