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.

Plasticity and functional recovery in neurology

Experiments on patients with phantom limbs suggest that neural connections in the adult human brain are much more malleable than previously assumed. Three weeks after amputation of an arm, sensations from the ipsilateral face are referred to the phantom; this effect is caused by the sensory input from the face skin 'invading' and activating deafferented hand zones in the cortex and thalamus. Many phantom arms are 'paralysed' in a painful position. If a mirror is propped vertically in the sagittal plane and the patient looks at the reflection of his/her normal hand, this reflection appears superimposed on the 'felt' position of the phantom. Remarkably, if the real arm is moved, the phantom is felt to move as well and this sometimes relieves the painful cramps in the phantom. Mirror visual feedback (MVF) has shown promising results with chronic regional pain syndrome and hemiparesis following stroke. These results suggest two reasons for a paradigm shift in neurorehabilitation. First, there appears to be tremendous latent plasticity even in the adult brain. Second, the brain should be thought of, not as a hierarchy of organised autonomous modules, each of which delivers its output to the next level, but as a set of complex interacting networks that are in a state of dynamic equilibrium with the brain's environment. Both principles can be potentially exploited in a clinical context to facilitate recovery of function.

Dissociation of phantom limb phenomena from stump tactile spatial acuity and sensory thresholds

Most amputees experience phantom limb sensations and/or phantom limb pain as well as residual limb (stump) pain that are resistant to treatment. Phantom phenomena are not homogeneous; each patient presents with a unique combination of spontaneous or evoked sensations, pain, and/or awareness. In an effort to understand the underlying mechanisms, postamputation pain has been subclassified based on the perceived sensory qualities reported by the individual. However, little is known about the relationship between subjective phantom phenomena and sensory function of the residual stump. The aim of the present study was to determine if sensory processing, as measured psychophysically, reflected subjective reports of specific qualities of phantom and/or stump sensory phenomena. Twelve individuals who had recently (within 6 months) undergone traumatic unilateral upper extremity amputation participated in the study. Limb temperature, thermal thresholds, tactile sensory thresholds and tactile spatial acuity were compared between the residual limb and the intact limb, and related to patient reports of specific stump and phantom sensory phenomena. All but one subject reported phantom sensations and/or phantom pain. The remaining subject reported only stump pain. Mean skin temperature of the residual limb was significantly lower than that of the intact contralateral limb by approximately 0.9 degrees C in the proximal portion of the stump and 1.7 degrees C at the stump tip. However, the temperature of the stump (compared with the intact limb) did not reflect subjective reports of stump or phantom limb thermal characteristics. Thermal threshold abnormalities differed among patients, and did not suggest any pattern of small fibre loss of function or generalized hyperexcitability. Other than within grafted tissue or near the scar area, skin areas that the patient described as abnormally sensitive or tender to touch were not accompanied by corresponding abnormalities in static tactile thresholds or tactile spatial acuity. Tactile spatial acuity was heightened near the scar area only. The proportion of subjects who had decreased two-point discrimination thresholds at the stump did not differ significantly according to the reporting or non-reporting of dual percepts. Thus, despite a common injury, the sensory abnormalities varied within this cohort of subjects. In addition, psychophysical threshold measures of sensory function did not reflect, in any simple way, subjective phantom phenomena. Therefore, classification of phantom phenomena based on peripheral sensory function may be a misleading step in the search for specific mechanisms underlying postamputation sensory phenomena.

Clinical, cognitive and anatomical evolution from nonfluent progressive aphasia to corticobasal syndrome: a case report

Recent clinical and pathological studies have suggested that frontotemporal lobar degeneration (FTLD) and corticobasal syndrome (CBS) show clinical and pathological overlap. We present four years of longitudinal clinical, cognitive and anatomical data in the case of a 56-year-old woman, AS, whose clinical picture evolved from FTLD to CBS. For the first three years, AS showed a progressive speech and language disorder compatible with a diagnosis of the nonfluent aphasia variant of FTLD. At year four, 10 years after her first symptom, AS developed the classical clinical signs of CBS, including alien limb phenomenon and dystonia. Voxel-based morphometry (VBM) applied to AS's four annual scans showed progression of atrophy from the inferior posterior frontal gyrus, to the left insula and finally to the medial frontal lobe. This case demonstrates the clinical overlap between FTLD and CBS and shows that the two can appear in the same patient at different stages of the disease in relation to the progression of anatomical damage.

A neuroanatomical model of passivity phenomena

Any attempt to elucidate the nature and mechanism of passivity phenomena, i.e., experiences that one's conscious actions or thoughts have not been 'willed' by oneself, requires an integrative philosophical-neurobiological approach. The model proposed here adopts some fundamental positions that have long been advocated by philosophers and theoretical psychologists and have now found support from functional neuroanatomy. First, we experience our actions not from the standpoint of the executive but through the perception of its effects. Second, the 'self' is not an agent of behaviour. Third, behaviour is energized and integrated by basic drives (instincts). Fourth, the view that the experience of an acting self is related to drive reduction associated with voluntary actions is perhaps less well developed. The model thus proposes that passivity phenomena are actions that are induced by the perception of salient events but that are not integrated with or conducive to the overall motivational state of the organism. It has been suggested that, following the perception of salient events, competition arises between automatic response tendencies seeking expression. The prefrontal cortex appears to play an important role not only in determining which events are to be perceived but also which of the corresponding response dispositions is to be selected and actualized in overt behaviour. Thus, action selection is the outcome of competition between response tendencies in the context of prefrontal biasing signals that represent drives and strivings for goals. Action selection may be uncoupled from drives and strivings as a result of a lowering of the threshold for action selection--as is suggested to be the case in schizophrenic passivity phenomena--or due to disconnection from prefrontal regions--as may be the case in the alien limb syndrome.

An interpretative phenomenological analysis of the embodiment of artificial limbs

PURPOSE

To gain an understanding of the embodied perceptual experience of successful prosthesis.

