Methods for Sitting Posture Evaluation: Static Posture and Applications

Pressure sores (PS), are frequent in subjects with spinal cord injuries, and to minimize PS these subjects must get used to frequently changing their posture; useful information to this aim may come by testing healthy subjects and studying their kinematic behaviour during long sitting sessions. Two different investigation systems have been developed to this aim in the Department of Mechanics and Aeronautics (DMA) of Rome University ‘‘La Sapienza’’: the two systems, a pressure map sensor arranged on a chair and a potentiometer-based device to measure trunk rotations at the base of the spine are shown in this paper and their outputs are compared and correlated. The behaviour of ten healthy subjects is then evaluated during a one hour sitting session for preliminary consideration: there is a postural change every 7.7 ± 6.7 minutes in the frontal plane and every 5.7 ± 2.7 minutes in the sagittal plane; pelvis movements can be resumed by Centre of Pressure (COP) displacements and the largest values of these displacements are 5.2 ± 2.4 cm in the frontal plane and 3.0 ± 1.4 cm in the sagittal plane; the largest rotations in the two planes are respectively 8.4 ± 0.7 and 20.7 ± 12.6. The results of the study are discussed and satisfactorily compared with literature results

A Facility for the Study of Pelvis and Trunk Displacements during Sitting Posture

1475-1305.2008.00606.

Changes of psychical and physical conditions in the elderly after a four-year follow-up

The elderly show a loss of both the intellectual functions and of motion ability. This happens also without particular pathologies; possible tests to highlight this loss are the Mini Mental State Examination (MMSE), and the Functional Reach (FR)-test. During 2004-2005 winter 50 healthy subjects were analyzed; the subjects were divided into three age-groups: from 55 to 64 years; from 65 to 74 years; over 75 years of age. The test results showed a significant decline of MMSE and FR from the first group to the other two groups, a same behavior of male and female subjects, a greater decline of physical characteristics compared to psychic characteristics. During 2008-2009 winter several subjects (34 of 50) were again analyzed, and a more accurate facility was used to measure the FR. The aim of the new test has been the exam of the cognitive conditions and of the physical performances after the 4 year follow-up. The results of the new tests confirm the previous results, both with regard to the decline of the psychophysical characteristics from the first age-group to the others but the decrease is not as significant as the previous, and with regard to the greater physical decline. What is surprising is that the decline of both the psychic and the physical characteristics concerns only the first age-group, not the other two. Maybe healthy subjects, without particular pathologies reach a stabilization of the above-mentioned characteristics; some hypothesis is given to explain what happens. (C) 2011 Elsevier Ireland Ltd. All rights reserved

Uncertainty evaluation of a method for the functional reach test evaluation by means of monte-carlo simulation

The Functional Reach Test (FRT) is a simple, portable, clinically accepted tool that is used to measure semi-static balance. In a recent study, video recordings and software elaborationshave beenperformed by a computerized system to determinethe FRT objectively (computerized FRT, cFRT):here an in-depthstudy on the measuring error of the above system is proposed.Main uncertainty sources identifiedare (a) geometrical errorsdue to the alignment of the camera calibration plane with the real motion plane, (b) the difference in depth between the above planes, (c) the image aberration due to the lens that compress the pixels and (d) the software error in position estimation using a template matching algorithm. The uncertainty evaluation is performed by means Monte CarloSimulationsand results suggest that both the depth error and the barrel distortion are the more relevant source of error, althoughthe aberration can be corrected by one of the many algorithms available in literature. Results can be useful to define a measurement protocol to improve the performances of thesystem for a better clinical effectiveness