Apple Hearing Study (AHS)

Apple Hearing Study: Characterization of Headphone Audio Levels, and Optional Wristwatch-Based Environmental Sound Levels, With Variable User Interface

The Apple Hearing Study is a partnership between the University of Michigan and Apple to study sound exposure and its impact on hearing health. This groundbreaking study will advance the understanding of how hearing could be impacted over time by exposure to sound at certain levels. The investigators will measure headphone and environmental sound exposures over time among participants, and determine how these exposures impact hearing and stress levels. US residents who own an iPhone, download the Apple Research app and consent to participate will be randomly assigned to two groups, one with a "Basic" user interface in the Research app, and one with an "Advanced" user interface. Users in the "Advanced" group will receive additional information about their exposures and be given additional surveys and hearing tests based on their music and environmental sound exposures. The study will provide investigators with a better understanding of listening behavior and its overall impact on hearing health. This information will in turn help guide public health policy and prevention programs designed to protect and promote hearing health in the US and globally.

Study Overview

• Status: Active, not recruiting
• Conditions: Hearing Loss; Tinnitus; Hearing Loss, Noise-Induced
• Intervention / Treatment: Behavioral: Advanced

• Study Type: Observational
• Enrollment (Estimated): 300000
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Michigan
    • Ann Arbor, Michigan, United States, 48109
      • University of Michigan School of Public Health

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

Adults age 18 or older that live in the U.S. or U.S. territories and have iPhone with the Research app installed.

Description

Inclusion Criteria:

• Age ≥ 18 years at time of eligibility screening, ascertained from self-reported date of birth. Potential subjects in the states of Alabama and Nebraska must be 19 or older (legal age of consent in these states), and 21 and older for any subjects in Puerto Rico.
• Live in the United States of America at time of eligibility screening, ascertained from self-report.
• Proficient in written and spoken English, defined by self-report.
• Participants must NOT share their iCloud account, iPhone or other devices such as Apple Watch with anyone else as this would make it challenging for researchers to use their information.

• Possession of the following, ascertained from automatic hardware/software/device pairing check:

  • iPhone with iOS versions capable of supporting the Research app used to complete screening eligibility.
  • Optional: Apple Watch (any model) paired with iPhone; an Apple Watch Series 4 or later is required to share environmental sound levels.

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

Cohort; Participants will be asked to read and sign the study ICF within the app if they agree and are willing to participate. After providing informed consent to participate, participants will be directed to select which data they want to share from the Health App via HealthKit and SensorKit to the Research app. All Research app users are asked to complete contact information and demographic questions that may be common across multiple Research app studies, such as age, race, sex, location of residence, and socioeconomic status. Participants will be asked to complete surveys approximately every other month for a total of about 1.5 hours over the entire year. Participants will be asked to complete three types of hearing tests 2-6 times per year; Interactive Tinnitus Tasks, Pure Tone Audiometry, and Speech in Noise. Participants will also be requested to complete brief on-demand surveys following high sound level measurements from headphones or the watch, at most monthly.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Headphone audio level patterns	For the entire cohort over various timeframes	From enrollment to the end of followup at 10 years
Difference in Headphone Audio Level patterns	This will include assessment of sound pressure level and time at baseline and over the duration of the study.	From enrollment to the end of followup at 10 years
Association between Headphone Audio Level patterns and Pure Tone Audiometry	Analysis will occur for each tested frequency (dB HL at 125 Hz, 250 Hz, 500 Hz, 1 kHz, 2 kHz, 4kHz, and 8 kHz assessed for both ears) for both ears at baseline and over the duration of the study.	From enrollment to the end of followup at 10 years
Association between Headphone Audio Level patterns and Speech in Noise	Analysis will assess the speech recognition threshold and it's relationships with HAL at baseline and over the duration of the study	From enrollment to the end of followup at 10 years
Association between Headphone Audio Level patterns and tinnitus matching	At baseline and over the duration of the study	From enrollment to the end of followup at 10 years
Association between general health and individual characteristics and sound levels and/or audiometry tasks	Headphone Audio Levels will be assessed as the sound level and the audiometry tasks assessed will be Pure Tone Audiometry, Speech in Noise, and tinnitus matching	From enrollment to the end of followup after 10 years
Change from baseline to final audiometry	Including both Pure Tone Audiometry and Speech in Noise	From enrollment to the end of followup after 10 years
Change from baseline in abbreviated Pure Tone Audiometry following high headphone audio level notification	This comparison will occur for two frequencies (1 kHz and 4 kHz for both ears) within 24 hours of acute loud Headphone Audio Level exposure (LEQ equivalent to >97 dBA for >30 minutes)	From enrollment to the end of followup after 10 years
Headphone Audio Level association with baseline survey questions	This will includes questions about typical headphone us, typical environmental exposures, and hearing ability.	From enrollment to the end of followup after 10 years
Baseline Audiometry association with baseline survey questions	Baseline Audiometry includes both Pure Tone Audiometry and Speech in Noise. Survey questions include those regarding typical headphone use, typical environmental exposures, and hearing ability.	From enrollment to the end of followup after 10 years
Final Audiometry association with end-of-study survey questions	Final Audiometry includes Pure Tone Audiometry and Speech in Noise. The end-of-study survey questions include typical headphone use, typical environmental exposures, and hearing ability.	At the end of followup after 10 years
Change in survey questions	Survey questions regarding exposure changes over the course of the study	From enrollment to the end of followup after 10 years
Association between hearing ability and changes in hearing health and related health conditions	Hearing ability is evaluated both as perceived and evaluated. Changes in hearing health include audiometry and tinnitus. Related health conditions include items such as cognition, sleep, mental health, activity, mobility, and more.	From enrollment to the end of followup after 10 years
Descriptive assessment of participant use and experience	Experience with hearing related tools and device	From enrollment to the end of followup after 10 years

