Tinnitus is a symptom that affects a great number of patients. Its diagnosis, treatment, and follow-up are difficult, owing to its subjectivity. The authors propose the use of distortion product otoacoustic emissions (DPOAEs) in tinnitus evaluation. They studied three groups: controls, having no complaint of tinnitus and normal hearing; group 1, presenting tinnitus and normal audiometry; and gr...

INTRODUCTION Tinnitus is an auditory sensation whose source comes from external stimulus to the body. All studies that can help people with this disorder are very imperative. OBJECTIVE This study investigates the cochlear function in patients with tinnitus, using Distortion Products Otoacoustic Emissions (DPOAE). MATERIAL AND METHODS Ears where the subjects referred to feel the tinnitus wer...

Scaling symmetry appears to be a fundamental property of the cochlea as evidenced by invariant distortion product otoacoustic emission (DPOAE) phase above ∼1-1.5 kHz when using frequency-scaled stimuli. Below this frequency demarcation, phase steepens. Cochlear scaling and its breaking have been described in the adult cochlea but have not been studied in newborns. It is not clear whether immatu...

UNLABELLED In experimental endolymphatic hydrops distortion-products otoacoustic emission (dpoae) amplitudes decrease and there is elevation on electrocochleographic thresholds. Some authors found type ii nitric oxide synthase (nos ii) expression in hydropic cochleas and they suggest nitric oxide (no) may be involved in endolymphatic hydrops pathogenesis. The aim of this study was to evaluate t...

HIV infection is associated with impairment of hearing function, at any stage of disease causing complication to the external, middle, inner ear and CNS. Audiological manifestation of HIV is a direct consequence of virus or secondary to the pharmacological treatment or viral complication. Objectives: There is paucity of information pertaining to hearing status in HIV. As the deafness can occur ...

The purpose of this study was to investigate the efferent medial olivocochlear system through the use of otoacoustic emissions and especially the modifications that occur at this level with age. The activity of outer hair cells (OHCs) (peripheral) and of the efferent medial olivocochlear (MOC) system (neural and central) was examined by means of distortion product otoacoustic emissions (DPOAEs)...

Introduction: Tinnitus is a perception of sound without external source. The exact etiology of tinnitus is not fully understood, although some researchers believe that the condition usually starts in the cochlea. The aim of this study was to determine the potential contribution of outer hair cell dysfunction to chronic tinnitus, by application of Distortion-Product Evoked Otoacoustic Emission (...

We investigated the effects of inorganic mercury exposure during gestational/lactational periods on the behaviour, learning and hearing functions in a total of 32, 5-week-old and 5-month-old WAG/Rij rats (equally divided into 4 groups as 5-week and 5-month control mercury exposure groups). We evaluated the rats in terms of locomotor activity (LA), the Morris-water-maze (MWM) test and the passiv...

Distortion product otoacoustic emission (DPOAE) is a widely used differential diagnostic method for diagnosing inner ear disorders. It provides us information on the condition of the outer hearing cells (OHCs). Otoacoustic emission occurs only when the OHCs are functioning normally. Changes in thresholds of DPOAE curves can provide us important information on the activity of the OHCs. The inner...

During auditory stimulation with several frequency components, distortion products (DPs) are generated as byproduct of nonlinear cochlear amplification. After generated, DP energy is reemitted into the ear channel where it can be measured as DP otoacoustic emission (DPOAE), and it also induces an excitatory response at cochlear places related to the DP frequencies. We measured responses of 91 i...