The Development of a System for Measurement of Tremor

This study aims to develop a way of objectively measuring the neurological disorders, Essential Tremor (ET) and Dystonia, and whether it is possible to quantify ET and dystonia using a measurement system in a virtual reality (VR) environment.

This study aims to develop a way of objectively measuring the neurological disorders, Essential Tremor (ET) and Dystonia. These conditions can affect the upper and lower limbs, head, voice, face and trunk. ET and dystonia can be difficult to assess and treat, particularly if severe, and therapies are limited. Currently the severity of these conditions is formally assessed by clinician rated scales such as the Essential Tremor Rating Assessment Scale (TETRAS) which is biased towards the upper limbs, requires training and is not objective. There is a need for a more precise, less variable measure of tremor that can used easily be non-expert clinicians. This study questions whether it is possible to quantify ET and dystonia using a measurement system in a virtual reality (VR) environment. We will collect data from measurement sensors embedded in the VR environment from control, ET and dystonic participants by placing them in a VR environment and instructing them to perform the TETRAS. This will help us to develop an algorithm which can measure ET severity using machine learning. We expect that the algorithm will provide a better assessment of ET and dystonia than the TETRAS.

The virtual reality (VR) platform, which detects whole-of-body movements. The VR environment is a series of sensors in a room that detect whole body motion and a series of sensors worn by the participant. As well the participant dons VR "goggles" that allows them to "see" a virtual environment in which they can perform the TETRAS. Within the VR platform, an avatar (an electronic image that represents the participant) is produced in the VR environment, and this will be used to review the participant. Sensors for the detection of wrist, head and voice tremor. The sensors are small devices worn on the wrists and head of the participant and are similar to those used in the VR system. A microphone is attached to the participants to detect voice tremor.

The TETRAS has 16 tasks each rated from 1 to 4 with 64 maximum points, with a score of 1 denoting a minimal or barely noticeable tremor and 4 denoting a severe tremor. Scoring for the head provides 8 points; the voice and lower limbs 4 points each; and the upper limb each obtains 20 points, with an extra 4 points for handwriting and 4 for postural tremor.

Inclusion Criteria - Control participants Aged 18 to 80 years Able to provide informed consent for self Able to comply with all study procedures Exclusion Criteria -Control participants Any neurological disorder Any other non-neurological cause of tremor e.g. medication induced Inclusion Criteria - ET participants Aged 18 to 80 years Able to provide informed consent for self Clinical diagnosis of ET or ET plus syndrome Able to comply with all study procedures Exclusion Criteria - ET Participants Tremor other than ET (e.g. parkinsonian, functional tremor) Presence of other movement disorder For DBS participants: willingness to turn off their IDU (deep brain stimulator battery) temporarily switched off during their assessment. Participants must have their own ability to turn this back on following the assessment.