Bilateral cortical representation of tactile roughness.

Roughness is the most important feature for texture discrimination. Here we investigate how the bilateral cortical representation of touch is modulated by tactile roughness by analyzing the neural responses elicited by stimuli with various coarseness levels ranging from fine to medium. A prolonged stimulation was delivered to 10 healthy subjects by passively sliding tactile stimuli under the fingertip while recording the EEG to study the modulation of Somatosensory Evoked Potentials (SEPs) as well as activity in the theta and alpha bands. Elicited long-latency SEPs, namely bilateral P100-N140 and frontal P240 were consistent across stimuli. On the contrary, the temporal lag N140 - P240 was nonlinearly modulated both in contralateral and ipsilateral sides, in agreement with literature. Using a time-frequency analysis approach, we identified a theta band power increase in the [0 0.5]s interval and a partially overlapped power decrease in the alpha band which lasted throughout the stimulation. The estimated time these two phenomena were overlapped was comparable across stimuli, whereas a linear decrease in alpha band amplitude was reported when increasing the stimulus roughness in both contralateral and ipsilateral sides. This study showed that the selected tactile stimuli generated physiological bilateral responses that were modulated in a diversified way according to the stimulus roughness and side. Specifically, we identified sensory processing features (i.e., theta and alpha time overlap) invariant to the stimulus roughness (i.e., associated to a basic cortical mechanism of touch) and roughness-dependent cortical outputs comparable in the contralateral and ipsilateral sides that confirm a bilateral processing of tactile information.

Long-latency components of somatosensory evoked potentials during passive tactile perception of gratings.

Perception of tactile stimuli elicits Somatosensory Evoked Potentials (SEPs) that can be recorded via non-invasive electroencephalography (EEG). However, it is not yet clear how SEPs localization, shape and latency are modulated by different stimuli during mechanical tactile stimulation of fingertips. The aim of this work is thus to characterize SEPs generated by the tactile perception of gratings during dynamic passive stimulation of the dominant fingertip by means of a mechatronic platform. Results show that a random sequence of stimuli elicited SEPs with two long-latency components: (i) a negative deflection around 140 ms located in the frontal-central-parietal side in the contralateral hemisphere; (ii) a positive deflection around 250 ms located in the frontal-central midline. Time-frequency analysis revealed significant continuous bilateral desynchronization in the alpha band throughout the passive stimulation. These results are a fundamental step towards building a model of brain responses during perception of tactile stimuli for future benchmarking studies.

Benefits of an intensive task-oriented circuit training in Multiple Sclerosis patients with mild disability.

BACKGROUND: Exercise is well tolerated and induces relevant improvements in physical and mental functioning of persons with Multiple Sclerosis (MS). Unfortunately, due to the wide variety of symptoms and the broad range of exercise interventions, it is not possible to make unified exercise recommendation as to what type of exercise is safe and effective for persons with MS. OBJECTIVE: The aim was to test the impact of an intensive task-oriented training on motor function and quality of life in 17 MS patients with an Expanded Disability Status Scale (EDSS) between 4 and 5.5. METHODS: Patients underwent a two-week intensive, task-oriented rehabilitation program. Outcome measures were: Berg Balance Scale, Gait Dynamic Index, 6 Minute Walking Test, Physiological Cost Index, Fatigue Severity Scale, 10 metres Walking Test, Timed Up and Go test, Short form 36, Multiple Sclerosis Impact Scale, Patient Health Questionnaire. RESULTS: All outcome measures showed a significant improvement after the treatment except for the 6 Minute Walking test and the Short form 36 that showed a trend of improvement although not statistically significant. CONCLUSIONS: An intensive task-oriented rehabilitation protocol is effective in improving motor function and has a positive impact on quality of life in MS patients with moderate disability.

A survey on virtual environment applications to fear of public speaking.

BACKGROUND: Social Anxiety Disorder (SAD) is one of the most prevalent anxiety disorders in Europe and comprises the fear of public speaking as its typical sub-type. Cognitive-Behavioural Therapy (CBT) is the intervention of choice for SAD, and it includes exposure to anxiety-provoking stimuli to induce systematic desensitization and reduce anxiety. Similarly, exposure therapy per se has been used and found effective, although it is not as specific as CBT for the treatment of SAD. Interestingly, exposure to anxiety-provoking situations can be achieved in Virtual Environments (VEs) through the simulation of social situations allowing individuals with public speaking anxiety to live and develop real exposure-like reactions. The Virtual Reality Exposure Therapy (VRET) is the treatment of anxiety disorders based on such VEs. AIM: This article aims to provide an overview of the scientific literature related to the applications of Virtual Reality to the treatment of fear of public speaking. MATERIALS AND METHODS: We conducted the literature review on PubMed and Google Scholar for studies including the fear-of-public-speaking VEs. RESULTS AND CONCLUSIONS: Reviewed studies addressed two main aspects: the design parameters of the VEs for adequate reactions to synthetic social stimuli, and the efficacy of VEs for fear of public speaking treatment. VEs resulted effective for triggering as-if-real reactions in relation to public speaking. VE-based exposures reduced public speaking anxiety measurements, decreased scores and maintained them at 3 month follow-up. Studies comparing VRET to pharmacological therapy are lacking, and there are few randomized controlled trials that compare VRET to CBT, especially on fear of public speaking treatment.