Long-term retention of a divided attention psycho-motor test combining choice reaction test and postural balance test: A preliminary study.

Driving in degraded psychophysical conditions, such as under the influence of alcohol or drugs but also in a state of fatigue or drowsiness, is a growing problem. The current roadside tests used for detecting drugs from drivers suffer various limitations, while impairment is subjective and does not necessarily correlate with drug metabolite concentration found in body fluids. This work is a validation step towards the study of feasibility of a novel test conceived to assess psychophysical conditions of individuals performing at-risk activities. Motor gestures, long-term retention and learning phase related to the protocol are analysed in unimpaired subjects. The protocol is a divided attention test, which combines a critical tracking test achieved with postural movements and a visual choice reaction test. Ten healthy subjects participated in a first set of trials and in a second set after about six months. Each session required the carrying out of the test for ten times in order to investigate learning effect and performance over repetitions. In the first set the subjects showed a learning trend up to the third trial, whilst in the second set of trials they showed motor retention. Nevertheless, the overall performance did not significantly improve. Gestures are probably retained due to the type of tasks and the way in which the instructions are conveyed to the subjects. Moreover, motor retention after a short training suggests that the protocol is easy to learn and understand. Implications for roadside test usage and comparison with current tests are also discussed.

On the relationship between mouth opening and "broken mirror neurons" in autistic individuals.

Electromyographies of the mylohyoid muscle (MH) during the execution of the goal-oriented action "grasping to eat" have been used to determine the time relationship between the opening of the mouth and the beginning of the movement. This has been used to distinguish the behaviour of typical developing (TD) children from that of highly functioning autistic (ASD) individuals. The results of previous studies appeared to provide evidence of a deficit in action chain organization in ASD subjects and prompted the hypothesis of a "broken" mirror neuron system (MNS) for these individuals. Our results show the MH activation timing is not reliable in discriminating between TD and ASD children and the distance between the food and the subject plays a key role on the MH activation timing and cannot be neglected when analysing these type of data. The preliminary investigation on the effects of external perturbations also shows that these might have an effect on the results and further investigations are warranted. It appears that there is not enough evidence to support a link between ASD and a broken mirror network system (MNS), and the experimental results must be carefully interpreted before developing therapeutic or rehabilitative protocols.

Improving calving management to further enhance reproductive performance in dairy cattle.

The aim of this study was to develop a system for the monitoring of calving to both reduce perinatal mortality and improve dairy cow fertility by preventing the majority of post-partum reproductive pathologies. Eighty dairy cows were assigned to the protocol of calving monitoring using GSM (Global System for Mobile Communications) technology. The application of GSM technology and the proper management of calving facilities comprise reliable approaches for calving assistance and improvements in reproductive efficiency and neonatal viability. Based on the results of this study, we advocate the use of GSM technology on large farms for intensive milk production.

On the introduction of a new parameter for the analysis of posture by acceleration of the centre of pressure.

AIM: With this study we wanted to determine whether the standard parameters for describing posture are sufficient. METHODS: The time-series analysis of statokinesigrams of 50 healthy volunteers and Parkinsonian subjects, the latter representing an excellent example of persons affected by a postural control disorder, were assessed and compared. The tests were carried out using a new parameter ''p'', which is introduced with this work. The novel parameter is adimensional and independent of the subjects' anthropometric data and can be easily computed with elementary mathematics. RESULTS: Parameter ''p'' was found to discriminate healthy subjects from parkinsonians (as an example of subjects affected by a disease of the central control system). CONCLUSIONS: A new tool for the early diagnosis of disease of the central control system could theoretically be developed from our results.

The stabilometric evaluation of the erect stance. Energy-based optimal control in a numerical model.

AIM: This paper proposes an anthropomorphic model developed in a virtual context, useful to simulate the maintenance of the erect stance. Such a model can be built through a suitable software which can identify the geometry of the articular parts and place mechanical constraints (e.g. joints, spherical links, etc.) between the single elements. METHODS: Our approach can be described as the assembly of rigid parts linked at the joints. The control is given by internal torques at the joints and driven by strategy for the balance aimed to the least amount of total muscular energy spent. The anthropomorphic model proposed underlines and solves the typical problems of a system characterized by a multiple number of degree of freedom placed in erect stance and perturbed by phenomena of endogenous and exogenous nature. This model is developed via the coupling of 2 separate bi-dimensional models, one representing the sagittal plane and the other the frontal plane. The numerical tests were validated through experimental tests in a group of healthy volunteers. For this purpose we employed a stabilometric platform (force-plate) to record the statokinesigram (SKG) on the rest surface. RESULTS: The shapes of the stabilometric plots show a good spatial similarity between the experimental and simulated SKG. Both SKGs present a good range in the frontal plane with concentration of points in some areas (or attractors) in the experimental SKG, but not in the simulated one. The tests also showed a postural oscillation at low frequency (= 0.02Hz), probably due to the differential tiredness of groups of muscles or because of a delayed action of the neurological control. CONCLUSIONS: On the numerical simulations, we claim the suitability of the antropomorphic model for a general description of the maintenance of the erect stance. Despite the simplification, with our approach it is possible to simulate some of the main characteristics of the postural act. In particular, the length and the areas of the simulated SKG's are comparable with those of the experimental tests.