Rubber hand illusion induced by touching the face ipsilaterally to a deprived hand: evidence for plastic "somatotopic" remapping in tetraplegics

Background: Studies in animals and humans indicate that the interruption of body-brain connections following spinal cord injury (SCI) leads to plastic cerebral reorganization.Objective: To explore whether inducing the Rubber Hand Illusion (RHI) via synchronous multisensory visuo-tactile bodily stimulation may reveal any perceptual correlates of plastic remapping in SCI.Methods: In 16 paraplegic, 16 tetraplegic and 16 healthy participants we explored whether RHI may be induced by tactile stimuli involving not only the left hand but also the left hemi-face. Touching the participants actual hand or face was either synchronous or asynchronous with tactile stimuli seen on a rubber hand. We assessed two components of the illusion, namely perceived changes in the real hand in space (indexed by proprioceptive drift) and ownership of the rubber hand (indexed by subjective responses to an ad-hoc questionnaire).Results: Proprioceptive drift and ownership were found in the healthy group only in the condition where the left real and fake hand were touched simultaneously. In contrast, no drift was found in the SCI patients who, however, showed ownership after both synchronous and asynchronous hand stroking. Importantly, only tetraplegics showed the effect also after synchronous face stroking.Conclusions: RHI may reveal plastic phenomena in SCI. In hand representation-deprived tetraplegics, stimuli on the face (represented contiguously in the somatic and motor systems), drive the sense of hand ownership. This hand-face remapping phenomenon may be useful for restoring a sense of self in massively deprived individuals

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

Motor versus body awareness: Voxel-based lesion analysis in anosognosia for hemiplegia and somatoparaphrenia following right hemisphere stroke

This is the accepted manuscript version of the following article: Valentina Moro, Simone Pernigo, Manos Tsakiris, Renato Avesani, Nicola M. J. Edelstyn, Paul M. Jenkinson, and Aikaterini Fotopoulou, ‘Motor versus body awareness: Voxel-based lesion analysis in anosognosia for hemiplegia and somatoparaphrenia following right hemisphere stroke’, Cortex, Vol 83, pp. 62-77, first published online 15 Jul 2016. The version of record is available online at doi: http://dx.doi.org/10.1016/j.cortex.2016.07.001 Published by Elsevier. © Elsevier Ltd. All rights reserved.Anosognosia for hemiplegia (AHP) is informative about the neurocognitive basis of motor awareness. However, it is frequently associated with concomitant symptoms, such as hemispatial neglect and disturbances in the sense of body ownership (DSO). Although double dissociations between these symptoms have been reported, there is ongoing debate about whether they are manifestations of independent abnormalities, or a single neuro- cognitive deficit. We aimed to investigate the specificity of lesions associated with AHP by surpassing four, existing methodological limitations: (a) recruit a relatively large sample of patients (total N 1⁄4 70) in a multi-centre study; (b) identify lesions associated with AHP in grey and white matter using voxel-based methods; (c) take into account the duration of AHP and concomitant neglect symptoms; and (d) compare lesions against a control hemiplegic group, patients suffering from AHP and DSO, and a few, rare patients with selective DSO. Results indicated that acute AHP is associated with a wide network, mainly including: (1) the Rolandic operculum, (2) the insula and (3) the superior temporal gyri. Subcortically, damage mainly involved the basal ganglia and white matter, mostly the superior corona radiate, arcuate fasciculus and the part of the ventral, superior longitu- dinal fasciculus. Persistent symptoms were linked with wider damage involving fronto- temporal cortex and long white matter tracts. A shift in the latero-medial direction (mainly involving the basal ganglia and surrounding white matter) emerged when DSO was taken accounted for. These results suggest that while bodily awareness is processed by areas widely distributed across the brain, intact subcortical structures and white matter tracts may be necessary to support basic feelings of owning and controlling contralateral body parts. An accurate and ‘up-to-date’ awareness of our motor abilities, however, may rely also on intact processing in cortical areas which presumably allow higher-order in- ferences about the current state of the body.Peer reviewedFinal Accepted Versio

On the relation between body and movement space representation: an experimental investigation on spinal cord injured people

