A System for the Measurement of the Subjective Visual Vertical using a Virtual Reality Device
The Subjective Visual Vertical (SVV) is a common test for evaluating the perception of verticality. Altered verticality has been connected with disorders in the otolithic, visual or proprioceptive systems, caused by stroke, Parkinson’s disease or multiple sclerosis, among others. Currently, this test is carried out using a variety of specific, mostly homemade apparatuses that include moving planes, buckets, hemispheric domes or a line projected in a screen. Our aim is to develop a flexible, inexpensive, user-friendly and easily extensible system based on virtual reality for the measurement of the SVV and several related visual diagnostic tests, and validate it through an experimental evaluation. Two different hardware configurations were tested with 50 healthy volunteers in a controlled environment; 28 of them were males and 22 females, with ages ranging from 18 to 49 years, being 23 the average age. The Intraclass Correlation Coefficient (ICC) was computed in each device. In addition, a usability survey was conducted. ICC = 0.85 in the first configuration (CI = 0.75–0.92), ICC = 0.76 in the second configuration (CI = 0.61–0.87), both with 95% of confidence, which means a substantial reliability. Moreover, 92.2% of subjects rated the usability of the system as “very good”. Our evaluation showed that the proposed system is suitable for the measurement of SVV in healthy subjects. The next step is to perform a more elaborated experimentation on patients and compare the results with the measurements obtained from traditional methods.
KeywordsSubjective visual vertical (SVV) Diagnostic tool Rehabilitation Virtual reality Mobile application
We acknowledge and appreciate the contributions to this work of Francisco Javier Molina Ortega, Alexander Achalandabaso Ochoa and Daniel Rodríguez Almagro which are members of Physiotherapy Department of the University of Jaén. Their ideas and feedback have been invaluable and they have provided all the subjects for our experimentation sessions.
This research was supported partially by the Spanish Ministry of Education, Culture and Sports via a doctoral grant to the first author (Ref. FPU16/01439).
Compliance with ethical standards
Conflicts of interest
All authors declare that they have no conflict of interests.
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
Informed consent was obtained from all individual participants included in the study.
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