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Difference in Environmental Sound Level Patterns	Including sound pressure level and time at baseline and over the duration of the study. This outcome is only among participants that use Apple Watch.	From enrollment to the end of followup after 10 years
Association between Headphone Audio Levels and Environmental Sound Level patterns	This outcome is only among participants that use Apple Watch.	From enrollment to the end of followup after 10 years
Association between Environmental Sound Level patterns and Pure Tone Audiometry.	At baseline and over the duration of the study. This outcome is only among Participants that use Apple Watch.	From enrollment to the end of followup after 10 years
Association between Environmental Sound Level patterns and Speech in Noise	At baseline and over the duration of the study. This outcome is only among Participants that use Apple Watch.	From enrollment to the end of followup after 10 years
Association between Environmental Sound Level patterns and tinnitus matching task	At baseline and over the duration of the study. This outcome is only among Participants that use Apple Watch.	From enrollment to the end of followup after 10 years
Association between general health and personal characteristics and sound levels and hearing tasks	Sound levels include Environmental Sound Levels. Hearing tasks includes Pure Tone Audiometry, Speech in Noise, and Tinnitus matching. This outcome is only among Participants that use Apple Watch.	From enrollment to the end of followup after 10 years
Change from baseline in abbreviated Pure Tone Audiometry following loud environmental noise notification	This assessment will be for two frequencies (1 kHz and 4 kHz for both ears) tested within 24 hours of acute loud Environmental Sound Level exposure (LEQ equivalent to >97 dBA for >30 minutes). This outcome is only among Participants that use Apple Watch.	From enrollment to the end of followup after 10 years
Assess reported participant experience	Experience will be assessed via survey delivered with a notification after a prolonged loud environmental sound level exposure (LEQ equivalent to >80 dBA for >40 hours). This outcome is only among Participants that use Apple Watch.	From enrollment to the end of followup after 10 years
Association between heart rate measures and Headphone Audio Level patterns	This will include heart rate during activity (as assessed by logged Workouts and Active Energy trends by Watch). This outcome is only among participants that use Apple Watch.	From enrollment to the end of followup after 10 years
Association between heart rate measures and Environmental Sound Level patterns	This includes heart rate during activity (as assessed by logged Workouts and Active Energy trends by Watch). This outcome is only among participants that use Apple Watch.	From enrollment to the end of followup after 10 years

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Impact of hearing ability on other related aspects of health	Health includes things such as activity, cognition, mental health, mobility, sleep, health conditions, and health outcomes.	From enrollment to the end of followup after 10 years
Assess novel versions of hearing assessments	These assessments will be delivered using Research app. This may include different variations of speech in noise, pure tone audiometry, and related assessments such as evoked otoacoustic emissions (EOAE).	From enrollment to the end of followup after 10 years

Collaborators and Investigators

• Sponsor: Apple Inc.
• Collaborators: World Health Organization
• Investigators: Principal Investigator: Richard L Neitzel, PhD, MS, CIH, University of Michigan; Study Director: Lauren M Smith, MS, MPH, University of Michigan; Study Chair: Joyce M Daniels, MA, University of Michigan

Publications and helpful links

General Publications

• Smith LM, Wang L, Mazur K, Carchia M, DePalma G, Azimi R, Mravca S, and Neitzel RL. Impacts of COVID-19-related social distancing measures on personal environmental sound exposures. Environmental Research Letters. Oct 2020. 15.10: 104094. https://iopscience.iop.org/article/10.1088/1748-9326/abb494
• Neitzel RL, Smith L, Wang L, Green G, Block J, Carchia M, Mazur K, DePalma G, Azimi R, Villanueva B. Toward a better understanding of nonoccupational sound exposures and associated health impacts: Methods of the Apple Hearing Study. J Acoust Soc Am. 2022 Mar;151(3):1476. doi: 10.1121/10.0009620.

Helpful Links

• UM Study Website

Study record dates

Study Major Dates

• Study Start (Actual): November 14, 2019
• Primary Completion (Estimated): August 31, 2029
• Study Completion (Estimated): December 1, 2029

Study Registration Dates

• First Submitted: November 13, 2019
• First Submitted That Met QC Criteria: November 19, 2019
• First Posted (Actual): November 21, 2019

Study Record Updates

• Last Update Posted (Actual): March 19, 2026
• Last Update Submitted That Met QC Criteria: March 17, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: Audiometry; Hearing Loss; Tinnitus; Heart rate; Music; Noise Induced Hearing Loss; Headphones; Noise Exposure; Listening Volume; Environmental Noise; Speech-in-Noise; Hearing Ability; Headphone audio level; Ambient noise; Occupational noise
• Additional Relevant MeSH Terms: Neurologic Manifestations; Nervous System Diseases; Otorhinolaryngologic Diseases; Sensation Disorders; Ear Diseases; Hearing Disorders; Hearing Loss, Sensorineural; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Hearing Loss; Hearing Loss, Noise-Induced; Tinnitus
• Other Study ID Numbers: Pro00037864; HUM00167885 (Other Identifier: University of Michigan IRB)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: N/A - no plan to share

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No