Controversy: Does repetitive transcranial magnetic stimulation/ transcranial direct current stimulation show efficacy in treating tinnitus patients?
BACKGROUND
Tinnitus affects 10% of the population, its pathophysiology remains incompletely understood, and treatment is elusive. Functional imaging has demonstrated a relationship between the intensity of tinnitus and the degree of reorganization in the auditory cortex. Experimental studies have further shown that tinnitus is associated with synchronized hyperactivity in the auditory cortex. Therefore, targeted modulation of auditory cortex has been proposed as a new therapeutic approach for chronic tinnitus.


METHODS
Repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) are noninvasive methods that can modulate cortical activity. These techniques have been applied in different ways in patients with chronic tinnitus. Single sessions of high-frequency rTMS over the temporal cortex have been successful in reducing the intensity of tinnitus during the time of stimulation and could be predictive for treatment outcome of chronic epidural stimulation using implanted electrodes.


RESULTS
Another approach that uses rTMS as a treatment for tinnitus is application of low-frequency rTMS in repeated sessions, to induce a lasting change of neuronal activity in the auditory cortex beyond the duration of stimulation. Beneficial effects of this treatment have been consistently demonstrated in several small controlled studies. However, results are characterized by high interindividual variability and only a moderate decrease of the tinnitus. The role of patient-related (for example, hearing loss, tinnitus duration, age) and stimulation-related (for example, stimulation site, stimulation protocols) factors still remains to be elucidated.


CONCLUSIONS
Even in this early stage of investigation, there is a convincing body of evidence that rTMS represents a promising tool for pathophysiological assessment and therapeutic management of tinnitus. Further development of this technique will depend on a more detailed understanding of the neurobiological effects mediating the benefit of TMS on tinnitus perception. Moreover clinical studies with larger sample sizes and longer follow-up periods are needed.
Langguth
Berthold
B
Department of Psychiatry, University of Regensburg, Germany. Berthold.Langguth@medbo.de
de Ridder
Dirk
D
Dornhoffer
John L
JL
Eichhammer
Peter
P
Folmer
Robert L
RL
Frank
Elmar
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Fregni
Felipe
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Gerloff
Christian
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Khedr
Eman
E
Kleinjung
Tobias
T
Landgrebe
Michael
M
Lee
Scott
S
Lefaucheur
Jean-Pascal
JP
Londero
Alain
A
Marcondes
Renata
R
Moller
Aage R
AR
Pascual-Leone
Alvaro
A
Plewnia
Christian
C
Rossi
Simone
S
Sanchez
Tanit
T
Sand
Philipp
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Schlee
Winfried
W
Pysch
Dipl
D
Steffens
Thomas
T
van de Heyning
Paul
P
Hajak
Goeran
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D000328:Adult; D006801:Humans; D011795:Surveys and Questionnaires; D014012:Tinnitus / Q000628:therapy*; D050781:Transcranial Magnetic Stimulation / Q000295:instrumentation / Q000379:methods*; D004561:Transcutaneous Electric Nerve Stimulation / Q000295:instrumentation / Q000379:methods*; D016896:Treatment Outcome