Is mirror therapy associated with progressive muscle relaxation more effective than mirror therapy alone in reducing phantom limb pain in patients with lower limb amputation?

Mirror therapy is a widely used treatment for phantom limb pain (PLP) relief in patients with limb loss. Less common is progressive muscle relaxation (PMR), used mostly in other medical conditions (psychological, terminal cancer pain, etc). The purpose of this study is to evaluate the efficacy of a mirror therapy preceded by PMR intervention compared to mirror therapy preceded by unguided generic relaxation-mirror therapy in patients with lower limb amputation suffering from PLP. This pilot study was a single-blind, controlled, randomized trial. Thirty lower limb amputees suffering from PLP were recruited and randomly assigned to three groups respectively undergoing a PMR-mirror therapy rehabilitative intervention, generic relaxation-mirror therapy, and conventional physiotherapy (ConvPT). Selected items from Prosthesis Evaluation Questionnaire (PEQ) and the Brief Pain Inventory (BPI) were used to test the pain features at the beginning and 1 week after 3 weeks of intervention. A decrease of about 65% was found in the rate and duration of PLP at the PEQ in PMR-mirror therapy with respect to generic relaxation-mirror therapy (about 30%) and ConvPT (about 6%). A decrease of about 90% in intensity (worst and average) of PLP in PMR-mirror therapy when compared to generic relaxation-mirror therapy (about 45%) and ConvPT (about 20%) was found at the BPI. We preliminary concluded, albeit with limitations due to the small sample of patients, that mirror therapy can improve PLP when associated with PMR. Further studies are required to confirm that PMR could be an effective technique for more successful PLP management.

Phantom limb syndrome: Assessment of psychiatric and medical comorbidities associated with Phantom pain in 44,028 below knee amputees

INTRODUCTION

Phantom limb syndrome is a debilitating complication after extremity amputation that poses significant challenges to recovery. This study aims to examine the relationship between phantom limb syndrome and mental and physical comorbidities, including a comparison between phantom limb pain and phantom limb syndrome without pain in below knee amputees.

METHODS

This is a retrospective cohort study of patients who underwent below knee amputation of the lower extremity in the PearlDiver database, as identified using CPT codes. Analysis was carried out to evaluate the absence or presence of phantom limb syndrome. Matched bivariate analysis accounting for age, sex, Charlson Comorbidity Index score, and region was used to assess whether the presence of pain in phantom limb syndrome patients was associated with increased comorbidity.

RESULTS

In total, 44,028 patients with below knee amputation were examined: 95% (42,493 patients) did not develop phantom limb syndrome while 4.8% (1,535 patients) of patients did develop phantom limb syndrome. Phantom limb syndrome was significantly associated with increased odds of coexistent major depressive disorder (OR = 1.86, p <0.0001), generalized anxiety disorder (OR = 2.14, p = 0.04), posttraumatic stress disorder (OR = 1.7, p <0.0001), suicidal ideation (OR = 1.62, p <0.0001), obesity (OR = 1.28, p = 0.0007), osteoarthritis (OR = 1.53, p <0.0001), osteoporosis (OR = 1.64, p <0.0001), and low back pain (OR = 2.31, p <0.0001). Analysis of patient cohorts of phantom limb syndrome with pain and those without pain did not reveal a statistically significant relationship between the presence of pain and any dependent variable.

CONCLUSIONS

This investigation of over 44,000 patients with below knee amputation revealed that patients with phantom limb syndrome exhibit significantly higher rate of psychiatric comorbidities compared to those without documented phantom limb pain. Suicidal ideation, major depressive disorder, generalized anxiety disorder, and post-traumatic stress disorder were especially common, and consequently a multi-disciplinary approach to management is essential.

Phantom limb syndrome induced by combined spinal and epidural anesthesia in patients undergoing elective open gynecological surgery

BACKGROUND

During regional anesthesia, including combined spinal and epidural anesthesia (CSEA), patients may develop a perceptual alteration of limb position known as phantom limb syndrome (PLS). We aimed to identify factors that influence the PLS onset, to explore whether PLS predisposes to other postoperative symptoms, and to document the relationship between PLS and sensorimotor impairment during recovery.

METHODS

Psychological questionnaires for anxiety and depression were completed beforehand, then multimodal tests of sensory and motor function, especially tests of proprioception, were performed regularly afterward. Two hundred participants undergoing elective gynecological surgery under CSEA reported their experiences of PLS and other symptoms using Likert rating scales.

RESULTS

Prolonged preoperative fasting (odds ratio (OR) 2.34; 95% confidence intervals (CI) 1.21-4.52), and surgical history (OR 2.56; 95% CI 1.16-5.62) predisposed to PLS, but patients with more extensive anesthetic histories may be at lower risk (OR 0.57; 95% CI 0.31-1.08). Furthermore, significant correlations were observed between the recovery from PLS and the perception of joint movement within the deafferented area (R = 0.82, P < .01) and motor functions (R = 0.68). PLS increases the chance of experiencing postoperative fatigue, physical discomfort, and emotional upset.

CONCLUSION

This study is the first to have identified the risk factors for PLS, assessed the relationship between PLS and postoperative sensorimotor impairment, and its influence on postoperative complications.

Gender Differences in Psychosocial and Physical Outcomes in Haitian Amputees

OBJECTIVE

The purpose of this study was to investigate the gender differences in psychosocial and physical outcomes in users of lower-extremity prostheses who became amputees after the 2010 earthquake in Haiti.

METHOD

We enrolled 140 unilateral amputees in this cross-sectional study in Port-au-Prince, Haiti. Trained staff administered the assessments by reading the questions aloud to participants. Participants completed the Trinity Amputation and Prosthesis Experience Scales and Locomotor Capabilities Index about 2 yr after the earthquake.

RESULTS

We found no gender differences in psychosocial adjustment and physical outcomes, except for strenuous physical activities and phantom pain, and both genders reported difficulty in social adjustment. After controlling for strenuous physical activities and phantom pain, we found that men showed worse psychosocial adjustment than women.

CONCLUSION

Services for psychosocial adjustment are critical for traumatic amputees and should be incorporated into rehabilitation programs after a disaster. Interventions should consider gender roles in the indigenous culture.

