Reduced medial olivocochlear bundle system function in children with auditory processing disorders.
A common complaint of children with auditory processing disorders (APD) is difficulty in understanding speech in the presence of background noise. Evidence from animal and human studies has suggested that the medial olivocochlear bundle (MOCB) may play a role in hearing in noise. The MOCB function can be evaluated by the suppression effect of the transient evoked otoacoustic emissions (TEOAE) in response to contralateral acoustic stimulation (CAS). The present study was conducted to investigate the suppression effect of TEOAE in APD children. The study groups comprised 15 APD children aged 8-13 years associated with learning disabilities and 15 controls matched for gender and age. The suppression effect of TEOAE was evaluated by comparing the TEOAE levels with and without CAS. A significantly reduced suppression effect of TEOAE was demonstrated in the APD group, when compared to the controls. In addition, higher TEOAE levels were found in the APD group, suggesting inherent reduced MOCB activity on the outer hair cells in APD children. These results imply that some APD children present low activity of the MOCB system, which may indicate a reduced auditory inhibitory function and affect their ability to hear in the presence of background noise.
Department of Communication Disorders, Sackler Faculty of Medicine, Tel Aviv University, Israel. muchinik@post.tau.ac.il
Chava
C
Muchnik
Daphne
D
Ari-Even Roth
Rima
R
Othman-Jebara
Hanna
H
Putter-Katz
Esther L
EL
Shabtai
Minka
M
Hildesheimer
D000293:Adolescent; D000704:Analysis of Variance; D001306:Auditory Pathways / Q000502:physiology; D002648:Child; D004525:Efferent Pathways / Q000502:physiology; D005260:Female; D018072:Hair Cells, Auditory, Outer / Q000502:physiology; D006801:Humans; D007805:Language Development Disorders / Q000503:physiopathology*; D008297:Male; D009847:Olivary Nucleus / Q000502:physiology*; D017084:Otoacoustic Emissions, Spontaneous / Q000502:physiology*; D013063:Speech Discrimination Tests