Body Representation (BR) and Movement Space Perception (MSP) are fundamental for human beings in order to move in space and interact with object s and other people. Both BR and space representation change after spinal cord injuries in complete paraplegic individuals (CPP), who suffer from lower limbs paralysis and anesthesia. To date, the interaction between BR and MSP in paraplegic individuals rem ains unexplored. In two consecutive experiments, we tested I ) if the individual\u2019s wheelchair is embodied in BR; and ii) if the embodied wheelchair modifies the MSP. For the first question a speeded detection task was used. Participants had to respond to v isual stimuli flashing on their trunk, legs or wheelchair. In three counterbalanced conditions across participant, they took part to the experiment while: 1) sitting in their wheelchair, 2) in another wheelchair, or 3) with the LEDs on a wooden bar. To in dicate the embodiment, there was no difference in the CPP\u2019s responses for LEDs on the body and personal wheelchair while these were slower in other conditions After this, while sitting in their or another wheelchair, CPPs were asked to judge the slope of a ramp rendered in immersive virtual reality and to estimate the distance of a flag positioned over the ramp. When on their own wheelchair, CPPs perceived the flag closer than in the other wheelchair. These results indicate that the continuous use of a too l induces embodiment and that this i mpact on the perception of MSP

Spinal cord lesions shrink peripersonal space around the feet, passive mobilization of paraplegic limbs restores it

Peripersonal space (PPS) is the space surrounding us within which we interact with objects. PPS may be modulated by actions (e.g. when using tools) or sense of ownership (e.g. over a rubber hand). Indeed, intense and/or prolonged use of a tool may induce a sense of ownership over it. Conversely, inducing ownership over a rubber hand may activate brain regions involved in motor control. However, the extent to which PPS is modulated by action-dependent or ownership-dependent mechanisms remains unclear. Here, we explored the PPS around the feet and the sense of ownership over lower limbs in people with Paraplegia following Complete spinal cord Lesions (PCL) and in healthy subjects. PCL people can move their upper body but have lost all sensory-motor functions in their lower body (e.g. lower limbs). We tested whether PPS alterations reflect the topographical representations of various body parts. We found that the PPS around the feet was impaired in PCL who however had a normal representation of the PPS around the hands. Significantly, passive mobilization of paraplegic limbs restored the PPS around the feet suggesting that activating action representations in PCL brings about short-term changes of PPS that may thus be more plastic than previously believed

Care pathways models and clinical outcomes in disorders of consciousness

Objective: Patients with Disorders of consciousness, are persons with extremely low functioning levels and represent a challenge for health care systems due to their high needs of facilitating environmental factors. Despite a common Italian health care path-way for these patients, no studies have analyzed information on how each region have implemented it in its welfare system correlating data with patients’ clinical outcomes. Materials and Methods: A multicenter observational pilot study was realized. Clinicians collected data on the care pathways of patients with Disorder of consciousness by ask-ing 90 patients’ caregivers to complete an ad hoc questionnaire through a structured phone interview. Questionnaire consisted of three sections: sociodemographic data, description of the care pathway done by the patient, and caregiver evaluation of health services and information received.Results: Seventy- three patients were analyzed. Length of hospital stay was different across the health care models and it was associated with improvement in clinical diag-nosis. In long- term care units, the diagnosis at admission and the number of caregivers available for each patient (median value=3) showed an indirect relationship with worsening probability in clinical outcome. Caregivers reported that communication with professionals (42%) and the answer to the need of information were the most critical points in the acute phase, whereas presence of Non- Governmental Organizations (25%) and availability of psychologists for caregivers (21%) were often missing during long-term care. The 65% of caregivers reported they did not know the UN Convention on the Rights of Persons with Disabilities. Conclusion: This study highlights relevant differences in analyzed models, despite a recommended national pathway of care. Future public health considerations and ac-tions are needed to guarantee equity and standardization of the care process in all European countries

