OBJECTIVES: Despite the increasing number of research concerning the applications of the Laser Doppler Vibrometry (LDV) in medicine, its usefulness is still under discussion. The aim of this study is to present a methodology developed in our Department for the LDV intraoperative assessment of ossicular chain reconstruction. METHODS: Ten patients who underwent "second look" tympanoplasty were involved in the study. The measurements of the acoustic conductivity of the middle ear were performed using the LDV system. Tone bursts with carrier frequencies of 500, 1,000, 2,000, and 4,000 Hz set in motion the ossicular chain. The study was divided into four experiments that examined the intra- and interindividual reproducibility, the utility of the posterior tympanotomy, the impact of changes in the laser beam angle, and the influence of reflective tape presence on measurements. RESULTS: There were no statistically significant differences between the two measurements performed in the same patient. However, interindividual differences were significant. In all cases, posterior tympanotomy proved to be useful for LDV measurements of the ossicular prosthesis vibrations. In most cases, changing the laser beam angle decreased signal amplitude about 1.5% (not significant change). The reflective tape was necessary to achieve adequate reflection of the laser beam. CONCLUSION: LDV showed to be a valuable noncontact intraoperative tool for measurements of the middle ear conductive system mobility with a very good intraindividual repeatability. Neither a small change in the angle of the laser beam nor performing the measurements through posterior tympanotomy showed a significant influence on the results. Reflective tape was necessary to obtain good quality responses in LDV measurements.
Acoustics ; Ear, Middle ; Hearing Loss, Conductive ; Humans ; Ossicular Prosthesis ; Otitis Media ; Tympanoplasty ; Vibration

Cortical deafness is a clinical rarity whereby a patient is unresponsive to all types of sounds despite the preserved integrity of the peripheral hearing organs. In this study, we present a patient who suddenly lost his hearing following ischaemic infarcts in both temporal lobes with no other neurological deficits. The CT confirmed damage to the primary auditory cortex (Heschl’s gyrus) of both hemispheres. Initially, the patient was unresponsive to all sounds, however, he regained some of the auditory abilities during 10 months follow up. Pure tone threshold improvement from complete deafness to the level of moderate hearing loss in the right ear and severe in the left was observed in pure tone audiometry. Otoacoustic emissions, auditory brainstem responses, and acoustic reflex findings showed normal results. The middle and late latency potential results confirmed objectively the improvement of the patient’s hearing, however, after 10 months still, they were somewhat compromised on both sides. In speech audiometry, there was no comprehension of spoken words neither at 3 nor at 10 months. The absent mismatch negativity confirmed above mentioned comprehension deficit. The extensive auditory electrophysiological testing presented in this study contributes to the understanding of the neural and functional changes in cortical deafness. It presents the evolution of changes after ischaemic cerebrovascular event expressed as auditory evoked potentials starting from short through middle and long latency and ending with event-related potentials and supported by neuroimaging.