METHOD

The data for this study were transcripts derived from in-depth semi-structured e-mail (n=21) and face-to-face (n=14) interviews, and the documentary analysis of an e-mail discussion group for prosthesis users. This qualitative data was subject to an Interpretative Phenomenological Analysis.

RESULTS

Analysis of the research data identified six themes in the perceptually embodied experiences of prosthesis users: Adjusting to a prosthetic; The Balance of the Body; Awareness of the Prosthesis; The Knowing Body; The Phantom Becomes the Prosthesis: Extending the Body; and The Prosthesis as Tool or Corporeal Structure.

CONCLUSION

The often-cited reasons for the rejection of prostheses are frequently part of the initial experiences of 'successful' prosthesis users also. This suggests the need to sufficiently motivate potential prosthesis users in the period between an experience of prosthesis use as unnatural and wieldy to one of pre-reflective, natural use. In addition, two broad forms of prosthesis experience were identified: one in which the prosthesis was experienced as a corporeal structure; and one in which it was viewed as a tool. While future work may be able to explore the psychosocial correlates of these experiences, it is nonetheless the case that persons with these differing experiences were able to enjoy the benefits imbued by prosthesis use.

A focus group study of health professionals' views on phantom sensation, phantom pain and the need for patient information

Focus groups with 32 health professionals from pre- and post-amputation care in central Scotland were used to explore perceptions of phantom sensation and pain, and current practice and potential improvements to patient information. Findings were compared to our parallel study of patients' experiences of phantom phenomena and information needs. Professionals' perceptions of phantom phenomena did not always match patient experiences: few professionals were fully aware of the nature, or the problems associated with phantom pain. There was uncertainty about who provided information and reported information was inconsistent and only weakly grounded in theory and mechanism-based management. Whilst there was awareness of the benefits of information, content, mode of delivery and co-ordination were all identified as areas for improvement. Our findings suggest that the information given to patients on phantom phenomena is inconsistent and insufficient. Possible solutions are the development of minimum standards of information and specifically targeted interprofessional education.

[Phantom sensations and peripheral induced neglect following implantation of total hip prosthesis]

OBJECTIVES

O. Sacks describes in his book "A leg to stand on" the inability to move his leg for along period after rupture of the tendon of m. quadriceps. He refers the history of similar cases, especially of a woman with a hip fracture. He discusses this as a result of disruption of proprioception (peripheral induced neglect). The aim of this investigation is to answer the question how frequently this symptom may be found in patients with hip fracture and/or arthrosis perioperativly after implantation of a total prosthesis.

METHODS

we examined 106 patients aged 70.35 +/- 10.01 years (36-male 67.54 +/- 9.74 years and 69 female 71.9 +/- 9.9 years) who underwent an implantation of a hip prosthesis - antero-lateral access Watson-Jones - (right side n = 61, left n = 44) because of arthrosis (n = 81) or a hip fracture (n = 18) on postoperative day 1./2. and 10. - 14. Besides exact neurologic examination, we particularly asked for changed perception of the operated leg.

RESULTS

by neurological examination we found only rarely signs of peripheral nerve lesion as a complication of implantation of hip prosthesis (1 femoral nerve lesion, 1 ischiadicus nerve lesion). 14 patients reported a changed perception at the first examination: 5 patients felt their operated leg shorter or longer, 4 patients described their leg changed in a strange manner (like a block of wood or lead), 2 patients felt their leg changed, but could not tell how. At follow-up examination there was no patient with a changed perception of the operated leg.

CONCLUSIONS

at first examination only a small number of patients report a changed perception of the operated leg. Early mobilization of the operated leg may be the cause of quick normalization of perception. The peripherally induced neglect, described by O. Sacks, was possibly caused by decrease of cortical representation because of immobilization, but not by disrupted proprioception.

Pain Management in Trauma Patients

Trauma is a major cause of mortality throughout the world. In recent years, major advances have been made in the management of trauma, the end result of which has been reduced mortality and enhanced function. One of these areas is pain control. Improved pain management has not only led to increased comfort in trauma patients, but has also been shown to reduce morbidity and improve long-term outcomes. This review focuses on the treatment of pain in the setting of acute injury and on pain management in trauma patients who go on to develop chronic pain. Emphasis is placed on pharmacologic interventions, invasive and noninvasive pain management techniques, analgesia in challenging patients, and pain control in commonly encountered trauma conditions.

Prospective Diary Study of Nonpainful and Painful Phantom Sensations in a Preselected Sample of Child and Adolescent Amputees Reporting Phantom Limbs

OBJECTIVE

To prospectively study factors associated with the occurrence of phantom sensations and pains in a pre-selected sample of child and adolescent amputees reporting phantom limbs.

DESIGN

Prospective diary study over 1 month.

PARTICIPANTS

Fourteen child and adolescent amputees from 10-18 years of age who were missing a limb due to trauma (n = 12) or congenital limb deficiency (n = 2), and who had previously reported having phantom sensations and pain.

MAIN OUTCOME MEASURE

Diary used to assess the occurrence of non-painful and painful phantom sensations. Items included age, sex, location and cause of amputation, past experience with stump pain and pre-amputation pain, and intensity, quality, duration, and triggers of the sensations and pains.

RESULTS

Thirteen amputees reported having 104 incidents of non-painful phantom sensations with an average intensity of 4.17 (SD = 2.14) on a 0-10 rating scale. Fifty-three incidents of phantom pain with an average intensity of 6.43 (SD = 1.76) were recorded by 8 amputees. Both amputees with a congenital limb deficiency reported phantom phenomena. Girls reported more psychosocial triggers than did boys whereas boys were more likely than girls to report that they could not identify a trigger (P = 0.0001). Boys also reported a higher proportion of physical triggers than psychosocial triggers while there were no differences for girls (P = 0.0001).

DISCUSSION

Child and adolescent amputees experience phantom sensations and pains on a regular basis over a 1-month period. Differences in triggers of phantom phenomena between boys and girls may be due to differences in activities, awareness, attribution, and willingness to report psychosocial triggers.

