Hearing Health among Medical Students

1. Introduction

Hearing loss is a significant public health concern affecting individuals across various demographics, with the World Health Organization reporting that approximately 1.5 billion individuals globally will be affected in 2023 [1]. Auditory impairment from hearing loss has been suggested to increase the risk of depression and cognitive decline and contribute to poor physical health [2,3,4]. Prolonged exposure to high noise levels from medical machines such as MRI machines, drills, ventilators, and operating room equipment, often exceeding safe decibel limits, may provide unique occupational risks of hearing loss among healthcare workers [5,6].

The use of headphones and personal listening devices has become increasingly prevalent among young adults, including medical students, for recreational and educational purposes. Studies have shown that prolonged and high-volume headphone [SS5] use—noise levels exceeding 85 dB—can lead to noise-induced hearing loss (NIHL), particularly when using headphones or earbuds, due to the direct transmission of sound into the inner ear at levels that can cause damage over time. Additionally, exposure to high peak levels, even for short durations, can contribute to NIHL and other auditory issues⁵. Research suggests that sensory presbycusis, a form of age-related hearing loss, may reflect years of wear and tear, with cumulative noise exposure playing a significant role in its development [6].

Assessing the baseline hearing of healthcare workers in their early medical education is a necessary step to inform screening measures, provide timely interventions, and preventative strategies. Additionally, earlier detection may prevent the development of social and emotional consequences of hearing loss and preserve cognitive function [7]. For medical students, earlier detection may improve educational and occupational outcomes [8].

This study explores the potential of self-reported health [SS16] information (SRHI) and phone-related health information (PRHI) as preliminary screening tools for hearing loss in medical students. These tools can be valuable for preliminary hearing loss screening, mainly when used with objective measures like pure tone audiometry (PTA). Bridging the gap between subjective experience and objective audiometry tests may help develop efficient early detection methods [4,9,10]

2. Methods

The California Northstate University Institutional Review Board #2306-02-121 approved the study. Participants provided written informed consent, and the study followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) reporting guidelines [11].

2.1. Study Design and Participants

This cross-sectional, single-blind, single-institution study was conducted between August 2023 and March 2024. Fifty medical students were recruited via message board for voluntary participation in the test group; control group data was sourced from a previously conducted study evaluating hearing loss in a similar cohort of US adults, and updated data from NHANES [12] was also used to conduct further analysis¹¹. Subjects were eligible for enrollment if greater than 18 years of age and excluded if presenting with a previously diagnosed otologic disorder or current ear infection.

2.2. Study Methods

The SRHI was completed to assess environmental and vocational noise exposure, hearing protection use, and history of otologic disorder. PRHI included using the “Health App” (Apple©, 2024) to record headphone levels over the past year, and environmental sound levels were obtained for anyone who uses an Apple © Watch similar to another study [13]. A self-reported questionnaire was used to validate their headphone usage via their phone and whether they wore their Apple Watches consistently.

Before audiometry, otoscopy and ambient sound measurements were done (RISEPRO® Digital Sound Level Meter). Researcher were required to demonstrate proficiency in all study methods via formal training.

2.3. Study Measures

2.3.1. Audiometry

Subjects were given the audiometry response button, and the audiometer was positioned beyond the subject’s visual field to reduce observation bias. Air conduction pure tone audiometry (PTA) was conducted using Amplivox© 270, with a standard Amplivox© audiometric headset, adhering to the standardized modified Hughson-Westlake audiometric technique. PTA measured hearing thresholds in dB across frequencies of 1 kHz, 2 kHz, 4 kHz, and 8 kHz. If a subject responded to the initial 40dB tone at 1 kHz, the tone intensity was reduced by 5 dB until no longer registered as determined via response cessation, which required confirmation via increasing by 10 dB and confirming the threshold. This was repeated across the 4 frequencies and in both ears.

2.3.2. Data Validity and Analysis

We calculated a modified high Fletcher index (HFI) as the mean hearing threshold in dB across 1, 2, 4, and 8 kHz [14,15]. Hearing loss was defined as having a high Fletcher index above 25 dB for this study [1].

2.3.3. Statistical Analysis

Data was analyzed using statistical tests, which included two-tailed unpaired t-tests and Pearson’s correlation coefficients with P values < .05 considered statistically significant. All data analysis was performed from November 2023 - March 2024 using Microsoft Excel 2020(Microsoft Corp) or R, version 3.6.0 (The R Foundation for Statistical Computing). Participant demographic data was illustrated in a chart, and each data category was quantified using descriptive statistics. The analysis assessed the extent to which subjects’ presenting symptoms indicative of hearing loss correlate with the audiometry result. A box chart was also created to compare demographics and hearing loss status (Figure 4). Additionally, 2017-2018 NHANES audiometric data was queried selectively for ages 18-33 years, and a modified high Fletcher index was calculated and then compared to our results via a two-tailed unpaired t-test.

