Identification of Visual Dependence in PPPD Patients With an Enhanced Rod and Disc Test (RDT) and Optokinetic After Nystagmus (OKAN) With the Aid of Virtual Reality.

The aim of this study is to evaluate whether increased visual dependence can be identified with the help of Virtual Reality (VR). Visual dependence is normally measured using the optokinetic after nystagmus (OKAN) and the rod and disc test (RDT). In this study, these two tests are performed with the aid of Virtual Reality. The OKAN is measured by eye tracking, a key item already used daily in instruments such as video nystagmography (VNG) and video head impulse test (vHIT). Another test representative of visual dependence is the Rod and Disc test (RDT). In the RDT, patients are asked to complete a visual task so that researchers gain more knowledge about visual dependence. Until now, these tests have been performed using a large set-up and many different materials. Moreover, the exact underlying mechanism of visual dependence in PPPD patients is still unknown. The aim of this study is to investigate whether Virtual Reality can be a useful tool when performing the OKAN and RDT. In this way, a better understanding of visual dependence is sought. This study aims to determine the normative values for the OKAN and RDT performed with the aid of Virtual Reality. Therefore, a healthy group of individuals will be compared with PPPD patients as they suffer from visual dependence. To evaluate the effectiveness of the OKAN and RDT via VR, the results will be compared with the scores of the visual vertigo analogue scale (VVAS), a questionnaire to assess visual dependence.