Earlens ∗ Tympanic Contact Transducer: A New Method of Sound Transduction to the Human Ear

Abstract

This article is an initial report on a new method of transducing sound to the human ear. The report describes the shortcomings of conventional acoustic amplification devices, the potential advantages afforded by the Earlens system (ReSound Corp., Redwood City, Calif), a description of the system, and preliminary clinical results. The system is composed of two elements: a transducer that is composed of a magnet mounted on a thin, conical silicone platform and a device that generates a magnetic field which causes the Earlens to vibrate. The Earlens transducer is placed on the umbo area of the tympanic membrane and maintains its position there by floating on a droplet of mineral oil. Two configurations of the magnetic field device are described: one that is placed within the external auditory canal and another that is worn around the neck. This feasibility study was done in seven patients during a 3-month period. All patients in the study maintained the position of the transducer for the duration of the study, and the tympanic membranes showed no evidence of inflammation or other problems. The presence of the transducer caused an average 5-dB threshold depression in the speech frequencies. In the neck-worn device, maximum mean functional gain was 25 dB at 2000 Hz. Variability in the functional gain at different frequencies was noted with poorer gain above 2000 Hz.