Auditory lateralization ability in children with [central] auditory processing disorder

ABSTRACT

The aim of the present study was to assess the auditory lateralization ability in children with [central] auditory processing disorder. Participants were divided in two groups 15 children with Central Auditory Processing Disorder [8-10 years] and 80 normal children [8-11 years] from both genders with pure-tone air-conduction thresholds better than 20 dB HL bilaterally and interaural pure tone threshold difference better than 5 dB . All subjects had normal IQ and normal otoscopy In the present study 9 imaginary positions were simulated in horizontal plane by Interaural Time Difference [ITD] and Interaural Intensity Difference [IID] to evaluate the auditory lateralization performance in normal and children with [central] Auditory Processing Disorder [C] APD. Lateralization performance were determined by ITD ranging from -880 to +880 microsecond and IID ranging from -10 to +10 dB for high pass and low pass noise[2 kHz cut off point]. Boltzmann function was used to describe the auditory lateralization performance and Independent Samples T-test was used to compare the two groups. According to Boltzmann function two major types of abnormalities were revealed in the lateralization performances 1- completely disoriented, 2- side-oriented. 86.6% of [C] APD children showed significant increase in mean of test errors compared with normal ones [p<0.001]. The study supports the hypothesis that most children with [C] APD have poor auditory lateralization and abnormal processing of binaural cues