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The Feasibility and Utility of a Mobile-Based Eye Movement Recording Application: A Randomized Trial

⋅Copyright c 2020 by The Korean Balance Society. All rights reserved. ⋅This is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Objectives: This study was performed to assess the efficacy and feasibility of mobile application-based Frenzel tests in dizziness clinics. Methods: We performed an investigator-initiated, blinded-outcome assessor, parallel, randomized controlled crossover trial at Chungnam National University Hospital between August 2019 and October 2019. Certified medical staffs were randomly assigned to the intervention group (i.e., a mobile application-based Frenzel glass system, n=15) or the observation group (i.e., a conventional desktop-based Frenzel glass system, n=15); the groups applied the respective systems for the preparation of eye movement recording and switched systems. The primary outcome was the elapsed time in seconds it took the participants to prepare the system for eye recording simulation. The secondary outcomes were perceived stress and satisfaction scores after completion of the operation, as measured by a questionnaire using 10-point Likert scales. Results: The mean time of machine preparation for eye recording simulation was reduced by 50% in the mobile application group compared to the desktop group in both study periods (38.0±7.1 sec vs. 76.0±8.7 sec). We detected no carryover effect. Participants also reported lower stress while using application than while using the desktop system (2.3±1.3 vs. 4.6±2.4; p<0.001). The application obtained a mean overall satisfaction score of 9.2 out of 10. Conclusions: The implementation of an eye movement recording application in a dizziness examination was well adopted by users and decreased the time and stress related to machine operation. Res Vestib Sci 2020;19(4):120-126


INTRODUCTION
Dizziness and vertigo are responsible for 4% of emergency department visits [1]. International Classification of Diseases 10th Revision codes R42 (dizziness) and H81 (vestibular diseases) are in the top 20 frequent illnesses reported in the 2018 hospitalization data from the Korea Health Insurance Review and Assessment Service [2]. In addition, the number of inpatients diagnosed with R42 or H81 and total medical expenses have increased in the last 3 years [2]. This means that frontline doctors are now taking care of many patients with dizziness/ vertigo. At present, examinations to record eye movement without fixation usually involve Frenzel glasses connected to a desktopbased personnel computer system. Compared with classical Frenzel glasses, the eyes can be observed more easily with a monitor; however, the size of the system is large, and it is inconvenient to wait for the machine to start every time a doctor uses it. The main reasons for this slow start are that Windows devices (Microsoft, Redmond, WI, USA) are large and consume a large amount of power. Such a process can be facilitated by the introduction of mobile application-based devices.
Therefore, we conducted a randomized controlled crossover trial to assess the feasibility and efficacy of a mobile application-based Frenzel system compared with a desktop-based system, focusing on the examiner's standpoint.

Trial Design and Participants
This was a randomized, controlled, crossover trial including two parallel groups to assess the clinical feasibility and efficacy

Randomization and Masking
Participants were randomized into either the mobile application device group or the desktop device group (Fig. 1).
Randomization was performed using a concealed computergenerated list of management assignments with a 1:1 allocation ratio based on the stochastic patient case assignment Python program (ver. 3.7.3; Python Software Foundation) provided by the author (HJC). Written informed consent was obtained from each participant after full information disclosure prior to participation in the study. Blinding to the type of machine was maintained during recruitment to minimize preparation bias.
Allocation concealment was ensured with allocation software and was not released until the participants started the experiment. All experiments were video recorded for later analysis. A post-experiment video review was performed without blinding by two reviewers (HJC and SK) who reviewed footage independently and were blinded to each other's reviews. The data analyst (ISK) was not blinded to treatment allocation.

The Eye Movement Recording Application
The application was developed at Chungnam National University Hospital (Daejeon, South Korea) following a user-centered and evidence-based approach by neurotologist (SHJ) and software developers. Based on eye movement observations, the team worked closely to identify the key functionalities and processes to be implemented. With one touch, an icon can be selected and shown on a binocular screen (Fig. 2, Supplementary Video 1). When using the application, the user can  interact with it by starting, pausing, and stopping it at any time.
All eye movement records by the user are sequentially saved locally on the device in archived files to preserve information that can be retrieved at any time for debriefing or medicolegal purposes. These files can also be erased or safely exported and saved.