3. Results

3.1. Participant Characteristics

50 subjects were enrolled for the test group with 0% subject attrition. Most subjects (78%) were aged between 22 and 25 years. 50% of subjects self-identified as male and 48% as female. A majority of subjects self-identified as Asian (62%) and Caucasian (18%). Non-binary (1%), African-American (4%), and Hispanic (2%) were underrepresented in the test group.

Table 1. Participant Characteristics.

	African American	Asian	Caucasian	Latino or Hispanic	Native Hawaiian or Pacific Islander	Other	Two or more	Total
Female	1	16	3	1	2		2	25
Male	1	15	5			1	2	24
Non-binary			1					1
Total	2	31	9	1	2	1	4	50

Table 1. Participant Characteristics.

	African American	Asian	Caucasian	Latino or Hispanic	Native Hawaiian or Pacific Islander	Other	Two or more	Total
Female	1	16	3	1	2		2	25
Male	1	15	5			1	2	24
Non-binary			1					1
Total	2	31	9	1	2	1	4	50

Mean hearing thresholds measured as FHI across both ears was 6.21 dB HL for participants. The average ambient noise level measured in this study was 41.66 dB.

3.2. Associations Between Self-Reported and Phone Reported Data Compared to Hearing Outcomes

Daily self-reported moderate headphone use (in-ear or over-ear) did not significantly affect hearing outcomes (Figure 3 and Figure 4). There were no differences between individuals using headphones for less than 3 hours daily compared to those using them for 3 or more hours per day (in-ear: p=0.633, over-ear: p=0.901). Neither self-reported migraines (0 vs. 1+ migraines) nor weekly exposure to loud sound was significantly associated with hearing test results (p=0.837 and p=0.37, respectively). Tinnitus was not significantly associated with hearing outcomes (p=0.661). No participants had missing data for age, gender, headphone use, hearing-associated health conditions, or hearing test results. Age did not significantly impact hearing, with no difference observed between students under 25 and those 25 years or older (p=0.919). Interestingly, gender was a significant factor. Females in the study exhibited slightly worse hearing than males (p=0.0199). Ethnicity did not significantly affect hearing results (Asian vs non-Asian) (p=0.417). No statistically significant difference was found for mean hearing thresholds, 4.74db, compared to NHANES 2017-2018 data in the 18-33 participant age range (p=0.1285). Finally, there was no correlation between the PRHI, including environmental (Pearson correlation coefficient: -0.450, P-value: 0.0920, n=16) and Headphone (Pearson correlation coefficient: -0.0311, p =0.847, n = 41) audio levels.

Figure 1.

Figure 1.

Figure 2.

Figure 2.

Figure 3. Sex Differences in Hearing Loss Among Medical Students.

Figure 3. Sex Differences in Hearing Loss Among Medical Students.

Figure 4.

Figure 4.

Figure 5. Correlation between PRHI environmental audio level and hearing thresholds.

Figure 5. Correlation between PRHI environmental audio level and hearing thresholds.

Figure 6. Correlation between PRHI headphone audio level and hearing thresholds

Figure 6. Correlation between PRHI headphone audio level and hearing thresholds

4. Conclusions

Investigation using a self-administered questionnaire to assess the hearing habits of medical students indicates that the two types of headphone use by medical students, in-ear or over-ear, did not lead to worse objective hearing outcomes. Additionally, utilizing phone-reported health information (PRHI) of headphone or environmental audio levels, there was no significant difference between self-reported habits and hearing. Age and ethnicity showed no significant association in the results. However, gender impacted hearing health in medical student communities where females exhibited slightly poorer hearing health than their male counterparts.

Collecting data on the hearing health of medical students is an evolving area of research. Early detection and intervention for hearing loss among medical students can facilitate timely interventions in hearing health and improve hearing care outcomes. Given the association between hearing loss and adverse health conditions such as depression and poor physical health, continuous monitoring of hearing health in the rigorous and demanding environment of medical school and clinical settings is crucial.

Self-reported screening tools and questionnaires are valuable due to their accessibility and ease of use. Similarly, PRHI can serve as a valuable tool in clinical and research settings. Additionally, demonstrating the safety of headphone use may reassure students regarding potential negative impacts on their hearing. Future randomized controlled studies can further refine and validate these screening methods and address any biases associated with using self-reported questionnaires to assess hearing health among medical students.