Handheld laser-fiber vibrometry probe for assessing auditory ossicles displacement

Area of Science:

• Biomedical Engineering
• Otoacoustic Emissions
• Vibrometry

Background:

• Laser-Doppler vibrometry (LDV) is the gold standard for measuring auditory ossicle displacement.
• LDV requires a direct line of sight, limiting in vivo applications.
• A handheld laser-fiber vibrometry probe (HLFVP) with a curved tip offers a potential alternative.

Purpose of the Study:

• To evaluate the feasibility of using an HLFVP with a curved tip for measuring sound-induced displacement of auditory ossicles.
• To assess the HLFVP's performance in measuring displacements of the incus and stapes.

Main Methods:

• An HLFVP with a fiber-optic cable guided the laser beam for displacement measurements.
• Measurements were taken on the incus body and posterior crus of the stapes in six fresh temporal bones.
• Tonal stimuli (0.5–4 kHz) were delivered via an insert earphone, with the probe fixed by tripod or hand.

Main Results:

• Multivariate analysis of variance revealed significant differences in displacement based on stimulus frequency, bone, and measurement site.
• No statistically significant differences were found based on the probe fixation method.
• Standard deviations for frequency, bone, site, and fixation were 6.9, 2.6, 1.9, and 0.6 nm/Pa, respectively.
• Ear transfer functions were consistent with existing literature data.

Conclusions:

• The feasibility of using HLFVP for auditory ossicle displacement measurement is confirmed.
• HLFVP allows for measurements at various angles, but standardization is needed considering anatomical and surgical factors.