title: Medial olivocochlear-induced transient-evoked otoacoustic emission amplitude shifts in individual subjects.
abstract: Activation of the medial olivocochlear reflex (MOCR) can be assessed indirectly using transient-evoked otoacoustic emissions (TEOAEs). The change in TEOAE amplitudes when the MOCR is activated (medial olivocochlear (MOC) shift) has most often been quantified as the mean value in groups of subjects. The usefulness of MOC shift measurements may be increased by the ability to quantify significant shifts in individuals. This study used statistical resampling to quantify significant MOC shifts in 16 subjects. TEOAEs were obtained using transient stimuli containing energy from 1 to 10 kHz. A nonlinear paradigm was used to extract TEOAEs. Transient stimuli were presented at 30 dB sensation level (SL) with suppressor stimuli presented 12 dB higher. Contralateral white noise, used to activate the MOCR, was presented at 30 dB SL and was interleaved on and off in 30-s intervals during a 7-min recording period. Confounding factors of middle ear muscle reflex and slow amplitude drifts were accounted for. TEOAEs were analyzed in 11 1/3-octave frequency bands. The statistical significance of each individual MOC shift was determined using a bootstrap procedure. The minimum detectable MOC shifts ranged from 0.10 to 3.25 dB and were highly dependent on signal-to-noise ratio at each frequency. Subjects exhibited a wide range of magnitudes of significant MOC shifts in the 1.0-3.2-kHz region (median = 1.94 dB, range = 0.34-6.51 dB). There was considerable overlap between the magnitudes of significant and nonsignificant shifts. While most subjects had significant MOC shifts in one or more frequency bands below 4 kHz, few had significant shifts in all of these bands. Above 4 kHz, few significant shifts were seen, but this may have been due to lower signal-to-noise ratios. The specific frequency bands containing significant shifts were variable across individuals. Further work is needed to determine the clinical usefulness of examining MOC shifts in individuals.
authors: Department of Communication Sciences and Disorders, University of Iowa, Iowa City, IA, 52242, USA, shawn-goodman@uiowa.edu.
authors: Shawn S
authors: SS
authors: Goodman
authors: Ian B
authors: IB
authors: Mertes
authors: James D
authors: JD
authors: Lewis
authors: Diana K
authors: DK
authors: Weissbeck
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D003051:Cochlea / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009847:Olivary Nucleus / Q000502:physiology*; D017084:Otoacoustic Emissions, Spontaneous / Q000502:physiology*; D012022:Reflex, Acoustic / Q000502:physiology*
references: J Neurophysiol. 1991 Mar;65(3):724-35
references: 2051201
references: J Acoust Soc Am. 1996 Mar;99(3):1604-10
references: 8819856
references: J Neurosci. 1992 Dec;12(12):4575-85
references: 1464757
references: Int J Audiol. 2008 Oct;47(10):607-14
references: 18923982
references: J Assoc Res Otolaryngol. 2007 Dec;8(4):484-96
references: 17932717
references: J Neurosci. 2008 May 7;28(19):4929-37
references: 18463246
references: Hear Res. 1993 Dec;71(1-2):1-11
references: 8113128
references: J Acoust Soc Am. 2006 Aug;120(2):901-14
references: 16938978
references: Ear Hear. 2001 Aug;22(4):316-32
references: 11527038
references: Proc Natl Acad Sci U S A. 2002 Mar 5;99(5):3318-23
references: 11867706
references: Hear Res. 1991 Jan;51(1):55-72
references: 2013546
references: J Acoust Soc Am. 1999 Feb;105(2 Pt 1):782-98
references: 9972564
references: J Acoust Soc Am. 2006 May;119(5 Pt 1):2889-904
references: 16708947
references: J Am Acad Audiol. 2003 Aug;14(6):302-13
references: 14552424
references: Ear Hear. 2006 Apr;27(2):153-60
references: 16518143
references: J Acoust Soc Am. 2011 Jan;129(1):245-61
references: 21303007
references: Audiol Neurootol. 2004 Mar-Apr;9(2):107-14
references: 14981358
references: Hear Res. 1996 Nov 1;101(1-2):113-8
references: 8951438
references: J Assoc Res Otolaryngol. 2003 Dec;4(4):521-40
references: 12799992
references: J Acoust Soc Am. 2009 Feb;125(2):1014-32
references: 19206876
references: J Acoust Soc Am. 2007 Mar;121(3):1588-603
references: 17407896
references: Otol Neurotol. 2001 May;22(3):350-5
references: 11347638
references: J Assoc Res Otolaryngol. 2006 Jun;7(2):125-39
references: 16568366
references: Ear Hear. 2006 Dec;27(6):589-607
references: 17086072
references: Hear Res. 1997 Apr;106(1-2):112-22
references: 9112111
references: J Neurosci. 2000 Jun 15;20(12):4701-7
references: 10844039
references: Hear Res. 1990 Jan;43(2-3):251-61
references: 2312416
references: J Acoust Soc Am. 1998 Jun;103(6):3499-508
references: 9637034
references: Ear Hear. 1990 Apr;11(2):93-105
references: 2340969
references: J Acoust Soc Am. 2007 Apr;121(4):2097-110
references: 17471725