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Background and Aim: Dichotic listening means presentation of two different auditory stimuli to each ear simultaneously. This study deals with the development of Persian version of Bergen dichotic listening test and its preliminary results on auditory attention and language laterality in adults with normal hearing.

Methods: Persian version of the Bergen dichotic listening test was instructed by six consonant-vowel syllables to evaluate three conditions of non-forced attention, attention to right and attention to left ears separately. Then, it was performed on 54 right-handed young adults with normal hearing and the mean age of 23.24 (SD=2.78) years from both genders.

Results: Frequency of correct response in the right ear was higher significantly in two conditions of non-forced attention (83.3%) and attention to the right ear (98.1%), and also was higher significantly in the left ear (-79.6%) in attention to the left (p<0.0001). Laterality index was 31.33% in non-forced attention, 73.30% in attention to the right and -37.50% in attention to the left which was significantly different (p<0.0001).

Conclusion: Right ear advantage was revealed in non-forced attention that was altered with selective attention to the right and left remarkably result from the effect of top-down processing of brain cortex on bottom-top processing of speech stimulus. These preliminary results showed the performance of Bergen dichotic listening test to test auditory attention and language laterality.

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Background and Aim: Staggered spondaic words (SSW) test examines central auditory nervous system . Some researches show stuttering causes hyperactivity in motor system of the right hemisphere and cerebellum and decreases activity in the left hemisphere. During stuttering also, central auditory processing is decreased . The aim of this study was to compare the Persian staggered spondaic word test results between persistent developmental stutterers and normal subjects.

Methods: Thirty people with persistent developmental stuttering were participants of this cross-sectional descriptive-analytic study, which were aged 11 to 40 years. The control group matched for gender and number with stutters. They were 8 females and 22 males, with the age of 11 to 40 years, without any stuttering history, neurological diseases and auditory disorders.

Results: Stutterers were in normal category in corrected staggered spondaic words test. The mean scores of errors of right compete, right ear, left compete, left ear and total in corrected s taggered spondaic words between control and stuttering group showed significant differences. There was a significant relationship between stuttering and effect, too (p<0.05).

Conclusion: Based on the obtained results of this study, stutterers may have different cortical and sub - cortical brain activity than people who have not stutter . Central auditory processing abilities of stutterers are weaker than normal people.

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Background and Aims: The dichotic listening subtest is considered as an important component of the test battery for auditory processing assessment in both children and adults. A randomized dichotic digits test (RDDT) was created to compensate for sensitivity weakness of double digits when detecting abnormal ear asymmetry during dichotic listening. The aim of this study was the development and initial evaluation of the Persian randomized dichotic digits test.

Method: Persian digits 1-10 (except for the bisyllabic digit, 4) uttered by a native Persian language speaker were recorded in a studio. After alignment of intensity and temporal characteristics of digit waveforms, lists 1 and 2 of the RDDT were reproduced. List 1 of the test was administered at 55 dBHL on 50 right-handed normal hearing individuals (with an equal sex ratio) in the age group of 18-25 years and hearing thresholds of 15 dBHL or better in audiometric frequencies.

Results: Mean (standard deviation) percent-correct score for right and left ears and right ear advantage of the subjects was 94.3 (5.3), 84.8 (7.7), and 9.5 (7.0) percent, respectively. Sixty percent of the subjects showed normal results and unilateral and bilateral deficits were seen in 24 percent and 16 percent, respectively.

Conclusion: It seems the Persian version of RDDT is the same as the original test as it is able to test ear asymmetry , unilateral and bilateral deficits in dichotic listening.