Non-Invasive Assessment of Middle Ear Function: Establishing Age-Specific Reference Ranges Using Innovative Pressureless Acoustic Immittance

Tympanometry, the current gold standard for assessing middle ear function, has limitations in infants and in cases of tympanic membrane perforation due to its potential invasiveness, as it requires the application of varying pressure in the ear canal. To overcome these issues, the Pressure-Less Acoustic Immittance (PLAITM) device was recently developed as a non-invasive alternative that does not require pressure application. However, reference values and age-specific norms are not yet established. This study aims to define age-specific reference ranges for key acoustic admittance parameters using PLAITM in healthy individuals and to offer a preliminary comparison with subjects affected by Otitis Media with Effusion (OME), a common middle ear pathology. A total of 318 healthy ears and 68 OME-affected ears were analyzed, covering an age range from 4 months to 80 years. Parameters extracted from PLAITM admittance curves included resonance frequency, admittance peak, minimum and maximum frequencies of the resonance peak, bandwidth, half peak height, and equivalent volume. Results indicate a strong age dependence for all parameters, best modeled with a logarithmic fit. Statistical analysis supports categorizing ages into three groups (0–3, 3–12, 12+ years), reflecting stages of ear development. Most parameters stabilized after age 12. Significant differences were observed between healthy and OME ears across several PLAITM metrics. These findings establish essential reference values and demonstrate the clinical potential of PLAITM for diagnosing middle ear dysfunctions, particularly in populations where conventional tympanometry is limited.