Apical hair cells and hearing

15 Pages·2002·1.42 MB·English

Hearing Research, 44 (1990) 179-194 971
reiveslE
SERAEH 92310
lacipA riah sllec dna gniraeh
aihtnyC .A ,nesorP divaD .B ,ydooM mailliW .C ,snibbetS divaD W. htimS ,*
llehctiM .S ,sremmoS J. enidaN ,nworB drahciR .A reluhcstlA
dna hpesoJ E. ,snikwaH Jr.
egserK Hearing Research Institute, The University of Michigan Medical School, Ann ,robrA Michigan, U.S.A.
devieceR( 52 yaM ;9891 detpecca 71 rebotcO )9891
sihT yduts dessessa eht noitubirtnoc fo eht lacipa riah sllec ot .gniraeh aeniuG ,sgip sallihcnihc dna syeknom erew yllaroivaheb
deniart gnisu evitisop tnemecrofnier ot dnopser ot enot-erup .ilumits nehW a elbats margoidua dah neeb ,denimreted hcae tcejbus
deviecer eno fo eerht latnemirepxe :stnemtaert cixototo gurd ,noitartsinimda ycneuqerf-wol esion ,erusopxe ro eht noitacilppa fo a
eborpoyrc ot eht ynob llaw fo eht raelhcoc .xepa retfA tnemtaert-tsop smargoidua ,dezilibats stcejbus erew dezinahtue dna eht
egatnecrep fo riah sllec gniniamer saw dessessa yb thgil .ypocsorcim stluseR etacidni taht a ycnadnuder fo gnidocne smsinahcem tsixe
ni eht nailammam aelhcoc rof ycneuqerf-wol .ilumits yehT osla tseggus taht a yrev llams egatnecrep fo lacipa riah sllec era tneiciffus
rof emos ycneuqerf-wol .gniraeh ,yllaniF atad morf siht dna rehto seiduts tseggus taht eht ycneuqerf-wol dlohserht tfihs desuac yb eht
ssol fo a niatrec egatnecrep fo lacipa riah sllec si ssel decnuonorp naht eht ycneuqerf-hgih dlohserht tfihs desuac yb eht ssol fo a
elbarapmoc egatnecrep fo lasab riah .sllec esehT atad eerga htiw lacimotana dna lacigoloisyhportcele ecnedive taht lanoitcnuf sa llew
sa lacimotana secnereffid yam tsixe neewteb eht xepa dna esab fo eht .aelhcoc
raelhcoC ;xepa ycneuqerf-woL ;gniraeh riaH ;sllec ssap-hgiH yrotidua gniksam
noitcudortnI dna ,enhoB ;6891 htimS et ,.la ;7891 sremmoS et
,.la 1987) evah detareneg ralimis .sgnidnif
,lacimotanA lacigoloisyhportcele dna -vaheb tnadnubA lacimotana secnereffid neewteb the
laroi data tseggus that the apex dna the esab of esab dna the apex of the aelhcoc evah neeb -ucod
the aelhcoc evah tcnitsid sedom of gnissecorp .detnem esehT secnereffid edulcni segnahc ni the
yrotidua .slangis thcenkuhcS dna Neff (1952) desu htdiw dna ssenkciht of the ralisab enarbmem ,miL(
yllaroivaheb denoitidnoc cats ot etartsnomed that 1980), the ,rebmun ,ssenffits dna thgieh of the
etelpmoc lacipa riah llec noitcurtsed detluser ni a ailicoerets ,miL( ;0891 ffoilertS dna ,kcolF 1984),
ycneuqerf-wol gniraeh ssol of 03-02 ,Bd elihw the htgnel of the retuo riah sllec enhoB( dna Carr,
etelpmoc lasab riah llec noitcurtsed decudorp a ;5891 itnaS dna ,nosirraH 1986), the ytisned of
hcum erom ereves gniraeh .ssol More tnecer -eb detanileym evren srebif enhoB( et ,.la 1982), the
laroivah stnemirepxe gnisu aeniug ,sgip -lihcnihc nrettap of tnereffe ihsI( dna ,hgolaB ;8691 -oR
,sal dna syeknom nosnehpetS( et ,.la ;4891 kralC nostreb et ,.la ;7891 thcenkuhcS et ,.la ;9591
,nildneopS ;9791 thgirW dna ,notserP 1973) dna
tnereffa ,nildneopS( 1979) evren rebif ,snoitcejorp
Correspondence to: .A.C ,nesorP 0304 egserK gniraeH hcraeseR the ytivitisnes of the stnereffa ot ciniak dica lojuP(
,etutitsnI ytisrevinU fo nagihciM lacideM ,loohcS nnA ,robrA et ,.la 1985), the ytisned of retuo riah llec
Ml ,90184 .A.S.U airdnohcotim otomihsaH( dna ,arumiK 1987), -fid
* tneserP Address: tnemtrapeD fo ,ygolognyralotO lacinilC
secneref ni the noitubirtsid of nitca-F ni the retuo
secneicS ,noisiviD 8037 lacideM secneicS ,gnidliuB 1 sgniK
riah sllec enrohT( et ,.la 1987), ni the -artnecnoc
egelloC ,elcriC ytisrevinU fo ,otnoroT ,otnoroT oiratnO S5M