Procedures
On the day of the experiment, each participant received three standardized training sessions on how to use each device. According to the random allocation, the participants were then asked to prepare for eye movement recording on the same upper torso model (Fig. 3). After this task had been completed, the crossover occurred. The time that the power was turned off corresponded to the end of the experiment. Before leaving the room, the participant was asked to complete a questionnaire about the experiment immediately afterwards.

Outcomes
The primary outcome was the elapsed time in seconds it took to prepare the system for eye recording simulation by the participants. The secondary outcomes were perceived stress and satisfaction scores after completion of the experiment, as measured by the questionnaire using 10-point Likert scales (Supplementary Fig. 1).

Statistical Analysis
Power calculations were based on a 50% reduction in the time to eye movement recording, which we considered to be a sufficient difference to modify the practice. Assuming 1 minute of recording time with the application and 2 minutes with the desktop device, three participants per group had to be recruited to provide 80% power with a two-sided α level of 0.05. To prevent a potential loss of power due to the misspecification of assumptions and to successfully perform parametric tests, 30 participants were recruited. The time to eye movement recording was reported for each method in each study period. For the primary analysis, the times to eye movement recording considering both experimental methods were compared by pooling both study periods. Paired data were then analyzed using a paired t-test for dependent groups, with a two-sided α level of 0.05. Potentially, the efficacy of the application could be different depending on the first method used in the crossover design, i.e., the carryover effect. To investigate this effect, we performed sensitivity analyses in which we compared the mean difference in the primary outcomes between the two preparation methods by study period (independent observations) using independent t-tests and by randomized group (paired observation) using paired t-tests. All of the differences were reported with exact 95% confidence intervals (CIs). The carryover effect was tested with a linear, multivariate, generalized estimating equation (GEE) model, with an exchangeable working correlation matrix as follows; the study period and the recording method were introduced as independent variables, and an intercept term was introduced to model a modification of the recording method's effect between the first and second study period. The null hypothesis, which stated that the interaction term was null, was tested to detect a carryover effect. The secondary outcomes (stress and satisfaction scores) were reported for each method and by study period. The same analyses were performed for the secondary outcomes. All statistical tests were two-sided, with a type-one error risk of 0.05. We used IBM SPSS ver. 20.0 (IBM Corp., Armonk, NY, USA) for the descriptive analyses and statistical tests.

RESULTS
From August 2019 to October 2019, we randomly assigned 30 participants to perform eye movement recording using the mobile application-based method first (n=15) or the desktopbased method first (n=15); there were no dropouts or missing data (Fig. 1). The baseline characteristics of the two groups seemed balanced (Table 1). We observed excellent interrater    The time was longer in both study periods when recording with a desktop PC-based system. The desktop group reported higher stress and lower satisfaction than the mobile application group in both study periods. In period 2, the time was longer, satisfaction was lower, and stress was higher than those in period 1, but the difference was not statistically significant for time (p=0.083), satisfaction (p=0.328), or stress (p=0.611). Fig. 4. Boxplots of elapsed time to machine operation for eye movement recording by participants when using the mobile application (app) compared with the desktop-based system. The solid horizontal lines denote medians and interquartile ranges the endpoints of the whiskers indicate the range. The difference between groups was significant for time to operation for eye movement recording using the t-test for paired data (p＜0.001). PC, personal computer.
differential points of nystagmus in recurrent vertigo such as vestibular migraine, Menière's disease, or benign paroxysmal positional vertigo [4]. The combination of video-oculography goggles with mobile devices could facilitate telemedicine in the future. The careful examination of eye movements in the management of dizziness patients is both complex and timeconsuming for many doctors [5,6]. We have noticed an overgeneralized approach to frontline management of patients with "dizziness" or "vertigo". Recent reports suggest that emergency doctors and other primary care providers may not be entirely comfortable interpreting bedside findings associated with vestibular disorders [7,8]. Therefore, the education of frontline used instead of an actual patient. We will prepare a follow-up study to determine the accuracy of mobile application-based eye recording.
In conclusion, the adoption of Frenzel glasses with mobile application-based recording decreased the elapsed time by 50% compared with the conventional desktop-based recording system. The medical staff also reported lower stress and higher satisfaction related to examination with mobile applicationbased devices than with desktop-based systems. As research in this area is scarce, the results generated from this study will be of importance and might promote change and improve the quality of dizziness management.