Computational fluid dynamic models as tools to predict aerosol distribution in tracheobronchial airways.

Aerosol and pollutants, in form of particulates 5-8 µm in main size face every day our respiratory system as natural suspension in air or forced to be inhaled as a coadjutant in a medical therapy for respiratory diseases. This inhalation happens in children to elderly, women and men, healthy or sick and disable people. In this paper we analyzed the inhalation of aerosol in conditions assimilable to the thermal therapy. We use a computational fluid dynamic 3D model to compute and visualize the trajectories of aerosol (3-7-10-25 µm) down to the sixth generation of bronchi, in a steady and dynamic condition (7 µm) set as breath cycle at rest. Results, compared to a set of milestone experimental studies published in literature, allow the comprehension of particles behavior during the inhalation from mouth to bronchi sixth generation, the visualization of jet at larynx constriction and vortices, in an averaged characteristic rigorous geometrical model including tracheal rings. Results on trajectories and deposition show the importance of the including transient physiological breath cycle on aerosol deposition analyses. Numerical and graphical results, may enable the design of medical devices and protocols to make the inhalations more effective in all the users' population.

Novel characterization of gait impairments in people with multiple sclerosis by means of the gait profile score.

The assessment of gait abnormalities in individuals with multiple sclerosis (MS) represents a key factor in evaluating the effectiveness of rehabilitation treatments. Despite the availability of sophisticated equipment to objectively evaluate the kinematic aspects of gait, there are still some difficulties in processing the large and complex amount of data they produce in the daily clinical routine. On the basis of the above-mentioned considerations we propose a novel characterization of gait kinematics in individuals with MS, based on a single measure (gait profile score, GPS) obtained from a quantitative three-dimensional analysis of gait performed using an opto-electronic system. We also investigated the correlation between GPS and the Expanded Disability Status Scale (EDSS) values. Thirty-four patients suffering from relapsing-remitting MS (13 female, 21 male, mean age 46.7 years) with an EDSS score of ≤6 underwent a gait analysis from which the GPS index was calculated. Their results were compared with those of a control group of healthy age- and gender-matched subjects. The GPS of individuals with MS was found significantly higher with respect to controls (9.12° vs. 5.67°, p<0.001) as the result of kinematic differences in gait patterns referring to pelvic tilt and rotation, hip flexion-extension and rotation, knee flexion-extension and ankle dorsi- and plantar-flexion. A moderate correlation was also found between the EDSS score of the participants and their GPS values (r = 0.63, p < 0.001). The GPS index thus appears suitable to represent gait deviations from physiological patterns in individuals affected by MS and potentially useful in assessing the outcomes related both to rehabilitation programs and pharmacologic/physical therapies.