Using PET-CT to Target and Validate Low-frequency TMS as Treatment for Tinnitus

One out of every five people experience tinnitus (a buzzing, ringing, or roaring sound in the ear) ranging from mild to severe impairment. To date there is no effective therapy that seems to help the tinnitus sufferer. The purpose of this study is to develop a therapy using a technique called Repetitive Transcranial Magnetic Stimulation (rTMS) to hopefully alleviate or reduce the symptoms of tinnitus. This research is being conducted at the University of Arkansas for Medical Sciences (UAMS). Up to twenty (20) right handed subjects, either males or females, 19-65 years of age, with tinnitus that is severe enough for those persons to seek medical attention will have been seen as patients in the UAMS Hearing and Balance Center, where routine testing includes a physical exam, hearing tests, evaluation of middle ear status, and an MRI scan (a machine that acquires visual images of the brain). A diagnosis of tinnitus will be established after ruling out all other possible causes of the tinnitus.

Subjects will be up to 20 right-handed patients (men and women), 19-65 years of age, with debilitating unilateral or bilateral tinnitus. All subjects must report experiencing the presence of their phantom auditory perception for at least 6 months and have a Tinnitus Handicap Questionnaire (THQ) score >30. Subjects will be recruited from the Otolaryngology Clinic at UAMS, where routine testing includes a physical exam; pure tone audiometry; and evaluation of middle ear status using tympanometry, stapedius reflex tests, and otoscopy. Patients will undergo a gadolinium-contrast MRI of the head to rule out acoustic neuroma or any other central nervous system pathology. All subjects will be thoroughly informed of the risks associated with the procedures in this study, as described in the Hazards to Subjects section, and written informed consent will be obtained. Subjects will be recruited for this study without regard to race or ethnicity.

TMS will initially be targeted to asymmetric cortical activation in one hemisphere, as defined by PET-CT imaging. TMS will then be optimized by identifying the area of maximal tinnitus suppression, within the area of asymmetry, by delivering single 1-Hz pulses of TMS at the MT. The area of maximal tinnitus suppression, as reported by the patient, will then be targeted for treatment with rTMS at 1-Hz frequency, delivering 1800 pulses at 110% MT on each of 5 consecutive treatment days.If no area of maximal tinnitus suppression can be found in the hemisphere initially targeted for treatment based on PET, we will perform the optimization procedure in a homologous region of the opposite cerebral hemisphere to determine if a maximal area of suppression can be found there. Each group will then crossover to sham and active stimulation conditions, respectively, 7 days following the completion of the first treatment session.

Change in calculated PET asymmetry index between left and right temporal lobe from baseline following active Tx

Inclusion Criteria: right-handed subjects 19-65 years of age debilitating unilaterial or bilateral tinnitus Experiencing the presence of phantom auditory preception for >6 months Tinnitus Handicap Questionnaire score of >30 Exclusion Criteria: significant neurological disease acoustic neuromas or glomus tumors active Meniere's disease profound hearing loss non English speaking personal or family history of epilepsy personal history of head injury, aneurysm, stroke, previous cranial neurosurgery, neurological or psychiatric disorders, metal implants in the head or neck, a pacemaker, pregnancy, migraines, medications that lower seizure threshold and are contraindicated individuals who have been taking certain medications claustrophobia patients who do not exhibit significant cortical asymmetries on PET

Smith JA, Mennemeier M, Bartel T, Chelette KC, Kimbrell T, Triggs W, Dornhoffer JL. Repetitive transcranial magnetic stimulation for tinnitus: a pilot study. Laryngoscope. 2007 Mar;117(3):529-34. doi: 10.1097/MLG.0b013e31802f4154.

Richter GT, Mennemeier M, Bartel T, Chelette KC, Kimbrell T, Triggs W, Dornhoffer JL. Repetitive transcranial magnetic stimulation for tinnitus: a case study. Laryngoscope. 2006 Oct;116(10):1867-72. doi: 10.1097/01.mlg.0000234936.82619.69.