Surgical treatment by electrical stimulation of the auditory cortex for intractable tinnitus

Abstract

Tinnitus is a public health issue in France. Around 1% of the population is affected and 30,000 people are handicapped in their daily life. The treatments available for disabling tinnitus have until now been disappointing. We are reporting on the surgical treatment by electrical stimulation of the auditory cortex of a female patient affected by disabling tinnitus that resisted classical treatments. The tinnitus appeared suddenly 10 years ago after a left ear tympanoplasty. The acouphenometry measures revealed a bilateral tinnitus, predominant on the right side, constant, with high frequency (6000 Hz). Transcranial magnetic stimulation (TMS) was performed at first with several supraliminal and infraliminal protocols. This showed promising results. Anatomic and functional magnetic resonance imaging (fMRI) of the auditory cortex before and after repetitive TMS (rTMS) demonstrated a modification of the cortical activity and where the ideal location for a cortical electrode might be, to straddle primary and secondary auditory cortex. After these investigations, two quadra polar electrodes (Resume, Medtronic Ltd, Hertfordshire, UK), connected to a stimulating device implanted under the skin (Synergy, Medtronic Ltd), were extradurally implanted. The surgical procedure was similar to the one performed for analgesic cortical stimulation. No surgical complications were reported. The activation of the stimulator provided a reduction of 65% of the tinnitus impact, with a persistent effect on the right side. The feasibility of the cortical stimulation in symptomatic treatment of tinnitus was proven by this preparatory work. The middle-and long-term therapeutic effects remain to be evaluated. Ó 2009 Elsevier Inc. All rights reserved.Keywords tinnitus; auditive cortex; electric stimulation; transcranial magnetic stimulation Tinnitus is a public health issue in France, with around 1% of the population affected and 30,000 people handicapped in their daily life.Available treatments have been disappointing for disabling tinnitus. The treatment is delicate because of the psychological and behavioral repercussions of tinnitus, which leads many physicians to wonder about the organic origin of tinnitus. However, several neuroscience case studies have demonstrated the credibility of this symptom as a peculiar entity. In particular, the relationship between tinnitus and cerebral metabolic activity. 1

Neuroimaging and Neuromodulation: Complementary Approaches for Identifying the Neuronal Correlates of Tinnitus

“…This approach has been replicated by other centers. A French study obtained long-lasting 65% tinnitus reduction in a woman using a fMRI based extradural auditory cortex implant (Litre et al, 2009, 2010). Another study of eight patients using a similar technique but different hardware found no permanent tinnitus suppression (Friedland et al, 2007).…”

Protocole de prise en charge neurochirurgicale des acouphènes invalidants : à propos de trois cas

“…Pour notre part, nous nous sommes basés sur des travaux réalisés sur la rTMS du cortex auditif secondaire de schizophrènes présen-tant des hallucinations auditives (Hoffman et al, 2003). Positionner l'électrode plus en arrière semble permettre une double action sur la réduction de l'acouphène : direct par le cortex auditif, et indirect sur le ressenti par les aires associatives hétéromodales (Litre et al, 2009). Enfin, il paraît admis actuellement que le positionnement de l'électrode doit être controlatéral à l'acouphène (Eichhammer et al, 2003).…”

“…Au deuxième jour postopératoire, nous avons mis en route le stimulateur, en adoptant des paramètres de stimulation proposés dans la littérature existante (Nguyen et al, 2000 ;Nguyen et al, 1999 ;De Ridder et al, 2006 ;Litre et al, 2009).…”

State of the Art: Novel Applications for Cortical Stimulation

“…Tinnitus is a prevalent symptom, with clinical, pathophysiological, and treatment features analogous to pain. Invasive auditory cortex stimulation (iACS) via implanted electrodes onto or into the primary auditory cortex (inside the posterior part of the Sylvian valley) or overlying the secondary auditory cortex (posterior part of the superior temporal gyrus) have been developed to treat severe cases of intractable tinnitus (16)(17)(18)(19)(20)(21)(22)(23)(24)(25)50).…”

“…The same holds for tinnitus. Whereas in most studies the electrodes are implanted extradurally or intradurally overlying the primary or secondary auditory cortex respectively (16)(17)(18)(19)(20)(21)(22)(23)(24), some patients have been treated with wire electrodes implanted inside the auditory cortex (25). We will consider any form of cortical stimulation, whether intracortical or onto the cortex, as cortical stimulation, and deep brain stimulation as specifically targeting deep nuclei, rather than cortical structures.…”