Removing own-limb visual input using mixed reality (MR) produces a "telescoping" illusion in healthy individuals

The purpose of the present study was to assess changes in body perception when visual feedback was removed from the hand and arm with the purpose of resembling the visual deprivation arising from amputation. The illusion was created by removing the visual feedback from the participants' own left forearm using a mixed reality (MR) and green screen environment. Thirty healthy persons (15 female) participated in the study. Each subject experienced two MR conditions, one with and one without visual feedback from the left hand, and a baseline condition with normal vision of the limb (no MR). Body perception was assessed using proprioceptive drift, questionnaires on body perception, and thermal sensitivity measures (cold, warm, heat pain and cold pain detection thresholds). The proprioceptive drift showed a significant shift of the tip of the index finger (p<0.001) towards the elbow in the illusion condition (mean drift: -3.71 cm). Self-report showed a significant decrease in ownership (p<0.001), shift in perceptual distortions, (e.g. "It feels as if my lower arm has become shorter") (p=0.025), and changes in sensations of the hand (tingling, tickling) (p=0.025). A significant decrease was also observed in cold detection threshold (p<0.001), i.e. the detection threshold was cooler than for the control conditions. The proprioceptive drift together with the self-reported questionnaire showed that the participants felt a proximal retraction of their limb, resembling the telescoping experienced by phantom limb patients. The study highlights the influence of missing visual feedback and its possible contribution to phantom limb phenomena.

[Psychotherapies for the Treatment of Phantom Limb Pain]

INTRODUCTION

The phantom limb pain has been described as a condition in which patients experience a feeling of itching, spasm or pain in a limb or body part that has been previously amputated. Such pain can be induced by a conflict between the representation of the visual and proprioceptive feedback of the previously healthy limb. The phantom limb pain occurs in at least 42 to 90% of amputees. Regular drug treatment of phantom limb pain is almost never effective.

METHODS

A systematic review of the literature was conducted in Medline and Cochrane using the MESH terms "phantom limb pain" and "psychotherapy", published in the last 10 years, in English and Spanish, finding 49 items. After reviewing the abstracts, 25 articles were excluded for not being related to the objective of the research. Additionally cross references of included articles and literature were reviewed.

OBJECTIVES

To describe the psychotherapies used in the management of phantom limb pain, their effectiveness and clinical application reported in the literature.

AIMS

The mechanisms underlying phantom limb pain were initially explained, as were the published studies on the usefulness of some psychotherapies such as mirror visual feedback and immersive virtual reality, visual imagery, desensitization and reprocessing eye movements and hypnosis.

CONCLUSIONS

The phantom limb pain is a complex syndrome that requires pharmacological and psychotherapeutic intervention. The psychotherapies that have been used the most as adjuvants in the treatment of phantom limb pain are mirror visual feedback, desensitization and reprocessing eye movements, imagery and hypnosis. Studies with more representative samples, specifically randomized trials are required.

The Effect of Prosthesis Use on Hand Mental Rotation After Unilateral Upper-Limb Amputation

Amputation of a limb induces changes in the so-called body schema, which might be influenced by the use of prosthetic devices. Changes in the body representation associated with prosthesis use could be investigated using a hand mental rotation task. However, direct neurophysiologic evidence for the effect of prosthesis use on hand mental rotation is still lacking. In this paper, we recruited two groups of unilateral upper-limb amputees, i.e., amputees using a prosthesis or with a history of prosthesis use (Pro group) and amputees without a prosthesis (non-Pro group), as well as a sample of matched healthy controls. Using concurrent behavioral and electrophysiological assessments, we found that Pro amputees were comparable to healthy controls in either behavior or event-related potentials (ERPs), while non-Pro amputees showed prolonged response time as well as divergent ERP patterns. The P200 amplitude of non-Pro amputees was significantly larger for the non-dominant hand pictures than that for the dominant hand pictures, while such a hand difference in P200 was not found in either healthy controls or Pro amputees. Furthermore, the typical angular modulation of the N200 amplitude in healthy controls and Pro amputees was not presented in non-Pro amputees. Our results suggest that prosthesis use could preserve mental rotation ability by maintaining the performance of motor imagery and visual perception of hands, which represents a preservation of the body schema.

Pain Phenotypes and Associated Clinical Risk Factors Following Traumatic Amputation: Results from Veterans Integrated Pain Evaluation Research (VIPER)

OBJECTIVE

To define clinical phenotypes of postamputation pain and identify markers of risk for the development of chronic pain.

DESIGN

Cross-sectional study of military service members enrolled 3-18 months after traumatic amputation injury.

SETTING

Military Medical Center.

SUBJECTS

124 recent active duty military service members.

METHODS

Study subjects completed multiple pain and psychometric questionnaires to assess the qualities of phantom and residual limb pain. Medical records were reviewed to determine the presence/absence of a regional catheter near the time of injury. Subtypes of residual limb pain (somatic, neuroma, and complex regional pain syndrome) were additionally analyzed and associated with clinical risk factors.

RESULTS

A majority of enrolled patients (64.5%) reported clinically significant pain (pain score ≥ 3 averaged over previous week). 61% experienced residual limb pain and 58% experienced phantom pain. When analysis of pain subtypes was performed in those with residual limb pain, we found evidence of a sensitized neuroma in 48.7%, somatic pain in 40.8%, and complex regional pain syndrome in 19.7% of individuals. The presence of clinically significant neuropathic residual limb pain was associated with symptoms of PTSD and depression. Neuropathic pain of any severity was associated with symptoms of all four assessed clinical risk factors: depression, PTSD, catastrophizing, and the absence of regional analgesia catheter.

CONCLUSIONS

Most military service members in this cohort suffered both phantom and residual limb pain following amputation. Neuroma was a common cause of neuropathic pain in this group. Associated risk factors for significant neuropathic pain included PTSD and depression. PTSD, depression, catastrophizing, and the absence of a regional analgesia catheter were associated with neuropathic pain of any severity.

[Chronic pain : Perception, reward and neural processing]

Many chronic pain syndromes are characterized by enhanced perception of painful stimuli as well as alterations in cortical processing in sensory and motor regions. In this review article the alterations in muscle pain and neuropathic pain are described. Alterations in patients with fibromyalgia and chronic back pain are described as examples for musculoskeletal pain and also in patients with phantom limb pain after amputation and complex regional pain syndrome as examples for neuropathic pain. In addition to altered pain perception, cumulative evidence on alterations in the processing of reward and the underlying mechanisms in chronic pain has been described. A description is given of what is known on how pain and reward interact and affect each other. The relevance of such interactions for chronic pain is discussed. The implications of these findings for therapeutic approaches are delineated with respect to sensorimotor training and behavioral therapy, focusing on the effectiveness of these approaches, mechanisms and future developments. In particular, we discuss operant behavioral therapy in patients with chronic back pain and fibromyalgia as well as prosthesis training in patients with phantom limb pain and discrimination, mirror and imaginary training in patients with phantom limb pain and complex regional pain syndrome. With respect to the processing of reward, the focus of the discussion is on the role of reward and associated learning in pain therapy.

