Supernumerary phantom limbs in spinal cord injury. Spinal Cord. 2011;49:588-595. [PMID: 21079624 DOI: 10.1038/sc.2010.143]

Embodiment of supernumerary robotic limbs in virtual reality

The supernumerary robotic limb system expands the motor function of human users by adding extra artificially designed limbs. It is important for us to embody the system as if it is a part of one's own body and to maintain cognitive transparency in which the cognitive load is suppressed. Embodiment studies have been conducted with an expansion of bodily functions through a "substitution" and "extension". However, there have been few studies on the "addition" of supernumerary body parts. In this study, we developed a supernumerary robotic limb system that operates in a virtual environment, and then evaluated whether the extra limb can be regarded as a part of one's own body using a questionnaire and whether the perception of peripersonal space changes with a visuotactile crossmodal congruency task. We found that the participants can embody the extra-limbs after using the supernumerary robotic limb system. We also found a positive correlation between the perceptual change in the crossmodal congruency task and the subjective feeling that the number of one's arms had increased (supernumerary limb sensation). These results suggest that the addition of an extra body part may cause the participants to feel that they had acquired a new body part that differs from their original body part through a functional expansion.

What the study of spinal cord injured patients can tell us about the significance of the body in cognition

Although in the last three decades philosophers, psychologists and neuroscientists have produced numerous studies on human cognition, the debate concerning its nature is still heated and current views on the subject are somewhat antithetical. On the one hand, there are those who adhere to a view implying 'disembodiment' which suggests that cognition is based entirely on symbolic processes. On the other hand, a family of theories referred to as the Embodied Cognition Theories (ECT) postulate that creating and maintaining cognition is linked with varying degrees of inherence to somatosensory and motor representations. Spinal cord injury induces a massive body-brain disconnection with the loss of sensory and motor bodily functions below the lesion level but without directly affecting the brain. Thus, SCI may represent an optimal model for testing the role of the body in cognition. In this review, we describe post-lesional cognitive modifications in relation to body, space and action representations and various instances of ECT. We discuss the interaction between body-grounded and symbolic processes in adulthood with relevant modifications after body-brain disconnection.

Pain Reduction after Short Exposure to Virtual Reality Environments in People with Spinal Cord Injury

Emerging literature suggests that virtual reality (VR) may be a viable therapy for neuropathic pain (NP). This pilot study aimed to investigate the immediate effect of VR in reducing NP in people with spinal cord injury (SCI). Eight individuals with chronic NP after SCI were recruited and underwent consecutive exposure to scenery and somatic virtual environments (VE). The numeric rating scale (NRS) was used to assess pain before and after exposure to each VE. The Immersive Tendencies Questionnaire (ITQ) and Presence Questionnaire (UQO-PQ) were used to investigate the interaction between reported pain relief post-intervention with immersion and presence. There was a significant reduction in pain levels (5.1 ± 0.4, mean ± SEM) after short exposure to the scenery (3.1 ± 0.7, p = 0.04) and somatic VE (3.0 ± 0.7, p = 0.04), with no difference between intervention types (p = 0.56). There was a statistically significant negative correlation between the total ITQ score and the change in NRS after the scenery VR intervention (r_s = 0.743, p = 0.035). PQ scores showed no significant correlation with changes in pain following either intervention type. We found that short-term exposure to VR environments results in a reduction in chronic NP intensity in people with SCI.

Victor Parant (1848-1924) and the first report of psychosis in the course of Parkinson's disease with dementia

Until the beginning of the twentieth century, neurologists considered that mental disorders in the course of Parkinson's disease (PD) occurred in the terminal phases of the disease or were due to coincidental pathologies. Benjamin Ball (1834-1893), in 1881 and 1882, drew attention to the frequency of cognitive and depressive disorders in PD. In 1883, Victor Parant (1848-1924), referring to Ball's work, published the first detailed observation of a PD patient with dementia and psychotic symptoms. Parant was an alienist running a private clinic for mental diseases in Toulouse, France. One of his main interests was the question of the responsibility of the insane, and he was called upon as a forensic expert in several cases. In this context, Parant examined a man who had been suffering from PD for several years, and later developed concurrently severe cognitive impairment and psychotic disorders. The patient would meet modern criteria for PD-associated psychosis: he had multimodal hallucinations (visual, auditory and somatic), visual illusions, and paranoid delusions. He also reported unusual symptoms: supernumerary limbs and Alice in Wonderland syndrome. Parant forwarded the far-sighted hypothesis that cognitive and psychotic disorders were due to the extension of PD lesions within the brain. The unheralded work of Victor Parant should be recognized in the history of neuropsychiatry.

