Michele Scandola

Robot-Assisted Laparoscopic Hysterectomy vs Traditional Laparoscopic Hysterectomy: Five Metaanalyses

To assess differences between laparoscopic hysterectomy performed with or without robot-assistance, we performed metaanalyses of 5 key indices strongly associated with societal and hospital costs, patient safety, and intervention quality. The 5 indexes included estimated blood loss (EBL), operative time, number of conversions to laparotomy, hospital length of stay (LOS), and number of postoperative complications. A search of PubMed, Medline, Embase, and Science citation index online databases yielded a total of 605 studies. After a systematic review, we proceeded with meta-analysis of 14 articles for EBL, with a summary effect of -0.61 (95% confidence interval [CI], -42.42 to 46.20); 20 for operative time, with a summary effect of 0.66 (95% CI, -15.72 to 17.04); 17 for LOS, with a summary effect of -0.43 (95% CI, -0.68 to -0.17); 15 for conversion to laparotomy (odds ratio, 0.50; 95% CI, 0.31 to 0.79 with a random model); and 14 for postoperative complications (odds ratio, 0.69; 95% CI, 0.43 to 1.09 with a random model). In conclusion, compared with traditional laparoscopic hysterectomy, robot-assisted laparoscopic hysterectomy was associated with shorter LOS and fewer postoperative complications and conversions to laparotomy; there were no differences in EBL and operative time. These results confirm that robot-assisted laparoscopy has less deletorious effect on hospital, society, and patient stress and leads to better intervention quality.

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.

Apparent Biological Motion in First and Third Person Perspective

Apparent biological motion is the perception of plausible movements when two alternating images depicting the initial and final phase of an action are presented at specific stimulus onset asynchronies. Here, we show lower subjective apparent biological motion perception when actions are observed from a first relative to a third visual perspective. These findings are discussed within the context of sensorimotor contributions to body ownership.

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.

Motor imagery in spinal cord injured people is modulated by somatotopic coding, perspective taking, and post‐lesional chronic pain

Motor imagery (MI) allows one to mentally represent an action without necessarily performing it. Importantly, however, MI is profoundly influenced by the ability to actually execute actions, as demonstrated by the impairment of this ability as a consequence of lesions in motor cortices, limb amputations, movement limiting chronic pain, and spinal cord injury. Understanding MI and its deficits in patients with motor limitations is fundamentally important as development of some brain-computer interfaces and daily life strategies for coping with motor disorders are based on this ability. We explored MI in a large sample of patients with spinal cord injury (SCI) using a comprehensive battery of questionnaires to assess the ability to imagine actions from a first-person or a third-person perspective and also imagine the proprioceptive components of actions. Moreover, we correlated MI skills with personality measures and clinical variables such as the level and completeness of the lesion and the presence of chronic pain. We found that the MI deficits (1) concerned the body parts affected by deafferentation and deefferentation, (2) were present in first- but not in third-person perspectives, and (3) were more altered in the presence of chronic pain. MI is thus closely related to bodily perceptions and representations. Every attempt to devise tools and trainings aimed at improving autonomy needs to consider the cognitive changes due to the body-brain disconnection.

The Representation of Objects in Apraxia: From Action Execution to Error Awareness

Apraxia is a well-known syndrome characterized by the sufferer’s inability to perform routine gestures. In an attempt to understand the syndrome better, various different theories have been developed and a number of classifications of different subtypes have been proposed. In this article review, we will address these theories with a specific focus on how the use of objects helps us to better understand upper limb apraxia. With this aim, we will consider transitive vs. intransitive action dissociation as well as less frequent types of apraxia involving objects, i.e., constructive apraxia and magnetic apraxia. Pantomime and the imitation of objects in use are also considered with a view to dissociating the various different components involved in upper limb apraxia. Finally, we discuss the evidence relating to action recognition and awareness of errors in the execution of actions. Various different components concerning the use of objects emerge from our analysis and the results show that knowledge of an object and sensory-motor representations are supported by other functions such as spatial and body representations, executive functions and monitoring systems.