,8Al .adanaC noit of seditisoniohpsohp iksleizdeiN( et ,.la 1988),
05.30$/09/5595-8730 0 0991 reiveslE ecneicS srehsilbuP .V.B lacidemoiB( )noisiviD
180
dna ni the noitubirtsid of ABAG ni the laidem ralucisso niahc dna lacigrus noitcurtsed of the
tnereffe sgnidne nilbayE( et ,.la ;8891 xeF dna thgir .aelhcoc
,reluhcstlA ;4891 xeF et ,.la ;6891 nospmohT et sallihcnihC (Chinchilla lunigeru ) deviecer a latot
,.la 1986). ,rehtruF enhoB et .la (1985) dna kralC of 10 g of aniruP allihcnihc chow ro/dna 45
et .la (1987) evah detseggus that there are -fid seyoN-gm alumroF N food stellep ,yliad -elppus
secneref ni the snrettap of ralullec noitcurtsed detnem htiw ,snisiar ,elppa dna .yah yehT were
gniwollof dna-wol ycneuqerf-hgih esion .serusopxe yllaudividni desuoh ni a moor htiw a desrever
lacigoloisyhP secnereffid edulcni the noitavresbo /thgil dark .elcyc llA sallihcnihc were -laruanom
that ni the apex, retuo riah sllec ecudorp -ed-llew dezi roirp ot the gninnigeb of laroivaheb gnitset
denif DC sesnopser ,sollaD( 1985). whereas ni the yb noitalucitrasid of the thgir ralucisso niahc dna
esab yeht do ton llessuR( dna ,kcilleS 1983). eborpoyrc noitcurtsed of the eritne thgir .aelhcoc
nI the tneserp ,yduts etulosba dlohserht -cnuf eerhT of the xis yeknom stcejbus were Eryth-
snoit were denimreted morf deniart-yllaroivaheb rocebus patas, dna three were Macuca nemestrina.
aeniug ,sgip sallihcnihc dna syeknom ,erofeb -rud yehT were fed a teid hcihw detsisnoc of aniruP
gni dna after the noitcudorp of na -yllatnemirepxe yeknom chow, vresoiB etamirp derovalf-ananab
decudni laruenirosnes gniraeh .ssol laroivaheB dna ,stellep dna fresh .tiurf
lacigolotsih data were yltneuqesbus .detalerroc A
yramirp evitcejbo was ot ecudorp yrev tnereffid Apparatus
snrettap of lacipa riah llec noitneter yb gnisu
lareves tcnitsid latnemirepxe :seuqinhcet ti was stcejbuS were tested ni CAI dellaw-elbuod
hoped that the noitalerroc neewteb the tnegrevid gnitaunetta-dnuos .srebmahc syeknoM were seated
snrettap of riah llec noitcurtsed dna the gniraeh ni a etamirp tniartser :riahc aeniug sgip dna
sessol detaicossa htiw meht dluow yfiralc the -nu sallihcnihc were decalp ni a eriw hsem gnitset cage
niatrec noitubirtnoc of the lacipa riah sllec ot detacol ni na CAI .rebmahc ehT gnitset sutarappa
.gniraeh for each seiceps dedulcni a feeder, a esnopser
ruO sgnidnif etacidni that tnelaviuqe snrettap .mudnalupinam a ,thgil dna a dnuos yreviled -sys
of riah llec noitcurtsed ni the apex dna ni the esab met gnitsisnoc of a speaker for the stnedor dna
of the aelhcoc ecudorp gniraeh sessol hcihw reffid senohprae for the syeknom aeniug( ,gip nesorP et
yllacitamard htob ni edutingam dna ,ssentpurba ,.la ;1891 ,allihcnihc htimS et ,.la ;7891 dna
gnitseggus that lanoitcnuf secnereffid yam tsixe ,etamirp ydooM et ..la 1976). ehT laroivaheb
neewteb the apex dna the esab of the .aelhcoc erudecorp for the aeniug sgip was dellortnoc yb
dilos state cigol stiucric EVL-SRB( ,)stib-igiD dna
Methods for the sallihcnihc dna syeknom yb a latigiD
noitaroproC E8-PDP .retupmoc
stcejbuS
ilumitS
nevelE aeniug ,sgip thgie sallihcnihc dna xis
dlroW-dlO syeknom devres as stcejbus ni siht ehT aeniug gip enot-erup yrotidua sulumits
.yduts llA stcejbus were devirped-doof ot %09-08 gnitareneg sutarappa has neeb debircsed erehwesle
of rieht gnimocni ydob ,thgiew after hcihw yeht nesorP( et ,.la 1978). roF those aeniug sgip morf
deniag thgiew tuohguorht the ,tnemirepxe -tcelfer hcihw gniksam data were ,detcelloc the reksam
gni lamron latnempoleved .segnahc retaW was detanigiro morf a lareneG oidaR ynapmoC -naR
