Auditory event-related potentials and function of the medial olivocochlear efferent system in children with auditory processing disorders.
Thierry Morlet, Kyoko Nagao, L Ashleigh Greenwood and 3 others
PMID 30682902WHAT IT FOUND
Children with auditory processing disorder had slower brain responses to a speech sound even in quiet, and stronger cochlear feedback under both-ear noise.
The slower responses were related to SCAN-3 and phonemic test scores, but the study does not show that any treatment works.
Key findings
01In quiet, children with APD had longer P2 and N2 latencies and larger P2-N2 amplitudes than typically developing children.
02Binaural noise produced more TEOAE suppression than ipsilateral or contralateral noise, and children with APD had greater binaural suppression than controls.
03Quiet P2 and N2 latencies in children with APD were significantly correlated with SCAN-3 auditory figure-ground, composite, competing words, and Phonemic Synthesis Test scores.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
Read the rest of this summary
You get three full summaries a month, free, and we do not ask for a card. Search, the TL;DRs and your library stay unlimited either way.
What it does not show
The study compared 19 children with APD and 24 controls, so it cannot show that any treatment changes these responses. The groups were selected for normal hearing and excluded autism, primary ADHD, hearing loss, neurological problems, and below-average intelligence, so the findings may not apply to children with those common co-occurring conditions. The APD group was diagnosed from a battery and can be heterogeneous, and the paper says different impaired mechanisms can lead to the same outcomes. Some event-related potential waveforms were discarded for noise contamination, although each child had at least one usable recording per condition and electrode. The medial olivocochlear result was higher suppression in APD, while earlier studies reported lower suppression or conflicting patterns, and the authors say the conditions for benefit or harm remain unclear. The study did not test whether these objective measures help diagnose APD or guide therapy in an individual child.
Declared interests
The paper is tagged as supported by NIH extramural research funding. The supplied text does not include an author conflict-of-interest declaration.
The easy way to misread this
Do not read the stronger binaural cochlear feedback as proof that APD is caused by an overactive efferent system. The study only compared groups, and it found no significant group difference for suppression across ipsilateral, contralateral, and binaural noise at 65 dB SPL.