Hearing and Biomechanics
Laser vibrometry can assist with eardrum diagnostics and research on the middle and inner ear. In addition, vibrometers have been used for vibration measurements on artificial heart valves, studying the mechanical properties of tendons, analysis of vibrations during bone drilling or medical laser ablation, and detection of bone crack propagation. Vibrometer can also function as a non-contact polygraph by measuring muscle vibrations, or as a remote voice detector as part of a surveillance system.
Ear Mechanics and Otology
The human ear is one of the most sophisticated sound and vibration amplification systems. State-of-the-art laser doppler vibrometers reveal the vibrational characteristics of hearing mechanics. They provide ease of use and unsurpassed accuracy and resolution, revealing new dimensions in our understanding of hearing mechanics. Laser vibrometry is indispensable to those actively involved in the design, development, quality control, calibration and certification of middle ear implants.
The vibrational response of the tympanic membrane gives direct insight into the important causes of hearing loss, like stapes fixation or sclerotic changes in the ossicular chain. Laser doppler vibrometry allows for quick measurement of the frequency response providing excellent data to the audiologist.
Basic Mechanism of Hearing
Intensive medical, molecular and biomechanical research activities have provided much insight into the function of signal processing inside the ear. However, we are still far from a comprehensive understanding of hearing mechanisms. Current research deals with the details of electromechanical signal transduction occurring in the cochlea of the inner ear. For investigation of inner ear biomechanics, laser-doppler vibrometers have proven to be highly sensitive sensors that don’t affect the specimen.
Biomechanics of Bones
Recently, finite element (FE) methods have been used in biomechanics to investigate and model components for medical applications. For example, to assist with bone surgery, various approaches to generating realistic bone models from computer tomography data are being evaluated. A Polytec 3-D Scanning Vibrometer was used to determine for the first time the modal parameters of a pelvic bone and provided spatial vibration modes with an accuracy and resolution that was not possible before.
“Regarding our fundamental research on biophysical processes in the cochlea, there is no other measurement technology providing appropriate sensitivity and a resolution below 1 pm” Prof. Anthony W. Gummer