Instruct: Given a question, retrieve relevant passages that answer the question.
Query: Is phantom pain experienced by amputees neurological?
Symptoms include:
Onset within the first few days of amputation.
Comes and goes or is continuous.
Often affects the part of the limb farthest from the body, such as the foot of an amputated leg
May be described as shooting, stabbing, boring, squeezing, throbbing or burning
Sometimes feels as if the phantom part is forced into an uncomfortable position
May be triggered by pressure on the remaining part of the limb or emotional stress
Phantom limb pain and phantom limb sensations are linked, but must be differentiated from one another. While phantom limb sensations are experienced by those with congenital limb deficiency, spinal cord injury, and amputation, phantom limb pain occurs almost exclusively as a result of amputation. Almost immediately following the amputation of a limb, 90–98% of patients report experiencing a phantom sensation. Nearly 75% of individuals experience the phantom as soon as anesthesia wears off, and the remaining 25% of patients experience phantoms within a few days or weeks. Of those experiencing innocuous sensations, a majority of patients also report distinct painful sensations.
Electromyographic (EMG) nerve-conduction studies may be required. X-rays may be needed to exclude bone abnormalities that might put pressure on the nerve; likewise CT or MRI scans to exclude soft tissue causes such as a tumor.
Abnormalities in the ascending and descending pathways involved in processing pain have been observed in fibromyalgia. 50% less stimulus is needed to evoke pain in those with fibromyalgia. A proposed mechanism for chronic pain is sensitization of secondary pain neurons mediated by increased release of proinflammatory cytokines and nitric oxide by glial cells. Inconsistent reports of decreased serum and CSF values of serotonin have been observed. There is also some data that suggests altered dopaminergic and noradrenergic signaling in fibromyalgia. Supporting the monoamine related theories is the efficacy of monoaminergic antidepressants in fibromyalgia.
Hallucinations of pain and touch are very rare in schizophrenic disorders but 20% of patients with schizophrenia experience some sort of tactile hallucinations along with visual and auditory hallucinations. The most common tactile hallucination in patients with schizophrenia is a sensation in which a patch of their skin is stretched elastically across their head. They vary in intensity, range and speed at which they feel this stretching painful sensation. They are usually triggered by emotional cues such as guilt, anger, fear and depression. Other types of tactile hallucinations takes on a sexual form in patients with schizophrenia. Patients with schizophrenia may sometimes experience the feeling of being kissed or the feeling of someone lying by their side in response to their emotion of being lonely. Additionally, they occasionally hallucinate the feeling of small animals such as snakes crawling over their body. Such vivid tactile sensation of an object that is not present results from the unsuccessful attempt of the brain trying to perceive objects that are novel and that represent unreal situations usually triggered by guilt and fear. Patients with schizophrenia also have a hard time portraying emotions as they divert most of their energy to control the pain from their tactile hallucinations.
Neurectomy is a surgical procedure in which a nerve or section of a nerve is severed or removed. Cutting a sensory nerve severs its basal lamina tubes, and without them to channel the regrowing fibers to their lost connections, over time a painful neuroma or deafferentation pain may develop. This is why the neurolytic is usually preferred over the surgical sensory nerve block. This surgery is performed in rare cases of severe chronic pain where no other treatments have been successful, and for other conditions such as involuntary twitching and excessive blushing or sweating.
Neurectomy involves cutting a nerve, and is (rarely) used in patients with short life expectancy who are unsuitable for drug therapy due to ineffectiveness or intolerance. The dorsal root or dorsal root ganglion (that carry mostly sensory signals) may be usefully targeted (called rhizotomy); with the dorsal root ganglion possibly the more effective target because some sensory fibers enter the spinal cord from the dorsal root ganglion via the "ventral" (motor) root, and these would not be interrupted by dorsal root neurectomy. Because nerves often carry both sensory and motor fibers, motor impairment is a possible side effect of neurectomy. A common result of this procedure is "deafferentation pain" where, 6–9 months after surgery, pain returns at greater intensity.