yleerf elbaliava ni the emoh cages. mod esioN rotareneG ledom( 1381), ot na nosillA
aeniuG sgip (Cauia porcellus) deviecer a latot seirotarobaL elbairav retlif ledom( .)RBA2-LA a
of 25 g of .aniruP aeniug gip chow ro/dna 45 evatco-3/l retnec ycneuqerf .rezilauqe a nworC
seyoN-gm alumroF D food stellep ,yliad dna fresh reifilpma (DC ,)A003 dna yllanif dereviled yb na
yelsrap .ylkeew eerhT of the nevele aeniug sgip oiduA scimanyD Speaker ledom( .)6-TX ehT
were dezilaruanom roirp ot the gninnigeb of -eb allihcnihc erup enot sulumits gnitareneg -arappa
laroivah gnitset yb noitalucitrasid of the thgir ,sut tnempiuqe desu gnirud gniksam ,stnemirepxe
181
dna dnuos dleif noitarbilac serudecorp evah neeb esaercni ni dlohserht at seicneuqerf of 0.71 kHz
debircsed yb htimS et .la (1987). enot-eruP -umits dna .rehgih gniksaM data were degduj elbats yb
sul noitareneg dna noitarbilac serudecorp for the the airetirc debircsed .evoba ehT gniksam -irepxe
yeknom evah neeb debircsed yb ydooM et .la tnem was detcudnoc ot etaulave the sisehtopyh
(1976). that ni secnatsni of lacipa riah llec noitcurtsed
citsuocA serusopxe for aeniug sgip dna syeknom htiw lasab riah llec ,noitneter riah sllec detacol
were deirrac tuo ni na CAI dnuos htoob hcihw lasab ot the lacipa noitcurtsed detect -wol
was deifidom ot esaercni sti .ecnarebrever ehT ycneuqerf senot yllamron detected yb the lacipa
esion was decudorp yb a lareneG oidaR modnar riah .sllec nI htob the lamron dna the degamad
esion rotareneg ledom( 1381), deretlif yb na -lA ear, a ssap-hgih reksam dluohs esaercni the
nosil seirotarobaL elbairav retlif ledom( 2BR), sdlohserht of seicneuqerf nihtiw the pass .dnab nI
passed hguorht a evatco-3/l retnec ycneuqerf the ear htiw lacipa riah llec ,noitcurtsed fi erom
,rezilauqe dna deifilpma yb a hsotnIcM power detacol-yllasab sllec detected ycneuqerf-wol
reifilpma ledom( MC2105). ehT esion was -ed ,slangis sdlohserht for the wol seicneuqerf dluohs
derevil ot the slamina aiv eno aeniug( )gip or two eb ,detavele too.
)yeknom( cetlA ’retaehT-ehT-fO-ecioV‘ speaker
,smetsys hcihw were detnuom no the gniliec dna Experimental treatment and post-treatment testing
detcerid at the slamina gnieb exposed. retfA elbats enilesab data were gathered, the
ehT dnuos dleif murtceps of the ,esion whether latnemirepxe tnemtaert .nageb
desu gnirud gniksam or ,erusopxe was detarbilac llA aeniug sgip were exposed ot rehtie a erup
htiw a drakcaP-ttelweH evaw rezylana ledom( enot or .esion owT stcejbus lPG( dna )2PG were
)A0953 dna a hcni-2/l resnednoc .enohporcim exposed ot a zHk-52.0 evatco dnab esion (OBN)
llarevO dnuos slevel were derusaem htiw a dnuos at 115 Bd ,LPS 22 yad/h for 7 evitucesnoc .syad
level retem (C .)gnithgiew ehT 0.71 kHz ffotuc owT other stcejbus 21PG( dna )31PG were -xe
ssap-hgih gniksam esion debircsed woleb had a posed ot a zHk-5.0 OBN at 110 Bd ,LPS 22
talf murtceps morf 0.71 ot 12.0 kHz, htiw a Bd-ol yad/h for 13 evitucesnoc .syad ruoF stcejbus
decrease morf 12.0 ot 22.0 kHz. ,3PG( ,4PG ,12PG dna )22PG were exposed ot a
zHk-5.0 OBN at 120 Bd ,LPS 22 yad/h for 7
Procedure evitucesnoc .syad ehT gniniamer three stcejbus
,23PG( ,83PG dna )14PG were exposed ot a -5.0
tnemtaert-erP testing kHz erup enot at 120 Bd ,LPS 22 ,yad/h for 7
The gniniart dna gnitset of each lamina seiceps evitucesnoc .syad sdlohserhT were detaulave at the
were detcudnoc gnidrocca ot a ralimis laroivaheb noisulcnoc of each yliad erusopxe .doirep
locotorp dna evah neeb debircsed ni liated llA sallihcnihc had a eborpoyrc deilppa ot the
erehwesle aeniug( :gip nesorP et ,.la ;8791 nesorP tfel .aelhcoc sihT erudecorp has neeb debircsed ni
