Otolaryngology

Dynamic characteristics of the horizontal vestibulo-ocular reflex (HVOR), the optokinetic response (OKR), and their interactions were investigated in alert albino rabbits. For stimulation of the horizontal semicircular canals, the whole rabbit was rotated sinusoidally on a motor-driven turntable at peak-to-peak amplitudes of 5 ~ to 30 ~ over a frequency range of 1/30 to 3/2 Hz. Optokinetic stimulation was provided by a narrow vertical slit light source presented in front of the eye to be tested. The evoked horizontal eye movements were observed and measured by means of a closed circuit television system adapted to provide an analog signal proportional to the eye movement. The net HVOR was obtained by rotation of the turntable in darkness and the net OKR by rotation of the light source. Combining rotation of the turntable with a stationary light source immediately increased the gain and reduced the phase shift of the HVOR. The light source moving in phase with the turntable, but at twice the angular amplitude, reduced the gain and advanced the phase of the HVOR. Eye movement curves of the HVOR modified by a fixed or moving slit light could be reconstructed approximately by a linear combination of the net HVOR and OKR.

Validity of the neurophysiological model of tinnitus (Jastreboff, 1990), outlined in this paper, was tested on data from multicenter trial of tinnitus masking (Hazell et aI., 1985). Minimal masking level, intensity match of tinnitus, and the threshold of hearing have been evaluated on a total of 382 patients before and after 6 months of treatment with maskers, hearing aids, or combination devices. The data has been divided into categories depending on treatment outcome and type of approach used. Results of analysis revealed that: i) the psychoacoustical description of tinnitus does not possess a predictive value for the outcome of the treatment; ii) minimal masking level changed significantly depending on the treatment outcome, decreasing on average by 5.3 dB in patients reporting improvement, and increasing by 4.9 dB in those whose tinnitus remained the same or worsened; iii) 73.9% of patients reporting improvement had their minimal masking level decreased as compared with 50.5% for patients not showing improvement, which is at the level of random change; iv) the type of device used has no significant impact on the treatment outcome and minimal masking level change; v) intensity match and threshold of hearing did not exhibit any significant changes which can be related to treatment outcome. These results are fully consistent with the neurophysiological interpretation of mechanisms involved in the phenomenon of tinnitus and its alleviation.

Tinnitus retraining therapy (TRT) is a method for treating tinnitus and decreased sound tolerance, based on the neurophysiological model of tinnitus. This model postulates involvement of the limbic and autonomic nervous systems in all cases of clinically significant tinnitus and points out the importance of both conscious and subconscious connections, which are governed by principles of conditioned reflexes. The treatments for tinnitus and misophonia are based on the concept of extinction of these reflexes, labeled as habituation. TRT aims at inducing changes in the mechanisms responsible for transferring signal (i.e., tinnitus, or external sound in the case of misophonia) from the auditory system to the limbic and autonomic nervous systems, and through this, remove signal-induced reactions without attempting to directly attenuate the tinnitus source or tinnitus/misophonia-evoked reactions. As such, TRT is effective for any type of tinnitus regardless of its etiology. TRT consists o...

Tinnitus problems affect a significant portion of the population and are difficult to treat. Sound therapy for Tinnitus is a promising, expensive, and complex treatment, where the complete process may span from several months to a couple of years. The goal of this research is to explore different combinations of important factors leading to a significant recovery, and their relationships to different category of Tinnitus problems. Our findings are extracted from the data stored in a clinical database, where confidential information had been stripped off. The domain knowledge spans different disciplines such as otology as well as audiology. Complexities were encountered with temporal data and text data of certain features. New temporal features together with rule generating techniques and clustering methods are presented with a ultimate goal to explore the relationships among the treatment factors and to learn the essence of Tinnitus problems.

Phantom auditory perception - tinnitus - is a symptom of many pathologies. Although there are a number
of theories postulating certain mechanisms of its generation, none have been proven yet. This paper analyses the
phenomenon of tinnitus from the point of view of general neurophysiology. Existing theories and their extrapolation
are presented, together with some new potential mechanisms of tinnitus generation, encompassing the involvement
of calcium an d calcium c hannels in co chlear functio n, with implications for malfunction and aging of the auditory
and vestibular systems.
It is hypothesize d that most tinnitus resu lts from the perc eption of ab normal ac tivity, defined as ac tivity
which cannot be induced by any combination of extern al sounds. Moreover, it is hypothesized that signal recognition
and classification circuits, working on holographic or neuronal network-like representation, are involved in the
perception of tinnitus and ar e subject to plastic modification. Furthermore, it is proposed that all levels of the nervous
system, to varying degrees, are involved in tinnitus manifestation. These concepts are used to unravel the
inexplicable, unique features of tinnitus and its masking. Some clinical implications of these theories are suggested.

Adaptation of the horizontal vestibulo-ocular reflex (HVOR) that occurs under sustained mismatching of vestibular and visual stimuli 4,s,10,12 provides a good material for investigating modifiability of the CNS. Two lines of evidence have lead to the hypothesis that the cerebellar flocculus is the site of the modifiability that underlies this adaptation: (1) the flocculus, having an elaborate computer-like layout as in other areas of the cerebellar cortex, receives both vestibular and visual inputs, and in turn projects to relay cells of the HVOR with axons of Purkinje cells 5; (2) chronic ablation of the flocculus impairs the modifiability of the HVOR s,l~. In the further effort to substantiate the hypothesis, it is important to establish any change in neuronal activities of the flocculus correlated with adaptation of the HVOR. The present article reports that the responsiveness of flocculus Purkinje cells to vestibular stimuli indeed exhibits such a change.