Repetitive Transcranial Magnetic Stimulation for Phantom Limb Pain in Land Mine Victims: A Double-Blinded, Randomized, Sham-Controlled Trial

We evaluated the effects of repetitive transcranial magnetic stimulation (rTMS) in the treatment of phantom limb pain (PLP) in land mine victims. Fifty-four patients with PLP were enrolled in a randomized, double-blinded, placebo-controlled, parallel group single-center trial. The intervention consisted of real or sham rTMS of M1 contralateral to the amputated leg. rTMS was given in series of 20 trains of 6-second duration (54-second intertrain, intensity 90% of motor threshold) at a stimulation rate of 10 Hz (1,200 pulses), 20 minutes per day, during 10 days. For the control group, a sham coil was used. The administration of active rTMS induced a significantly greater reduction in pain intensity (visual analogue scale scores) 15 days after treatment compared with sham stimulation (-53.38 ± 53.12% vs -22.93 ± 57.16%; mean between-group difference = 30.44%, 95% confidence interval, .30-60.58; P = .03). This effect was not significant 30 days after treatment. In addition, 19 subjects (70.3%) attained a clinically significant pain reduction (>30%) in the active group compared with 11 in the sham group (40.7%) 15 days after treatment (P = .03). The administration of 10 Hz rTMS on the contralateral primary motor cortex for 2 weeks in traumatic amputees with PLP induced significant clinical improvement in pain.

PERSPECTIVE

High-frequency rTMS on the contralateral primary motor cortex of traumatic amputees induced a clinically significant pain reduction up to 15 days after treatment without any major secondary effect. These results indicate that rTMS is a safe and effective therapy in patients with PLP caused by land mine explosions.

Psychophysical Evaluation of the Capability for Phantom Limb Movement in Forearm Amputees

A phantom limb is the sensation that an amputated limb is still attached to the body and is moving together with other body parts. Phantom limb phenomenon is often described on the basis of the patient’s subjective sense, for example as represented using a visual analog scale (VAS). The aim of this study was to propose a novel quantification method for behavioral aspect of phantom limb by psychophysics. Twelve unilateral forearm amputees were asked to perform phantom wrist motion with various motion frequencies (60, 80, 100, 120, 140, 160, 180, 200, 220, 240% of preferred speed). The attainment of phantom limb motion in each session was rated by the VAS ranging from 0 (hard) to 10 (easy). The relationship between the VAS and motion frequency was mathematically fitted by quadric function, and the value of shift and the degree of steepness were obtained as evaluation variables for the phantom limb movement. In order to test whether the proposed method can reasonably quantify the characteristics of phantom limb motion, we compared the variables among three different phantom limb movement conditions: (1) unilateral (phantom only), (2) bimanual, and (3) bimanual wrist movement with mirror reflection-induced visual feedback (MVF). While VAS rating showed a larger extent of inter- and intra-subject variability, the relationship of the VAS in response to motion frequency could be fitted by quadric curve, and the obtained parameters based on quadric function well characterize task-dependent changes in phantom limb movement. The present results suggest the potential usefulness of psychophysical evaluation as a validate assessment tool of phantom limb condition.

Acupuncture for the treatment of phantom limb pain in lower limb amputees: study protocol for a randomized controlled feasibility trial

BACKGROUND

Phantom limb pain is a prevalent condition that is difficult to manage, with a lack of robust evidence to support the use of many adjunctive treatments. Acupuncture can be effective in the management of many painful conditions but little is known about its effectiveness in treating phantom limb pain. The aim of this study is to explore the feasibility of conducting a randomized controlled trial comparing acupuncture and routine care in a group of lower limb amputees with phantom limb pain.

METHODS/DESIGN

An unstratified, pragmatic, randomized, two-armed, controlled trial of parallel design comparing acupuncture and usual care control will be conducted. A total of 20 participants will be randomly assigned to receive either usual care or usual care plus acupuncture. Acupuncture will include eight 1 hour treatments delivered pragmatically over 4 weeks by practitioners trained in traditional Chinese medicine. As outcome measures, the Numerical Pain Rating Scale, short-form McGill Pain Questionnaire 2, EQ-5D-5 L, Hospital Anxiety and Depression Scale, 10-Item Perceived Stress Scale, Insomnia Severity Index, and Patient Global Impression of Change will be completed at baseline, weekly for the duration of the study and at 1 month after completion of the study. After completion of the trial, participants will provide feedback though semi-structured interviews. Feasibility will be determined through the ability to recruit to the study, success of the randomization process, completion of acupuncture intervention, acceptability of random allocation and completion of outcome measures. Acceptability of the acupuncture intervention will be determined through semi-structured interviews with participants. The appropriateness of outcome measures for a future trial will be addressed through completion rates of questionnaires and participant feedback.

DISCUSSION

Data generated on effect size will be used for future sample size calculations and will inform the development of an appropriate and feasible protocol for use in a definitive multicentre randomized controlled trial.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT02126436.

Post-amputation pain is associated with the recall of an impaired body representation in dreams-results from a nation-wide survey on limb amputees

The experience of post-amputation pain such as phantom limb pain (PLP) and residual limb pain (RLP), is a common consequence of limb amputation, and its presence has negative effects on a person’s well-being. The continuity hypothesis of dreams suggests that the presence of such aversive experiences in the waking state should be reflected in dream content, with the recalled body representation reflecting a cognitive proxy of negative impact. In the present study, we epidemiologically assessed the presence of post-amputation pain and other amputation-related information as well as recalled body representation in dreams in a sample of 3,234 unilateral limb amputees. Data on the site and time of amputation, residual limb length, prosthesis use, lifetime prevalence of mental disorders, presence of post-amputation pain, and presence of non-painful phantom phenomena were included in logistic regression analyses using recalled body representation in dreams (impaired, intact, no memory) as dependent variable. The effects of age, sex, and frequency of dream recall were controlled for. About 22% of the subjects indicated that they were not able to remember their body representation in dreams, another 24% of the amputees recalled themselves as always intact, and only a minority of less than 3% recalled themselves as always impaired. Almost 35% of the amputees dreamed of themselves in a mixed fashion. We found that lower-limb amputation as well as the presence of PLP and RLP was positively associated with the recall of an impaired body representation in dreams. The presence of non-painful phantom phenomena, however, had no influence. These results complement previous findings and indicate complex interactions of physical body appearance and mental body representation, probably modulated by distress in the waking state. The findings are discussed against the background of alterations in cognitive processes after amputation and hypotheses suggesting an innate body model.

