About this Research Topic
Major limb amputation affects a large number of people worldwide, with estimates in the United States as high as 2 million. One of the most common conditions following limb amputation is phantom limb sensation. The majority of patients who have undergone traumatic limb loss also experience phantom limb pain (PLP). There is no consensus on potential differences in the frequency or severity of phantom pain between men and women. This project is seeking out studies that look at the experience of PLP: what people feel, frequency and duration of PLP episodes, if there is a difference in experience between men and women, as well as if there is a relationship between PLP experiences and cause of amputation.
Although PLP has been recognized since the mid-16th century, the etiology is still unknown. There are several proposed mechanisms, including learned paralysis, cortical reorganization, and proprioceptive memory. It has been proposed that the mechanism of learned paralysis, whereby PLP arises because the brain does not receive visual feedback that a motor movement has occurred, thus creating the sensation that the limb is paralyzed. Cortical reorganization theory states that areas near those corresponding to the amputated limb slowly expand into those corresponding to the amputated limb. This theory has been supported by the correlation of more severe PLP with increased neural plasticity. Proprioceptive memory refers to a theory that the brain remembers sensations associated with specific perceived positions of the phantom limb. This project welcomes any study concerning the cause of phantom limb pain, as well as any new proposed mechanisms.
While many treatments for PLP have yielded little success, mirror therapy (MT) appears to be a promising method for relieving PLP. Several small-scale studies have been conducted to evaluate the efficacy of MY, with most patients seeing some reduction in PLP. One group performed the first randomized, sham-controlled study demonstrating that MT was more effective in reducing PLP in lower-limb amputees compared to covered mirror therapy or mental visualization of movements. The efficacy of nearly complete pain relief continued for at least 2 years after therapy. The physiological reason for mirror therapy’s effectiveness remains unknown, but the effectiveness would correspond with the theory of cortical reorganization in that MT would reset the original reorganization present in the brain before amputation and would also support the theory of proprioceptive memories in that it could remove recall of those memories. This project will discuss further investigation into the factors relating to success in MT, as well as the efficacy of MT in relation to proposed mechanisms that cause PLP. Discussion of other forms of novel treatment will also be included.
This Research Topic attempts to further explain the etiology of phantom limb pain, better understand the experience of phantom limb pain, and explore treatment options for phantom limb pain. This project will include a review of the current understanding of phantom limb pain, its causes, and treatment. Article types appropriate for submission include case reports, original investigations, hypothesis and theory, technology reports, empirical studies, clinical trials, opinions and perspectives.
Keywords: Phantom limb pain, amputees, mirror therapy, phantom limb sensation, neurology
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