Protection from the deleterious effects of the interaction of environmental stress and salicylate by calcium supplement was investigated in 96 pigmented rats. Within a 2 x 2 x 4 factorial design, rats were assigned to groups defined by: A) ad lib access to 1) plain tap water, or 2) 50 mM calcium chloride solution; B) exposure to stressors consisting of daily 10 h periods of 1) 98 dB SPL noise, or 2) confinement precluding movements; C) daily injections of 233, 350, or 410 mg/kg of sodium salicylate or the saline vehicle. For subjects maintained on tap water, weight loss and mortality increased with salicylate levels, with all subjects dying in the group drinking water and injected with 410 mg/kg. Calcium protected all of the subjects in the noise stress group but not in the confined group.

Tinnitus Retraining Therapy (TRT) is a structured method of tinnitus treatment that has been performed since 1990. The TRT Initial Interview form was developed to guide clinicians in obtaining essential information from patients that would specify treatment needs. The TRT Follow-up Interview form is similar to the initial interview form and is designed to evaluate outcomes of treatment. The clinician administers these forms verbally. The forms have been used in a highly abbreviated format with the potential for inconsistent interview administration between examiners. This project was to expand the forms to provide specific wording for each question. The expanded forms are presented in this article, and the intent of each question is explained. Standardized administration of these interview forms will facilitate greater uniformity in the initial evaluation and outcomes analyses of patients treated with TRT.

We used quantitative electron microscopy to determine the effect of precocious visual experience on the time course, magnitude, and pattern of perinatal synaptic overproduction in the primary visual cortex of the rhesus monkey. Fetuses were delivered by caesarean section 3 weeks before term, exposed to normal light intensity and day/night cycles, and killed within the first postnatal month, together with age-matched controls that were delivered at term. We found that premature visual stimulation does not affect the rate of synaptic accretion and overproduction. Both of these processes proceed in relation to the time of conception rather than to the time of delivery. In contrast, the size, type, and laminar distribution of synapses were significantly different between preterm and control infants. The changes and differences in these parameters correlate with the duration of visual stimulation and become less pronounced with age. If visual experience in infancy influences the maturation of the visual cortex, it must do so predominantly by strengthening, modifying, and/or eliminating synapses that have already been formed, rather than by regulating the rate of synapse production.

The main objective of Tinnitus Retraining Therapy (TRT) is habituation of activation of the autonomic nervous system, evoked by signals present in the auditory pathways. Sound therapy aims at decreasing the strength of these signals. The same systems in the brain are involved in tinnitus and decreased sound tolerance, and the same basic neurophysiological mechanisms are utilised for decreasing the tinnitusrelated neuronal activity and, in case of hyperacusis, abnormally enhanced activity induced by external sounds. The similarity of TRT treatment between tinnitus and misophonia is even closer, as in both situations the goal is to achieve extinction of functional connections between the auditory and the limbic and autonomic nervous systems. The increased gain within the auditory pathways that are presumably responsible for hyperacusis could enhance the tinnitus signal, thus it is possible to expect coexistence of tinnitus and hyperacusis, and the predisposition of hyperacusis patients to develop tinnitus. As such, for some patients tinnitus and hyperacusis may be considered the double manifestation of the same internal phenomenon.

Clinical management for patients complaining of severe tinnitus has improved dramatically in the last 25 years. During that period of time, various methods of treatment have been introduced and are being used with varying degrees of success. One method that has received considerable attention is tinnitus retraining therapy (TRT). This method is being practiced by hundreds of clinicians worldwide, and retrospective clinical data indicate that TRT has been effective for the majority of patients. This article provides a guide for clinicians to evaluate their patients for treatment with TRT. Included in this guide is the expanded version of the TRT initial interview and specific instructions for the clinician administering the interview.

Medical records contain feature values on specific dates, which brings a very unstable sampling rate. Therefore, popular temporal features, which have been successfully applied to sound data, failed to fully describe the vital behaviors of features and factors of patient and treatment. The authors developed a flexible temporal feature retrieval system based on grouping of similar visiting patterns with connection to an actionrules engine and observed interesting and useful results about how the changes of treatment factors affect the changes of recovery.

In two behavioral experiments, normal hearing or salicylate-induced phantom auditory perception were investigated in young pigmented rats. Twenty-four hours prior to training in Experiment 1,45 preweanling pups (14-21 days of age) were exposed to continuous background noise. They were injected with sodium salicylate or saline either before or after training to suppress approach responses to a lactating dam during noise offset periods. The sequence of injection initiation affected acquisition and extinction rates, and the oldest subjects behaved similarly to adults reported in studies of salicylate-induced auditory effects. Adapting the task in Experiment 2 for 18 postweanling pups 32 days of age produced greater suppression and prolonged extinction when salicylate was administered prior to both acquisition and extinction sessions, whereas subjects injected with saline before training and salicylate before extinction showed rapid recovery from suppression. The experiments support the notion that the auditory system undergoes functionally important change at around 15-16 days of age.

The aim of this paper is to provide information about the neurophysiologic model of tinnitus and Tinnitus Retraining Therapy (TRT). With this overview of the model and therapy, professionals may discern with this basic foundation of knowledge whether they wish to pursue learning and subsequently implement TRT in their practice. This paper provides an overview only and is insufficient for the implementation of TRT.