dna ,snibbetS ;0891 :allihcnihc htimS et ,.la ;7891 liated erehwesle nworB( dna ,llattuN ;7891 htimS
:yeknom ydooM et ,.la 1976). aeniuG gip et ,.la 1987). ,ylfeirB elihw each tcejbus was rednu
sdlohserht were denimreted yb the dohtem of -noc lareneg ,aisehtsena the tfel allub was denepo dna
tnats ,ilumits elihw allihcnihc dna yeknom the pit of a delooc-negortin-diuqil eborpoyrc was
sdlohserht were denimreted yb a gnikcart -ecorp decalp no the apex. roF xis of the stcejbus (CH15,
.erud enilesaB data were deredisnoc elbats nehw 4 CH83, CH84, CH94, CH98, dna CH118), the
tuo of 5 evisseccus sdlohserht at each test eborp deniamer ni ecalp for 1.5 ;nim ti was neht
ycneuqerf were nihtiw 10 .Bd devomer for 3 ,nim dna deilppaer for na -da
retfA the noitcelloc of elbats enilesab data, lanoitid 1.5 .nim CH34 had eborpoyrc tnemecalp
three of the aeniug sgip dna evif of the sallihcnihc snoitarud of 2 dna 3 ,nim htiw a 4 nim lavretni
were stcejbus ni a ssap-hgih (0.71 kHz )ffotuc neewteb .stnemecalp CH47 had eno nim-3
gniksam .tnemirepxe etulosbA sdlohserht were eborpoyrc .noitacilppa laroivaheB gnitset of the
detaulave ni the ecneserp of the ,reksam hcihw sallihcnihc demuser nihtiw 3-2 syad after .yregrus
was detsujda ni level ot ecudorp a 02-ol Bd owT syeknom (M54 dna M49) were exposed ot
281
a zHk-5.0 OBN at 120 ,Bd 8 yad/h for 20 .syad .)tsivqret raelhcoC seussit were prepared yb -orcim
serusopxE were ton detcudnoc no .sdnekeew noitcessid as debircsed yb snikwaH dna nossnhoJ
gniraeH ni htob ears was detaulave at the -ulcnoc (1976).
nois of the yliad erusopxe .doirep ehT ecafrus snoitaraperp were denimaxe htiw a
ehT gniniamer ruof syeknom were treated htiw thgil epocsorcim htiw phase tsartnoc .scitpo ehT
na cidisocylgonima .scitoibitna M44 dna M62, rebmun of gnissim riah sllec was assessed ni lla
htob patas ,syeknom were treated htiw -ordyhid stnemges of the eritne raelhcoc .larips -otyC
nicymotperts (DHSM) 100 /gm kg/ yad -ni smargoelhcoc were detcurtsnoc morf the ecafrus
;ylralucsumart M44 deviecer DHSM for 110 ,syad ,snoitaraperp ni hcihw the egatnecrep of renni dna
dna M62 for 75 .syad M91, the driht patas ,yeknom retuo riah sllec gniniamer was dettolp as a -cnuf
deviecer 20 yad/gk/gm DHSM for 100 .syad noit of the tnecrep ecnatsid morf the apex of the
,yllaniF M21 deviecer nicym~n (NM) 50 /gm .aelhcoc slleC were detnuoc as tneserp fi rehtie the
yad/gk ylralucsumartni for 15 .syad dlohserhT ailicoerets or the llec suelcun dluoc eb .dezilausiv
gnitset deunitnoc tuohguorht the gniggurd -ecorp No tpmetta was edam ot assess the degree of
.erud elbissop ralullec egamad ot gnivivrus .sllec -eB
gniraeH of lla stcejbus was assessed litnu the esuac gniraeh ni sall~c~ihc dna syeknom was
dlohserht tfihs dezilibats gnidrocca ot the noiretirc assessed yllaruanom sallihcnihc( were -laruanom
debircsed .evoba sdlohserhT of the aeniug sgip dezi dna syeknom were tested htiw ,)senohprae
(three) dna the sallihcnihc )evif( were neht -ed smargoelhcocotyc morf these stcejbus were -erroc
denimret ni the ecneserp of the ssap-hgih .reksam detal htiw the laroivaheb data morf the ear desu
Data noitcelloc morf these stcejbus was detanimret gnirud .gnitset nI those aeniug sgip hcihw were
nehw the sdlohserht tem the denimreted-erp -ats ton dezilaruanom roirp ot laroivaheb ,gnitset the
ytilib .noiretirc margoelhcocotyc morf each tcejbus htiw the tsael
tnuoma of ralullec egamad was detalerroc htiw the
laroivaheb dlohserht tfihs data, rednu the -pmussa
Histology noit that the lamina desu sti tseb ear elihw -rofrep
tA the noisulcnoc of laroivaheb ,gnitset aeniug gnim the lacisyhpohcysp task.