"Imprisoned" in pain: analyzing personal experiences of phantom pain

This article explores the phenomenon of "phantom pain." The analysis is based on personal experiences elicited from individuals who have lost a limb or live with a paralyzed body part. Our study reveals that the ways in which these individuals express their pain experience is an integral aspect of that experience. The material consists of interviews undertaken with men who are living with phantom pain resulting from a traumatic injury. The phenomenological analysis is inspired by Zahavi (J Conscious Stud 8(5-7):151-167, 2001) and Merleau-Ponty (Phenomenology of perception. Routledge and Kegan Paul, London, 1962/2000). On a descriptive level the metaphors these patients invoke to describe their condition reveal immense suffering, such as a feeling of being invaded by insects or of their skin being scorched and stripped from their body. Such metaphors express a dimension of experience concerning the self that is in pain and others whom the sufferer relates to through this pain, as well as the agony that this pain inflicts in the world of lived experience. This pain has had a profound impact on their lives and altered their relationship with self (body), others and the world. Their phantom pain has become a reminder of their formerly intact and functioning body; they describe the contrast between their past and present body as an ambiguous and disturbing experience. We conclude that these sensitive and personalized experiences of phantom pain illuminates how acts of expression--spoken pain--constitute a fundamental dimension of a first-person perspective which contribute to the field of knowledge about "phantom pain".

Vibrotactile stimulation promotes embodiment of an alien hand in amputees with phantom sensations

Tactile feedback is essential to intuitive control and to promote the sense of self-attribution of a prosthetic limb. Recent findings showed that amputees can be tricked to experience this embodiment, when synchronous and modality-matched stimuli are delivered to biological afferent structures and to an alien rubber hand. Hence, it was suggested to exploit this effect by coupling touch sensors in a prosthesis to an array of haptic tactile stimulators in the prosthetic socket. However, this approach is not clinically viable due to physical limits of current haptic devices. To address this issue we have proposed modality-mismatched stimulation and demonstrated that this promotes self-attribution of an alien hand on normally limbed subjects. In this work we investigated whether similar effects could be induced in transradial amputees with referred phantom sensations in a series of experiments fashioned after the Rubber Hand Illusion using vibrotactile stimulators. Results from three independent measures of embodiment demonstrated that vibrotactile sensory substitution elicits body-ownership of a rubber hand in transradial amputees. These results open up promising possibilities in this field; indeed miniature, safe and inexpensive vibrators could be fitted into commercially available prostheses and sockets to induce the illusion every time the prosthesis manipulates an object.

Phantoms in artists: the lost limbs of Blaise Cendrars,Arthur Rimbaud, and Paul Wittgenstein

There have been an increasing number of reports of postamputation pain and problems linked to phantom limbs over recent years, particularly in relation to war-related amputations. These problems, which are often poorly understood and considered rather mysterious, are still relevant because they are difficult to treat medically. Functional neuroimaging techniques now enable us to better understand their pathophysiology and to consider new rehabilitation techniques. Phantom limbs have often been a source of inspiration to writers, particularly in the period following the First World War, which was responsible for thousands of amputees. Some artists have suffered from postamputation complications themselves and have expressed them through their artistic works. Blaise Cendrars (1887-1961), one of the greatest authors of the twentieth century, suffered from stump pain and phantom limb phenomena for almost half a century following the amputation of his right arm during the First World War. He suffered from these phenomena until the end of his life and his literary work and personal correspondence are peppered with references to them. Arthur Rimbaud (1854-1891), one of the most famous poets in world literature, developed severe stump pain after his right leg was amputated due to a tumor. He survived for only six months after the procedure but left behind an account of the pain he experienced in correspondence to his family. The famous pianist Paul Wittgenstein (1887-1961), whose right arm was amputated during the First World War, became a famous left-handed concert pianist. The phantom movements of his right hand helped him to develop the dexterity of his left hand. The impact on the artistic life of these three men provides an original illustration of the various postamputation complications, specifically phantom limbs, stump pain, and moving phantom.

Body image and self-esteem in lower-limb amputees

Background

Limb amputation is often an inevitable procedure in the advanced condition of various diseases and poses a dramatic impact on a patient's life. The aim of the present study is to analyze the impact of lower-limb amputations on aesthetic factors such as body image and self-esteem as well as quality of life (QoL).

Methods

298 patients (149 uni- or bilateral lower-limb amputees and 149 controls) were included in this cross-sectional study in three centers. Demographic data was collected and patients received a 118-item questionnaire including the Multidimensional Body-Self Relations Questionnaire (MBSRQ), the Rosenberg Self-esteem (RSE) scale and the SF-36 Health Survey (QoL). ANOVA and student's t-test were used for statistical analysis.

Results

Unilateral lower-limb amputees showed a significant lower MBSRQ score of 3.07±0.54 compared with 3.41±0.34 in controls (p<0.001) and a lower score in the RSE compared to controls (21.63±4.72 vs. 21.46±5.86). However, differences were not statistically significant (p = 0.36). Patients with phantom pain sensation had a significantly reduced RSE (p = 0.01). The SF-36 health survey was significantly lower in patients with lower-limb amputation compared to controls (42.17±14.47 vs. 64.05±12.39) (p<0.001).

Conclusion

This study showed that lower-limb amputations significantly influence patients' body image and QoL. Self-esteem seems to be an independent aspect, which is not affected by lower-limb amputation. However, self-esteem is influenced significantly by phantom pain sensation.

Inter-individual difference in the effect of mirror reflection-induced visual feedback on phantom limb awareness in forearm amputees

Objective

To test whether the phantom limb awareness could be altered by observing mirror reflection-induced visual feedback (MVF) in unilateral forearm amputees.

