Development of a Mobile App FFVT vs FFCT : A RCT

This is an open-labelled randomized controlled trial involving 2 groups which are Free Field voice test vs Free Field Click test (digital hand-held device). There will be no follow up for these participants as it is a one off assessment in most cases. Participants from the Otolaryngology clinic of Hospital Sultanah Aminah Johor Bahru will initially be screened during office hours for suitability based on our inclusion and exclusion criteria. Participants whom are interested will then be counselled and a consent form will be provided to the participants and he/she will be given sufficient time to consider before providing a signature on the consent forms.

The app is designed by the investigators using a broadband (500-3000 Hz) click sound of 30-40 dB for soft sound/whisper and 60-70dB for loud sound/conversation voice. This app is designed by using the Flutter-Dart programming tool and the speaker is produced via hand-held devices of Apple and Android brands. The tone is produced 3 times, with 2 out of 3 answers are considered as the participant's hearing threshold. The investigators stands at the distance of 2 feet away behind the seated participant and a soft sound from the FFCT is tested. The participant is then asked to respond yes or to nod if able to hear the sound. When the participant is unable to answer or no response is received upon third testing, the examiner then moves closer to 6 inches to the participant and again the soft sound is tested thrice. Loud sound is then tested if the participant is unable to respond, starting from 2 feet distance for three times. And then, the loud sound is tested at 6 inches of distance if no further response is obtained.

The same is done for the group of participants randomised into the Free Field voice test group. The investigator will inform the participant to repeat a sequence of Spondees words or a combination of numbers and letters whispered by the examiner initially. The investigator will be standing at the same distances as in the Free Field Click test examination (starting with 2 feet). If the participant fails to hear the whispered voice at 2 feet, the investigator increases the loudness of voice to conversational tone at the same distance. The test is repeated thrice each time with a different set of Spondee words to avoid the participants from recognizing the same sequence. If the participant is unable to respond, the investigator moves closer to 6 inches and whispers to the participant, and if no further response, then, conversational voice is used. The participant's free-field threshold is the voice and distance level at which more than 50% correct is obtained.

Both the FFVT and FFCT tests are done in a sound-proof room or a reasonably quiet room. The investigator stands behind the participant throughout the examination to prevent any lip reading. Each ear is tested individually, starting with the better ear and the non-test ear is masked by the participant by either gently occluding the ear canal with a finger or by tragal rubbing. The other ear is assessed similarly. Expected duration for the completion of a FFVT or FFCT is estimated to be approximately 5-10 minutes depending on severity of hearing loss where-else the duration for a diagnostic PTA would take between 10-20 minutes depending on complexity of hearing loss. This is a standard procedure in PTA practice and no additional steps were undertaken specifically for the purpose of this study.

As this is a study to compare the sensitivity and specificity of FFVT and FFCT, the study end-point involves the subjective hearing threshold obtained from the participant upon hearing the tested sound. The subjective threshold is measured under 5 categories which is whispering sounds at 2 feet (from the participants), whispering sounds at 6 inches, Conversational sounds at 2 feet, Conversational sounds at 6 inches and finally not being able to hear at all. The measurements of the 2 groups will then be compared to the pure tone average obtained through pure tone audiogram.