Increased motor control of a phantom leg in humans results from the visual feedback of a virtual leg

Although previous research reported that the visual feedback of a 'virtual arm' increased the control of a phantom arm, it did not consider that the repeated attempt to move the phantom may have contributed to the effect. Twenty-one lower limb amputees reported the response of their phantom leg during repeated attempts to move both legs in one of two conditions, a control condition in which the amputee only viewed the movements of their intact leg and an experimental condition in which the amputee additionally viewed the movements of a 'virtual' leg. It was found that viewing a virtual leg resulted in amputees reporting a significantly greater number of movements of their phantom leg than with attempted movement alone. The implications were discussed in terms of visuo-motor adaptation and theories of motor control.

The effect of tactile and visual sensory inputs on phantom limb awareness

Multiple sensory stimuli contribute to the conscious awareness of the body. It is well known that limb amputation can result in abnormal body awareness, but the manner in which the CNS constructs and updates a body schema after injury is largely unknown. The purpose of the present study was to systematically evaluate the effects of sensory inputs on phantom limb awareness (PLA) shortly after unilateral upper extremity amputation. The location, quality and intensity of spontaneous and tactile-evoked phantom sensations and awareness were assessed in 13 amputees who were referred sequentially for their initial post-operative rehabilitation. Subjects were tested in three visual conditions: (i) with their eyes open; (ii) with their eyes closed; and (iii) while they viewed their intact hand in a mirror, which created an illusion of their amputated hand (i.e. mirror visual illusion). The mirror illusion was also used to test the effect of combined visual and movement-related stimuli during active voluntary movement. Spontaneous PLA was reported by 12 of the 13 amputees and was not affected by normal visual inputs. Tactile stimulation of the residual limb or face evoked dual percepts in six amputees; i.e. these amputees perceived these touch stimuli as if they were being applied both to the stimulus site and also to a location on the missing limb. This mislocalization phenomenon was most prevalent in the eyes-closed condition. Thus, normal vision can strongly override the phantom component of touch-evoked dual percepts. In eight cases, the visual illusion of the missing limb transiently enhanced the spontaneous conscious awareness of the phantom limb. However, the visual illusion did not change the capacity of a tactile stimulus to induce dual percepts. These findings demonstrate that (i) phantom awareness of an amputated body part is common within the 14 months after traumatic upper extremity amputation, (ii) evoked dual percepts are less common than spontaneous PLA, (iii) visual, tactile and sensorimotor systems contribute to PLA, (iv) subtle changes in congruence of sensory information affects both evoked dual percepts and spontaneous PLA, however, (v) sensorimotor information pertaining to the state of the motor system can strongly influence spontaneous PLA, whereas the visual system can predominantly influence evoked PLA.

Psychological aspects of mutilating hand injuries

The immediate and long-term outcome of a mutilating hand injury can be positively influenced by health care professionals adopting a biopsychosocial perspective toward treatment and management. Such an injury produces a psychological and social impact that should be openly and candidly addressed with the injured individual and with the family. The earlier and the more skillfully these issues are addressed, the more likely it is that psychological factors will not impede functional outcome.

Psychological correlates of illusory body experiences

Postamputation phantom sensations and phantom pain, i.e., sensation or pain in the amputated limb, can be extremely distressing for people who have had amputations. Recent research on treating phantom phenomena has used the experimental induction of illusory body experiences. Although the suggestion has been that such experiences may influence the cortical remapping that occurs after amputation, the role of psychological factors in these experimental inductions has not been addressed. We used an able-bodied sample to investigate whether a common underlying propensity exists for illusory body experiences and whether the occurrence of these experiences is associated with previously neglected psychological variables. Psychometric measures of body plasticity, somatic preoccupation, and creative imagination were significantly and differentially associated with the occurrence of illusory body experiences. Hence, these measures have potential use in identifying patients most likely to benefit from treatment interventions using the induction of illusory body experiences.

Association of pain with employment status and satisfaction among amputees in Japan

OBJECTIVE

To assess the relationship between residual and phantom limb pain and working life among persons with limb amputation.

DESIGN

Cross-sectional study in which amputee patients completed a mailed questionnaire about their residual limb and phantom limb pain, employment status, and satisfaction with working life.

SETTING

Department of rehabilitation medicine of a major hospital in Japan.

PARTICIPANTS

All participants were registered at the industrial rehabilitation center of a general hospital in Japan. Responses were received from 101 of the 147 patients (response rate, 68.7%) who were sent the questionnaire.

INTERVENTION

An amputation pain and employment status survey that included a standardized pain measure.

MAIN OUTCOME MEASURES

A self-report questionnaire, with 1 part concerning employment status and satisfaction with working life, and the other regarding amputation-related pain, which the participant described according to the Chronic Pain Grade (CPG).

RESULTS

We found (1) no statistically significant association between types of pain and the return to work rate, (2) no statistically significant association between the pain severity as graded by the CPG and return to work rate, and (3) satisfaction with working life was significantly related to the CPG categories.

CONCLUSION

The severity of pain does not appear to be associated with return to work among limb amputees. However, it is associated with satisfaction with working life. Appropriate treatment of pain may therefore improve work-related satisfaction.

Gabapentin in postamputation phantom limb pain: a randomized, double-blind, placebo-controlled, cross-over study

BACKGROUND AND OBJECTIVES

Severe phantom limb pain after surgical amputation affects 50% to 67% of patients and is difficult to treat. Gabapentin is effective in several syndromes of neuropathic pain. Therefore, we evaluated its analgesic efficacy in phantom limb pain.

METHODS

Patients attending a multidisciplinary pain clinic with phantom limb pain were enrolled into this randomized, double-blind, placebo-controlled, cross-over study. Other anticonvulsant therapy was discontinued. Each treatment was 6 weeks separated by a 1-week washout period. Codeine/paracetamol was allowed as rescue analgesia. The daily dose of gabapentin was titrated in increments of 300 mg to 2400 mg or the maximum tolerated dose. Patients were assessed at weekly intervals. The primary outcome measure was visual analog scale (VAS) pain intensity difference (PID) compared with baseline at the end of each treatment. Secondary measures were indices of sleep interference, depression (Hospital Anxiety and Depression [HAD] scale), and activities of daily living (Bartel Index).