Management of nonpainful supernumerary phantom limbs after incomplete spinal cord injury with visual-tactile feedback therapy: a case report

INTRODUCTION

Supernumerary phantom limb (SPL) is an uncommon phantom sensation where the patient experiences the illusory presence of one or more limbs in addition to their existing limbs. SPL after a spinal cord injury (SCI) is rare with few documented cases. There is minimal treatment guidance available, with some reports of visual-tactile feedback therapy used to manage SPL.

CASE PRESENTATION

A 43-year-old male sustained a C4 ASIA Impairment Scale grade C SCI, developing the sensation of two SPL arms originating from his shoulders 6 days after injury. He developed a self-directed method of visual-tactile feedback as a means to improve the SPL sensations, consisting of shrugging his shoulders repeatedly for 1 min while observing the movement of his actual arms. After completion of this routine, the SPL moved to the same location as his arms, providing relief. Also, an elastic band was placed on a sensate region of his arm, providing additional visual-tactile feedback. The SPL improved and resolved by day 45.

DISCUSSION

SPL after SCI is poorly characterized, usually occurring within 6-7 days of injury after a complete or incomplete cervical SCI. While the mechanism is unclear, the inability to integrate visual, tactile, and proprioceptive information after deafferentation may contribute to development. Similarities between SPL and phantom limb sensation after an amputation have resulted in the use of visual and visual-tactile feedback therapy for painful SPL management. This is the first case documenting successful use of visual-tactile feedback therapy to manage nonpainful SPL.

Effects of combined rTMS and visual feedback on the rehabilitation of supernumerary phantom limbs in a patient with spinal cord injury: A case report

BACKGROUND

Supernumerary phantom limb (SPL) caused by spinal cord injury (SCI) has previously been reported in several studies. However, the mechanisms and management of SPL in SCI patients are still not fully understood. Herein, we report a rare case of SPL in a patient with incomplete SCI.

CASE SUMMARY

A 46-year-old man complained of four hands 7 d after SCI. He was diagnosed with SPL complicated with actual limb neuropathic pain. Following a period of treatment with neurotrophic agents and Chinese traditional and analgesic medications, SPL symptoms and actual limb pain did not improve. However, his symptoms gradually lessened after combined treatment with high-frequency repetitive transcranial magnetic stimulation (rTMS), a promising neuromodulation technique, over the M1 cortex and visual feedback. After 7 wk of this treatment, SPL disappeared completely and actual limb pain was significantly relieved.

CONCLUSION

Cerebral plasticity changes may be a mechanism underlying the occurrence of non-painful SPL in SCI patients, and high-frequency rTMS applied to the M1 cortex could be a promising treatment method for SPL.

Anticipation of wheelchair and rollerblade actions in spinal cord injured people, rollerbladers, and physiotherapists

Embodied Cognition Theories (ECT) postulate that higher-order cognition is heavily influenced by sensorimotor signals. We explored the active role of somatosensory afferents and motor efferents in modulating the perception of actions in people who have suffered a massive body-brain disconnection because of spinal cord injury (SCI), which leads to sensory-motor loss below the lesion. We assessed whether the habitual use of a wheelchair enhances the capacity to anticipate the endings of tool-related actions, with respect to actions that have become impossible. In a Temporal Occlusion task, three groups of participants (paraplegics, rollerbladers and physiotherapists) observed two sets of videos depicting an actor who attempted to climb onto a platform using a wheelchair or rollerblades. Three different outcomes were possible, namely: a) success (the actor went up the step); b) fail (the actor stopped before the step without going up) and c) fall (the actor fell without going up). Each video set comprised 5 different durations increasing in complexity: in the shortest (600ms) only preparatory body movements were shown and in the longest (3000ms) the complete action was shown. The participants were requested to anticipate the outcome (success, fail, fall). The main result showed that the SCI group performed better with the wheelchair videos and poorer with rollerblade videos than both groups, even if the physiotherapists group never used rollerblades. In line with the ECT, this suggests that the action anticipation skills are not only influenced by motor expertise, but also by motor connection.

