Use of amplitude-modulated focused ultrasound for diagnosis of hearing disorders

Focused ultrasound with a frequency of 2.5 MHz and amplitude-modulated in the range of audiometric frequencies (125–8000 Hz) was employed to examine 50 normal hearing persons and in complex diagnostics of over 500 patients suffering from sensorineural deafness, otosclerosis, chronic otitis media, and acoustic neurinoma. Typical diagnostic signs of these diseases were revealed. Modulated ultrasound is shown to offer an improved diagnosis of hearing diseases. The results confirm the previous observation that amplitude-modulated ultrasound may excite not only the acoustic receptors but also the acoustic nerve fibres. Possible mechanisms of the stimulating effect of focused modulated ultrasound are discussed.