RESULTS

Nineteen eligible patients (mean age, 56 years; range, 24 to 68 years; 16 men) were randomized, of whom 14 completed both arms of the study. Both placebo and gabapentin treatments resulted in reduced VAS scores compared with baseline. PID was significantly greater than placebo for gabapentin therapy at the end of the treatment (3.2 +/- 2.1 v 1.6 +/- 0.7, P =.03). There were no significant differences between placebo and gabapentin therapy in terms of the number of tablets of rescue medication required, sleep interference, HAD scale, or Bartel Index. The medication was well tolerated with few reports of adverse effects.

CONCLUSIONS

After 6 weeks, gabapentin monotherapy was better than placebo in relieving postamputation phantom limb pain. There were no significant differences in mood, sleep interference, or activities of daily living, but a type II error cannot be excluded for these variables.

The modification of cortical reorganization and chronic pain by sensory feedback

Recent neuroscientific evidence has revealed that the adult brain is capable of substantial plastic change in areas such as the primary somatosensory cortex that were formerly thought to be modifiable only during early experience. We discuss research on phantom limb pain as well as chronic back pain that revealed functional reorganization in both the somatosensory and the motor system in these chronic pain states. In phantom limb pain patients, cortical reorganization is correlated with the amount of phantom limb pain; in low back pain patients the amount of reorganizational change increases with chronicity. We present a model of the development of chronic pain that assumes an important role of somatosensory pain memories. In phantom limb pain, we propose that those patients who experienced intense pain prior to the amputation will later likely develop enhanced cortical reorganization and phantom limb pain. We show that cortical plasticity related to chronic pain can be reduced by behavioral interventions that provide feedback to the brain areas that were altered by somatosensory pain memories.

Treatment of neuropathic pain in Sierra Leone

During Sierra Leone's violent decade-long war, the warring parties used amputation, especially of arms, as a means of terror. In a camp for amputees in the capital city Freetown, Médecins Sans Frontières established a clinic and a treatment programme for neuropathic pain. Insecurity and cultural and language barriers have complicated this work, but medical and humanitarian benefits have been demonstrated. Pain services are virtually non-existent in less-developed countries. There have recently been no major treatment advances for neuropathic or phantom pain; however, the general body of knowledge about amputation pain can be increased by observations from these difficult settings.

Phantom-limb pain: characteristics, causes, and treatment

Phantom-limb pain is a common sequela of amputation, occurring in up to 80% of people who undergo the procedure. It must be differentiated from non-painful phantom phenomena, residual-limb pain, and non-painful residual-limb phenomena. Central changes seem to be a major determinant of phantom-limb pain; however, peripheral and psychological factors may contribute to it. A comprehensive model of phantom-limb pain is presented that assigns major roles to pain occurring before the amputation and to central as well as peripheral changes related to it. So far, few mechanism-based treatments for phantom-limb pain have been proposed. Most published reports are based on anecdotal evidence. Interventions targeting central changes seem promising. The prevention of phantom-limb pain by peripheral analgesia has not yielded consistent results. Additional measures that reverse or prevent the formation of central memory processes might be more effective.

Whose arm is it anyway? An fMRI case study of supernumerary phantom limb

Under normal circumstances, information from a number of sources is combined to compute a unitary percept of the body. However, after pathology these influences may be perceived simultaneously, resulting in multiple dissociated conscious representations. In a recent paper, we described subject E.P., a right-handed female stroke patient with a right frontomesial lesion who sporadically experiences a supernumerary 'ghost' left arm that occupies the previous position of the real left arm after a delay of 60-90 s. We used a delayed response paradigm with functional MRI to examine the haemodynamic correlates of E.P.'s illusion. Comparison of periods of time during scanning when the ghost arm was present against when it was not revealed a single cluster (9 voxels, t = 5.11, P < 0.012 corrected for multiple comparisons) located on the right medial wall in the supplementary motor area ('SMA proper'). Our results suggest that areas traditionally classified as part of the motor system can influence the conscious perception of the body. We propose that, as a consequence of her injury, E.P. is aware of the position of the phantom limb in this 'action space' while also continuing to be aware of the true position of her real limb on the basis of afferent somatosensory information.

Patient information on phantom limb pain: a focus group study of patient experiences, perceptions and opinions

Educating patients about their condition is regarded as a fundamental step in pain management. This study used focus groups with patients to explore their experiences and perceptions of the information on phantom pain that they received before and after amputation, and their views on improving this information. Thirty-one patients with a lower limb amputation attended one of seven focus groups. The majority reported phantom pain although there were individual variations in character, severity and persistence. There were wide variations in what people were told from occasional reports of good information to instances of people reporting little or no information from professionals. There were strong feelings that information should be given before or soon after amputation with a preference for verbal one-to-one explanations. Professionals, particularly nurses and surgeons, were regarded as the best source of information, although peer support was seen to be important. These findings indicate that people require timely up-to-date information on phantom pain which sensitively addresses the variability of the experience and provides the foundation for ongoing pain management. We propose that the information process could be improved by ensuring that professionals use standard information for patients derived from purposefully written sections in national guidelines.

On the syndrome of the "spare limb": one case

We describe a case of a brain-damaged patient who had a peculiar bodily illusion which could not be labelled an hallucination but seemed somatognosically and phenomenologically similar to the phantom limb without amputation. The patient, who showed left hemiplegia, felt a third upper limb (without seeing it) which he himself defined as "spare." The spare limb was not deformed; it could be moved and controlled by the patient, and there was no sensation of pain. The patient did not show psychopathological or cognitive disorders. A possible interpretation of the phenomenon is as a "phantom movement" of the paralysed limb: the mental representation of the movement of the limb was dissociated from the bodily representation of his own limb and so was still present in his consciousness despite the paralysis.