Error-based training and emergent awareness in anosognosia for hemiplegia

Residual forms of awareness have recently been demonstrated in subjects affected by anosognosia for hemiplegia, but their potential effects in recovery of awareness remain to date unexplored. Emergent awareness refers to a specific facet of motor unawareness in which anosognosic subjects recognise their motor deficits only when they have been requested to perform an action and they realise their errors. Four participants in the chronic phase after a stroke with anosognosia for hemiplegia were recruited. They took part in an “error-full” or “analysis of error-based” rehabilitative training programme. They were asked to attempt to execute specific actions, analyse their own strategies and errors and discuss the reasons for their failures. Pre- and post-training and follow-up assessments showed that motor unawareness improved in all four patients. These results indicate that unsuccessful action attempts with concomitant error analysis may facilitate the recovery of emergent awareness and, sometimes, of more general aspects of awareness.

Anosognosia for apraxia: Experimental evidence for defective awareness of one's own bucco-facial gestures

Anosognosia is a multifaceted, neuro-psychiatric syndrome characterized by defective awareness of a variety of perceptuo-motor, cognitive or emotional deficits. The syndrome is also characterized by modularity, i.e., deficits of awareness in one domain (e.g., spatial perception) co-existing with spared functions in another domain (e.g., memory). Anosognosia has mainly been reported after right hemisphere lesions. It is however somewhat surprising that no studies have thus far specifically explored the possibility that lack of awareness involves apraxia, i.e., a deficit in the ability to perform gestures caused by an impaired higher-order motor control and not by low-level motor deficits, sensory loss, or failure to comprehend simple commands. We explored this issue by testing fifteen patients with vascular lesions who were assigned to one of three groups depending on their neuropsychological profile and brain lesion. The patients were asked to execute various actions involving the upper limb or bucco-facial body parts. In addition they were also asked to judge the accuracy of these actions, either performed by them or by other individuals. The judgment of the patients was compared to that of two external observers. Results show that our bucco-facial apraxic patients manifest a specific deficit in detecting their own gestural errors. Moreover they were less aware of their defective performance in bucco-facial as compared to limb actions. Our results hint at the existence of a new form of anosognosia specifically involving apraxic deficits.

Visual appearance of a virtual upper limb modulates the temperature of the real hand: a thermal imaging study in Immersive Virtual Reality

To explore the link between Sense of Embodiment (SoE) over a virtual hand and physiological regulation of skin temperature, 24 healthy participants were immersed in virtual reality through a Head Mounted Display and had their real limb temperature recorded by means of a high‐sensitivity infrared camera. Participants observed a virtual right upper limb (appearing either normally, or with the hand detached from the forearm) or limb‐shaped non‐corporeal control objects (continuous or discontinuous wooden blocks) from a first‐person perspective. Subjective ratings of SoE were collected in each observation condition, as well as temperatures of the right and left hand, wrist and forearm. The observation of these complex, body and body‐related virtual scenes resulted in increased real hand temperature when compared to a baseline condition in which a 3d virtual ball was presented. Crucially, observation of non‐natural appearances of the virtual limb (discontinuous limb) and limb‐shaped non‐corporeal objects elicited high increase in real hand temperature and low SoE. In contrast, observation of the full virtual limb caused high SoE and low temperature changes in the real hand with respect to the other conditions. Interestingly, the temperature difference across the different conditions occurred according to a topographic rule that included both hands. Our study sheds new light on the role of an external hands visual appearance and suggests a tight link between higher‐order bodily self‐representations and topographic regulation of skin temperature.

The role of visual-haptic discrepancy in virtual reality environments

Visual-haptic interactions are of utmost importance for VR surgical simulators. We investigate the role of spatial visual-haptic discrepancy by manipulating the presentation order of visual and force feedback. Participants were asked to indicate the nearer wall between a visual and an pliable haptic virtual surface. We factorially manipulated the discrepancy levels (±5, 15, 25 mm) and the stiffness values of the pliable haptic wall, 83 (human fat) and 331 N/m (human skin). Psychophysical curves over depth penetration and latency time inside the wall were estimated. Results showed that haptic and visual walls were indistinguishable among the discrepancy range of 10.57±23.12 mm for 83N/m and -3.07±9.11 mm for 331 N/m. The trend of psychophysical curves show as, in presence of discrepancies or errors between an haptic and a visual surface, the overall perception is influenced by the stiffness of the haptic surface, in according with a weighted summation model, showing a direct relation between the stiffness factor and the weight of the haptic component in the model.