Background and Aim: Laryngeal muscles contribute in sound production play a key role in specific language. Needle electromyography is the specific complementary method for muscle activity evaluation which is awfully painful and needs serenity of patient. The purpose of this study was to use Surface electromyography as a probable new approach for evaluation of laryngeal muscles activity.
Methods: 34 healthy women and 34 healthy men aged 20-30 years old were enrolled in this study. Each individual was seated in an armchair. Recording electrodes were placed bilaterally (right and left) in the low anterior neck at approximately one centimeter from midline on thyroarytenoid and cricothyroid muscles. Silent activity and fricative voice (/z/ , /ž/) and voiceless (/s/ , /š/) activities were recorded for ten seconds followed by 10 seconds of rest, for 5 repetition. All data were processed and frequency and non linear measurements were assessed. And were compared in time and frequency domain.
Results: Muscle activity in fricative voice in both groups was greater than rest condition (p<0.05). Moreover, muscle activity median frequency was significantly more in men than women (p<0.001).
Conclusion: Activity evaluation of thyroarytenoid and cricothyroid muscles using surface electromyography is difficult in women. That may be due to anatomical features such as length and width of neck in women.

Background and Aim: Conventional balance tests such as electronystagmography and videonystagmography, which are vision-dependant, are not practical in blind patients. Instead, vestibular evoked myogenic potential , not needing any vision, seems to be a more appropriate test for evaluating the vestibular system, in these patients. This study aimed to assess the prevalence and the latencies of p13 and n23 waves among congenitally blind and sighted participants evaluated by vestibular evoked myogenic potential.
Methods: In a cross-sectional study, vestibular evoked myogenic potential was recorded for 20 sighted and 20 congenitally blind subjects, aged 18 to 30 years old, using 500 Hz-tone bursts (95 dBnHL).
Results: Vestibular evoked myogenic potentials responses were present in all (100%) of the participants. Considering the results of the both ears, there was no significant difference between mean p13 and n23 latencies of the two groups (p>0.05).
Conclusion: Formation of vestibular evoked myogenic potentials reflex arc and neural pathway in congenitally blind patients is similar to sighted individuals hence, the development of this pathway is independent of the visual system. Vestibular evoked myogenic potentials test is a useful test to assess vestibular function of the blinds.

Background and Aim: Sound conditioning is exposure to a non-traumatic, moderate level of sound which increases inner ear resistance against further severe noise. In this study, we aimed to survey the effect of sound conditioning on auditory brainstem response (ABR) threshold shifts using click stimulus, and the effect of the frequency of conditioning on hearing protection.
Methods: Fifteen guinea pigs were randomly divided into 3 groups. Two conditioned groups were exposed to 1 kHz, and 4 kHz octave band noise at 85 dB SPL, 6 hours per day for 5 days, respectively. On the sixth day, the animals were exposed to 4 kHz octave band noise at 105 dB SPL, for 4 hours. The control group was exposed to intense noise, 4 kHz at 105 Db SPL for 4 hours (without conditioning). After exposure, ABR thresholds using click were recorded an hour, and 7 days after noise exposure.
Results: The results of the ABR with click stimulus showed less thresold shifts in conditioned groups than control (p≤0.001). Comparison of the results of conditioned groups, showed less threshold shift by 4 kHz conditioning, however, this difference was not statistically significant (p>0.05).
Conclusion: Electrophysiological data of our study showed that sound conditioning has a protective effect against subsequent intensive noise exposure, and the frequency of conditioning does not have significant effect on ABR threshold shifts when using click stimulus.

Background and Aim: There are four fundamental processes of attention: working memory, top-down sensitivity control, competitive selection, and automatic bottom-up filtering for salient stimuli. Each process makes an essential contribution to attention. Voluntary control operates on the first three processes in a recurrent loop. We reviewed comprehensive researches, theories, mechanisms, and central nervous system functions of auditory attention.

Methods: In this study, publications on auditory attention from 1953 to 2012 in PubMed, Scopus, ProQuest, Iran Medex, and Goole scholar were reviewed. Keywords were auditory attention and related words.

Conclusion: In general, auditory attention plays an important role in auditory processing and modulates this process from cochlea to auditory cortex through its four primary components.

Background and Aim: Diabetes mellitus is a metabolic disorder that affects multiple systems including the auditory and vestibular systems. Patients with diabetes mellitus complain of tinnitus and dizziness. The objective of this study is to assess the effects of diabetes mellitus types I and II on auditory and vestibular systems.

Methods: We compared pure-tone audiometric results and cervical vestibular evoked myogenic potentials ( cVEMPs) between 15 patients with diabetes mellitus type I (43.80 with SD 4.246), 15 patients with diabetes mellitus type II (48.13 with SD 2.973), and 10 normal volunteers (45.30 with SD 4.448). Age range of the participants was 40-50 years old.

Results: Audiometric results showed normal hearing in both types of diabetes mellitus. In contrast, comparing amplitude of cVEMPs between diabetes mellitus and control groups showed statistically significant differences (p<0.05).

Conclusion: In spite of normal audiometric results in patients with diabetes mellitus types I and II, there was abnormal vestibular responses involving vestibular end-organ and related central pathway.