A bio-inspired force control for cyclic manipulation of prosthetic hands.

The human hand is considered as the highest example of dexterous system capable of interacting with different objects and adapting its manipulation abilities to them. The control of poliarticulated prosthetic hands represents one important research challenge, typically aiming at replicating the manipulation capabilities of the natural hand. For this reason, this paper wants to propose a bio-inspired learning architecture based on parallel force/position control for prosthetic hands, capable of learning cyclic manipulation capabilities. To this purpose, it is focused on the control of a commercial biomechatronic hand (the IH2 hand) including the main features of recent poliarticulated prosthetic hands. The training phase of the hand was carried out in simulation, the parallel force/position control was tested in simulation whereas preliminary tests were performed on the real IH2 hand. The results obtained in simulation and on the real hand provide an important evidence of the applicability of the bio-inspired neural control to real biomechatronic hand with the typical features of a hand prosthesis.

Comparative analysis and quantitative evaluation of ankle-foot orthoses for foot drop in chronic hemiparetic patients.

BACKGROUND: Ankle-foot-orthoses (AFOs) are frequently prescribed for hemiparetic patients to compensate for the foot drop syndrome. However, there is not a systematic study either on the effectiveness of AFOs in the gait recovery process or pointing out the therapeutic differences among the various types of AFOs available on the market. AIM: To perform a comparative evaluation of solid and dynamic Ankle-Foot-Orthoses (AFOs) on hemiparetic patients affected by foot drop syndrome by means of spatio-temporal, kinematic and electromyographic indicators. DESIGN: Crossover design with randomization for the interventions. SETTING: A rehabilitation center for adults with neurologic disorders. POPULATION: Ten chronic hemiparetic patients with foot drop syndrome met inclusion criteria and volunteered to participate. METHODS: Biomechanical gait analysis was carried out on hemiparetic subjects with foot drop syndrome under 3 conditions with randomized sequences: 1) without AFO; 2) wearing a solid AFO; 3) wearing a dynamic AFO. Significant changes in spatio-temporal, kinematic and electromyographic features of gait were investigated. RESULTS: Gait analysis outcomes showed that there were no significant differences among the solid and the dynamic AFO on the spatio-temporal parameters. Both AFOs led to a reduction of the range of motion of the ankle dorsi-plantar-flexion during stance with respect to the ambulation without AFO. They also had the effect of reducing the asymmetry between the paretic and the contralateral limb in terms of ankle angle at initial contact and hip flexion. The solid AFO generally led to an increase of the co-contraction of the couples of muscles involved in the gait. CONCLUSION: The proposed set of indicators showed that the AFOs were capable of limiting the effect of the foot-drop in hemiparetic patients and balancing the two limbs. Main differences between the two orthoses were related to muscular activity, being the level of co-contraction of the two couples of analysed muscles typically lower when the dynamic AFO was worn and closer to a normal pattern. CLINICAL REHABILITATION IMPACT: A more extensive use of the proposed indicators in the clinical practice is expected in order to enable the definition of clinical guidelines for the prescription of the two devices.

Effect of patient characteristics on hospital costs for cirrhosis: implications for the disease-related group (DRG) reimbursement system.

The Prospective Payment System uses Diagnosis-Related Groups (DRG) as a reimbursement system. DRG 202 is a disease-related group including liver cirrhosis as a whole. Patients referring to the inpatient unit complain of variable severity and complications of cirrhosis, possibly implying different expenditure of resources. Aim of the investigation was to identify factors affecting cost variability in patients with cirrhosis. A total of 73 consecutive, DRG 202-assigned, cirrhotic patients classified according to demographic and clinical variables were evaluated for length and costs of hospitalization calculated on a full-cost basis. Mean length of hospitalization was 10.2 +/- 7 days. Mean cost of hospitalization was Lit. 4.348.000 +/- 2.718.000. Medical, nursing, diagnostic, drug and general charges accounted for 13%, 29%, 37%, 5% and 16% of the cost, respectively. Child-Pugh score significantly correlated with drug consumption (p < 0.005), length (p < 0.01) and costs (p < 0.001) of hospitalization, but not with cost per day. Age, sex, admission status, referral reason, associated diseases and liver transplant susceptibility did not correlate with duration and costs of hospitalization. Disease severity significantly modifies costs of hospital admission in cirrhotic patients mostly on account of longer hospital stay. Surrogate indexes of disease severity, derived from ISTAT/DRG records, cannot identify patients consuming larger resources. In liver cirrhosis, the DRG system could be improved by introducing parameters, such as Child-Pugh score, directly taking into account disease severity.