DENVER – A simple illusion created using a mirror provides a low-cost, low-risk therapy for phantom limb pain in the intensive care unit, a study has shown.
Investigators at Walter Reed Army Medical Center have reported that mirror therapy for phantom limb pain was strikingly effective in a randomized, sham-controlled trial when used on an outpatient basis in rehabilitation therapy for individuals capable of sitting upright in a chair (N. Engl. J. Med. 2007;357:2206-7). But it can work in a bed-bound ICU patient as well, Dr. Nicholas H. Carter reported at the annual meeting of the American Neuropsychiatric Association.
He presented a case report involving a 24-year-old woman with systemic lupus erythematosus who developed severe, drug-refractory phantom limb and stump pain following a series of surgeries that culminated in an above-the-knee amputation of her left leg. Her hospitalization was prolonged because of numerous complications, including pneumonia, bilateral pneumothoraxes, sepsis, and pericardial effusion with tamponade. She had stump pain that improved only modestly, from 10 on a 10-point scale to 8, in response to hydromorphone. The patient also had two to three episodes of excruciating phantom limb pain per day, each lasting 10-15 minutes; numerous medications failed to provide any relief.
With the patient in a semi–Fowler’s position in her ICU bed and her stump and pelvis draped with sheets, a 2-by-3-foot mirror was positioned between her legs in the parasagittal plane so she could see the reflection of her exposed bare right leg.
Immediately prior to the initial session of mirror therapy the patient rated her stump pain as a 9, and 10 minutes earlier she had experienced what she described as a shock of phantom limb pain. After viewing the mirror for just 3 minutes, the patient reported that her stump pain had decreased to 4, with no further phantom limb sensations, according to Dr. Carter of Brown University, Providence, R.I.
The mirror was brought out again every time the patient felt the onset of phantom limb pain. She reported that 3-5 minutes of viewing the mirror typically decreased the phantom limb pain intensity from 7 to 3. Instead of lasting 10-15 minutes, as previously, the episodes now lasted about 5 minutes and decreased in number from two to three per day to one truncated episode per day or none. This was accompanied by complete resolution of the intense phantom itch.
Interestingly, the patient’s stump pain responded only to her first viewing of the mirror, Dr. Carter said. Subsequent sessions or mirror therapy had no substantial benefit for the stump pain.
This case sheds little new light on the mechanism of benefit for mirror therapy, a topic of considerable debate in the medical literature, he noted.
Some researchers have theorized that limb amputation may cause central neurologic remapping and deranged cortical output, which gets interpreted as pain. The theory that proprioceptive memory of the amputated limb accounts for phantom limb pain enjoys wide popularity.
Regardless, it’s axiomatic that when multiple senses provide conflicting input to the brain, vision trumps. Mirror therapy might activate mirror neurons in the brain hemisphere contralateral to the amputated limb and provide visual feedback against painful proprioceptive stimuli, Dr. Carter suggested.
He said he had no relevant financial disclosures.