Brain Functional Connectivity Plasticity Within and Beyond the Sensorimotor Network in Lower-Limb Amputees

Cerebral neuroplasticity after amputation has been elucidated by functional neuroimaging. However, little is known concerning how brain network-level functional reorganization of the sensorimotor system evolves following lower-limb amputation. We studied 32 unilateral lower-limb amputees (LLAs) and 32 matched healthy controls (HCs) using resting-state functional magnetic resonance imaging (rs-fMRI). A regions of interest (ROI)-wise connectivity analysis was performed with ROIs in eight brain regions in the sensorimotor network to investigate intra-network changes, and seed-based whole-brain functional connectivity (FC) with a seed in the contralateral primary sensorimotor cortex (S1M1) was used to study the FC reorganization between the sensorimotor region (S1M1) and other parts of the brain in the LLAs. The ROI-wise connectivity analysis showed that the LLAs had decreased FC, mainly between the subcortical nuclei and the contralateral S1M1 (p < 0.05, FDR corrected). Seed-based whole-brain FC analysis revealed that brain regions with decreased FC with the contralateral S1M1 extended beyond the sensorimotor network to the prefrontal and visual cortices (p < 0.05, FDR corrected). Moreover, correlation analysis showed that decreased FC between the subcortical and the cortical regions in the sensorimotor network progressively increased in relation to the time since amputation. These findings indicated a cascade of cortical reorganization at a more extensive network level following lower-limb amputation, and also showed promise for the development of a possible neurobiological marker of changes in FC related to motor function recovery in LLAs.

Birth and death of a phantom

Patients with supernumerary phantom limb report experiencing an additional limb duplicating its physical counterpart, usually following a stroke with sensorimotor disturbances. Here, we report a short‐lasting case of a right upper supernumerary phantom limb with unusual visuomotor features in a healthy participant during a pure Jacksonian motor seizure unexpectedly induced by continuous Theta‐Burst Stimulation over the left primary motor cortex. Electromyographic correlates of the event followed the phenomenological pattern of sudden appearance and brutal dissolution of the phantom, adding credit to the hypothesis that supernumerary phantom limb results from a dynamic resolution of conflictual multimodal information.

Supernumerary phantom limb in a patient with basal ganglia hemorrhage - a case report and review of the literature

Background

Supernumerary phantom limb (SPL) is a rare neurologic phenomenon, in which a patient misperceives an extra limb in addition to the original set of limbs. We report a case of SPL in a patient with a right basal ganglia hemorrhage and review the previous literature about this peculiar phenomenon.

Case presentation

Two days after the event of a right basal ganglia hemorrhage, a 78-year-old male reported a phantom arm protruding from his left shoulder. He could not see or touch the phantom arm but he felt the presence of an addition arm lateral to his paretic arm. Pain or sensory discomfort were absent in either the paretic arm or the phantom arm. He stated that he could intentionally move the phantom arm independent of his paretic arm. The examination showed that the passive movement of his paretic arm did not elicit any movement of his phantom arm. We diagnosed the SPL as a complication of the hypertensive basal ganglia hemorrhage and treated him with anti-hypertensive medications. His phantom arm persisted for 3 weeks, and it gradually faded away.

Conclusion

SPL had been reported as a rare complication of various types of cerebral lesions. Right hemispheric lesions were most frequently associated with the SPL. Considering the intentional movement of the phantom arm, we deduced that the SPL might result from the impairment of the sensory feedback system for both internal body image and motor movement.