Methods

Ten unilateral forearm amputees were asked to perform bilateral (intact and phantom) synchronous wrist motions with and without MVF. During wrist motion, electromyographic activities in the extensor digitorum longus (EDL) and flexor carpi radialis muscles (FCR) were recorded with bipolar electrodes. Degree of wrist range of motion (ROM) was also recorded by electrogoniometry attached to the wrist joint of intact side. Subjects were asked to answer the degree of attainment of phantom limb motion using a visual analog scale (VAS: ranging from 0 (hard) to 10 (easy)).

Results

VAS and ROM were significantly increased by utilizing MVF, and the extent of an enhancement of the VAS and wrist ROM was positively correlated (r = 0.72, p<0.05). Although FCR EMG activity also showed significant enhancement by MVF, this was not correlated with the changes of VAS and ROM. Interestingly, while we found negative correlation between EDL EMG activity and wrist ROM, MVF generally affected to be increasing both EDL EMG and ROM.

Conclusions

Although there was larger extent of variability in the effect of MVF on phantom limb awareness, MVF has a potential to enhance phantom limb awareness, in case those who has a difficulty for the phantom limb motion. The present result suggests that the motor command to the missing limb can be re-activated by an appropriate therapeutic strategy such as mirror therapy.

'You don't need a body to feel a body': phantom limb syndrome and corporeal transgression

One of the central tensions within the literature on body studies concerns the degree to which the physical body is constituted by or through language, knowledges, and practices and the degree to which the body has foundational, purely material, or essential attributes. Three theoretical approaches have been at the heart of this debate: social constructionism, phenomenology, and structuration theory. Recently, body studies theorists have challenged scholars to move beyond the widely recognised limitations of dominant theorising by taking into account all three perspectives and conceptualising the body as surface, vehicle, and circuit. Because they embrace agnosticism and relational materialism, science and technology studies scholars are in a distinctive position to answer this call. Proponents fully acknowledge the materiality of the body without espousing essentialist claims by effacing the analytic division between agency and structure. Starting from this perspective, I use the concept of corporeal transgression and the phenomenon of phantom limb to reveal how 'immaterial'--indeed, at times, fictive and fanciful--body parts became socially and materially substantive, engendering transformations within the bodies, minds, and brains of amputees, as well as within the field of neuroscience.

Motor and sensory rehabilitation after lower limb amputation: state of art and perspective of change

The rehabilitation of the amputated patient is based on a coordinated sequence of diagnostic, prognostic and therapeutic procedures carried out by an interdisciplinary rehabilitation team, that works globally on all patient problems. The objectives of the different phases of the rehabilitation treatment were reviewed. Due to their relevance in conditioning the final outcome of the treatment, aspects requiring further studies and remarks, were also reviewed. Among these the psychological aspects, the alterations of all sensory inputs, the secondary alterations at the bone, articular and muscular level, pain of the residual limb and the phantom limb. Finally, the basic criteria to be used to choose the kind of prosthesis in relation to the characteristics and expectations of the amputated person, and the results of the recovery of the autonomy and walking ability, will be schematically described.

A randomized controlled study to evaluate the efficacy of noninvasive limb cover for chronic phantom limb pain among veteran amputees

OBJECTIVE

To assess the efficacy of a noninvasive limb cover for treating chronic phantom limb pain (PLP).

DESIGN

Randomized, double-blind, placebo-controlled trial.

SETTING

Outpatient clinic.

PARTICIPANTS

We randomly assigned 57 subjects to 2 groups: true noninvasive limb cover (n=30) and sham noninvasive limb cover (n=27). Inclusion criteria included age of 18 years or greater, upper or lower extremity amputation with healed residual limb, and 3 or more episodes of PLP during the previous 6 weeks.

INTERVENTIONS

Subjects received 2 true or sham noninvasive limb covers to be worn over the prosthesis and residual limbs 24 hours a day for 12 weeks.

MAIN OUTCOME MEASURES

Primary outcome measure was the numerical pain rating scale of PLP level (0-10). Secondary outcomes included overall pain level (0-10), PLP frequency per week, and the Veterans RAND 12-Item Health Survey (VR-12). We collected data at baseline and at 6- and 12-week follow-up visits.

RESULTS

Demographic and clinical characteristics were not significantly different between groups. The true noninvasive limb cover group reported nonsignificant reductions in PLP from 5.9±1.9 at baseline to 3.9±1.7 at the 12-week follow-up. The sham noninvasive limb cover group also had nonsignificant reducations in PLP from 6.5±1.8 to 4.2±2.3. PLP did not differ significantly between the 2 groups at 6 weeks (mean difference, 0.8; 95% confidence interval [CI], -1.4 to 3) or at 12 weeks (mean difference, 0.2; 95% CI, -1.9 to 2.3). Similarly, overall pain level, PLP episodes per week, and VR-12 physical and mental health component scores did not differ between the 2 groups at 6 and 12 weeks.

CONCLUSIONS

A true noninvasive limb cover did not significantly decrease PLP levels or the frequency of PLP episodes per week, overall bodily pain levels, or VR-12 physical and mental health component scores compared with a sham noninvasive limb cover in our veteran amputee sample.

Atypical electrophysiological activity during pain observation in amputees who experience synaesthetic pain

There are increasing reports of people experiencing pain when observing pain in another. This describes the phenomenon of synaesthetic pain which, until recently, had been primarily reported in amputees with phantom pain. In the current study, we used electroencephalography (EEG) to investigate how amputees who experience synaesthetic pain process pain observed in another. Participants were grouped according to amputees who experience phantom and synaesthetic pain (n=8), amputees who experience phantom pain but not synaesthetic pain (n=10) and healthy controls (n=10). Participants underwent EEG as they observed still images of hands and feet in potentially painful and non-painful situations. We found that pain synaesthetes showed some reduced event-related potential (ERP) components at certain electrode sites, and reduced theta- and alpha band power amplitude at a central electrode. The finding of reduced ERP amplitude and theta band power may reflect inhibition of the processing of observed pain (e.g. avoidance/guarding as a protective strategy), and reduced alpha band power may indicate a disinhibition in control processes that may result in synaesthetic pain. These results provide the first documentation of atypical neurophysiological activity in amputees who experience synaesthetic pain when processing pain in another.

