Understanding Aided Speech Perception in Noise: Behavioral and Electrophysiological Measures
Trial Snapshot
- Phase
- Not Applicable
- Status
- Recruiting
- Sponsor
- University of South Florida
- Enrollment
- 121
- Locations
- 1
- Primary Endpoint
- Neural Segregation
Study Overview
Brief Summary
The overarching hypothesis to be evaluated using this protocol is that age-related hearing loss (ARHL) leads to shifts in the functional spatial boundaries between segregated and integrated auditory streams, and that hearing aid intervention that relies on directional processing schemes is most effective for those that have the poorest spatial sensitivity. One key component of the research design is to measure both behavioral and neurophysiological indices of an individual's spatial segregation boundary. The second key component is to measure the cost or benefit associated with hearing aid intervention in older hearing-impaired listeners. The final component is to relate cost and benefit of hearing aid intervention to spatial sensitivity measures that might predict the efficacy of clinical intervention.
Detailed Description
STUDY DESIGN:
This is a between-group and within-subject, repeated-measures design. A detailed protocol, visit schedule, intervention methodology, and battery of outcome measures will be used to assess audition, spatial sensitivity, and pre- and post-intervention of behavioral and neurophysiological indices of spatial segregation. The study includes two control groups (young normal-hearing [YNH] and older normal-hearing [ONH]) and the test group (older hearing-impaired [OHI]) with three aided interventions: omnidirectional processing, fixed directional processing, and variable directional processing. There are two study arms: Arm 1 tests spatial segregation in the presence of a fixed masker in front of the listener; Arm 2 tests spatial segregation in the presence of a diffuse masker presented from three (narrow) or seven (wide) loudspeakers surrounding the frontal spatial hemisphere.
DESCRIPTION OF THE PROTOCOL:
All listeners receive an intake protocol consisting of standard clinical and laboratory measures of auditory function (roughly two-hour visit). The baseline measures include audiogram, loudness discomfort levels (LDLs), middle ear status (tympanometry), acoustic reflex thresholds, and words in noise. Pre-treatment measures of spatial sensitivity are measured in a single two-hour visit. Measures include the minimum audible angle (MAA), speech localization error, and spatial release from masking. The Pre-treatment measures of the spatial segregation boundary are conducted in a single two-hour visit. Post-treatment measures (OHI group only) are counter balanced across three additional two-hour visits. Pre- and post-treatment measures of the spatial segregation boundary include measures of a fixed spatial separation between target and masker speech, and a roving (moving) target condition at multiple spatial separations spanning 0° to 90° in 15° steps.
DELIVERY OF INTERVENTION:
Study Design
- Study Type
- Interventional
- Allocation
- Non Randomized
- Intervention Model
- Single Group
- Primary Purpose
- Basic Science
- Masking
- Single (Participant)
Masking Description
Participants will not be told which hearing aid processing is active during testing.
Eligibility Criteria
- Ages
- 18 Years to 80 Years (Adult, Older Adult)
- Sex
- All
- Accepts Healthy Volunteers
- Yes
Inclusion Criteria
- •Target candidates for this study will be 38 young normal-hearing (YNH), 38 older normal-hearing (ONH), and 55 older hearing-impaired (OHI) subjects. Eligible NH listeners will have ≤20 dB HL at octave frequencies from 0.25 to 4 kHz and ≤30 dB HL up to 8 kHz. Eligible HI listeners will have bilateral (symmetric), moderate sensorineural hearing loss characterized by pure-tone thresholds between 35 to 50 dB HL from 0.25 to 2 kHz and 50 to 70 dB HL between 3 and 8 kHz. Age is restricted from 60 to 80 years for the older listening groups and from 18 to 35 for younger listeners. A balance of male and female participants will be recruited to assess sex as a biological variable in the data analyses. This age range for older listeners was chosen to be maximally inclusive of potential presbycusic participants, to promote generality of the results, and to facilitate uniform sampling within this age range. The investigators want to avoid the scientific need to stratify by age, which would make the scope of the project unmanageable given the constraints of this five-year award. The investigators have no evidence that lower or higher ages would affect aided intervention. Thus, inclusion of a larger age range would weaken the rigor of the investigation and complicate interpretation of the findings. The target range of hearing loss was chosen for similar reasons, reflecting the largest segment of older adults with hearing loss while avoiding the need to stratify by hearing loss to evaluate the stated hypotheses.
