PP1508 - Decreasing Warm-Air Caloric Irrigation Time in Young Adults

Clinical use of warm-air calorics has been previously established by the British Society of Audiology (BSA), but limited research currently exists to evaluate the use sixty-second irrigations. The purpose of this study is to examine the relationship between irrigation time and excitatory response during warm-air caloric testing in typical young adults. To evaluate this relationship, we compared the slow-phase velocity (SPV) of the following time intervals: 60, 50, 40, 30, 20, and 10 seconds. We hypothesize that by identifying a consistent response pattern, we can better interpret results in patients who previously could not complete a full caloric test battery.

Summary:

Caloric testing is used to assess the function of a patient’s horizontal semicircular canal by directing a medium (either air or water) into the subject’s ear canal that can be either cold or warm. This is completed regularly during Videonystagmography (VNG) testing and can also provide information regarding the function of excitation and inhibition that is driven by the vestibulo-ocular reflex (VOR). The deviation from standard body temperature changes the density of the fluid within the vestibular organ, eliciting nystagmus. For the patient, the test can give them the perception of turning/moving even though they are still. In an effort to reduce caloric testing time, previous research has verified the use of monothermal warm irrigations (Bush et al., 2013), but caloric testing can be distressing to patients. A study completed by Kelly et. al. in 2018 found that patients had higher rates of distress during caloric testing compared to rotary chair testing and this was further heightened in patients with anxiety. Standards for time intervals in air caloric testing have been previously established by the British Society of Audiology (BSA) but there is limited knowledge to why sixty seconds is commonly used for this assessment other than it is comparable to water caloric results (Zapala et al., 2008). Based on the results from the study, we hope to better interpret results in patients who previously cannot complete the full battery of caloric testing.

Participants were screened for a history of hearing or balance concerns through a brief case history form and hearing screening including otoscopy, tympanometry, pure-tone air, and bone threshold finding. A General Anxiety Disorder – 7 (GAD-7) screener was administered to control for patients with heighted VOR responses due to anxiety (Zapala et al., 1995). Following the screening, a 60-second bilateral warm-air caloric was conducted to establish a baseline and confirm normal responses prior to reducing irrigation time. After initial screening and baselines were collected, further caloric testing was completed using different time intervals in each ear including: 10, 20, 30, 40, and 50 seconds. The order of the time intervals and the starting ear was counterbalanced with 5 minutes between each ear. Statements on results and conclusions cannot yet be made as we have not finished data analysis. After data is collected, we analyze the maximum SPV in each time condition to determine if there is a consistent pattern in the relationship of the responses between participants. If we are able to determine there is significant consistency in the responses, clinicians may be able to have validity in shortening irrigation times for patients who report high distress during testing.`