sgip dna sallihcnihc were ylivaeh dezitehtsena htiw
nupmor-enimatek dna .detatipaced laropmeT
stluseR
senob were ylkciuq ,devomer dna the allub dna
the dnuor dna lavo swodniw exposed dna .denepo
evitaxiF was neht yltneg desufrep hguorht the Data morf the stcejbus ni siht tnemirepxe are
dnuor .wodniw evitaxiF was rehtie 2.5% -laratulg depuorg no the sisab of the nrettap of riah llec
edyhed or 2.5% edyhedlaratulg dna 2% -rofarap ssol gniwollof the latnemirepxe ,tnemtaert as nees
edyhedlam ni phosphate .reffub retfA 1 ruoh of ni elbaT 1. puorG 1 stcejbus had laitrap ssol of
,noitaxif eaelhcoc were desnir ni .reffub nI aeniug lacipa riah sllec dna good noitneter of lasab riah
,sgip tub ton ,sallihcnihc siht was dewollof yb na .sllec puorG 2 stcejbus had etelpmoc ssol of lacipa
ralacsartni noisufrep of 1% 40~0 dna a dnoces riah sllec htiw good noitneter of lasab riah .sllec
seires of .sesnir eaelhcoC were yltneuqesbus -yhed puorG 3 stcejbus had etelpmoc lacipa riah llec
drated hguorht 70% .lohocla ehT ynob llehs was noitcurtsed dna laitrap ssol of lasab .sllec puorG 4
neht ,devomer dna airts dna stnemges of the stcejbus had emos lacipa riah sllec gniniamer tub
raelhcoc larips derevocer ni etelpmoc .snrut esehT on lasab .sllec sihT noitacifissalc emehcs -netop
ecafrus snoitaraperp were neht talf deddebme ni yllait serongi riah sllec morf the elddim noiger of
etidlara-tsacdem ni edils .sdlom the ;aelhcoc nehw these sllec appeared ,lamron
tA the noisulcnoc of the yeknom laroivaheb rieht elor ni noitceted si .deredisnoc esuaceB of
,gnitset stcejbus were ylivaeh dezitehtsena htiw the egral rebmun of stcejbus ni siht ,yduts -erper
muidos ,latibrabotnep dna the suonarbmem evitatnes data morf each puorg were detceles dna
htnirybal was dexif dna deniats ni oviv yb -rep are debircsed ,woleb dna snoitaived morf these
citahpmyli noisufrep of 1% 40~0 noitulos -teZ( evitatneserper stluser are .deton
381
ELBAT I 14PG was exposed ot a zHk-5.0 erup enot at
RIAH LLEC NOITIDNOC DNA GNIRAEH SSOL IN 120 ,Bd htiw the noitatcepxe of gnicudorp erom
SPUORG 4-l riah llec noitcurtsed naht had neeb decudorp ni
stcejbus exposed ot rewol .slevel sA nees ni .giF 3,
puorG lacipA riah lasaB riah gniraeH ssol htiw %06-ol of the OHCs gnissim ni the lacipa
rebmun llec noitidnoc llec noitidnoc
15% of the ,aelhcoc sdlohserht woleb 0.25 kHz
1 laitrap ot oN ssol 52-O Bd detfihs yb 10 Bd at ,tsom whereas the ssol at 16.0
laitnatsbus ycneuqerf-wol ssol
dna 32.0 kHz was 15 ot 20 ,Bd dna at 1.0 kHz ti
ssol
was 30 .Bd nI ,lareneg stcejbus exposed ot siht
2 etelpmoC ssol oN ssol 52-O Bd rehgih level (120 dB) dereffus greater -hgih
ycneuqerf-wol ssol
ycneuqerf gniraeh ssol naht dluow evah neeb -erp
3 etelpmoC ssol laitraP ssol 06-04 Bd detcid morf the .margoelhcocotyc neT lanoitidda
ssol ta lla
sets of smargoelhcocotyc dna smargoidua were
seicneuqerf
detcelloc morf 6 aeniug sgip dna 2 syeknom hcihw
4 laitnatsbuS etelpmoC ssol 04-02 Bd were exposed ot dnuos at 120 Bd ,LPS the aeniug
ssol ycneuqerf-wol ;ssol sgip for 7 ,syad 22 ,yad/h dna the syeknom for 20
001-06 Bd
,syad 8 .yad/h nI thgie of these sets of data, emos
ycneuqerf-dim
;ssol on gniniamer ycneuqerf-hgih gniraeh ssol was ,deton -moccanu
ycneuqerf-hgih deinap yb yna laitnatsbus lasab riah llec .ssol nI
gniraeh enon of these sets of data did the gniraeh ssol at
seicneuqerf woleb 1.0 kHz exceed 20 ,Bd hguohtla
lacipa riah llec ssol degnar morf 09-02 %.