Phantom limb pain: a report of two cases

The efficacy of pre-emptive analgesia for phantom limb pain is still unclear. It is generally accepted that pre hyphen;amputation pain increases the incidence of phantom and stump pain, even if pre-emptive analgesia is performed before and during surgery and in the postoperative period. Two cases of traumatic upper limb amputations are described here with no pre-existing pain. Both received similar antinociceptive treatment by continuous block of the brachial plexus through infusion of ropivacaine 0.375% at 5 ml/h for 10 days. Treatment of case 1 was initiated immediately after surgery; however, this amputee developed intensive phantom limb pain which persisted at 6 months. Early use of the prosthesis after surgery was not possible for this patient. The intensity of phantom limb pain in case 2 decreased significantly after 6 months, even though brachial plexus blockade was not started until 5 weeks post-trauma. This patient used a functional prosthesis intensively beginning early after amputation. Serial magnetoencephalographic recordings were performed in both patients. Only case 2 showed significant changes of cortical reorganization. In case 1 markedly less cortical plasticity was found. A combination of relevant risk factors such as a painful neuroma, behavioural and cognitive coping strategies and the early functional use of prostheses are discussed as important mechanisms contributing to the development of phantom pain and cortical reorganization.

Cognitions, coping and social environment predict adjustment to phantom limb pain

Biopsychosocial models of chronic pain hypothesize a role for psychological and environmental factors in adjustment to chronic pain. To test the utility of such models for understanding phantom limb pain, 61 persons with recent amputations were administered measures of average phantom limb pain intensity, pain interference, depression, pain coping use, pain cognitions and appraisals, and social environmental variables 1 month post-amputation, and the measures of pain intensity, pain interference, and depression again 5 months later. Multiple regression analyses showed that the psychosocial predictors made a statistically significant contribution to the concurrent prediction of average phantom limb pain, pain interference, and depression at the initial assessment, and a significant contribution to the prediction of subsequent change in pain interference and depression over the course of 5 months. The results support the utility of studying phantom limb pain from a biopsychosocial perspective, and identify specific biopsychosocial factors (e.g., catastrophizing cognitions, social support, solicitous responses from family members, and resting as a coping response) that may play an important role in adjustment to phantom limb pain.

Phantom finger phenomena and the effects of toe-to-finger transplantation

Phantom finger phenomena and the effects of toe-to-finger transplantation were studied in 76 patients who had had traumatic finger amputation. Phantom finger phenomena were observed in 48 (63%) patients with the presence of phantom finger only in 30, phantom finger with sensation in nine, and phantom finger with motion also in nine. After toe transplantation, phantom finger phenomena disappeared immediately in about half of the transplanted fingers that had phantom phenomena before toe transplantation, and also in about half of the amputated fingers without the surgery. Conversely, phantom toe phenomena occurred in 13 (17%) patients. Although some patients had mild-to-moderate unpleasant phantom sensations, none had severe or distressing phantom finger pain or phantom toe pain. It is concluded that phantom phenomena occurred in both finger and toe amputations, and that toe-to-finger transplantation appeared to facilitate the disappearance of phantom phenomena not only in the transplanted fingers but also in the amputated but untransplanted fingers. Possible mechanisms for these observations are discussed.

Variation in phantom limb pain: results of a diary study

Amputees experience multiple, complex problems in addition to phantom limb pain. Although studies have yielded useful data on the relationship between phantom limb pain and other variables, this research generally has evaluated only one aspect of phantom limb pain and measured it at only one time point. The present study examined ongoing phantom limb pain and associated factors prospectively through the use of hourly pain diaries that are completed over a 7-day period. The sample comprised a subset of 89 lower limb amputees taking part in a longitudinal research study. Subjects had a mean age of 46.1 years. Forty-seven per cent were female, 53% male. Subjects completed a Pain/Coping Diary that measured phantom limb pain intensity, activity levels, medication use, and alcohol use on an hourly basis over a 7-day period. It also asked subjects to list the coping strategies used on the same hourly basis over a 7-day period. The diaries highlighted the following: Phantom limb pain appears to be episodic in nature and there is great variation in its intensity. Amputees use a limited repertoire of coping strategies to deal with episodes of phantom limb pain, and of those strategies that are used, few reduce the level of pain. This variability in phantom limb pain has important implications for those involved in the care of amputees as a report of phantom limb pain at a given point in time may not reflect the amputee's overall pain experience.

Psychological distress in amputees with phantom limb pain

Research suggesting that psychological factors play a role in phantom limb pain abounds in the literature. Despite recent research suggesting that these factors exacerbate rather than cause phantom limb pain, clinicians still frequently use personality as a rationale to explain amputees' phantom limb pain. The present study aimed to examine psychological distress in a working-age population of amputees not specifically seeking help for their pain. The study was conducted in two phases. Phase 1 included 315 amputees who completed the General Health Questionnaire (GHQ). Phase 2 included a subset of the original sample who completed the Beck Depression Inventory (BDI). In Phase 1, although over 50% of the sample reported GHQ scores over the threshold used to detect "caseness," this was not related to phantom limb pain. In Phase 2 of the study, only 15% of the sample reported moderate to severe symptoms of depression. Only 4% of the variance in phantom limb pain was accounted for using the overall BDI score. When BDI items were examined individually within regression models, a number significantly predicted phantom limb pain. However, the items most related to phantom limb pain were those involved in "performance difficulties" rather than "negative affect." The present study suggests that negative affect in amputees may be related to disability rather than pain.

