Phantom limb: feeling a limb that was lost

By: Hello Doctor Updated 30 May 2022, 18: 01 pm EDT

Have you ever heard that people with amputated limbs can feel pain or itching in the limb they lost?

This is called phantom limb syndrome. Here we review what science says about its possible causes.

It is estimated that 90% of people who have had a limb amputated may feel as if the limb is still there, including:

• Pain.
• Hot or cold.
• Numbness.
• Tingling.
• Mobility of the fingers that are no longer there.
• Punctures.

There are ways to alleviate or reduce these discomforts:

• Rubbing or exercising the remaining part of the limb to keep it warm.
• Tricking the brain through distractions, hobbies , relaxation techniques or exercises.
• Use non-invasive therapies, such as acupuncture.

The exact cause of this syndrome is currently unknown, although imaging from two centers research in Rio de Janeiro, Brazil, identified changes in how certain areas of the brain communicate, as a result of an amputation.

These alterations occur in the brain regions that control movement and process touch.

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Although there are many studies on phantom limb pain, the main author of this work Ivanei E. Bramati, a medical physicist at the D’Or Institute for Research and Education, said his research found there is an imbalance in brain function in patients who report phantom sensations, even if they don’t feel pain.

Their findings were published in Scientific Reports.

The secret of sensation

Brain plasticity is the ability of the brain to adapt its structure and function to changing situations.

There is a “general acceptance” that the adult brain can change in response to different factors:

• Learning.
• Stress.
• Drugs.
• Hormones.
• Stimulation.
• Aging.

In the new work, the authors refer to studies that have linked the phantom limb with a failure in brain plasticity. However, they also point out that more recent research has challenged this idea.

These contradictions suggest that the phantom limb could not be due to a cause, but to many.

To delve into this phenomenon, the researchers analyzed the brain connection in 9 individuals with lower limb amputation who experienced phantom sensations without pain, and 9 individuals without amputations.

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MRI revealed the following:

• Touching the stump of a limb caused the brain to overreact.
• Amputation seems to weaken the structure that connects and allows communication between the left and right hemispheres of the brain.
• The area that controls movement and touch of a limb is located on the side of the brain that is opposite the limb. itself.

Based on these findings, the authors concluded that the amputation of a limb can cause a disorder in the organization of brain connections, causing a variety of sensations.

Options to treat it

If the pain or discomfort caused by phantom limb syndrome becomes persistent, a doctor may prescribe some medications to find relief:

• Analgesics or opiates.
• Anticonvulsants.
• Antidepressants.
• Baclofen (muscle relaxant).
• Chlorpromazine (used to treat schizophrenia).
• Clonidine (useful against pain generated in the brain).

There is also research showing that stimulation of the nerves or regions of the brain involved in pain could help some patients. The most common options to achieve this are:

• Spinal Cord Stimulation: An electrode is placed and a small electrical current is applied to the spinal cord to relieve pain.
• Transcranial Magnetic Stimulation: It is a procedure that involves a strong magnetic impulse through the scalp to the brain. Although it is believed that this option would only provide temporary relief.
• Transcutaneous Electrical Nerve Stimulation: A small electrical current is sent through the skin to points along the nerve pathway.

Sources consulted: US National Library of Medicine, Mayo Clinic, National Institute of Mental Health.