Giorgia Chini

Local Stability of the Trunk in Patients with Degenerative Cerebellar Ataxia During Walking.

This study aims to evaluate trunk local stability in a group of patients with degenerative primary cerebellar ataxia and to correlate it with spatio-temporal parameters, clinical variables, and history of falls. Sixteen patients affected by degenerative cerebellar ataxia and 16 gender- and age-matched healthy adults were studied by means of an inertial sensor to measure trunk kinematics and spatio-temporal parameters during over-ground walking. Trunk local dynamic stability was quantified by the maximum Lyapunov exponent with short data series of the acceleration data. According to this index, low values indicate more stable trunk dynamics, while high values denote less stable trunk dynamics. Disease severity was assessed by means of International Cooperative Ataxia Rating Scale (ICARS) according to which higher values correspond to more severe disease, while lower values correspond to less severe disease.Patients displayed a higher short-term maximum Lyapunov exponent than controls in all three spatial planes, which was correlated with the age, onset of the disease, and history of falls. Furthermore, the maximum Lyapunov exponent was negatively correlated with ICARS balance, ICARS posture, and ICARS total scores.These findings indicate that trunk local stability during gait is lower in patients with cerebellar degenerative ataxia than that in healthy controls and that this may increase the risk of falls. Local dynamic stability of the trunk seems to be an important aspect in patients with ataxia and could be a useful tool in the evaluation of rehabilitative and pharmacological treatment outcomes.

Resting state cortical electroencephalographic rhythms in covert hepatic encephalopathy and Alzheimer's disease.

Patients suffering from prodromal (i.e., amnestic mild cognitive impairment, aMCI) and overt Alzheimers disease (AD) show abnormal cortical sources of resting state electroencephalographic (EEG) rhythms. Here we tested the hypothesis that these sources show extensive abnormalities in liver cirrhosis (LC) patients with a cognitive impairment due to covert and diffuse hepatic encephalopathy (CHE). EEG activity was recorded in 64 LC (including 21 CHE), 21 aMCI, 21 AD, and 21 cognitively intact (Nold) subjects. EEG rhythms of interest were delta (2-4 Hz), theta (4-8 Hz), alpha 1 (8-10.5 Hz), alpha 2 (10.5-13 Hz), beta 1 (13-20 Hz), and beta 2 (20-30 Hz). EEG cortical sources were estimated by LORETA. Widespread sources of theta (all but frontal), alpha 1 (all but occipital), and alpha 2 (parietal, temporal) rhythms were higher in amplitude in all LC patients than in the Nold subjects. In these LC patients, the activity of central, parietal, and temporal theta sources correlated negatively, and parietal and temporal alpha 2 sources correlated positively with an index of global cognitive status. Finally, widespread theta (all but frontal) and alpha 1 (all but occipital) sources showed higher activity in the sub-group of LC patients with CHE than in the patients with aMCI or AD. These results unveiled the larger spatial-frequency abnormalities of the resting state EEG sources in the CHE compared to the AD condition.

Receding horizon multi-vehicle routing for emergency scenarios

This paper deals with dynamic Multi-Vehicle Routing Problem in both deterministic and stochastic scenarios; the objective is to find the best paths for a fleet of vehicles, with the aim of visiting a set of targets. Based on the Cooperative Receding Horizon approach proposed in [4] for the Euclidean case, this paper i) develop a routing algorithm for graph-represented mission spaces, ii) presents a switching algorithm, which is able to dynamically change the vehicle behaviour according to the time-variable configuration of both vehicles and targets, as well as to handle the discovery of unknown targets. Simulations show the algorithm effectiveness.

Neck and Shoulder Muscle Fatigue in High Performance Aircrafts Pilots: A Case Study

Neck injury because of exposure to increased Gz acceleration is a well-known problem in literature and has been studied by several air forces. Jet pilots reported a high prevalence of neck pain if compared to the general population. Some interventions focused on aircraft design and personal protective equipment, while others were directed toward pilot training. In literature, various primary prevention strategies are reported such as preflight warm-up, in-flight techniques, muscle resistance training, neck-specific training regimens and techniques. However, results from all of these studies showed discordant results. The aim of the study is to investigate muscle fatigue of left and right sternocleidomastoid, upper trapezius and middle trapezius by means of the Joint Analysis of the Spectrum and Amplitude of sEMG which analyzes the temporal changes in the amplitude of the sEMG signal, evaluated using the Root Mean Square and the frequency of the sEMG signal, expressed as Median Frequency. In this study, we investigated a fighter pilot before and soon after a diurnal flight, therefore we did not take into account night vision goggles and counterweight usage. We found that the fatigue indexes calculated from the neck and shoulder muscles are quite sensitive in detecting jet pilots’ fatigue. More in detail, it can be observed that as far as the right side is concerned, soon after the flight all the fatigue events of the JASA plot fall in the fatigue quadrant. The results of this study strengthen the suggestion aimed previously at helicopter pilots, to incorporate neck and shoulder specific training in the list of operational duties. These myoelectric fatigue indicators may be useful to evaluate neck and shoulder muscle engagement, and they may be helpful to define physical exercise limits. In conclusion, this study showed that it is possible to obtain more detailed information about neck stress through sEMG fatigue parameters, and provide an insight for helmet and seat design improvements. The reduction in some of the causative factors for neck pain may help to increase the career longevity of jet pilots, reducing the work compensation cost and the costs associated with training new aircrew.