Post-traumatic Visualized Supernumerary Phantom Limbs: A Case Presentation

The experience of supernumerary phantom limbs (SPLs) is a rare phenomenon known to occur following a variety of neurological ailments. This case report details visualized supernumerary phantom arms and legs in a polytrauma patient with suspicion of seizure as the primary contributing factor. Fewer than 30 cases of SPLs have been previously described. SPLs are usually confined to the phantom proprioception/sensation of the limb, with only 6 prior cases reporting visualized SPLs, all of which occurred in the setting of isolated stroke. This case presentation is notable because it is the first to describe visualized SPLs in a polytrauma patient.

LEVEL OF EVIDENCE

V.

Third International Congress on Epilepsy, Brain, and Mind: Part 2

Epilepsy is both a disease of the brain and the mind. Here, we present the second of two papers with extended summaries of selected presentations of the Third International Congress on Epilepsy, Brain and Mind (April 3-5, 2014; Brno, Czech Republic). Humanistic, biologic, and therapeutic aspects of epilepsy, particularly those related to the mind, were discussed. The extended summaries provide current overviews of epilepsy, cognitive impairment, and treatment, including brain functional connectivity and functional organization; juvenile myoclonic epilepsy; cognitive problems in newly diagnosed epilepsy; SUDEP including studies on prevention and involvement of the serotoninergic system; aggression and antiepileptic drugs; body, mind, and brain, including pain, orientation, the "self-location", Gourmand syndrome, and obesity; euphoria, obsessions, and compulsions; and circumstantiality and psychiatric comorbidities.

Re-establishing the disrupted sensorimotor loop in deafferented and deefferented people: The case of spinal cord injuries

Acting efficiently in the world depends on the activity of motor and somatosensory systems, the integration of which is necessary for the proper functioning of the sensorimotor loop (SL). Profound alterations of SL functioning follow spinal cord injury (SCI), a condition that brings about a disconnection of the body from the brain. Such disconnection creates a substantial deprivation of somatosensorial inputs and motor outputs. Consequent somatic deficits and motor paralysis affect the body below the lesion level. A complete restoration of normal functions of the SL cannot be expected until basic neuroscience has found a way to re-establish the interrupted neural connectivity. Meanwhile, studies should focus on the development of technical solutions for dealing with the disruption of the sensorimotor loop. This review discusses the structural and functional adaptive reorganization of the brain after SCI, and the maladaptive mechanisms that impact on the processing of body related information, which alter motor imagery strategies and EEG signals. Studies that show how residual functions (e.g. face tactile sensitivity) may help people to restore a normal body image are also reviewed. Finally, data on how brain and residual body signals may be used to improve brain computer interface systems is discussed in relation to the issue of how such systems may help SCI people to re-enter the world and interact with objects and other individuals.

The effect of virtual visual feedback on supernumerary phantom limb pain in a patient with high cervical cord injury: a single-case design study

We characterized the effect of virtual visual feedback (VVF) on supernumerary phantom limb pain (SPLP) in a patient with high cervical cord injury. The subject was a 22-year-old man diagnosed with complete spinal cord injury (level C2) approximately 5 years ago. We applied the ABA'B' single-case design and set phases B and B' as intervention phases for comparison. SPLP significantly improved in comparison of phase A with phase B and phase A with phase B'. We suggest that VVF reduces SPLP and the effect lasts after VVF.

Atypical supernumerary phantom limb and phantom limb pain in a patient with spinal cord injury: case report

Supernumerary phantom limb (SPL) resulting from spinal cord lesions are very rare, with only sporadic and brief descriptions in the literature. Furthermore, the reported cases of SPL typically occurred in neurologically incomplete spinal cord patients. Here, we report a rare case of SPL with phantom limb pain that occurred after traumatic spinal cord injury in a neurologically complete patient. After a traffic accident, a 43-year-old man suffered a complete spinal cord injury with a C6 neurologic level of injury. SPL and associated phantom limb pain occurred 6 days after trauma onset. The patient felt the presence of an additional pair of legs that originated at the hip joints and extended medially, at equal lengths to the paralyzed legs. The intensity of SPL and associated phantom limb pain subsequently decreased after visual-tactile stimulation treatment, in which the patient visually identified the paralyzed limbs and then gently tapped them with a wooden stick. This improvement continued over the 2 months of inpatient treatment at our hospital and the presence of the SPLs was reduced to 20% of the real paralyzed legs. This is the first comprehensive report on SPLs of the lower extremities after neurologically complete spinal cord injury.