Functional MRI analyses of the anterior cingulate cortex have also led to the introduction of bilateral cingulotomy for the treatment of chronic pain. Such application was introduced since the anterior cingulate cortex has been found to be related to the processing nociceptive information input. In particular the role of the anterior cingulate cortex is in the interpretation of how a stimulus affects a person rather than its actual physical intensity.
The body's physical arousal response (vaginal lubrication and engorgement of the clitoris in women and erection in men) occurs due to two separate pathways which normally work together: psychogenic and reflex. Arousal due to fantasies, visual input, or other mental stimulation is a psychogenic sexual experience, and arousal resulting from physical contact to the genital area is reflexogenic. In psychogenic arousal, messages travel from the brain via the spinal cord to the nerves in the genital area. The psychogenic pathway is served by the spinal cord at levels T11–L2. Thus people injured above the level of the T11 vertebra do not usually experience psychogenic erection or vaginal lubrication, but those with an injury below T12 can. Even without these physical responses, people with SCI often feel aroused, just as uninjured people do. The ability to feel the sensation of a pinprick and light touch in the dermatomes for T11–L2 predicts how well the ability to have psychogenic arousal is preserved in both sexes. Input from the psychogenic pathway is sympathetic, and most of the time it sends inhibitory signals that prevent the physical arousal response; in response to sexual stimulation, excitatory signals are increased and inhibition is reduced. Removing the inhibition that is normally present allows the spinal reflexes that trigger the arousal response to take effect.
Surgery can be done in case a nerve has become cut or otherwise divided. Recovery of a nerve after surgical repair depends mainly on the age of the patient. Young children can recover close-to-normal nerve function. In contrast, a patient over 60 years old with a cut nerve in the hand would expect to recover only protective sensation, that is, the ability to distinguish hot/cold or sharp/dull. Many other factors also affect nerve recovery. The use of autologous nerve grafting procedures that involve redirection of regenerative donor nerve fibers into the graft conduit has been successful in restoring target muscle function. Localized delivery of soluble neurotrophic factors may help promote the rate of axon regeneration observed within these graft conduits.
About 10% of people with PCS develop sensitivity to light or noise, about 5% experience a decreased sense of taste or smell, and about 14% report blurred vision. People may also have double vision or ringing in the ears, also called tinnitus. PCS may cause insomnia, fatigue, or other problems with sleep.
Surgery can be done in case a peripheral nerve has become cut or otherwise divided. This is called peripheral nerve reconstruction. The injured nerve is identified and exposed so that normal nerve tissue can be examined above and below the level of injury, usually with magnification, using either loupes or an operating microscope. If a large segment of nerve is harmed, as can happen in a crush or stretch injury, the nerve will need to be exposed over a larger area. Injured portions of the nerve are removed. The cut nerve endings are then carefully reapproximated using very small sutures. The nerve repair must be covered by healthy tissue, which can be as simple as closing the skin or it can require moving skin or muscle to provide healthy padded coverage over the nerve. The type of anesthesia used depends on the complexity of the injury. A surgical tourniquet is almost always used.
The cause of fibromyalgia is unknown. However, several hypotheses have been developed including "central sensitization". This theory proposes that people with fibromyalgia have a lower threshold for pain because of increased reactivity of pain-sensitive nerve cells in the spinal cord or brain. Neuropathic pain and major depressive disorder often co-occur with fibromyalgia – the reason for this comorbidity appears to be due to shared genetic abnormalities, which leads to impairments in monoaminergic, glutamatergic, neurotrophic, opioid and proinflammatory cytokine signaling. In these vulnerable individuals, psychological stress or illness can cause abnormalities in inflammatory and stress pathways which regulate mood and pain. Eventually, a sensitization and kindling effect occur in certain neurons leading to the establishment of fibromyalgia and sometimes a mood disorder. The evidence suggests that the pain in fibromyalgia results primarily from pain processing pathways functioning abnormally. In simple terms, it can be described as the volume of the neurons being set too high and this hyper-excitability of pain processing pathways and under-activity of inhibitory pain pathways in the brain results in the affected individual experiencing pain. Some neurochemical abnormalities that occur in fibromyalgia also regulate mood, sleep, and energy, thus explaining why mood, sleep, and fatigue problems are commonly co-morbid with fibromyalgia.
