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The work presented in this thesis has two distinct parts: (i) development of a spinal motion measurement technique and (ii) incorporation of the spinal motion measurement with galvanic vestibular stimulation (GVS) technology, acting as a balance assist device hereafter referred to as a galvanic vestibular stimulation device (GVSD). The developed spinal motion measurement technique fulfills seven desired attributes: accuracy, portability, real-time data capture of dynamic data, non-invasive, small device footprint, clinically useful and of non-prohibitive cost. Applications of the proposed system range from diagnosis of spine injury to postural and balance monitoring, on-field as well as in the lab setting. The system is comprised of three inertial measurement sensors, respectively attached and calibrated to the head, torso and hips, based on the subject’s anatomical planes. Sensor output is transformed into meaningful clinical parameters of rotation, flexion-extension and lateral bending of each body segment with respect to a global reference space, then collected and visualized via an interactive graphical user interface (GUI). The accuracy of the proposed sensing system has been successfully verified with subject trials using a VICON optical motion measurement system. Next, the proposed motion measurement system and technique has been used to record a standing iv subject’s motion response to GVS. The data obtained allows the development of a new GVSD with the attributes of: eligibility for commercial licensing, portability, and capable of safely providing controlled stimulating current to the mastoid bones at varying levels and frequencies. The successful combination of the spinal motion measurement technique and GVSD represents the preliminary stage of a balance prosthesis.

Fabrication of hemispherical structures for application in hemispherical resonator gyro-scopes (HRG) is an integral part of modern sensing systems, especially in relation to space navigation. First, it is important for these structures to be as symmetric as possible in order to accurately track both in-plane and out-of-plane acceleration that occurs in fast moving satellites and space crafts. Next, they need to be larger for easier application in current mm scale systems and to maintain a lower noise floor and high quality factor. The work in this paper introduces a methodology for the analyzation of the micromachining process for larger symmetric hemispherical shell resonators (HSR). This is in order to increase their size while maintaining symmetry through isotropic etching using HNA and the pop-up ring mask design. The implementation of the pop-up ring mask allows for symmetric etching of<111> silicon and larger MEMS structures at a low cost while giving more design control to the user in comparison to alternative designs such as the pinhole. The investigation of how hemispheric structures are affected based on the adjustment of the pop-up ring design serves to both create larger symmetric HSRs and create a better model for future designs and applications. During this investigation, a range of design tests were done to create the hemispherical resonator molds in order to gauge the effectiveness of the pop-up ring changes. These results were then used to develop a method for achieving the desired larger symmetric HSRs.