RESUMO
Objectives: All subjects suspected of Central Auditory Processing Disorder [CAPD] were previously tested by free recall dichotic digits test [DDT]
The study objective was normalization and reliability evaluation of two-pair DDT in 750 native Persian subjects aged 8 to 12 years
Materials: A total of 750 subjects were divided into five age groups varying between 8 years and 12 years and 11 months old. Each age group had 150 subjects. DDT was tested in free recall condition. For evaluating DDT test-retest reliability, 300 participants [60 subjects in each age group] were tested again after one month
Results: Right and left ear mean score increased from 71.68[+/-2.19] and 58.51[+/-1.71] in the 8-year-old group to 90.26[+/-1.96] and 88.38[+/-1.36] in 12-year-old group, respectively
The mean Right Ear Advantage [REA] decreased from 13.16[+/-2.58] in the 8-year-old group to 1.88[+/-2.49] in the 12-year-old group. A high stability was observed between test-retest results [P0.0001]
Discussion: Persian version of two-pair dichotic digits exhibited proper reliability for evaluating 8 to 12-year-old subjects, and the study results can be used for evaluating the dichotic hearing function in subjects of the same age group
RESUMO
Contralateral stimulation with noise can improve auditory intensity discrimination. This may be related to function of the efferent system. The purpose of this study was to determine the relationship between the auditory intensity discrimination and the efferent system function. Twenty students with normal hearing were included in this descriptive-analytic study. We examined Difference Limen for Intensity [DLI], Otoacoustic Emissions suppression and Speech In Noise. DLI was evaluated with and without contralateral noise stimulation at two different stimulus levels [20, 70 dB SL]. There was significant difference between mean DLI scores of with contralateral masking comparing to without it, which was more prominent as frequency increased. Mean DLI score while masking with white noise was more than scores when masking with narrow band noise [p<0.05]. Transient evoked otoacoustic emissions responses decreased significantly in amplitude with contralateral masking. [p<0.05]. These results suggest that medial olivocochlear bundle functions as a key role in auditory intensity discrimination