Post-concussion syndrome, also known as postconcussive syndrome or PCS, is a set of symptoms that may continue for weeks, months, or a year or more after a concussion – a mild form of traumatic brain injury (TBI). The rates of PCS vary, but most studies report that about 15% of individuals with a history of a single concussion develop persistent symptoms associated with the injury. A diagnosis may be made when symptoms resulting from concussion last for more than three months after the injury. Loss of consciousness is not required for a diagnosis of concussion or post-concussion syndrome.
Agnosia is the inability to process sensory information. Often there is a loss of ability to recognize objects, persons, sounds, shapes, or smells while the specific sense is not defective nor is there any significant memory loss. It is usually associated with brain injury or neurological illness, particularly after damage to the occipitotemporal border, which is part of the ventral stream. Agnosia only affects a single modality, such as vision or hearing. More recently, a top-down interruption is considered to cause the disturbance of handling perceptual information.
In the past, the term PCS was also used to refer to immediate physical symptoms or post-concussive symptoms following a minor TBI or concussion. The severity of these symptoms typically decreases rapidly. In addition, the nature of the symptoms may change over time: acute symptoms are most commonly of a physical nature, while persisting symptoms tend to be predominantly psychological. Symptoms such as noise sensitivity, problems with concentration and memory, irritability, depression, and anxiety may be called 'late symptoms' because they generally do not occur immediately after the injury, but rather in the days or weeks after the injury. Nausea and drowsiness commonly occur acutely following concussion. Headache and dizziness occur immediately after the injury, but also can be long lasting.
Perineal pain after childbirth has immediate and long-term negative effects for women and their babies. These effects can interfere with breastfeeding and the care of the infant. The pain from injection sites and possible episiotomy is managed by the frequent assessment of the report of pain from the mother. Pain can come from possible lacerations, incisions, uterine contractions and sore nipples. Appropriate medications are usually administered. Routine episiotomies have not been found to reduce the level of pain after the birth.
The basis for the original "Nightmare on Elm Street" has been said to have been inspired by several newspaper articles printed in the "LA Times" in the 1970s on a group of Khmer refugees, who, after fleeing to America from the Khmer Rouge Genocide in Cambodia, were suffering disturbing nightmares after which they refused to sleep. Some of the men died in their sleep soon after. Medical authorities called the phenomenon "Asian Death Syndrome". The condition itself afflicted only men between the ages of 19-57 and is believed to be sudden unexplained death syndrome and/or Brugada syndrome. The 1970s pop song "Dream Weaver" by Gary Wright sealed the story for Craven, giving him not only an artistic setting to "jump off" from, but a synthesizer riff from the "Elm Street" soundtrack as well. It has also been stated that he drew some inspiration after studying eastern religions.
In some cases, foot diseases and painful conditions can be treated. Synovium hydrates the cartilage in the heel and can bring pain relief quickly. Synovium gel looks as well as strongly smells like urine, straying some consumers away. However this only occurs after expiration. Blood thinners can also work however are deemed as bad relievers by medical practitioners due to the fact that they can contribute to headaches and in some cases increase foot pain afterwards.
In a case reported only due to its rarity, triplegia was reported following a tonsillectomy (surgical removal of the tonsils). An eight-year-old male patient was sent to Willard Parker Hospital on August 12, 1929 and had been diagnosed with poliomyelitis. After an unrelated, and routine, tonsillectomy there was complete flaccid paralysis and loss of feeling in both the legs, right arm, and muscles in the trunk.