[Illusions of body normality in amputees and paraplegic patients]

Phantom limbs in amputees, or body illusion in hemiplegics, have been the subject of wide ranging descriptions. The detected abnormalities involve morphological, postural and/or kinetic features. The aim of this prospective study carried out in 25 amputees and 10 adult paraplegics was to describe the typology of these perceptions. Data were collected from free and semi-directive investigations before and after caloric vestibular stimulation. Amputees and paraplegics perceived normal, deformed and painful body phantom segments, reffered perceptions and "normal limbs" which took on the request posture considering the general body position (illusion of body normality). This perception corresponds to an image of the body, such as it should be and not such as it is. In amputees, the limb follows the movements of the prothesis. These perceptions conform quite well reality so that the loss of the paralyzed limb is not perceived as a missing limb. This illusion of body normality should be distinguished from the normal phantom limb, characterized by a stronger perception of the lost limb compared with the other. In both amputees and paraplegics, vestibular stimulation can generate or modify phantoms limbs or body illusion and can abolish painful phantom limbs. The neuromatrix, which rebuilds body representations, could get its information from reorganized cortical areas (instantaneous body image), autobiographical engrams (painful phantoms limbs), or innate engrams (identity body schema) that, via congruence mechanisms, could be identified as a somatic reference, particularly for motor programming. This interpretation is compatible with current knowledge and suggests how amputees can easily use a prothesis.

Common pathways in mental imagery and pain perception: an fMRI study of a subject with an amputated arm

The present paper reviews data from two previous studies in our laboratory, as well as some additional new data, on the neuronal representation of movement and pain imagery in a subject with an amputated right arm. The subject imagined painful and non-painful finger movements in the amputated stump while being in a MRI scanner, acquiring EPI-images for fMRI analysis. In Study I (Ersland et al., 1996) the Subject alternated tapping with his intact left hand fingers and imagining "tapping" with the fingers of his amputated right arm. The results showed increased neuronal activation in the right motor cortex (precentral gyrus) when tapping with the fingers of the left hand, and a corresponding activation in the left motor cortex when imagining tapping with the fingers of the amputated right arm. Finger tappings of the intact left hand fingers also resulted in a larger activated precentral area than imagery "finger tapping" of the amputated right arm fingers. In Study II (Rosen et al., 2001 in press) the same subject imagining painful and pleasurable finger movements, and still positions of the fingers of the amputated arm. The results showed larger activations over the motor cortex for movement imagining versus imagining the hand being in a still position, and larger activations over the sensory cortex when imagining painful experiences. It can therefore be concluded that not only does imagery activate the same motor areas as real finger movements, but also that adding instructions of pain together with imaging moving the fingers intensified the activation compared with adding instructions about non-painful experiences. From these studies, it is clear that areas activated during actual motor execution to a large extent also are activated during mental imagery of the same motor commands. In this respect the present studies add to studies of visual imagery that have shown a similar correspondence in activation between actual object perception and imagery of the same object.

[Phantom pain after amputation of extremities]

Phantom pain is experienced by about 70% of patients following limb amputation. In most patients, both the frequency and the intensity of pain attacks diminish with time, but severe pain persists in about 5-10%. The mechanisms underlying pain in amputees are not fully understood, but factors in both the peripheral and central nervous system play a role. Pain before the amputation seems to increase the risk of phantom pain, but the relation is not simple. Treatment of phantom pain is not successful; a recent study on prevention of the pain with a preoperative epidural blockade showed negative results. The future may reveal new specific drugs for treatment.

Treatment of phantom limb pain with combined EMG and thermal biofeedback: a case report

Phantom pain is a frequent consequence of the amputation of an extremity and causes considerable discomfort and disruption of daily activities. This study describes a patient with extreme phantom limb pain following amputation of the right upper limb. The treatment consisted of 6 sessions of EMG biofeedback followed by 6 sessions of temperature biofeedback. The patient did not use a prosthesis and had not received previous treatment for chronic pain. Results demonstrated complete elimination of phantom limb pain after treatment, which was maintained at a 3- and 12-month follow-up. Pain relief covaried with increase in skin temperature at stump and perceptual telescoping (retraction of phantom limb into stump).

Caring for patients with phantom limb sensation

Phantom limb pain is increasingly perceived as a complex condition that is likely to have multifactorial causes. Although acknowledgement of the existence of the condition is more prevalent than it was, its treatment remains elusive. Nurses caring for people with phantom limb pain have a unique role to play in the overall holistic therapy of the amputee.

Perceptual phenomena after unilateral arm amputation: a pre-post-surgical comparison

Painful and non-painful phantom phenomena occur frequently after amputations but are rarely investigated in the perioperative stage. The goal of the present study was the assessment of phantom phenomena, pain and changes in primary somatosensory cortex prior to and after upper limb amputation. Two patients who suffered from metastatic carcinoma were examined 2 days prior to and 7 days after the amputation of an arm using comprehensive psychometric assessments and neuroelectric source imaging. Both patients reported phantom limb pain that was similar to their pre-amputation pain. In one patient, reorganization of the mouth area into the deafferented hand area took place immediately after the amputation. In the other patient reorganization had occurred prior to the amputation possibly related to non-use of the arm several years prior to the amputation.

Central neuroplasticity and pathological pain

The traditional specificity theory of pain perception holds that pain involves a direct transmission system from somatic receptors to the brain. The amount of pain perceived, moreover, is assumed to be directly proportional to the extent of injury. Recent research, however, indicates far more complex mechanisms. Clinical and experimental evidence shows that noxious stimuli may sensitize central neural structures involved in pain perception. Salient clinical examples of these effects include amputees with pains in a phantom limb that are similar or identical to those felt in the limb before it was amputated, and patients after surgery who have benefited from preemptive analgesia which blocks the surgery-induced afferent barrage and/or its central consequences. Experimental evidence of these changes is illustrated by the development of sensitization, wind-up, or expansion of receptive fields of CNS neurons, as well as by the enhancement of flexion reflexes and the persistence of pain or hyperalgesia after inputs from injured tissues are blocked. It is clear from the material presented that the perception of pain does not simply involve a moment-to-moment analysis of afferent noxious input, but rather involves a dynamic process that is influenced by the effects of past experiences. Sensory stimuli act on neural systems that have been modified by past inputs, and the behavioral output is significantly influenced by the "memory" of these prior events. An increased understanding of the central changes induced by peripheral injury or noxious stimulation should lead to new and improved clinical treatment for the relief and prevention of pathological pain.

