BIOMEDICAL INSTRUMENTATION
Functional Head Impulse Test (fHIT)
Peripheral vestibular function may be tested quantitatively by measuring the gain of the rotational vestibulo-ocular reflex (eye velocity/head velocity), or functionally, by assessing how well the rotational vestibulo-ocular reflex (rVOR) per-forms with respect to its goal of stabilizing gaze in space. We developed a functional head impulse testing device (fHIT) based on an inertial sensing system allowing to investigate the functional performance of the rVOR by testing its gaze stabilization ability, independently from the subject’s visual acuity, in response to head impulses at different head angular accelerations ranging from 2000 to7000 deg/s2. The system assesses the ability of the patient to read an optotype briefly presented during head rotation. The outcome of the test is the percentage of correctly read optotypes at different head accelerations. Thus, vestibular function can be assessed without measuring eye movements.
In order to find the relation between the functional (percentage of reading) and quantitative (gain) measure and to understand the role of corrective saccades, we also developed a new software and hardware research tool allowing the combined measurement of eye and head movements, together with the timing of the optotype on screen, based on the EyeSeeCam system.
Wearable and Modular Inertial Motion Unit
Measuring human movement has many useful applications ranging from fall risk assessment, to quantifying sports exercise, studying people habits and monitoring the elderly. We developed a versatile, wearable device based on a 9-degrees-of-freedom inertial measurement unit conceived for providing objective measurements of trunk or limb movements for the assessment of motor and balance control abilities. The proposed device measures linear accelerations, angular velocities and heading and can be configured to either wirelessly transmit the raw or preprocessed data to a computer for online use, e.g. visualization or further processing, or to store the acquired data locally for long term monitoring during free movement. Further, the device can work in either single sensor or multiple sensors configuration, to simultaneously record several body parts for monitoring full body kinematics.
In collaboration with Laboratorio Microcalcolatori e Strumentazione Elettromedicale (Ing. Cristiani A., Ing. Bertolotti G.M.)
A device to assess static ocular torsion
In clinical settings, static ocular torsion is assessed by taking a fundus photograph and measuring the angle between a horizontal line and the line connecting the fovea to the head of the optic nerve (centro-cecal axis rotation; CCAR).We developed and tested a system specifically aimed at CCAR measurements, based on low-cost commercial hardware, that implements an adaptive research algorithm that selects and presents bright dots on a monitor to outline the borders of the blind spot, locate its center, and measure CCAR. The developed V-CCAR consists of low-cost commercial hardware: two off-the-shelf webcams (Digicomm HU061 with resolution 640 × 480 pixels, which we subjected to removal of the IR filters), a 37 inch 16:9 monitor (LGelectronic 37LH4000), a custom-made wooden head holder, and a pushbutton to be held by the subject during the experimental trials. Custom software was developed in LabView.
An Instrumented Insole for Long Term Monitoring Movement, Comfort and Ergonomics
We developed a new electronic insole for wireless monitoring of motor activities and shoe comfort. The proposed device, equipped with both ZigBee transmission and local data storage allows unobtrusive, long term monitoring of subjects outside the laboratory, during natural behaviour such as activities of daily living as well as sports. The system detailed in this work includes humidity and temperature sensors, as well as a three axis accelerometer and four pressure sensors, all fitted within a 3.7 mm thick insole.
In collaboration with Laboratorio Microcalcolatori e Strumentazione Elettromedicale (Ing. Cristiani A., Ing. Bertolotti G.M.)