Group I laitraP( apical ,ssol good basal retention)
nevelE of the puorG 1 stcejbus were -xe-esion
Percent Distance from Apex
posed aeniug ,sgip two were desopxe-esion
0 10 20 30 40 50 60 70 60 90 100
,syeknom dna eno was a detaert-eborpoyrc
.allihcnihc ehT data morf the syeknom (M49 dna
M54) were tsrif reported yb ydooM et .la (1978).
lPG was exposed ot a zHk-52.0 OBN, 115 Bd
,LPS ,yad/h22 for 7 .syad ehT reppu flah of .giF
1 shows the margoelhcocotyc for the tfel ear of
,lPG elihw the rewol flah of siht erugif stciped the
dlohserht .tfihs nI the lacipa 25% of s’lPG tfel
,aelhcoc %09-ol of OHCs were ,tnesba elihw sCHI
here were .deniater-llew gnidnopserroC ot siht -20
nrettap of riah llec ,ssol on elbarusaem dlohserht
tfihs was deton at yna .ycneuqerf 0 g
31PG was exposed ot a zHk-5.0 OBN, 110 Bd E
2o ;
,LPS 22 ,yad/h for 13 .syad nI the lacipa 40% of
e
the thgir ,aelhcoc yletamixorppa 50% of the OHCs 40 2I
c
were ,tnesba elihw sCHI here were deniater -aer u
ylbanos ,llew as nees ni .giF 2. ycneuqerf-woL 60 a
::
sdlohserht were detfihs yb 10 Bd at .tsom owT <
80
lanoitidda puorG 1 aeniug sgip were exposed ot a 0.125 0.5 2.0 6.0 32.0
0.5 kHz OBN, eno at 110 dna eno at 115 Bd Frequency (kHz)
.giF .1 tfeL rae margoelhcocotyc dna etulosba dlohserht tfihs
LPS : htob slamina had yletamixorppa 50% OHC
noitcnuf fo .lPG a aeniug gip desopxe ot a 52.0 zHK NBO ta
ssol ni the lacipa 30% of the ,aelhcoc htiw on
511 Bd LPS (C .)elacs 22 ,yad/h rof 7 .syad ycneuqerF dna
gniraeh ssol at yna .ycneuqerf ecnatsid sexa era dengila sa debircsed yb nesorP et .la .)8791(
481
Percent Distance morf Apex ehT lanif puorG 1 tcejbus was a -el-eborpoyrc
0 10 20 30 40 50 60 70 80 90 100 denois .allihcnihc yletamixorppA 70% of the OHCs
dna %08-ol of the sCHI ni the lacipa flah of the
aelhcoc were .deyortsed elihW the lacipa egamad
was erom evisnetxe ni siht tcejbus naht ni the
other puorG 1 ,stcejbus the gniraeh ssol was -imis
ral ni :edutingam the mumixam dlohserht tfihs
deton at yna ycneuqerf was 15 .Bd
Group 2 (Complete apical .ssol good basal retention)
llA ruof stcejbus ni puorG 2 were sallihcnihc
that had a eborpoyrc deilppa ot the tfel raelhcoc
apex, ni the noitatcepxe that erom laitnatsbus
lacipa riah llec ssol dluow eb decudorp yb siht
erudecorp naht yb .erusopxe-dnuos nI fact, lla of
the stcejbus ni siht puorg showed elbaredisnoc
lacipa riah llec .noitcurtsed Data morf two of the
0.125 0.5 2.0 8.0 320
Frequency (kHz)
.giF .2 thgiR rae margoelhcocotyc dna etulosba dlohserht tfihs ~+?rcentD istancelrom Apex
noitcnuf fo ,31PG a aeniug gip desopxe ot a 5.0 zHk NBO ta 0 IO 20 30 40 50 60 70 80 90 100
011 Bd LPS (C ,)elacs 22 ,yad/h rof 31 .syad ycneuqerF dna
lO(
ecnatsid sexa era dengila sa debircsed yb nesorP et .la .)8791(
tI dluoc eb deugra that ni the ecneserp of lacipa
riah llec ,noitcurtsed dna-dim nrut-lasab riah sllec
dnopser ot ycneuqerf-wol ilumits ,hcihw ni the
lamron ear. are dednopser ot yb lacipa riah .sllec
oT etaulave siht ,ytilibissop a ssap-hgih (0.71 kHz
