Effectiveness of repetitive Transcranial Magnetic Stimulation (rTMS) treatment in patients with chronic tinnitus.

Tinnitus is a phantom auditory perception of meaningless sound, which implies
that there is registration of sound in the absence of an external or internal
acoustic stimulus. It is a common problem (prevalence (7-19%) which may
interfere with the ability to lead a normal life. Unfortunately, it is a very
difficult symptom to treat because therapeutic options for the treatment of the
cause of the tinnitus hardly exist. Tinnitus is thought to be generated in the
brain, as a result of functional reorganization of auditory neural pathways and
tonotopic maps in the central auditory system, following damage to the
peripheral auditory system. Repetitive Transcranial Magnetic Stimulation (rTMS)
is a therapy, based on this concept of reorganization in the auditory cortex.
It uses a pulsed magnetic field to disrupt the neural circuit and to thereby
(temporarily) excite or inhibit certain brain areas, leading to the suppression
of tinnitus. Studies until now have showed promising results but none of these
results can be considered reliable as all of the studies show major flaws in
their design, explanation of used methods and depiction of the results. With
this study we intend to answer the question whether rTMS can be an effective
treatment for tinnitus.

To study the effectiveness of low-frequency rTMS in patients with chronic
tinnitus.

Double-blind, randomized, placebo-controlled intervention study.

In the intervention group neuronavigated rTMS will be applied bilaterally to
the auditory cortices, which will be identified through a structural MRI scan.
Stimulation will be performed with 1Hz frequency on an intensity of 110% motor
threshold for 2000 stimuli (32 minutes) on each side, on five subsequent days.
In the placebo group sham stimulation will follow the same placement protocol
and will also last 2x32 minutes on five subsequent days.

For this study, patients will visit the UMC Utrecht five times for the rTMS
treatment and three times for follow-up testing. Throughout the entire study,
patients will repeatedly fill in Visual Analog Scales and questionnaires to
monitor the changes in perception of tinnitus. rTMS is a safe, non-invasive
technique that has few side effects. The main concern is the potential to
induce a seizure, but this is a very rare complication which has only been seen
with high-frequency stimulation in patients with prior central nervous system
disorders. We do not expect to encounter significant problems as we will use
low frequency stimulation. Another potential adverse effect is the occurrence
of persistent muscle tension-type headache, which usually responds well to
analgesics. As we plan to stimulate relatively close to the face patients may
experience somewhat uncomfortable facial muscle twitches.