简介：Theelectricallyevokedsomaticmotilityofouterhaircells(OHC),brieflytermedOHCelectromotility,playsacrucialroleincochlearamplificationthatunderliestheremarkablyhighsensitivityandfrequencyselectivityofthemammalianhearing.AccompanyingOHCelectromotilityisavoltage-dependentgatingchargemovementwithinthecelllateralmembrane,manifestedasameasurablenonlinearcapacitance(NLC)inOHCs.TheelectromotilityandNLCofOHCsarehighlycorrelatedbysharingacommonmolecularsubstrate,themotorproteinprestin.Inthisstudy,wesystematicallycharacterizedthequantitativerelationshipbetweenOHCelectromotilityandNLCintheirvoltagedependencesforthepurposeoffurtherunderstandingtheelectromechanicaltransductioninOHCs.TheresultsdemonstratedthatthetwopossessdifferingvoltagedependenceswiththeV1/2ofelectromotilityconsistentlybeing～20mVdepolarizedincomparisonwiththatofNLCalthoughtheirslopefactorsαarestatisticallyidentical.FurtherinvestigationsshowedthattheinitialstateofOHCsinfluencesthevoltagedependenceofelectromotilitybutnotthatofNLC,indicatingthatsomebiophysicalfactorsotherthanthemotorproteinperseareinvolvedintheprocessofOHClengthchanges.Weproposedthatthecytoskeletalspectrin-actinframeworkunderneaththeOHCplasmamembraneandthecell'sturgorarethetwomostprobablefactorsthatcausethevoltage-dependencediscrepancybetweenOHCelectromotilityandNLC.

简介：Manypatientswithsensorineuralhearinglosshaveaprecipitoushigh-frequencylosswithrelativelygoodthresholdsinthelowfrequencies.Thispresentpaperbrieflyintroducesandcomparesthebasicprinciplesoffourtypesoffrequencyloweringalgorithmswithemphasisonnonlinearfrequencycompression(NLFC).AreviewoftheeffectsoftheNLFCalgorithmonspeechandmusicperceptionandsoundqualityappraisalisthenprovided.Forvowelperception,itseemsthatthebenefitsprovidedbyNLFCarelimited,whichareprobablyrelatedtotheparametersettingsofthecompression.Forconsonantperception,severalstudieshaveshownthatNLFCprovidesimprovedperceptionofhighfrequencyconsonantssuchas/s/and/z/.However,afewotherstudieshavedemonstratednegativeresultsinconsonantperception.Intermsofsentencerecognition,persistentuseofNLFCmightprovideimprovedperformance.Comparedtotheconventionalprocessing,NLFCdoesnotalterthespeechsoundqualityappraisalandmusicperceptionaslongasthecompressionsettingisnottooaggressive.Inthesubsequentsection,therelevantfactorswithregardtoNLFCsettings,time-courseofacclimatization,listenercharacteristics,andperceptualtasksarediscussed.AlthoughtheliteratureshowsmixedresultsontheperceptualefficacyofNLFC,thistechniqueimprovedcertainaspectsofspeechunderstandingincertainhearing-impairedlisteners.LittleresearchisavailableonspeechperceptionoutcomesinlanguagesotherthanEnglish.MoreclinicaldataareneededtoverifytheperceptualefficacyofNLFCinpatientswithprecipitoushigh-frequencyhearingloss.Suchknowledgewillhelpguideclinicalrehabilitationofthosepatients.