dna )evoba gniksam esion was decudortni otni the
gnitset tnemnorivne of .14PG sdlohserhT -aem
derus ni the ecneserp of siht reksam are deyalpsid
ni .giF 3. elihW sdlohserht for seicneuqerf of 1.0
kHz dna evoba desaercni 02-ol Bd ni the -serp
ecne of the ,reksam sdlohserht for rewol -neuqerf
seic were .degnahcnu ylraeN lacitnedi gniksam
data were detcelloc morf a dnoces desopxe-dnuos
aeniug ,gip elihw gniksam data morf a driht aeniug
0.125 0 5 2.0 6.0 32.0
gip detartsnomed a Bd-02 gniraeh ssol for
ycneuqerF )zHk(
egnar-dim seicneuqerf ni the ecneserp of the -hgih
.giF .3 thgiR rae margoelhcocotyc dna etulosba dlohserht tfihs
pass reksam dna a erom tsedom Bd-5 gniraeh ssol snoitcnuf fo ,14PG a aeniug gip desopxe ot a 5.0 zHk erup
for wol .seicneuqerf esehT data tseggus that ni the enot ta 021 Bd LPS (C .)elacs 22 ,yad/h rof 7 .syad PTS atad
ecneserp of laitrap lacipa OHC ,ssol ycneuqerf-wol refer ot eht dlohserht tfihs derusaem ni eht ecnesba fo a
,reksam elihw -74 dna Bd-75 reksam atad refer ot eht dlohserht
ilumits yam eb dednopser ot rehtie yb the -niamer
tfihs derusaem ni eht ecneserp fo a 17.0 zHk ssap-hgih reksam
gni detacol-yllacipa riah ,sllec or yb tnecajda -nu
tes ta 74 dna 75 Bd LPS (C .)elacs ycneuqerF dna ecnatsid sexa
degamad riah .sllec era dengila sa debircsed yb nesorP et .la .)8791(
581
Percent Distance from Apex ni the lacipa 30% of the ,aelhcoc sdlohserht detfihs
0 20 40 60 60 100 yb at tsom 20 .Bd Data morf CH94, nees ni .giF 6,
etaroborroc the sgnidnif morf CH47 dna ;48HC ni
101
the ecnesba of ylraen lla of the lacipa riah ,sllec
P
''e5 8 ycneuqerf-wol sdlohserht detfihs yb at tsom 15
E
.Bd ehT margoelhcocotyc dna dlohserht tfihs
'6
Y noitcnuf of CH83, the htruof puorG 2 ,tcejbus
d
.$ 4 detacidni that ni the ecnesba of lla riah sllec ni the
I
E lacipa 35% of the ,aelhcoc ycneuqerf-wol
$$2 sdlohserht detfihs at tsom yb 20 .Bd elihw lasab
a
riah sllec were lamron dna ycneuqerf-hgih
sdlohserht were .degnahcnu
ssap-hgiH gniksam data were detcelloc morf lla
t
of these .stcejbus Data morf CH47 dna CH84
etartsnomed that ni the ecneserp of the ,reksam
sdlohserht at lla seicneuqerf were ,detavele -gus
gnitseg that nehw lacipa sCHI are yletelpmoc
0.125 0.5 2.0 6.0 32.0 Percent ecnatsiD from Apex
Frequsncy(kHz) 0 20 40 60 60 100
.giF .4 tfeL rae margoelhcocotyc dna etulosba dlohserht tfihs
100
snoitcnuf fo ,74HC a allihcnihc hcihw dah a eborpoyrc deilppa
ot eht xepa fo eht ynob llaw fo eht aelhcoc ecno rof 3 .nim PTS P
''E3 60
atad refer ot eht dlohserht tfihs derusaem ni eht ecnesba fo a
E
,reksam elihw reksam atad refer ot eht dlohserht tfihs -aem
==" 60
derus ni eht ecneserp fo a 17.0 zHk ssap-hgih .reksam ehT
8
drawnwod worra setacidni taht eht tnetxe fo eht dlohserht tfihs
$ 40
dluoc ton eb denimreted ta eht gnidnopserroc .ycneuqerf I
ycneuqerF dna ecnatsid sexa era dengila gnidrocca ot eht
E 20
dohtem fo egderdlE et .la .)1891( ataD( morf htimS et .la tf
.)7891 0
puorG 2 stcejbus (CH47 dna CH94) evah neeb
reported yb htimS et .la (1987).
