Ear canal impressions will be will be packaged and sent to a professional third-party manufacturer for fabrication in an acrylic material-type. These will serve as the control earmolds, by which the in-house study/intervention earmolds will be compared against. To control for style of earmolds, all earmolds will be made in a skeleton style with a sound bore that accommodates size #13 tubing and a separate select-a-vent (SAV).

Custom earmold impressions will be scanned and edited using computer-aided design software. These 3D earmold meshes will then be converted to g-code using licensed software and sent to a stereolithography 3D printer for fabrication. Participants will only wear these study earmolds for the duration of testing.To control for style of earmolds, all earmolds will be made in a skeleton style with a sound bore that accommodates size #13 tubing and a separate select-a-vent (SAV).

Custom earmold impressions will be scanned and edited using computer-aided design software. These 3D earmold meshes will then be converted to g-code using licensed software and sent to a fused deposition modeling 3D printer for fabrication. Participants will only wear these study earmolds for the duration of testing. To control for style of earmolds, all earmolds will be made in a skeleton style with a sound bore that accommodates size #13 tubing and a separate select-a-vent (SAV).

Hearing aids will be fit with three different types of customized earmolds. They will only wear each earmold group for the duration of the test (total = ~2.5 hours). Hearing aids will be programmed to a simulated mild, flat, sensorineural hearing loss of 30 dB HL from 250-8000Hz. A short washout period will follow completion of testing with ear earmold group.

Evaluation of ear canal acoustics with participant wearing a hearing aid and earmold type (3d party control, in-house_Resin, in-house_PLA). Then, a thin microphone tube is placed in the ear canal to measure the average amount gain (dB SPL) across various frequencies (250-8000Hz) while the participant sits in front of a speaker playing sound samples. Results are recorded in gain (dB SPL) across frequencies. Once complete, the earmold type is changed and recording is repeated until all ear mold material types have been tested for each individual. Arms/Groups were collapsed for RM-ANOVA to compare between various earmold types. A post-hoc paired t-test w/ Bonferroni correction was utilized to compare ear mold material types.

A questionnaire eliciting patient perception of physical comfort, quality of voice, and overall self-perceived satisfaction. Includes 12 items (5 point) that are scored on a 0 to 100, with 100 representing best possible function/rating

Physical dimensions of each ear mold type (3rd party Control, in-house_Resin, in-house_PLA) were taken using digital calipers in millimeters prior to being worn by participants.

The total raw cost ($) for each ear mold type (3rd party_control, in-house_RES, and in-house_PLA).

Crossover trial of 30 individuals with normal hearing

Evaluation of ear canal acoustics with participant wearing a hearing aid and earmold type (3d party control, in-house_Resin, in-house_PLA). Then, a thin microphone tube is placed in the ear canal to measure the average amount gain (dB SPL) across various frequencies (250-8000Hz) while the participant sits in front of a speaker playing sound samples. Results are recorded in gain (dB SPL) across frequencies. Once complete, the earmold type is changed and recording is repeated until all ear mold material types have been tested for each individual. Arms/Groups were collapsed for RM-ANOVA to compare between various earmold types. A post-hoc paired t-test w/ Bonferroni correction was utilized to compare ear mold material types.

Each participant was fit with a 3rd party control, then in-house_PLA, then in-house_Resin ear mold. Each ear mold was worn for 10-15 minutes while outcome measures were collected. Each ear mold was separated by a brief washout period of 10 minutes.

Study involves minimal risk and limited wear time (less than 15min) and skin contact for each earmold type. Participants were directly monitored during wear time. Patients are not at risk of mortality or serious injury.