ABSTRACT
Background and Objectives@#The integration of auditory-visual speech information improves speech perception; however, if the auditory system input is disrupted due to hearing loss, auditory and visual inputs cannot be fully integrated. Additionally, temporal coincidence of auditory and visual input is a significantly important factor in integrating the input of these two senses. Time delayed acoustic pathway caused by the signal passing through digital signal processing. Therefore, this study aimed to investigate the effects of hearing loss and hearing aid digital delay circuit on sound-induced flash illusion. @*Subjects and Methods@#A total of 13 adults with normal hearing, 13 with mild to moderate hearing loss, and 13 with moderate to severe hearing loss were enrolled in this study. Subsequently, the sound-induced flash illusion test was conducted, and the results were analyzed. @*Results@#The results showed that hearing aid digital delay and hearing loss had no detrimental effect on sound-induced flash illusion. @*Conclusions@#Transmission velocity and neural transduction rate of the auditory inputs decreased in patients with hearing loss. Hence, the integrating auditory and visual sensory cannot be combined completely. Although the transmission rate of the auditory sense input was approximately normal when the hearing aid was prescribed. Thus, it can be concluded that the processing delay in the hearing aid circuit is insufficient to disrupt the integration of auditory and visual information.
ABSTRACT
Background and Objectives@#The blockage of adenosine receptors by caffeine changes the levels of neurotransmitters. These receptors are present in all parts of the body, including the auditory and vestibular systems. This study aimed to evaluate the effect of caffeine on evoked potentials using auditory brainstem responses (ABRs) and cervical vestibular-evoked myogenic potentials (cVEMPs) in a double-blind placebo-controlled study. @*Subjects and Methods@#Forty individuals (20 females and 20 males; aged 18-25 years) were randomly assigned to two groups: the test group (consuming 3 mg/kg pure caffeine powder with little sugar and dry milk in 100 mL of water), and the placebo group (consuming only sugar and dry milk in 100 mL water as placebo). The cVEMPs and ABRs were recorded before and after caffeine or placebo intake. @*Results@#A significant difference was observed in the absolute latencies of I and III (p0.050). @*Conclusions@#It seems that the extent of caffeine’s effects varies for differently evoked potentials. Latency reduction in ABRs indicates that caffeine improves transmission in the central brain auditory pathways. However, different effects of caffeine on auditory- and vestibular-evoked potentials could be attributed to the differences in sensitivities of the ABR and cVEMP tests.
ABSTRACT
To determine SOAE,TEOAE, and DPOAE, characteristics in normal -hearing school boys. This cross-sectional study was conducted on 7-11 year-old normal -hearing boys [n 100] living in 12th zone of Tehran. OAEs also performed and investigated if otoscopy, pure tone and immittance audiometry were normal. Both handedness and ear effects was also considered. 31% had SOAEs. No significant differrence between the right and lefe ear SOAEs frequency and amplitude means. 1,3 kHz and total response TEOAEs amplitude was significantly different between two ears. There was no significant difference between both ear DPOAEs amplitudes, whereas the letf-handed boys' DPOAE amplitude is greater than the right - handed ones' amplitudes. As some results including equal SOAEs of both ears , no difference between both ears SPOAEs amplitude , and handedness effect on the amplitude do not agree with other studies , these finding should be considered in testing OAEs of school boys