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Biomedical subjects

Daniele Giansanti

Publications and source records attributed to Daniele Giansanti.

8 recordsLinked to original sources
PubMed2006

Investigation of fall-risk using a wearable device with accelerometers and rate gyroscopes.

A clinical tool and an associated test that can assess fall-risk in elderly patients have been designed. The clinical tool was based on a wearable device with accelerometers and rate gyroscopes to identify trunk kinematic parameters. The test was based on a posturography protocol with different constraints and statistical analysis of the kinematic parameters. Statistical clustering based on the Mahalanobis distance was carried out using three groups of 30 subjects (1, age < 65 years; 2, age > or = 65 years and 3, age > or = 65 years and a fall history). The method was statistically validated using three groups of 100 subjects. The test allowed discrimination of elderly subjects with a high fall-risk with high specificity > or = 0.930 and sensitivity > or = 0.939.

Acceleration↗
PubMed2006

Does centripetal acceleration affect trunk flexion monitoring by means of accelerometers?

Micro electro-mechanical and NANO technologies are sensibly reducing circuit and geometrical errors in accelerometer sensors. These sensors are often used as portable inclinometer sensors for trunk flexion monitoring in clinical applications. In this case, the rotating trunk generates centripetal acceleration, an error source that technological efforts cannot eliminate. This study analysed the effect of this source for typical human monitoring conditions by simulations and clinical validation using a wearable device with rate gyroscopes and accelerometers (Giansanti and Maccioni 2005 Physiol. Meas. 26 689-705). Results showed that this error source did not affect long-term monitoring applications (Mathie et al 2004 Physiol. Meas. 25 R1-R20) but in the short-term monitoring caused a mean angular error equal to 0.96 degrees for the most critical single-task application represented by the sit-to-stand.

Acceleration↗
PubMed2005

Comparison of three different kinematic sensor assemblies for locomotion study.

The decrease in the costs of electronic components and devices, conjugated to the advancement of the miniaturization technologies, has promoted a large profusion of the use of motion sensors for human movement analysis in clinics. The errors in the design are numerous, from circuital errors to positioning and orientation errors; a preliminary approach to the problem by means of simulations is necessary. We developed an environment for the simulation of mixed kinematic sensor assemblies with accelerometers and rate gyroscopes; it was tested by means of three different assemblies in the simulation of the trajectory reconstruction. The first assembly was represented by a 6-accelerometer assembly, the second by a 9-accelerometer assembly and the third was based on three rate gyroscopes and three accelerometers. The circuital error, given as an input to the environment, was determined during a bench test, the positioning error was set to p(e) = 5 x 10(-4) m and the orientation error to alpha(e) = 6 x 10(-2) deg. Results showed the agreement between estimated and experimental data from the bench test. Simulation results also showed that the errors in trajectory reconstruction in the sagittal plane were lower than 3-4% during 4 s of simulation.

Biomechanical Phenomena↗
PubMed2005

The development and test of a device for the reconstruction of 3-D position and orientation by means of a kinematic sensor assembly with rate gyroscopes and accelerometers.

In this paper, we propose a device for the Position and Orientation (P&O) reconstruction of human segmental locomotion tasks. It is based on three mono-axial accelerometers and three angular velocity sensors, geometrically arranged to form two orthogonal terns. The device was bench tested using step-by-step motor-based equipment. The characteristics of the six channels under bench test conditions were: crosstalk absent, non linearity < +/- 0.1% fs, hysteresis < 0.1% fs, accuracy 0.3% fs, overall resolution better than 0.04 deg/s, 2 x g x 10(-4). The device was validated with the stereophotogrammetric body motion analyzer during the execution of three different locomotion tasks: stand-to-sit, sit-to-stand, gait-initiation. Results obtained comparing the trajectories of the two methods showed that the errors were lower than 3 x 10(-2) m and 2 deg during a 4s of acquisition and lower than 6 x 10(-3) m and 0.2 deg during the effective duration of a locomotory task; showing that the wearable device hereby presented permits the 3-D reconstruction of the movement of the body segment to which it is affixed for time-limited clinical applications.

Acceleration↗
PubMed2005

Audio-biofeedback for balance improvement: an accelerometry-based system.

This paper introduces a prototype audio-biofeedback system for balance improvement through the sonification using trunk kinematic information. In tests of this system, normal healthy subjects performed several trials in which they stood quietly in three sensory conditions while wearing an accelerometric sensory unit and headphones. The audio-biofeedback system converted in real-time the two-dimensional horizontal trunk accelerations into a stereo sound by modulating its frequency, level, and left/right balance. Preliminary results showed that subjects improved balance using this audio-biofeedback system and that this improvement was greater the more that balance was challenged by absent or unreliable sensory cues. In addition, high correlations were found between the center of pressure displacement and trunk acceleration, suggesting accelerometers may be useful for quantifying standing balance.

Acceleration↗
PubMed2003

Objective analysis of finger function.

Hand motor tasks, even those commonly required by daily life activities, entail complex muscle activation. This article describes a self-contained experimental set-up for the objective kinetic and kinematic analysis of each finger function under several working conditions. Special attention is given to grasping and pressing under isometric conditions. The analysis of the contribution of the thumb is particular to this system. This system has proved accurate, reliable, easy-to-use, and suitable for applications in research environments, and as a support to clinicians for diagnosis and during rehabilitation.

Adult↗
PubMed2003

Is it feasible to reconstruct body segment 3-D position and orientation using accelerometric data?

The analysis of the mechanics of the musculo-skeletal system during the execution of a motor task requires the determination of the instantaneous position and orientation of the body segments involved in relation to an inertial system of reference. By using adequately assembled uniaxial accelerometric sensors, an easy-to-manage measurement system can be obtained that estimates the three-dimensional position and orientation (P&O) of a body segment through an appropriate analytical model. However, the extent to which experimental errors, in particular accelerometers (ACs) assembly inaccuracies, affect such estimation has never been systematically investigated. This paper systematically analyzes the sensitivity of analytical models of body segment P&O reconstruction through a six-AC system and a nine-AC system to different sources of experimental error. We simulated and statistically assessed the performance of these models in the case of body segment motions typical of movements under muscular control. The results obtained indicated that the inaccuracy in the orientation of the individual AC's active axes and the offset error in the AC responses were the major sources of P&O estimation errors. In particular, no accurate estimation of position was possible with the analytical models analyzed. Under the motion conditions simulated in this study, no substantial advantages were found in using a nine-AC system rather than a six-AC system. Considering that the magnitudes of the simulated experimental errors were quite low (< or = 0.1 deg: AC's orientation; < or = 10(-4) m: uncertainty of the distance between two ACs; < or = 10(-2) ms(-2): random error; 0.5 x 10(-2) ms(-2): offset error), the results indicate that none of the two ACs systems analyzed is suitable for body segment P&O estimation in routine biomechanical applications.

Acceleration↗