One is the neuroscientists' "objective" way. They dissect the brain with scalpel and microscope or look at it with brain scans and then trace neurochemical pathways. Neurology observes "mind" from outside, that is, by means of the neurological examination: questionnaires, the Boston Naming test or Wisconsin Sorting, bisecting lines, acting out how you use a screwdriver, and so on. Neurologists can compare the changes in psychological function that the neurological examination shows with the associated changes in the brain, either post mortem or by means of modern imaging technology.
Others such as Dennett have argued that the notion of a philosophical zombie is an incoherent, or unlikely, concept. In particular, nothing proves that an entity (e.g., a computer or robot) which would perfectly mimic human beings, and especially perfectly mimic expressions of feelings (like joy, fear, anger, ...), would not indeed experience them, thus having similar states of consciousness to what a real human would have. It is argued that under physicalism, one must either believe that anyone including oneself might be a zombie, or that no one can be a zombie—following from the assertion that one's own conviction about being (or not being) a zombie is a product of the physical world and is therefore no different from anyone else's.
It has been suggested that symptoms of mirror-touch synesthesia can occur in amputees. 98% of amputees report phantom sensations in their amputated limb, and one of the studied treatments for phantom limb pain has involved a mirror box. In this treatment, the amputee places their good arm into a mirror box, allowing the image of the arm to reflect where the amputated arm normally would be. When touch is applied to the good arm, amputees have reported corresponding sensations in their phantom limb. These cases can be considered mirror-touch synesthesia because a visual stimulus was able to elicit a tactile sensation. Studies have looked further into determining whether amputees actually experience mirror touch synesthesia. Four amputees were recruited in a study and asked to observe an assistant's arm being touched at various angles. 61 out of the 64 trials experienced mirror-touch sensations, and when the arm was wiggled, the sensations were enhanced. Finally, one amputee experienced a cold sensation when observing ice cubes touching the assistant's arm. Although there is evidence that mirror-touch synesthesia occurs in amputees, recent data has been inconclusive.
Phantom limbs are sensations felt by amputees that make it feel like their amputated extremity is still there. Sometimes amputees can experience pain from their phantom limbs; this is called phantom limb pain (PLP).
Under ordinary circumstances, the genetically determined circuitry in the brain remains largely stable throughout life. It was thought, until about 30 years ago, that no new neural circuits could be formed in the adult mammalian brain. Recently, functional MRI studies in amputees have shown that almost all patients have experienced motor cortical remapping. The majority of motor reorganization has occurred as a downward shift of the hand area of the cortex onto the area of face representation, especially the lips. Sometimes there is a side shift of the hand motor cortex to the ipsilateral cortex. In patients with phantom limb pain, the reorganization was great enough to cause a change in cortical lip representation into the hand areas only during lip movements. It has also been found that there is a high correlation between the magnitude of phantom limb pain and the extent to which the shift of the cortical representation of the mouth into the hand area in motor and somatosensory cortical reorganization has occurred. Additionally, as phantom pains in upper extremity amputees increased, there was a higher degree of medial shift of the facial motor representation. There are multiple theories that try to explain how cortical remapping occurs in amputees, but none have been supported to a great extent.
In limb amputees, some, but not all, studies have found a correlation between preoperative pain in the affected limb and postoperative phantom pain. There is a significant association between painful and non-painful phantom experiences, preoperative pain in the symptomatic eye and headache. Based on the present data, it is difficult to determine if headaches or preoperative eye pain play a causal role in the development of phantom phenomena or if headache, preoperative eye pain, and postoperative phantom eye experiences are only epiphenomena of an underlying factor. However, a study in humans demonstrated that experimental pain leads to a rapid reorganization of the somatosensory cortex. This study suggests that preoperative and postoperative pain may be an important co-factor for somatosensory reorganization and the development of phantom experiences.