AN OVERVIEW AND OUR APPROACH IN THE TREATMENT OF MALIGNANT CUTANEOUS TUMOURS OF THE HAND.

INTRODUCTION: Diagnosis of malignant cutaneous tumours of the hand is often difficult because of the different anatomic structures present in this region and yet clinicians must be able to distinguish typical benign entities from life-threatening or limb-threatening malignant diseases. Due to the hand's complex structures located in a small area, surgeons must evaluate constantly the balance of inadequate surgery against functional and cosmetic aspects. Thus, a multidisciplinary approach is recommended for a correct diagnosis and treatment design. MATERIALS AND METHODS: Between 2006 and 2017, 354 consecutive patients with basal and squamous cell carcinomas, and melanoma of the hand were retrospectively analysed at the Department of Plastic and Reconstructive Surgery at the University of Palermo, treatment was surgical for all of them; also radio- and chemotherapy were necessary based on the histological diagnosis. RESULTS: The most common tumour was basal cell carcinoma (BCCs), followed by squamous cell carcinoma (SCCs). Melanoma was the most frequent lesion diagnosed in the digits. Radical excision was the main treatment of choice. In 29 cases (11 with SCC, 18 with melanoma) axillary lymphadenectomy was performed, because of lymph nodes metastases. In the follow up, the spread of cancer to distant organs caused the death in three cases. Recurrence rate was higher in case of infiltrative SCCs and BCCs. CONCLUSIONS: The major references provide only limited information on malignant soft-tissue tumours of the hand. Our retrospective study aims to present the most commonly observed malignant soft-tissue tumours of the hand, analysing their causes, their objective and instrumental evaluation, and their treatments.

Effect of tool-use observation on metric body representation and peripersonal space.

In everyday life, we constantly act and interact with objects and with others' people through our body. To properly perform actions, the representations of the dimension of body-parts (metric body representation, BR) and of the space surrounding the body (peripersonal space, PPS) need to be constantly updated. Previous evidence has shown that BR and PPS representation are highly flexible, being modulated by sensorimotor experiences, such as the active use of tools to reach objects in the far space. In this study, we investigate whether the observation of another person using a tool to interact with objects located in the far space is sufficient to influence the plasticity of BR and PPS representation in a similar way to active tool-use. With this aim, two groups of young healthy participants were asked to perform 20 min trainings based on the active use of a tool to retrieve far cubes (active tool-use) and on the first-person observation of an experimenter doing the same tool-use training (observational tool-use). Behavioural tasks adapted from literature were used to evaluate the effects of the active and observational tool-use on BR (body-landmarks localization task-group 1), and PPS (audio-tactile interaction task - group 2). Results show that after active tool-use, participants perceived the length of their arm as longer than at baseline, while no significant differences appear after observation. Similarly, significant modifications in PPS representation, with comparable multisensory facilitation on tactile responses due to near and far sounds, were seen only after active tool-use, while this did not occur after observation. Together these results suggest that a mere observational training could not be sufficient to significantly modulate BR or PPS. The dissociation found in the active and observational tool-use points out differences between action execution and action observation, by suggesting a fundamental role of the motor planning, the motor intention, and the related sensorimotor feedback in driving BR and PPS plasticity.

Non-invasive brain stimulation of motor cortex induces embodiment when integrated with virtual reality feedback.

Previous evidence highlighted the multisensory-motor origin of embodiment - that is, the experience of having a body and of being in control of it - and the possibility of experimentally manipulating it. For instance, an illusory feeling of embodiment towards a fake hand can be triggered by providing synchronous visuo-tactile stimulation to the hand of participants and to a fake hand or by asking participants to move their hand and observe a fake hand moving accordingly (rubber hand illusion). Here, we tested whether it is possible to manipulate embodiment not through stimulation of the participant's hand, but by directly tapping into the brain's hand representation via non-invasive brain stimulation. To this aim, we combined transcranial magnetic stimulation (TMS), to activate the hand corticospinal representation, with virtual reality (VR), to provide matching (as contrasted to non-matching) visual feedback, mimicking involuntary hand movements evoked by TMS. We show that the illusory embodiment occurred when TMS pulses were temporally matched with VR feedback, but not when TMS was administered outside primary motor cortex, (over the vertex) or when stimulating motor cortex at a lower intensity (that did not activate peripheral muscles). Behavioural (questionnaires) and neurophysiological (motor-evoked-potentials, TMS-evoked-movements) measures further indicated that embodiment was not explained by stimulation per se, but depended on the temporal coherence between TMS-induced activation of hand corticospinal representation and the virtual bodily feedback. This reveals that non-invasive brain stimulation may replace the application of external tactile hand cues and motor components related to volition, planning and anticipation.

Oculomotor prismatic training is effective in ameliorating spatial neglect: a pilot study.

Visuomotor prismatic training has been demonstrated to be among the most effective rehabilitative techniques of spatial neglect, a neurological syndrome manifested by a number of right brain-damaged patients characterized by unawareness of the egocentric left half of the world. In the present study, we demonstrate that a novel oculomotor prismatic training procedure only consisting in a sequence of gaze shifts to visual targets, can reduce spatial neglect symptoms. Following oculomotor prismatic training, patients show a significant decrease in neglect severity in straight ahead and paper and pencil tasks. We propose that during oculomotor prismatic training, the inconsistency between the prisms-biased visual/oculomotor input and the unbiased head-on-trunk proprioceptive information relative to the straight-ahead position determines the observed aftereffects and the amelioration of spatial neglect symptoms.