Analgesia through the looking-glass? A randomized controlled trial investigating the effect of viewing a ‘virtual’ limb upon phantom limb pain, sensation and movement

The extent to which viewing a 'virtual' limb, the mirror image of an intact limb, modifies the experience of a phantom limb, was investigated in 80 lower limb amputees before, during and after repeated attempts to simultaneously move both intact and phantom legs. Subjects were randomly assigned to one of two conditions, a control condition in which they only viewed the movements of their intact limb and a mirror condition in which they additionally viewed the movements of a 'virtual' limb. Although the mirror condition elicited a significantly greater number of phantom limb movements than the control condition, it did not attenuate phantom limb pain and sensations any more than the control condition. The potential of a 'virtual' limb as a treatment for phantom limb pain was discussed in terms of its ability to halt and/or reverse the cortical re-organisation of motor and somatosensory cortex following acquired limb loss.

[On hallucinations, bizarre sensations, phantom phenomena and body-image disturbances]

Subjective descriptions of neuropsychological phenomena which reflect body-image disturbances, are well known to neurologists, psychiatrists, neuropsychologists and rehabilitation medicine physicians. These phenomena may accompany patients with mental illnesses, after brain injury or with various neuro-orthopedic disabilities. It is also well documented in people who are exposed to extreme isolation or harsh situations.

The moving phantom: motor execution or motor imagery?

Amputees who have a phantom limb often report the ability to move this phantom voluntarily. In the literature, phantom limb movements are generally considered to reflect motor imagery rather than motor execution. The aim of this study was to investigate whether amputees distinguish between executing a movement of the phantom limb and imagining moving the missing limb. We examined the capacity of 19 upper-limb amputees to execute and imagine movements of both their phantom and intact limbs. Their behaviour was compared with that of 18 age-matched normal controls. A global questionnaire-based assessment of imagery ability and timed tests showed that amputees can indeed distinguish between motor execution and motor imagery with the phantom limb, and that the former is associated with activity in stump muscles while the latter is not. Amputation reduced the speed of voluntary movements with the phantom limb but did not change the speed of imagined movements, suggesting that the absence of the limb specifically affects the ability to voluntarily move the phantom but does not change the ability to imagine moving the missing limb. These results suggest that under some conditions, for example amputation, the predicted sensory consequences of a motor command are sufficient to evoke the sensation of voluntary movement. They also suggest that the distinction between imagined and executed movements should be taken into consideration when designing research protocols to investigate the analgesic effects of sensorimotor feedback.

Phantom pain after eye amputation

PURPOSE

To characterize the quality of phantom pain, its intensity and frequency following eye amputation. Possible triggers and relievers of phantom pain are investigated.

METHODS

The hospital database was searched using surgery codes for patients who received ocular evisceration, enucleation, orbital exenteration or secondary implantation of an orbital implant in the period between 1993 and 2003. A total of 267 patients were identified and invited to participate; of these, 173 agreed to participate. These patients' medical records were reviewed. A structured interview focusing on pain was conducted by a trained interviewer.

RESULTS

Of the 173 patients in the study, 39 experienced phantom pain. The median age of patients who had experienced phantom pain was 45 years (range: 19-88). Follow-up time from eye amputation to participation in the investigation was 4 years (range: 2-46). Phantom pain was reported to be of three different qualities: (i) cutting, penetrating, gnawing or oppressive (n = 19); (ii) radiating, zapping or shooting (n = 8); (iii) superficial burning or stinging (n = 5); or a mixture of these different pain qualities (n = 7). The median intensity on a visual analogue scale, ranging from 0 to 100, was 36 (range: 1-89). One-third of the patients experienced phantom pain every day. Chilliness, windy weather and psychological stress/fatigue were the most commonly reported triggers for pain.

CONCLUSIONS

  Phantom pain after eye amputation is relatively common. The pain appears to be similar to the phantom pain suffered by limb amputees. Patients should be informed about this potential complication before surgery.

Sex differences in pain and psychological functioning in persons with limb loss

Sex differences in pain are frequently reported in the literature. However, less is known about possible sex differences in the experience of pain secondary to a disability. The current study explored these issues in persons with limb loss (n = 335, 72% men) who were recruited as part of a postal survey. Participants provided ratings of phantom limb pain (PLP), residual limb pain (RLP), and general pain intensity. Participants also completed measures of pain-related interference, catastrophizing, coping, and beliefs. Results indicated that a greater proportion of males than females (86% vs 77%, respectively) reported the presence of PLP; however, this difference was no longer prominent when cause of limb loss was controlled. No sex differences were found in the presence of RLP, or in average intensity ratings of PLP or RLP. In contrast, females reported greater overall average pain intensity and interference than males. Females also endorsed significantly greater catastrophizing, use of certain pain-coping strategies, and beliefs related to several aspects of pain. This study did not find prominent sex differences in pain specific to limb loss. However, several sex differences in the overall biopsychosocial experience of pain did emerge that are consistent with the broader literature.

PERSPECTIVE

The current study contributes to the literature on sex differences in the experience of pain. Although males and females with limb loss did not significantly differ in their disability-specific pain, sex differences in their broader experience of pain were significant and are worthy of future clinical and empirical attention.

[Eye movement desensitisation and reprocessing (EMDR) as a treatment for phantom limb pain]

A 68-year-old man, who had had phantom limb pain in his leg and foot for 27 years, was referred for EMDR treatment. This case study shows that after 10 sessions of EMDR the pain intensity had diminished from 10 to 1 (on a scale of 10). Further sessions, consisting mainly of discussions, focused on consolidation of the result, namely on finding a new physical and mental balance and on strengthening self-confidence in the new situation.

Phantom limb after stroke: an underreported phenomenon

The presence of a phantom limb (PL) resulting from a cerebral lesion has been reported to be a rare event. No prior study, however, has systematically investigated the prevalence of this syndrome in a group of post-stroke individuals. Fifty post-stroke individuals were examined with structured interview/questionnaire to establish the presence and perceptual characteristics of PLs. We document the presence of phantom experiences in over half of these individuals (n=27). We provide details of these phantom experiences and further characterize these symptoms in terms of temporal qualities, posture, kinesthesia, and associated features. Twenty-two participants reported postural phantoms, which were perceived as illusions of limb position that commonly manifested while lying in bed at night - a time when visual input is removed from multi-sensory integration. Fourteen participants reported kinesthetic phantoms, with illusory movements ranging from simple single joint sensations to complex goal-directed phantom movements. A striking syndrome of near total volitional control of phantom movements was reported in four participants who had immobile plegic hands. Reduplicative phantom percepts were reported by only one participant. Similarly, phantom pain was present in only one individual - the sole participant with a pre-stroke limb amputation. The results suggest that stroke results in phantom experiences more commonly than previously described in the literature. We speculate that subtotal deafferance or defective motor efference after stroke may manifest intermittently as a PL.

