DESIGN AND STRUCTURE OF A NEW DEVICE FOR AUDITORY ELECTRICAL STIMULATION FOR SUPPRESSION OF TINNITUS

Auditory Electrical Stimulation for Tinnitus Suppression Tinnitus is the conscious experience of sound which arises in the head of its owner, but without a voluntary origin obvious to that person. About 10-15% of all adults report prolonged spontaneous tinnitus (PST). There are a lot of methods for suppressing this complaint. One of these methods is electrical stimulation. Electrical stimulation for tinnitus suppression was investigated by many authors that reported its effectiveness from 22% by Grahams and Hazell (1989) to 87% by Portman (1979). The purpose of the present project was to design and structure a new Auditory Electrical Stimulation device for tinnitus relief in patients who suffer from tinnitus. Our other goal was to execute a pilot project by modelling of our new device on animals. In this project an instrument for applying Auditory Electrical Stimulation (AES) is designed. This device consists of two generators: one is a carrier square wave generator (30 KHz to 100 KHz), the second is another low frequency square signal (1 Hz through 20 KHz) that has an adjustable duty cycle. The entire user interface is on PC, and there are a lot of options that the user can adjust. The PC is connected to a circuit by a serial port and the serial port is isolated from the other pat1s of the circuit. Modulation can optionally be enabled or disabled. The amplitude of current flow can vary from 1 microamp to 1000 microamp (lmilli- Amp) with 1 microamp resolution. The impulse duration can be adjusted (this is a third pulse generator) by the user from 500 microsec delivered at 1/sec to 2000/sec. The combined electrical signal has the maximum peak to peak amplitude of 10 V, which varies to make a constant current through electrodes. A warning device indicates insufficient skin electrode contact. In addition the impedance between electrodes can be monitored on PC. There are several parts that increase the safety of this system. The dimension of the PC board is 11 cm x 14cm. By now the first version which could be used in hospital and/or clinics is made and could be used by patients who suffer from tinnitus. We believe that tinnitus reduction occurred or even disappeared during and after the treatment period by AES. Our results applying Auditory Electrical Stimulation (AES) were effective in our many patients who had clinically been identified as having peripheral or central lesion tinnitus sites. We made a new auditory electrical stimulation device for tinnitus relief in patients suffering from tinnitus that can do electrical stimulations. Also, in an experimental study design on rabbits, we had tested this new device, and evaluated the efficiency to deliver electrical currents and other capabilities in tinnitus suppression. Although study comparisons are confounded by differences in success criteria, subject sampling, methodology and acute tinnitus suppression have been reported in up to 62.5% of subjects (Mahmoud ian et aI., 2001), AES reduces the effects of tinnitus several factors could be involved in this reduction, i.e. synchronizing discharge of auditory nerve fibers, inhibition of the abnormal activity of the cochlear nerve, the revival neural coding and positive neural plasticity.