The effect of opioids on phantom limb pain and cortical reorganization

The efficacy of oral retarded morphine sulphate (MST) was tested against placebo in a double-blind crossover design in 12 patients with phantom limb pain after unilateral leg or arm amputation. Two counterbalanced treatment phases of 4 weeks each were initiated with an intravenous test infusion of MST or Placebo. The titration phase was 2 weeks. The dose of MST was titrated to at least 70 mg/day and at highest 300 mg/day. Pain intensity was assessed hourly on visual analog scales during a 4-week treatment-free phase, both treatment phases and at two follow-ups (6 and 12 months). Reorganization of somatosensory cortex, electric perception and pain thresholds as well as selective attention were measured pre- and post-treatment. A significant pain reduction was found during MST but not during placebo. A clinically relevant response to MST (pain reduction of more than 50%) was evident in 42%, a partial response (pain reduction of 25-50%) in 8% of the patients. Neuromagnetic source imaging of three patients showed initial evidence for reduced cortical reorganization under MST concurrent with the reduction in pain intensity. Perception and pain thresholds were not significantly altered whereas attention was significantly lower under MST. Thus, opioids show efficacy in the treatment of phantom limb pain and may potentially influence also cortical reorganization. These data need to be replicated in larger patient samples.

Different brain areas activated during imagery of painful and non-painful 'finger movements' in a subject with an amputated arm

The purpose of the present study was to investigate differences in brain activation with functional magnetic resonance imaging (fMRI) during imagery of painful and non-painful 'finger movements' and 'hand positioning' in a subject with an amputated arm. The subject was a right-handed man in his mid-thirties who lost his right arm just above the elbow in a car-train accident. MRI was performed with a 1.5 T Siemens Vision Plus scanner. The basic design involved four conditions: imagining 'painful finger movements', 'non-painful finger movements', 'painful hand positioning', 'non-painful hand positioning'. Imagery of finger movements uniquely activated the contralateral primary motor cortex which contains the classic 'hand area'. The lateral part of the anterior cerebellar lobe was also activated during imagery of finger movements. Imagery of pain uniquely activated the somatosensory area, and areas in the left insula and bilaterally in the ventral posterior lateral nucleus of the thalamus. It is suggested that the insula and thalamus may involve neuronal pathways that are critical for mental processing of pain-related experiences, which may relate to a better understanding of the neurobiology of phantom limb pain.

Abnormalities in the awareness and control of action

Much of the functioning of the motor system occurs without awareness. Nevertheless, we are aware of some aspects of the current state of the system and we can prepare and make movements in the imagination. These mental representations of the actual and possible states of the system are based on two sources: sensory signals from skin and muscles, and the stream of motor commands that have been issued to the system. Damage to the neural substrates of the motor system can lead to abnormalities in the awareness of action as well as defects in the control of action. We provide a framework for understanding how these various abnormalities of awareness can arise. Patients with phantom limbs or with anosognosia experience the illusion that they can move their limbs. We suggest that these representations of movement are based on streams of motor commands rather than sensory signals. Patients with utilization behaviour or with delusions of control can no longer properly link their intentions to their actions. In these cases the impairment lies in the representation of intended movements. The location of the neural damage associated with these disorders suggests that representations of the current and predicted state of the motor system are in parietal cortex, while representations of intended actions are found in prefrontal and premotor cortex.

Dissociation of anosognosia and phantom movement during the Wada test

OBJECTIVE

Patients who misperceive that they are moving their paralysed arm (phantom movements) may not recognise its weakness. Therefore, the relation between phantom limb movements and anosognosia for hemiplegia during selective right hemispheric anaesthesia (the Wada test) was examined.

METHODS

Nine patients with intractable epilepsy underwent the Wada test. During the right hemispheric injection, after the onset of hemiparesis, anosognosia was assessed by asking patients if they were weak. The patient's vision was limited such that they could not see the position of their limbs. Phantom movements were tested for by asking patients to attempt to lift their left upper limb, and to demonstrate their left limb's position by placing their right limb in the same position as their left. Proprioception was tested by lifting the patient's paretic upper limb and having patients demonstrate this position by lifting their right limb to the same position.

RESULTS

Three patients experienced left phantom limb movements, and five were anosognosic for their hemiplegia. However, phantom movement occurred in only one patient with anosognosia. The other two patients with phantom movement were without anosognosia. The patient with phantom movement and anosognosia had impaired proprioception. The two patients with phantom movement but without anosognosia had intact proprioception.

CONCLUSIONS

Phantom movement in the presence of a proprioceptive deficit could contribute to anosognosia. However, anosognosia and phantom movement are dissociable; therefore phantom movement cannot alone account for anosognosia. Because phantom movement occurred with and without proprioceptive deficits, proprioceptive loss is not a prerequisite for phantom movement.

Sexuality in persons with lower extremity amputations

PURPOSE

There is a paucity of information regarding sexual functioning in persons with lower extremity amputations. The purpose of this study was to describe sexual and psychological functioning and health status in persons with lower extremity amputation.

METHODS

Self-report surveys assessed sexual functioning (Derogatis Inventory), depression (Beck Depression Inventory, anxiety (State-Trait Anxiety Inventory), and health status (Health Status Questionnaire) in a convenience sample of 30 men with lower extremity amputations. Mean age of the participants was 57 years (range 32-79). Mean duration since amputation was 23 months (range 3-634 months). Twenty one subjects (70%) had trans-tibial and seven subjects (23%) had trans-femoral amputations.

RESULTS

A majority of subjects were experiencing problems in several domains of sexual functioning. Fifty three percent (n = 16) of the subjects were engaged in sexual intercourse or oral sex at least once a month. Twenty seven percent (n = 8) were masturbating at least once a month. Nineteen subjects (63%) reported orgasmic problems and 67% were experiencing erectile difficulties. Despite these problems, interest in sex was high in over 90% of the subjects. There was no evidence of increased prevalence of depression or anxiety in these subjects when compared to other outpatient adult populations.