The treatment of phantom limb pain using immersive virtual reality: Three case studies

PURPOSE

This paper describes the design and implementation of a case study based investigation using immersive virtual reality as a treatment for phantom limb pain.

METHOD

Three participants who experienced phantom limb pain (two with an upper-limb amputation, and one with a lower-limb amputation) took part in between 2 and 5 immersive virtual reality (IVR) sessions over a 3-week period. The movements of participants' anatomical limbs were transposed into the movements of a virtual limb, presented in the phenomenal space of their phantom limb.

RESULTS

Preliminary qualitative findings are reported here to assess proof of principle for this IVR equipment. All participants reported the transferal of sensations into the muscles and joints of the phantom limb, and all participants reported a decrease in phantom pain during at least one of the sessions.

CONCLUSION

The authors suggest the need for further research using control trials.

The relationship between catastrophizing and disability in amputees experiencing phantom pain

PURPOSE

In recent years, researchers have noted that catastrophizing predicts both self-reported and objective measures of disability in a variety of chronic pain conditions. The present study sought to examine this in a working-age amputee population experiencing phantom pain.

METHOD

Participants completed a postal questionnaire incorporating measures of pain, disability and coping. A response rate of 62% resulted in 315 completed data sets being incorporated into the study.

RESULTS

Utilizing the three subscales of the Sickness Impact Profile, catastrophizing uniquely predicted 11% of the variance in overall level of disability, 6% in physical disability and 13% in psychosocial disability after accounting for demographic, amputation and pain-related variables.

CONCLUSION

The findings suggest that catastrophizing is a significant predictor of self-reported disability in an amputee population. This population have lifetime rehabilitation needs in that prostheses have to be remade on a regular basis. The service provided tends to focus on physical rehabilitation with the goal of providing amputees with limbs that most closely resemble the appearance and function of the intact limb. This study provides tentative support for development of an intervention that specifically targets catastrophizing.

Understanding amputation

Approximately 134,000 amputations occur annually in the United States, resulting mostly from peripheral vascular disease. The risk of amputation increases with age, peaking among those 85 years of age and older. As a lifesaving and life-defining procedure, amputations result in physical and emotional changes affecting quality of life. Phantom pain is problematic for many patients, and agents approved by the Food and Drug Administration for phantom pain are nonexistent. Pharmacists should be knowledgeable about weight-based dosing as well as patient education guidelines.

Preventing and modulating learned wound pain

Wounds cause pain but the consequences of wound pain remain largely unknown. Studies from other disciplines have shown that pain can contribute to the long-term physiological and emotional consequences of the pain experience, setting the stage for the phenomenon referred to as "learned pain." Providing ways to help patients avoid learning pain--ie, modulating pain anticipation/expectation, peripheral nerve blocks, pretreatment analgesics, biophysical technologies, modification of patient and provider behavior, judicious choice of dressings, and behavioral therapies--has been found to play a significant role in decreased physical and emotional discomfort and improved outcomes. Existing evidence on pain suggests that wound pain most likely consists of a combination of local, systemic, and learned phenomena retained by the patient as long-term "pain memories" as well as acute reaction to stimuli. Until the consequences of wound pain are fully appreciated, healthcare providers should consider application of research findings from other disciplines to reduce pain and prevent the learning and development of pain memories.

A randomised double blind trial of the effect of pre-emptive epidural ketamine on persistent pain after lower limb amputation

Persistent pain has been reported in up to 80% of patients after limb amputation. The mechanisms are not fully understood, but nerve injury during amputation is important, with evidence for the crucial involvement of the spinal N-methyl d-aspartate (NMDA) receptor in central changes. The study objective was to assess the effect of pre-emptively modulating sensory input with epidural ketamine (an NMDA antagonist) on post-amputation pain and sensory processing. The study recruited 53 patients undergoing lower limb amputation who received a combined intrathecal/epidural anaesthetic for surgery followed by a randomised epidural infusion (Group K received racemic ketamine and bupivacaine; Group S received saline and bupivacaine). Neither general anaesthesia nor opioids were used during the peri-operative period. Pain characteristics were assessed for 12 months. The primary endpoint was incidence and severity of post-amputation pain. Persistent pain at one year was much less in both groups than in comparable studies, with no significant difference between groups (Group K=21% (3/14) and 50% (7/14); and Group S=33% (5/15) and 40% (6/15) for stump and phantom pain, respectively). Post-operative analgesia was significantly better in Group K, with reduced stump sensitivity. The intrathecal/epidural technique used, with peri-operative sensory attenuation, may have reduced ongoing sensitisation, reducing the overall incidence of persistent pain. The improved short-term analgesia and reduced mechanical sensitivity in Group K may reflect acute effects of ketamine on central sensitisation. Longer term effects on mood were detected in Group K that requires further study.

A Prospective Study of Factors Associated With the Presence of Phantom Limb Pain Six Months After Major Lower Limb Amputation in Patients With Peripheral Vascular Disease

Because of a lack of evidence to support any treatment for phantom limb pain (PLP), interest has turned to preventing it instead. However, like other areas of PLP research, there is little consensus regarding factors that may be associated with the development of PLP. This study was devised to identify physical and psychological factors associated with PLP development and maintenance. It was a prospective study of 59 patients listed for amputation of a lower limb due to peripheral vascular disease. Each was interviewed before amputation, and the survivors were reinterviewed 6 months afterward. Pain and coping style were the primary outcome measures. The use of high levels of passive coping strategies (P = .001), especially catastrophizing (P = .02) before amputation, were found to be associated with PLP development. Pain was only weakly associated with the presence of PLP 6 months after amputation. The ability to move the phantom (P = .01) and stump pain (P = .01) were postamputation factors associated with PLP. The complexity of the relationship between previous pain and coping style and the development of PLP is discussed alongside aspects of pain memory. Pre-emptive treatment of PLP will need to include psychological as well as physical interventions.

PERSPECTIVE

During this study, preamputation passive coping (especially catastrophizing) was found to be associated with the development of PLP. This knowledge will help researchers and clinicians to identify future targets for pre-emption of this condition because once established, PLP is difficult to treat.

