Phantom Limb Neurology
Phantom limb symptoms can occur in anyone who has suffered the trauma of losing a limb. These symptoms are not just limited to pain. Any sensation that was there prior to amputation may be experienced. To understand phantom limb symptoms we must first understand some basics on how our brain functions.
Simply speaking, our brain works like a two lane highway. We have neurologic signals that travel from our brain to our body (efferent signals). We also have neurologic signals that travel from our body to our brain (afferent signals). For the purposes of this article we can also use the words motor signals for efferent commands and sensory signals for afferent input.
Afferent input to our brain is extremely important and provides the needed drive to keep our brains healthy. Without this sensory stimulation from our environment our overall brain function declines and this decline can lead to symptomatic changes.
Our brains also have a map of our bodies. This map is called a homunculus. The homunculus represents where the neurons are that control or sense areas of the body. Some areas have a lot of neurons that are devoted to them while other areas do not.
Phantom limb symptoms occur because the neurons in the sensory homunculus are no longer receiving signals as they used to. For example, when a person has all of their appendages their arms are sending signals to the brain about muscle coordination, sensory changes such as hot/cold, hard/soft, etc… All of these signals are sent to our sensory cortex. These signals drive our sensory cortex to function properly and keep it healthy.
When someone loses a limb, these signals are no longer sent to the sensory cortex from that limb. As a result the neurons in the area of the homunculus that represented that limb begin to atrophy. When this atrophy takes place the neurons become unstable and can fire spontaneously. This spontaneous firing is what causes the symptoms that we feel. As an example, if the neurons that represented cold spontaneously activate, then you will feel cold in your amputated limb.
Treatment of phantom limb symptoms consists of providing sensory stimulus to the atrophied and spontaneously firing neurons in the sensory cortex. There are many ways of doing this and what works for one person may not work for another. Seeking out a physician that specializes in neurorehabilitation will be your best source of treatment. At our office only a few visits are required to teach each individual the best exercises to perform to keep their symptoms at a reduced level. These exercises are likely to include the use of mirrors and mental imagery. It is also highly recommended that each individual get a competent neurologic examination as there may be other areas that need rehabilitation as well.
Phantom limb symptoms can be managed and there is help for those suffering from these symptoms. In many cases only a few office visits are needed to learn the exercises needed to keep the symptoms at bay.
Dr. Dax K. Sirucek
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