CONCLUSIONS

Sexual problems were common in the subjects studied. Despite these problems, interest in sex remained high. Few investigations have been directed toward identifying the psychological and social factors that may contribute to these problems and more research with a larger population is needed in this area.

Beyond re-membering: phantom sensations of congenitally absent limbs

Phantom limbs are traditionally conceptualized as the phenomenal persistence of a body part after deafferentation. Previous clinical observations of subjects with phantoms of congenitally absent limbs are not compatible with this view, but, in the absence of experimental work, the neural basis of such "aplasic phantoms" has remained enigmatic. In this paper, we report a series of behavioral, imaging, and neurophysiological experiments with a university-educated woman born without forearms and legs, who experiences vivid phantom sensations of all four limbs. Visuokinesthetic integration of tachistoscopically presented drawings of hands and feet indicated an intact somatic representation of these body parts. Functional magnetic resonance imaging of phantom hand movements showed no activation of primary sensorimotor areas, but of premotor and parietal cortex bilaterally. Movements of the existing upper arms produced activation expanding into the hand territories deprived of afferences and efferences. Transcranial magnetic stimulation of the sensorimotor cortex consistently elicited phantom sensations in the contralateral fingers and hand. In addition, premotor and parietal stimulation evoked similar phantom sensations, albeit in the absence of motor evoked potentials in the stump. These data indicate that body parts that have never been physically developed can be represented in sensory and motor cortical areas. Both genetic and epigenetic factors, such as the habitual observation of other people moving their limbs, may contribute to the conscious experience of aplasic phantoms.

Hypnosis: useful, neglected, available

Hypnosis is presented as a valuable and frequently neglected resource for many patients with chronic and terminal illness. Particular attention is given herein to the use of hypnosis in attaining relaxation, overcoming insomnia, helping the patient achieve pain relief, and, most particularly, teaching the patient to work with relatives and other persons close to them, as caregivers in a special relationship that can be a very important source of relief to the patient. A brief overview of indications, contraindications, errors, and safeguards is given. Sources of education and training are briefly reviewed and a bibliography is included to identify the nature of professional societies, three in the United States and one international, together with some standard publications. The purpose of this article is to affirm the value of hypnosis as a complementary or alternative therapy for hospice patients, to summarize its clinical applications, and to list the most standard and best known professional societies and publications.

[Neurogenic pain after deafferentation through trauma. Little-known pain syndrome following amputation, brachial plexus injury and nerve root avulsion]

Amputations may be followed by such phenomena as phantom-limb pain, and pain and involuntary movements of the stump. The sequelae of brachial plexus injuries or cervical root avulsion--the second large group of deafferentiation lesions associated with neurogenic pain--are less varied, and most of these cases involve damage to the substantia gelatinosa of the spinal cord. The two groups of deafferentiation lesions are described on the basis of our own experience and reports in the literature. A generally applicable effective form of treatment is not known, and possible therapeutic approaches, which need to be adapted individually, are discussed.

Coping with amputation and phantom limb pain

Phantom limb pain is a common, distressing phenomenon that can occur after the amputation or denervation of a part of the body. No conclusive etiological models or theories have emerged, although the problem was identified some time ago. This empirical-diagnostic study deals with correlations between coping with limb loss, body image, and the occurrence of phantom limb pain. It is based on Melzack's concept of a neuromatrix. Coping strategies were evaluated using semistructured interviews and analysis of patients' drawings of their body images. The results of the study, based on 43 amputees, show a significant association between coping strategies and pain. Patients who cope better with the loss suffer less from phantom limb pain. A difference can also be noted in subjective representation of the body image: patients suffering from phantom limb pain tend to have an image of their bodies as a complete and undamaged entity.

Phantom limb pain: a review of the literature on attributes and potential mechanisms

This study presents a review of the literature on the attributes and potential mechanisms involved in phantom limb pain, encompassing studies describing pain in the residual limb, phantom sensation and phantom limb pain, and the difficulties that may arise when making these distinctions. A variety of theories have been proposed to explain causal mechanisms for phantom limb pain. Conceptually, research into phantom limb pain is informed by the particular theory of chronic pain that is dominant at the time the research is undertaken. For example, early physiological theories on the etiology of phantom limb pain were grounded in specificity or pattern theories of pain. Later physiological research was based on the framework provided by Gate Control Theory and focused on identifying peripheral, spinal, and central neural mechanisms. Psychological explanations were grounded in psychoanalytic or personality theories of chronic pain which propose that phantom limb pain results from pre-amputation psychological disturbance. Despite numerous studies examining phantom limb pain, much of this research has both conceptual and methodological shortcomings. As such, the application of these research findings to clinical practice has limited utility.

Stiff upper lip: coping strategies of World War II veterans with phantom limb pain

OBJECTIVE

Study of coping with phantom pain in nonclinical war veteran amputees.

DESIGN

Semistructured interview with amputees in their home setting.

SETTING

Residential home for war veteran amputees or respondents' own homes.

PATIENTS

Amputee veterans of World War II with phantom pain.

OUTCOME MEASURES

Pain (McGill Pain Questionnaire) and pain history, coping (daily coping; Stone and Neale, J Pers Soc Psychol 1984;46:892-906), size of social network, and quality of war memories.

RESULTS

No differences in pain or coping were associated with place of residence (and prevalence of cues) or social networks; war memories appeared not to be associated with availability of cues, whether media coverage or other amputees. There was some association between the emotional tone of war memories and pain intensity. Veteran amputees were in general accepting of high levels of pain and made little use of medical resources, relating that to past experience of their pain being dismissed.

CONCLUSION

Coping with phantom pain in war veteran amputees is predominantly silent acceptance of the pain, with little use of social support however available, and rare recourse to medical help, based on past unhelpful experience. Pain and mood appeared to be unrelated to specific war cues, but higher pain scores were reported by those with unhappier war memories.