Worsening of chronic pain: the treatment

Chronic pain is a symptom that inevitably goes along with a condition of critical ischemia of the lower limbs, termed also as "obstructive peripheral arteriopathy". This sometimes displays worsening, provoking difficult physical and psychological behaviors of the patients. The complexity of this kind of patients results in difficulties in their clinical management. A multidisciplinary team, namely the close and coordinated collaboration of various kinds of professionists, could give better results, than an individual approach, thanks to strategies of re-equilibrating the systemic homeostasis of the given patient.

Felt presence: paranoid delusion or hallucinatory social imagery?

Cheyne and Girard characterize felt presence (FP) during sleep paralysis attacks as a pre-hallucinatory expression of a threat-activated vigilance system. While their results may be consistent with this interpretation, they are nonetheless correlational and do not address a parsimonious alternative explanation. This alternative stipulates that FP is a purely spatial, hallucinatory form of a common cognitive phenomenon-social imagery-that is often, but not necessarily, linked with threat and fear and that may induce distress among susceptible individuals. The occurrence of both fearful and non-fearful FPs in a multiplicity of situations other than sleep paralysis attacks supports the notion that FPs are hallucinatory variants of social imagery and that they are not necessarily bound to threat-activated vigilance. Evidence linking FPs with anxiety disorders supports the notion that the distress they evoke may be mediated by a more general affective distress personality factor. To illustrate the predominantly spatial character of FP hallucinations, similarities between FP and phantom limbs are summarized and the possibility that these two phenomena are parallel expressions (self- vs. other-presence) of a mirror neuron system is considered.

Incidence of Phantom Phenomena Including Phantom Limb Pain 6 Months After Major Lower Limb Amputation in Patients With Peripheral Vascular Disease

OBJECTIVES

Contentions exist regarding the true incidence of phantom limb pain (PLP) and other associated post-amputation phenomena. Recognizing and understanding these phenomena would assist in the rehabilitation of amputees. This study was designed to investigate all post-amputation phenomena in a homogenous group of amputees.

METHODS

Prospective amputees were recruited prior to amputation of a lower limb due to peripheral vascular disease. All survivors were followed 6 months after surgery and interviewed to identify post-amputation phenomena, including phantom sensations, PLP, and stump pain.

RESULTS

Sixty amputees were recruited and 52 survived until the 6-month interview. Phantom sensations were universal, and aspects of the non-painful phenomena, including kinetic, kinesthetic, and exteroceptive components, were identified at varying rates within the sample. PLP was found in 78.8% of the survivors, and 51.2% had stump pain. Super-added phenomena occurred in 15.4%. Links were found between PLP and stump pain (P=0.01) and PLP and the ability to move the phantom (P=0.01). No link was found between PLP and telescoping of the phantom (P=0.47).

CONCLUSIONS

Phantom phenomena are associated with many myths. This study starts to unravel myth from fact, but further study is required before this enigmatic condition and its influence on rehabilitation are fully understood.

Immersive Virtual Reality as a Rehabilitative Technology for Phantom Limb Experience: A Protocol

This paper describes a study protocol to investigate the use of immersive virtual reality as a treatment for amputees' phantom limb pain. This work builds upon prior research using mirror box therapy to induce vivid sensations of movement originating from the muscles and joints of amputees' phantom limbs. The present project transposes movements of amputees' anatomical limbs into movements of a virtual limb presented in the phenomenal space of their phantom limb. It is anticipated that the protocol described here will help reduce phantom limb pain.

[Sociodemographic factors and their influence on anxiety and depression in patients after limb amputation]

AIM

The aim of this study was to assess the score of HADS and the correlation with sociodemographic factors and personality traits in patients after limb amputation.

METHOD

45 patients after limb amputation due to atherosclerosis and 30 persons from a control group participated in the study. HADS Scale and the Maudsley Personality Inventory created by Eysenck were used in the study. Socidemographic data were collected by means of the Sociodemographic data questionnaire.

RESULTS

In comparison to the control group, patients after limb amputation achieved a higher score in HADS-A and HADS-D and in the N scale of the Maudsley Personality Inventory. Higher levels of anxiety and depression were noticed in patients suffering from phantom limb pain and in patients with neurotic personality traits.

CONCLUSION

Patients after limb amputation need multidisciplinary care because of higher levels of anxiety and depression (especially patients with phantom limb pain and those with neurotic personality traits).

Can immersive virtual reality reduce phantom limb pain?

This paper describes the design and implementation of a case-study based investigation using immersive virtual reality as a treatment for phantom limb pain. The authors' work builds upon prior research which has found the use of a mirror box (where the amputee sees a mirror image of their remaining anatomical limb in the phenomenal space of their amputated limb) can reduce phantom limb pain and voluntary movement to paralyzed phantom limbs for some amputees. The present project involves the transposition of movements made by amputees' anatomical limb into movements of a virtual limb which is presented in the phenomenal space of their phantom limb. The three case studies presented here provide qualitative data which provide tentative support for the use of this system for phantom pain relief. The authors suggest the need for further research using control trials.

Topiramate for Phantom Limb Pain: A Time-Series Analysis

There is growing evidence of topiramate's efficacy in treating neuropathic pain. This article reports a detailed analysis of the response of four amputee subjects with phantom limb pain. Individual time-series analyses revealed that three out of four amputee participants receiving topiramate had statistically significant decreases in pain, with the peak effect noted at 800 mg daily. This analysis supports a hypothesis that topiramate may be effective in reducing phantom limb pain, and suggests a definitive study is indicated.

Puzzling Pain Conditions: How Philosophy Can Help Us Understand Them

CONTEXT

Pain is a complicated area of inquiry. To progress in our scientific understanding of the topic, it may be useful to learn how other disciplines are grappling with the subject. Philosophy is one discipline actively engaged in trying to understand pain.

OBJECTIVE

We present one philosophical view of pain to help broaden the understanding of pain in those who are trained to look at it from a biomedical perspective.

DISCUSSION

One current philosophical theory of pain is the externalist perceptual theory of pain. This theory states that pain is a form of perception and can be likened to other perceptions, for example, visual, tactile, etc. The way a pain feels can be explained as the relationship between this perception and some bodily damage occurring. and just as other perceptions can be mistaken, such as in a visual illusion, pain can also be inaccurate. We explore how the theory deals with puzzling conditions such as phantom limb pain, complex regional pain syndrome, and allodynia. We contrast this view with a competing theory of pain and briefly consider how these philosophical views may impact clinical medicine.