Applied Forces and sEMG Activity Contribution to Risk Assessment for Assistance Workers Helping Passengers with Restricted Mobility

As air travel grows the numbers of passengers with varying degrees of motor disability have grown too. The aim of this study is to analyze the task of pushing Passengers with Restricted Mobility (PRM) on three different wheelchairs (WhCh) currently supplied to PRM service of a Rome airport. The WhChs differed in their width, weight and wheels dimension. We investigated initial and sustained forces, according to the Annex D of ISO 11228-2 standard, by means of a digital dynamometer. Surface Electromyography (sEMG), was also recorded bilaterally from Erector Spinae and Anterior Deltoid only in the initial phase.

Biomechanical characterization of the Junzuki karate punch: indexes of performance

Abstract The aims of this study were: (i) to determine kinematic, kinetic, and electromyographic characteristics of Junzuki karate punch in professional karate athletes; (ii) to identify biomechanical parameters that correlate with punch force and lead to a higher punching performance; (iii) to verify the presence of muscle co-activation in the upper limb, trunk, and lower limb muscles. Data were collected from nine experienced karatekas from the Accademia Italiana Karate e Arti Marziali during the execution of the specific punch. Mean punch forces (181.2 N) delivered to the target, the range of motion of both right and left knees (1.13 and 0.82 rad) and right elbow (1.49 rad) joints, and the angles at impact (knee: 0.81 and 0.91 rad; elbow: 1.19 rad) in the sagittal plane were computed. Furthermore, the trunk rotational angular acceleration (63.1 rad s−2), force related to the lower limbs (550.2 and 425.1 N), and co-activation index for the upper limb (36.1% and 34.7%), trunk (24.5% and 16%), and lower limbs (16.0% and 16.1%) muscles were evaluated bilaterally. Significant positive correlations were found between the punch force and both right and left knee flexion at the instant of impact and right and left leg force. Significant negative correlation was found between the punch force and maximum trunk angular acceleration. Significant differences (p = .03) in the co-activation index among the upper limb, trunk, and lower limbs muscles highlighted a rostro-caudal gradient on both body sides. This research could be of use to performers and coaches when considering training preparations.

sEMG Activity Contribution to Risk Assessment for PRM Assistance Workers

Aim of this study is to analyze the task of pushing Passengers with Restricted Mobility (PRM) on three different wheelchairs currently supplied in an Italian airport. The wheelchairs differed in their width, weight and wheel dimensions. We investigated the task with two different PRMs weight (100 and 55 kg) and three different caster wheels positions (0°, 90° and 180°). We computed the Average Rectified Value, as percentage of maximum voluntary contraction, recorded from Erector Spinae and Anterior Deltoid muscles bilaterally in the starting phase of pushing. We can conclude that by means of sEMG it is possible to obtain useful data about the risks of pushing and pulling tasks in addition to those obtained by measuring the applied forces. In future research, it could be useful to analyze also muscle co-activation to better understand the biomechanical risks of pushing and pulling tasks

Upper Limb Repetitive Movement Risk Assessment by Means of sEMG Parameters

The aim of the study was to provide a biomechanical risk assessment in a mechanical engineering industry using sEMG fatigue parameters. Two experienced right-handed workers were enrolled for the study. sEMG signals were recorded bilaterally from the following upper limb muscles: middle Trapezius, anterior Deltoid, lateral Deltoid and long head of Biceps Brachii. The envelopes of the activity of each muscle were computed as a percentage of the Maximal Voluntary Contraction (%MVC). We also computed Root Mean Square (RMS) and Median Frequency (MDF) to investigate localized muscle fatigue. For the studied workstations, right muscles were more involved than left ones and consequently by means of JASA fatigue plot we observed more fatigue events in the right than in the left upper limb in both workers. Results showed different muscular behavior for each workstation and specific motor patterns. Despite the fact that the mean cycle activity failed to exceed 10% of MVC, activity peaks frequently reached up to 30% of MCV. These short-term peak values could be the cause of increased biomechanical risk. By studying sEMG fatigue parameters, it is possible to obtain a more detailed risk assessment and to provide insight towards workstation improvements.

Use of dynamic movement orthoses to improve gait stability and trunk control in ataxic patients

BACKGROUND Patients with cerebellar ataxia show increased upper body movements, which have an impact on balance and walking. AIM In this study, we investigated the effect of using dynamic movement orthoses (DMO), designed as elastic suits, on trunk motion and gait parameters. DESIGN Longitudinal uncontrolled study. SETTING Outpatient rehabilitation unit. POPULATION Eleven patients (7 men, 4 women; mean age: 49.9±9.5 years) with degenerative cerebellar ataxia were enrolled in this study. METHODS Linear overground gait of patients was recorded by means of an optoelectronic gait analysis system before DMO use (DMO-) and during DMO use (DMO+). Time-distance parameters, lower limb joint kinematics, body sway, trunk oscillations, and gait variability (coefficient of variation [CV]) were recorded. Patient satisfaction with DMO device was measured using Quebec user evaluation of satisfaction with assistive technology. RESULTS When using the DMO, patients showed a significant decrease in stance phase duration, double support phase duration, swing phase CV, pelvic range of motion (ROM), body sway, and trunk ROMs. A significant increase was observed in the swing phase duration and knee joint ROM. Out of 11 patients, 10 were either quite satisfied (8 points) or very satisfied (2 points) with the assistive device. CONCLUSIONS The DMO reduce the upper body motion and in improve balance-related gait parameters. CLINICAL REHABILITATION IMPACT We propose use of DMO as an assistive/rehabilitative device in the neurorehabilitation of cerebellar ataxia to improve the trunk control and gait stability. DMO may be considered a prototype that can be modified in terms of material characteristics, textile layers, elastic components, and diagonal and lateral seams.