Effects of the HBP passive exoskeleton on brain functions: Application on multiple sclerosis patients

Human exoskeletons are used for enhancing people’s strength, endurance and speed in many activities, and they have recently been shown to improve the quality of life in people with disabilities (Rahman et al., 2007). In present study we report the benefits of a passive and fully articulated exoskeleton on multiple sclerosis patients by means of behavioral and electrophysiological measures, paying particular attention to the prefrontal cortex activity. Multiple sclerosis is a neurological condition characterized by lesions of the myelin sheaths that encapsulate the neurons of the brain, spine and optic nerve, and it causes transient or progressive symptoms and impairments in gait and posture. Up to 50% of multiple sclerosis patients require walking aids and 10% are wheelchair-bound 15 years following the initial diagnosis. We tested the ability of a new orthosis, the “Human Body Posturizer”, to improve the structural and functional symmetry of the body through proprioception in multiple sclerosis patients. The results showed that a single Human Body Posturizer application improved mobility and ambulation in all tested patients. Most importantly, we associated these effects and brain measurements, particularly prefrontal cortex activity

Cortical dynamics in visual areas induced by the first use of multifocal contact lenses in presbyopes

A common non-spectacle strategy to correct presbyopia is to provide simultaneous images with multifocal optical designs. Understanding the neuroadaptation mechanisms behind multifocal devices usage would have important clinical implications, such as predicting whether patients will be able to tolerate multifocal optics. The aim of this study was to evaluate the brain correlates during the initial wear of multifocal contact lenses (CLs) using high-density visual evoked potential (VEP) measures. Fifteen presbyopes (mean age 51.8 ± 2.6 years) who had previously not used multifocal CLs were enrolled. VEP measures were achieved while participants looked at arrays of 0.5 logMAR Sloan letters in three different optical conditions arranged with CLs: monofocal condition with the optical power appropriate for the distance viewing; multifocal correction with medium addition; and multifocal correction with low addition. An ANOVA for repeated measures showed that the amplitude of the C1 and N1 components significantly dropped with both multifocal low and medium addition CL conditions compared to monofocal CLs. The P1 and P2 components showed opposite behavior with an increase in amplitudes for multifocal compared to monofocal conditions. VEP data indicated that multifocal presbyopia corrections produce a loss of feedforward activity in the primary visual cortex that is compensated by extra feedback activity in extrastriate areas only, in both early and late visual processing

An 8-week rehabilitation training using the HBP exoskeleton improves cognitive brain functions in multiple sclerosis patients

It has been showed that a single application of the exoskeleton (HBP) in multiple sclerosis patients is able to improve mobility and ambulation. These effects have been associated with brain changes in high-level executive functions decisive for improving patients’ motor control [1]. We applied an 8-weeks rehabilitation protocol in 12 MS patients, half of them randomly assigned to a standard protocol (control group, CG) and the other half to a protocol based on the HBP use (experimental group, EG). Patients were evaluated before and after rehabilitation training using multiple neurological, physiotherapeutic and cognitive testing. During the cognitive task, high-resolution EEG was also recorded for ERP analysis. Results showed that both groups improved their performance in the Barthel, Rivermead, 2-WT, 25-FWT, Tinetti and BBS tests. Only in the EG, other positive treatment effects were observed as measured by the EDSS disability scale and the FSS. Accordingly, in cognitive testing, only the EG showed significant benefits in response time (RT) and accuracy. At brain level the EG showed enhancement in task-related preparatory activity in frontal and prefrontal cortices and stronger post-stimulus activity in the anterior Insula, whose activity is related to more efficient decision making. The CG didn’t show enhanced performance in the cognitive task but only large activity in visual areas, as observed in EG. Concluding, both rehabilitation protocols brought substantial neurophysiological benefits to MS patients, however, the HBP protocol was particularly effective, boosting cognitive functions in prefrontal and frontal brain areas, it allowed improvements in RT and accuracy. The integration of HBP with standard rehabilitation procedure may considerably reduce disability in MS patients

Bridging the gap before and after birth: Methods and technologies to explore the functional neural development in humans

Infant brain damage is a serious condition that affects millions of babies each year. The period from late gestation to the first year of life is the most critical one for the development of central and autonomous nervous systems. Medical conditions such as preterm birth may compromise brain function and the end result usually is that the baby may experience long-term neurological problems related to a wide range of psychological, physical and functional complications, with consequent life-long burdens for the individuals and their families, and a high socio-economic impact for the health care system and the whole of society. During the last years, several techniques have been employed to monitor the brain functional development in utero and after birth. As well, various analytical methods have been used to understand the functional maturation of the brain and the autonomous nervous system. However, in spite of the rapid improvement of diagnostic methods and procedures, there is still a widely recognized, severe shortage of clinically viable means for the high quality monitoring of the brain function in early life with a direct relevance to acute neurological illness and future neurocognitive outcomes. The studies collected in this e-book document the most recent advancements in monitoring systems, analytical methods and clinical diagnostic procedures that contribute to increase our knowledge of the functional development of the human brain and autonomous nervous system during pregnancy and after birth, with the ultimate goal of reducing fetal impairment and improving healthcare in the neonatal and infant period

The neurophysiology of central and peripheral fatigue during sub-maximal lower limb isometric contractions