Anosognosia for Theory of Mind deficit: a single case study

Objective Theory of Mind (ToM) refers to the ability to understand and predict others’ mental states, emotions, intentions and beliefs. Deficits in ToM have been reported in adult following brain lesions involving the anterior cingulate and orbitofrontal cortices. Although these disorders impact on patients’ social life, the issue regarding their awareness of deficits is to date unresolved. Anosognosia is the lack of awareness regarding an individual’s deficits. In this study, we investigated the anosognosia for deficits in ToM. Participants and Methods A.P. is a middle-aged male, who suffered from a traumatic brain injury. The cognitive and affective components of ToM were investigated through ToM-test, Faux Pas, Eye Reading and Irony-Comprehension test. Furthermore, the awareness was assessed in three ways: i) a non-structured interview; ii) the DEX, and iii) the PCRS tests. By means of a neuroanatomical study, we investigated the regions and the main white matter tracts associated with the patient’s specific deficits. Results A shortfall of patient’s performance was observed during the ToM assessment (both cognitive and affective ToM). Moreover, he presented a selective impairment in awareness for ToM deficits. His performance in the other cognitive functions, in particular, executive functions (BADS), did not result defective. The lesion analysis showed bilateral lesions in the orbitofrontal and lateral basal-temporal regions. The explorative DTI suggested a disconnection of the arcuate fasciculus and the anterior cingulum. Conclusions We reported a specific deficit in awareness regarding ToM deficits in a traumatic brain injured patient. The lesion analysis is consistent with the previously described neural bases of ToM and supports the hypothesis of modularity in anosognosia, according to which there is a certain degree of awareness that is specific for different cognitive functions (Mograbi & Morris, 2013). Further investigations are needed in order to better understand the networks involved in deficits of awareness

The role of the frontal lobes in anosognosia for Theory of Mind deficit: A single case study

Theory of Mind (ToM) refers to the ability to understand and predict others’ mental states. Frontal regions play a key role in ToM and lesion studies reported damages within the anterior cingulate and orbitofrontal cortices in adults showing ToM deficits. However, it is still debated the role of patients’ awareness of ToM deficits and its neural substrates. In this study, we investigated the anosognosia for ToM deficits. In this single-case study, we tested A.P., a traumatic brain injury (TBI) patient. The ToM abilities were investigated through ToM-test, Faux Pas, Eye Reading, and Irony-Comprehension test. The awareness was assessed by means of a non-structured interview, the Dysexecutive- Questionnaire, and the Patient-Competency-Rating-Scale. The Behavioral- Assessment-of-Dysexecutive-Syndrome was assessed as to control for the executive functioning. The neural correlates of patient’s specific deficits were investigated through a neuroanatomical study. The patient showed impaired performance during ToM assessments. Interestingly, he presented a selective lack of awareness for ToM deficits. His performance in the executive functions assessment was spared. The lesion analysis showed bilateral lesions in the orbitofrontal and lateral basal temporal regions. An explorative tracts analysis suggested damage of the arcuate fasciculus and the anterior cingulum. We reported a specific deficit in awareness regarding ToM impairment in a TBI patient. The lesion analysis suggested a role of the frontal lobe in anosognosia for ToM and supported the hypothesis of functional modularity in anosognosia (Mograbi & Morris, 2013). Further investigations are needed in order to better understand the networks involved in deficits of awareness

Modulating anosognosia for hemiplegia: The role of dangerous actions in emergent awareness

Anosognosia for hemiplegia is a lack of awareness of motor deficits following a right hemisphere lesion. Residual forms of awareness co-occur with an explicit denial of hemiplegia. The term emergent awareness refers to a condition in which awareness of motor deficits is reported verbally during the actual performance of an action involving the affected body part. In this study, two tasks were used to explore the potential effects of i) attempting actions which are impossible for sufferers of hemiplegia and ii) attempting actions which are potentially dangerous. Sixteen hemiplegic patients (8 anosognosic, and 8 non-anosognosic) were asked to perform both potentially dangerous and neutral actions. Our results confirm an increase in emergent awareness in anosognosic patients during the execution of both of these types of action. Moreover, actions that are potentially dangerous improved the degree of awareness. However, lesions in the fronto-temporal areas appear to be associated with a reduced effect of action execution (emergent awareness) while lesions in the basal ganglia and amygdale and the white matter underlying the insula and fronto-temporal areas are associated with a lesser degree of improvement resulting from attempting to perform dangerous actions

The request of dangerous actions improves awareness in anosognosia for hemiplegia

Anosognosia for hemiplegia is a multifaceted syndrome where implicit forms of awareness may be spared. Among these, emergent awareness has been described as the incrising of verbal acknowledgment of deficits after attempting to act. We investigsted whether the request to perform potentially dangerous actions may influence patients' awareness. The results confirm the role of emergent awareness and bring evidence of emotional stimuli in improving anosognosia for hemiplegia