- •Additional Inclusion Criteria for HI group:
- •Bilateral sensorineural hearing losses within the mild-to-moderately severe range as indicated by pure tone air- and bone-conduction audiometry and screening (Y-226 Hz, Type "A") tympanograms.
- •Candidates for hearing aids or experienced users.
- •Fluent speaker of English as speech testing will be in English.
- •MoCA (Montreal Cognitive Assessment; Nasreddine et al., 2005) score of >
- •This cut point has been used frequently in investigations of aging and will better ensure that cognitive related problems will not restrict the abilities of subjects to perform the study tasks.
Exclusion Criteria
- •Exclusion criteria include conditions for which one could anticipate that hearing or cognitive status might change markedly during the course of study. To hedge against such changes, participants will be excluded if they have undergone clinical management for any of the following in the past 12 months:
- •Head trauma
- •Traumatic brain injury
- •Other neurological disorders
- •Otologic surgical procedures
- •Actively fluctuating hearing loss
- •Acute Meniere's disease
- •Labyrinthitis
- •Conductive hearing loss
- •Use of ototoxic medications
Arms & Interventions
Older listeners with normal hearing
Control group, no intervention.
Younger listeners with normal hearing
Control group, no intervention.
Older listeners with hearing loss
Test group, tested with and without the intervention (openMHA device) fit to their audiometric profile.
Intervention: Open-source master hearing aid (Device)
Outcomes
Primary Outcomes
Neural Segregation
Time Frame: Acute: Outcome measures are collected with and without treatment over multiple sessions spanning roughly 2 weeks.
Using two neural entrainment models (forward and backward), the investigators will measure the probability that the brain is able to encode attended speech during a speech-on-speech task. Listeners are tasked with identifying digits during the task carried by either the male or female speaker. The neural entrainment models will be conducted for each spatial separation (between 0° and 90°), from which the investigators will derive a single probability metric for fixed spatial separations or for multiple locations, revealing a neurometric curve. From the neurometric curve, the investigators can extract the spatial separation needed to get a desired percent correct, like 75%, and the investigators call this the Neural Spatial Segregation Boundary (in degrees).
Digit Identification
Time Frame: Acute: Outcome measures are collected with and without treatment over multiple sessions spanning roughly 2 weeks.
The investigators will measure the behavioral accuracy of listeners identifying digits in a continuous stream of monosyllabic words. In a roughly two-minute run, about 30 digits are presented and listeners are tasked with immediately identifying each one as they are presented. The target stream can be stationary or moving in space, and the masker speech stream can be stationary at the front loudspeaker or diffused around the front speaker (i.e., played from multiple speakers). For static or fixed spatial separations between target and masker (between 0° and 90°), the digit identification accuracy is in percent correct. For multiple spatial separations, the investigators can derive a psychometric curve from which the investigators can extract the spatial separation needed to get a desired percent correct, like 75%, and the investigators call this the Spatial Segregation Boundary (in degrees).
Secondary Outcomes
- Speech Localization Error(Acute: Outcome measures are collected with and without treatment over multiple sessions spanning roughly 2 weeks.)
- Minimum Audible Angle (MAA)(Acute: Outcome measures are collected with and without treatment over multiple sessions spanning roughly 2 weeks.)
- Fixed Spatial Release from Masking(Acute: Outcome measures are collected with and without treatment over multiple sessions spanning roughly 2 weeks.)