Background and Aim: Hearing loss results in impairment of  muscles coordination and survival essential that are engaged in motor speech timing tasks. It will negatively affect the acquisition of speech sounds. The purpose of this study was to compare the oral diadochokinesis in normal-hearing and hearing - impaired adolescents
Materials and Methods: This research was conducted on sixty-one adolescents aged 15-18 years old. Forty-six had moderately severe, severe, or profound hearing loss and fifteen were normal. The time spent to perform each oral diadochokinesis tasks was measured by speech analyzer of Dr. speech software, version four.
Results: Results indicated that hearing - impaired performed significantly slower on all speech timing tasks than their normal hearing peers except those with moderately severe hearing-impaired group. There were significant differences between profound hearing-impaired group and both other groups.
Conclusion: The results of this study point out  the motor speech problems in hearing impairment. The differences, in general, indicate that speech-timing coordination deficits are compromise with hearing loss degree.

Background and Aim: Preterm birth is one of the risk factors need comprehensive audiological assessment. In this study, the effect of sex and rate of stimulation on response of children with history of preterm birth was investigated by auditory brainstem response (ABR).

Methods: This cross-sectional study was conducted using convinience sampling. Click-evoked a uditory brainstem response test with both low (21.1 c/s) and high (51.1 c/s) stimulus rates was recorded in 30 children with a history of preterm birth and 30 ones with history of term labor, as controls.

Results: Significant differences were observed in inter-peak latencies of I-III in both rates, III-V in the low rate, I-V in the high rate, and absolute latency of III wave between high and low stimulus rates (p<0.05 for all). Rate of stimulus affect on auditory brainstem response of preterm birth group was more than controls. Sex also affected on some parameters of auditory brainstem response test.

Conclusion: Preterm birth group showed longer latencies than normal group in both rates. Rate of stimulus had significant effect on results of children with history of preterm birth compared normal group. These findings may reflect the negative effect of preterm birth on neural synchronization function in response to transient stimuli.

Background and Aim: While most of the people with tinnitus have some degrees of hearing impairment, a small percent of patients admitted to ear, nose and throat clinics or hearing evaluation centers are those who complain of tinnitus despite having normal hearing thresholds. This study was performed to better understanding of the reasons of probable causes of tinnitus and to investigate possible changes in the auditory brainstem function in normal-hearing patients with chronic tinnitus.

Methods: In this comparative cross-sectional, descriptive and analytic study, 52 ears (26 with and 26 without tinnitus) were examined. Components of the auditory brainstem response (ABR) including wave latencies and wave amplitudes were determined in the two groups and analyzed using appropriate statistical methods.

Results: The mean differences between the absolute latencies of waves I, III and V was less than 0.1 ms between the two groups that was not statistically significant. Also, the interpeak latency values of waves I-III, III-V and I-V in both groups had no significant difference. Only, the V/I amplitude ratio in the tinnitus group was significantly higher (p=0.04).

Conclusion: The changes observed in amplitude of waves, especially in the latter ones, can be considered as an indication of plastic changes in neuronal activity and its possible role in generation of tinnitus in normal-hearing patients.