The insula cortex (Brodmann's 13-16) has distinct auditory and multisensory areas that have been identified through imaging to be active or hypoactive in cases of severe tinnitus. As such, the insula is a candidate for inclusion in the final common pathway (FCP) for tinnitus. The insula has connection with the prefrontal and auditory cortices, amygdala, thalamus, parabrachial nucleus, orbitofrontal cortex, striate, cuneus, and cerebellum.
View Article and Find Full Text PDFThe final common pathway in severe tinnitus is modified to include the parabrachial nucleus, which has been identified by c-fos immunocytochemistry as an active, non-auditory site. The parabrachial nucleus acts in conjunction with the amygdala and insula (part of the medial temporal lobe system) to produce a somatic emotional sense that can result in a "bad" feeling. The activation of the final common pathway is rapid, suggesting that early treatment is prudent to prevent neuroplastic changes that would likely lessen affect.
View Article and Find Full Text PDFWe assessed ultrasonic transmission in a dry skull; in a dry skull with water, simulating the living condition; in a cadaver head; and in six human subjects, one of whom exhibited no measurable hearing. By using these preparations, we concluded that fluid conduction is essential in the propagation of sound across the head, whereas the bone pathway is far less effective in that regard. Thus, there is little ear isolation beyond 10 dB even up to 80 kHz, extending the masking dilemma in cases of unilateral hearing loss.
View Article and Find Full Text PDFA masking dilemma occurs when energy from a non-test ear crosses over the head to a test ear. In cases of bilateral atresia, obtaining thresholds on the poorer ear is problematic. Near threshold, however, sufficient ear-bone isolation exists to test with validity but not so much above threshold, even for the ultra-high (> 10 kHz) frequencies.
View Article and Find Full Text PDFWe proposed a method for patient selection and application of criteria for predicting success with bone-conduction external acoustic stimulation using high-audio-frequency sound in the ranges of 10-20 kHz and 20-26 kHz for individuals with subjective idiopathic tinnitus (SIT) of the severe disabling type. Ultra-high-frequency (UHF) stimulation for tinnitus relief has been found to be most effective when residual neuronal function exists in the acoustic ranges of 10-14 kHz, with thresholds no greater than 40-50 dB sound pressure level (SPL). Ultrasonic (US) acoustic stimulation is recommended for patients with audiometric thresholds greater than 50-60 dB SPL for frequencies of 10-14 kHz.
View Article and Find Full Text PDFThis study reports on the long-term benefit of ultra-high-frequency masking with the UltraQuiet device. A commercial product, UltraQuiet provides a new form of high-frequency bone conduction therapy. To assess its effectiveness in tinnitus treatment, we selected 15 patients with problematic tinnitus and randomly assigned them to three variations of the medical-audiological tinnitus patient protocol modified for the UltraQuiet study.
View Article and Find Full Text PDFUltra-high-frequency (UHF) external acoustic stimulation with the UltraQuiet device (UQ) has been reported to provide significant relief of severe disabling-type tinnitus. The nuclear medicine imaging technique of positron emission tomography (PET) was selected as a monitoring system to compare objectively metabolic alterations in brain function before and after UHF/UQ and to correlate the PET data with the subjective behavioral response of patients reporting tinnitus relief. PET of brain was completed on 6 patients randomly selected from a cohort of 15 patients included in a protocol to establish long-term tinnitus relief with UHF/UQ.
View Article and Find Full Text PDFAlthough tinnitus is defined as an internal auditory sensation, external auditory stimuli can mask tinnitus under some circumstances. High-frequency vibration delivered as bone conduction stimulation is effective in masking high-pitched tinnitus. In this preliminary report, somatosensory stimulation in the form of low-frequency muscle vibration can also mask high-frequency tinnitus.
View Article and Find Full Text PDFThis reports recommends the consideration of development of additional outcome measures to be used as a battery of subjective self-assessment questionnaires for patients with tinnitus. The goal is improved overall care for the tinnitus patient. Five existing outcome measurements have been incorporated into this profile, which is called the tinnitus outcome profile: the tinnitus intensity index, the tinnitus annoyance index, the tinnitus stress test, the tinnitus handicap inventory, and the measurement of depression scale.
View Article and Find Full Text PDFOur goal was to attempt to establish neuropharmacological tinnitus control (i.e., relief) with medication directed to restoration of a deficiency in the gamma-aminobutyric acid-benzodiazepine-chloride receptor in tinnitus patients with a diagnosis of a predominantly central type tinnitus.
View Article and Find Full Text PDFFor assessment of safety, it is necessary to measure the maximum possible force exerted by a bone conduction device coupled to the human head. Calibration of bone conduction hearing aids and vibrators in the audiometric range is based on measurement of acceleration and force using an artificial mastoid. Extending the measurement to the high audio range was accomplished using a live head.
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