Fatigue has been defined as an exercise-induced decline in force generation capacity because of changes at both the peripheral and central levels. Movement is preceded and accompanied by brain activities related to the preparation and execution of movement (movement related cortical potentials, MRCP), which have been correlated with the perception of effort (RPE). We combined force measurements, surface electromyography (sEMG), peripheral electrical stimulation (maximal twitch, MT) and MRCP analysis to further our understanding of the neural correlates of peripheral and central changes during a fatiguing task involving the lower limbs. Eighteen healthy volunteers performed 4 blocks of isometric knee extensions at 40% of the maximal voluntary contraction (MVC) for a total of 240 2-s contractions. At the baseline and after each block, we measured RPE, MT and MVC. We simultaneously recorded the force of the knee extensor muscles, root mean square (RMS) of the sEMG of the vastus lateralis muscle, and electroencephalography (EEG) from 64 channels. The MRCPs were extracted from the EEG recordings and averaged in the early (Block 1–2) and late (Block 3–4) blocks. Two cohorts were obtained by cluster analysis based on the RPE (i.e., perception of effort) and MT (i.e., peripheral fatigue). We observed a significant decline in both the MVC (−13%) and RMS (−25%) of the sEMG signal over the course of the task; thus, muscle fatigue had occurred in all of the participants regardless of the cohort. The MRCP amplitude was larger in the fatigued than the non-fatigued MT cohort in the supplementary and premotor areas, whereas the MRCP amplitude was larger in the fatigued than the non-fatigued RPE cohort in the aforementioned areas, and also in the primary motor and prefrontal cortices (PFC). The increase in the positive activity of the PFC, along with the perception of effort, represents a novel result, suggesting that it is modulated more by the perception of effort than peripheral fatigue

Short-term monocular deprivation alters early components of visual evoked potentials

Very little is known about plasticity in the adult visual cortex. In recent years psychophysical studies have shown that short-term monocular deprivation alters visual perception in adult humans. Specifically, after 150 min of monocular deprivation the deprived eye strongly dominates the dynamics of binocular rivalry, reflecting homeostatic plasticity. Here we investigate the neural mechanisms underlying this form of short-term visual cortical plasticity by measuring visual evoked potentials (VEPs) on the scalp of adult humans during monocular stimulation before and after 150 min of monocular deprivation. We found that monocular deprivation had opposite effects on the amplitude of the earliest component of the VEP (C1) for the deprived and non-deprived eye stimulation. C1 amplitude increased (+66%) for the deprived eye, while it decreased (-29%) for the non-deprived eye. Source localization analysis confirmed that the C1 originates in the primary visual cortex. We further report that following monocular deprivation, the amplitude of the peak of the evoked alpha spectrum increased on average by 23% for the deprived eye and decreased on average by 10% for the non-deprived eye, indicating a change in cortical excitability. These results indicate that a brief period of monocular deprivation alters interocular balance in the primary visual cortex of adult humans by both boosting the activity of the deprived eye and reducing the activity of the non-deprived eye. This indicates a high level of residual homeostatic plasticity in the adult human primary visual cortex, probably mediated by a change in cortical excitability

Modulatory role of sport factors on amateur and competitive athletes’ aggressive and antisocial behaviors

Aggressiveness and unethical behaviors are an important problem in sports today. Understanding how to properly measure and manage an athlete's aggressive tendency is a crucial lesson to be learned within the rulesets of a sporting environment. This study aims at validating the Italian version of the Competitive Aggressiveness and Anger Scale (CAAS), specifically developed to measure aggressiveness and anger in athletes. The second aim is to investigate how aggressive and antisocial behaviors are modulated by sex, competitive level (i.e., amateur and competitive), sport contact (i.e., contact and no-contact), and sport type (i.e., team and individual). Two hundred and ninety-six athletes (mean age = 22.42 years, SD = 2.86) were asked to fill out a survey about sociodemographic variables, sport specific data, attitudes to moral decisions, past cheating behavior, and aggression. The Italian version of the CAAS presented a good fit of the data, adequate internal consistency and its construct validity was supported via convergent and discriminant validity. Both aggressiveness and anger dimensions of CAAS positively related with acceptance of cheating and gamesmanship, and past cheating behavior, while only the aggressiveness dimension of the CAAS negatively related with prosocial attitude. Competitive male athletes practicing contact sport showed the highest levels of aggressiveness, while competitive athletes practicing team sport showed the highest level of anger. This study represents the first empirical construct validity evidence of CAAS among Italian athletes and provides a deeper understanding of how athletes' aggressive tendencies and antisocial behavior differ across athlete populations

The effects of aging on conflict detection.

Several cognitive changes characterize normal aging; one change regards inhibitory processing and includes both conflict monitoring and response suppression. We attempted to segregate these two aspects within a Go/No-go task, investigating three age categories. Accuracy, response times and event-related potentials (ERPs) were recorded. The ERP data were analyzed, and the Go and No-go trials were separated; in addition, the trials were organized in repeat trials (in which the subjects repeated the action delivered in the previous trial) and switch trials (in which the subjects produced a response opposite to the previous response). We assumed that the switch trials conveyed more conflict than the repeat trials. In general, the behavioral data and slower P3 latencies confirmed the well-known age-related speed/accuracy trade-off. The novel analyses of the repeat vs. switch trials indicated that the age-related P3 slowing was significant only for the high conflict condition; the switch-P3 amplitude increased only in the two older groups. The 'aging switch effect' on the P3 component suggests a failure in the conflict conditions and likely contributes to a generalized dysfunction. The absence of either a switch effect in the young group and the P3 slowing in middle-aged group indicate that switching was not particularly demanding for these participants. The N2 component was less sensitive to the repeat/switch manipulation; however, the subtractive waves also enhanced the age effects in this earlier time window. The topographic maps showed other notable age effects: the frontal No-go N2 was nearly undetectable in the elderly; in the identical time window, a large activity in the posterior and prefrontal scalp regions was observed. Moreover, the prefrontal activity showed a negative correlation with false alarms. These results suggest that the frontal involvement during action suppression becomes progressively dysfunctional with aging, and additional activity was required to reach a good level of accuracy