Assessment of inertial and gravitational inputs to the vestibular system

A new device for the assessment of instantaneous angular and linear acceler ations of the head is presented, which is based on four lineal tri-axial ac celerometers suitably attached to the head by an helmet. A procedure for re producible helmet placement and calibration is given. A method is also illu strated to work out the different linear accelerations sensed by the vestib ular organs in the left and light labyrinths and the components of the angu lar acceleration sensed by their semicircular canals. The computation is ba sed on few individual parameters describing the helmet position with respec t to external landmarks and on the average internal position and orientatio n of the vestibula. The purpose is to study the components of internal iner tial forces, which represent the primary inputs to the vestibular system de voted to equilibrium and oculomotor control. The system is designed to be o f easy application during rehabilitation exercises and in clinical environm ent during diagnostic and therapeutic manoeuvres. The prototype is tested w ith simple free movements such as "yes", "no", and gait. (C) 2001 Elsevier Science Ltd. All rights reserved.