The sense of the body in individuals with spinal cord injury

Increasing evidence suggests that the basic foundations of the self lie in the brain systems that represent the body. Specific sensorimotor stimulation has been shown to alter the bodily self. However, little is known about how disconnection of the brain from the body affects the phenomenological sense of the body and the self. Spinal cord injury (SCI) patients who exhibit massively reduced somatomotor processes below the lesion in the absence of brain damage are suitable for testing the influence of body signals on two important components of the self–the sense of disembodiment and body ownership. We recruited 30 SCI patients and 16 healthy participants, and evaluated the following parameters: (i) depersonalization symptoms, using the Cambridge Depersonalization Scale (CDS), and (ii) measures of body ownership, as quantified by the rubber hand illusion (RHI) paradigm. We found higher CDS scores in SCI patients, which show increased detachment from their body and internal bodily sensations and decreasing global body ownership with higher lesion level. The RHI paradigm reveals no alterations in the illusory ownership of the hand between SCI patients and controls. Yet, there was no typical proprioceptive drift in SCI patients with intact tactile sensation on the hand, which might be related to cortical reorganization in these patients. These results suggest that disconnection of somatomotor inputs to the brain due to spinal cord lesions resulted in a disturbed sense of an embodied self. Furthermore, plasticity-related cortical changes might influence the dynamics of the bodily self.

Functional expansion of sensorimotor representation and structural reorganization of callosal connections in lower limb amputees

Previous studies have indicated that amputation or deafferentation of a limb induces functional changes in sensory (S1) and motor (M1) cortices, related to phantom limb pain. However, the extent of cortical reorganization after lower limb amputation in patients with nonpainful phantom phenomena remains uncertain. In this study, we combined functional magnetic resonance (fMRI) and diffusion tensor imaging (DTI) to investigate the existence and extent of cortical and callosal plasticity in these subjects. Nine "painless" patients with lower limb amputation and nine control subjects (sex- and age-matched) underwent a 3-T MRI protocol, including fMRI with somatosensory stimulation. In amputees, we observed an expansion of activation maps of the stump in S1 and M1 of the deafferented hemisphere, spreading to neighboring regions that represent the trunk and upper limbs. We also observed that tactile stimulation of the intact foot in amputees induced a greater activation of ipsilateral S1, when compared with controls. These results demonstrate a functional remapping of S1 in lower limb amputees. However, in contrast to previous studies, these neuroplastic changes do not appear to be dependent on phantom pain but do also occur in those who reported only the presence of phantom sensation without pain. In addition, our findings indicate that amputation of a limb also induces changes in the cortical representation of the intact limb. Finally, DTI analysis showed structural changes in the corpus callosum of amputees, compatible with the hypothesis that phantom sensations may depend on inhibitory release in the sensorimotor cortex.

Body integrity identity disorder: deranged body processing, right fronto-parietal dysfunction, and phenomenological experience of body incongruity

Body integrity identity disorder (BIID) is characterised by profound experience of incongruity between the biological and desired body structure. The condition manifests in "non-belonging" of body parts, and the subsequent desire to amputate, paralyse or disable a limb. Little is known about BIID; however, a neuropsychological model implicating right fronto-parietal and insular networks is emerging, with potential disruption to body representation. We argue that, as there is scant systematic research on BIID published to date and much of the research is methodologically weak, it is premature to assume that the only process underlying bodily experience that is compromised is body representation. The present review systematically investigates which aspects of neurological processing of the body, and sense of self, may be compromised in BIID. We argue that the disorder most likely reflects dysregulation in multiple levels of body processing. That is, the disunity between self and the body could arguably come about through congenital and/or developmental disruption of body representations, which, together with altered multisensory integration, may preclude the experience of self-attribution and embodiment of affected body parts. Ulimately, there is a need for official diagnostic criteria to facilitate epidemiological characterisation of BIID, and for further research to systematically investigate which aspects of body representation and processing are truly compromised in the disorder.