Direct Electrical Stimulation of Heschl's Gyrus for Tinnitus Treatment

Abstract

The purpose of the study was to determine the effect of electrical stimulation of the auditory cortex in patients with tinnitus. Nonrandomized clinical trial. Two patients with debilitating tinnitus refractory to conventional therapies were treated. Patients were evaluated with validated questionnaires and psychoacoustic measures to determine the frequency and pitch of their tinnitus. Tones at these frequencies were then presented to the first patient (RP) under magnetoencephalography (MEG) and functional magnetic resonance imaging (fMRI) to determine the tonotopic map for these frequencies in Heschl's gyrus. These tonotopic sites were targeted for implant with a quadripolar electrode. In the second patient (MV), only the fMRI tonotopic map was performed. These fMRI results detected an area of increased activity, which was selected as the site for the implanted bipolar electrode. Patient RP (bilateral tinnitus for 2 years) has experienced a sustained reduction to near elimination of tinnitus with intracerebral implanted electrodes, whereas patient MV (unilateral tinnitus for 7 years) had an unsustained reduction in her tinnitus. These findings suggest that the perception and annoyance of tinnitus may be modulated or reduced through electrical stimulation of the auditory cortex. These unsustained effects for patient MV may have been influenced by the longstanding nature of her tinnitus or by another reason as yet undetermined.