Spatial Cues, Task Demands, and Auditory Selective Attention
Trial statusRecruiting
Trial phaseNot applicable
Trial typeInterventional
Biological sexAll
Age18-90
SponsorUniversity of South Florida
About this trial
Understanding speech in restaurants and other noisy environments is the most common complaint from the more than 60 million Americans with hearing impairment. Succeeding in such environments requires a listener to first segregate sound sources and then selectively attend to the source of interest. This study examines how individual auditory spatial cues (interaural time differences and interaural level differences) support spatial selective attention, the cortical processes that underlie this ability, and how these processes are modulated by task demands. Participants with normal hearing and participants who use bilateral cochlear implants will perform listening tasks while brain and physiological responses are recorded (electroencephalography, functional near-infrared spectroscopy, pupillometry, and, for normal-hearing participants only, functional magnetic resonance imaging). The findings will provide new insights into the mechanisms of spatial selective attention and help guide clinical solutions for cochlear implant users, individuals with hearing impairment more generally, and older normal-hearing adults who have difficulty understanding speech in noisy environments.
Eligibility criteria
This trial accepts healthy volunteersQualifiers
Adults with normal hearing, confirmed by audiometric assessment (thresholds within 20 dB HL of normal through 8 kHz), OR adults with bilateral cochlear implants who have used their implants for at least one year
Native speakers of American English
Normal or corrected-to-normal vision
Disqualifiers
Known neurological disorders
For fMRI sessions (normal-hearing participants only): contraindications to MRI scanning; cochlear implant users do not complete MRI sessions
Trial design
Design model
Parallel
Treatments tested in this trial
Existing bilateral cochlear implants
DeviceParticipants in this arm are recruited from a population who have existing bilateral cochlear implants. The implants are the participants' own clinical devices, used as clinically programmed; no investigational device or modification is provided by the study. Auditory attention tasks are presented with manipulated spatial cues (interaural time differences, interaural level differences, or HRTFs).
Normal Hearing Control
Other interventionControl group recruited from the normal hearing population. Participants perform the same auditory attention tasks with manipulated spatial cues (interaural time differences, interaural level differences, or HRTFs) under EEG/fNIRS/pupillometry and fMRI.
Treatment groups
80 Participants
are divided into 2 treatment groupsGroup A: Bilateral Cochlear Implant UsersOther 1 intervention
Group B: Normal Hearing ControlsOther 1 intervention
Trial outcomes
Primary outcomes
1
EEG
EEG data acquired using 32 Ag-Ag/Cl electrodes embedded in an elastic cap (Brain Products), impedances below 20 kOhms, locations per the extended 10-20 system, recorded at 5 kHz from 0.1-100 Hz. Event-related potentials (including attentional modulation of the N1) and parietal alpha lateralization are compared across spatial-cue and task-demand conditions.
Time frame
2 hours2
NIRS
Functional near-infrared spectroscopy collected with a montage targeting bilateral superior temporal gyrus (STG) and bilateral prefrontal cortex, using a NIRSport 2 8x8 channel system (NIRx) with long- and short-distance channel probes; 3D structural head scanning registers probe placement. Optical signals recorded at 10 Hz with an average source-detector distance of 35 mm. Oxygenated and deoxygenated hemoglobin responses are compared across conditions.
Time frame
2 hours3
Pupillometry
Pupil dilation from both eyes recorded with the EyeLink 1000 at a sampling rate of 1000 Hz, normalized to each participant pupillary dynamic range, as an index of listening effort across conditions.
Time frame
2 hours4
MRI
Data acquired on a 3 Tesla Siemens Prisma MRI scanner (64-channel head coil). High-resolution (0.8 mm iso) T1-weighted multi-echo MP-RAGE and T2-weighted SPACE images collected for cortical reconstruction (FreeSurfer); functional MRI measures stimulus-induced lateralization and spatial receptive fields in auditory cortex. Normal-hearing arm only.
Time frame
2 hoursSponsors and contacts
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University of South Florida
Lead sponsor
National Institute on Deafness and Other Communication Disorders (NIDCD)
Collaborator
Carnegie Mellon University
Collaborator
Source ClinicalTrials.gov