[Magnetic stimulation of the auditory cortex for disabling tinnitus: preliminary results].

OBJECTIVE: Tinnitus - the perception of sound in one or both ears or in the head when no external sound is present - can be disabling and is especially difficult to treat. Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive technique for activating or inactivating specific areas of the cortex. The aim of this study was to assess the feasibility of magnetic neurostimulation of the primary and secondary auditory cortex in the treatment of disabling chronic tinnitus. PATIENTS AND METHODS: Thirteen patients with tinnitus refractory to several conventional treatments underwent transcranial magnetic stimulation guided by functional magnetic resonance imaging (fMRI). We compared two types of stimulation of targets in the auditory cortex, identified by fMRI: 3-second pulses at high frequency (10 Hz) and 20-minute stimulations at a lower frequency (1 Hz).
RESULTS: Brief high-frequency pulses of cortical magnetic stimulation (10 Hz) were not effective. On the other hand, prolonged low frequency (1 Hz) stimulation was effective in 62.5% of patients; the effect appeared 48 h after treatment and lasted for approximately 5 days. DISCUSSION: RTMS may be a new noninvasive technique for studying the cortical plasticity associated with the pathophysiologic mechanisms of chronic tinnitus and may lead to new treatment strategies for patients with disabling tinnitus resistant to all treatment.