.giF 4 shows the tfel ear margoelhcocotyc dna
dlohserht tfihs noitcnuf of CH47. llA of the ,sCHI
dna tsom of the OHCs, were gnissim ni the lacipa
30% of the ;aelhcoc ycneuqerf-wol sdlohserht
detfihs yb at tsom 15 ,Bd elihw ycneuqerf-hgih
sdlohserht were .degnahcnu drawnwoD arrows ni 0.125 0.5 2.0 6.0 32.0
ycneuqerF (kHz)
the rewol flah of siht dna tneuqesbus serugif -idni
.giF .5 tfeL rae margoelhcocotyc dna etulosba dlohserht tfihs
cate that the tnetxe of the dlohserht tfihs dluoc
snoitcnuf fo ,48HC a allihcnihc hcihw dah a eborpoyrc deilppa
ton eb denimreted at the gnidnopserroc .ycneuqerf
ot eht xepa fo eht ynob llaw fo eht aelhcoc ,eciwt htiw
dlohserhT tfihs was semitemos tluciffid ot -aem noitacilppa snoitarud fo 5.1 nim dna na noitacilpparetni -retni
erus at yrev hgih dna yrev wol seicneuqerf esuaceb lav fo 3 .nim PTS atad refer ot eht dlohserht tfihs derusaem ni
the ’stcejbus lamron etulosba sdlohserht were hgih eht ecnesba fo a ,reksam elihw reksam atad refer ot eht
dlohserht tfihs derusaem ni eht ecneserp fo a 17.0 zHk ssap-hgih
at these .seicneuqerf ehT margoelhcocotyc dna
reksam tes ot 46 Bd LPS (C .)elacs drawnwoD sworra sa ni
dlohserht tfihs noitcnuf of CH84, nwohs ni .giF 5,
.giF .4 ycneuqerF dna ecnatsid sexa era dengila gnidrocca ot
etacidni that ni the ecnesba of lla of the riah sllec eht dohtem fo egderdlE et .la .)1891(
6X1
Percent D~staoce from Apex
0 20 40 60 80 100
ehT three stcejbus ni siht ,puorg htiw etelpmoc
1oc
ssol of lacipa dna laitrap ssol of lasab riah ,sllec
were dezilaruanom sallihcnihc whose gniniamer
)tfel( ear was treated htiw a .eborpoyrc Data morf
CH34 were reported yb htimS et .la (1987). .giF 7
shows the tfel ear margoelhcocotyc dna dlohserht
tfihs noitcnuf of CH34. OHCs were deyortsed
tuohguorht the ,aelhcoc elihw sCHI were ,tneserp
except ni the lacipa 20% of the .aelhcoc sdlohserhT
C
detfihs at lla seicneuqerf yb 06--04 ,Bd except at
22.4 kHz, where the tfihs was 22 .Bd
.giF 8 shows the tfel ear margoelhcocotyc dna
tnenamrep dlohserht tfihs noitcnuf for CH98.
OHCs were tneserp ylno ni the tsom-lasab 10% of
the .aelhcoc sCHI were yleritne tnesba morf the
1 reppu 20%, dna tuohguorht tsom of the lacipa
,flah tub were yltsom deniater ni the lasab flah of
the aelhcoc .)%09-06( ,sdlohserhT ,revewoh -ni
0.125 0.5 2.0 8.0 320
Frequency (kHz)
.giF .6 tfeL rae margoelhcocotyc dna etulosba dlohserht tfihs
snoitcnuf fo .49HC a allihcnihc hcihw dah a ehorpoyrc deilppa Percent D~stancefrom Apex
ot eht xepa fo eht ynob ttaw fo eht aelhcoc ,eciwt htiw 0 20 40 60 80 100
snottachppa snoitarud fo 5.1 nim dna na noitacilpparetni
lavretni fo 3 .nim PTS atad refer ot eht dlohserht tfihs -aem
derus ni eht ecnesba fo a ,reksam elihw -74 dna Bd-75 atad
refer ot eht dlohserht tfihs derusaem ni eht ecneserp fo a 17.0
zHk ssap-hgih reksam tes ot 74 dna 75 Bd LPS (C .)rlacs
ycneuqerF dna ecnatsid sexa era dengila gnidrocca ot eht
dohtem fo egderdlE et .la .)1891(
,deyortsed degamadnu -dim dna nrut-lasab riah
sllec detect ycneuqerf-wol .ilumits gniksaM data
morf CH94 appear ot tcidartnoc siht :tnemetats ni
the ecneserp of the ssap-hgih ,reksam ylno -hgih
ycneuqerf sdlohserht were .detavele ,revewoH esolc
noitnetta ot .giF 6 stseggus that emos degamadnu
sCHI deniamer hcihw were detacol ni na area of
the aelhcoc that dedocne seicneuqerf woleb the
ycneuqerf-wol ffotuc of the .reksam Perhaps the
0.125 0.5 2.0 8.0 32.0
esnopser of the lacipa-non sllec ot ycneuqerf-wol
FrequencyjkHz)
ilumits si ylno delaever nehw lla lacipa sCHI evah .giF .7 tfeL rae margoelhcocotyc dna etulosba dlohserht tfihs
neeb .deyortsed tahT .si lasab sllec yam dnopser noitcnuf fo .43HC a allihcnihc hcihw dah a eborpoyrc deilppa
ot level-hgih ycneuqerf-wol noitalumits at lla semit ot eht xepa fo eht ynob llaw fo eht aelhcoc .eciwt htiw
noitacilppa snoitarud fo 0.2 dna 0.3 nim dna na -achpparetni
ni the lamron ear, tub yeht yam etaidem wol
noit favretni fo 4 .nim drawnwoD sworra sa ni .giF .4 ycneuqerF
ycneuqerf gniraeh ylno nehw lacipa snoiger are
dna ecnatsid sexa cra dengila gnidrocca ot eht dohtem fo
.deyortsed egderdlE et .la .)1891( ataD( morf htimS et ..la .)7891
781
Percent Distance from Apex that ycneuqerf-wol gniraeh nac eb detaidem yb
0 20 40 60 80 100 lasab riah .sllec
Group 4 (Partial apical loss, complete basal loss)
ehT ruof stcejbus ni siht puorg were syeknom
treated htiw .sedisocylgoninra Data morf three of
these syeknom (M44, M62, dna M91) were -ed
debircs yb snikwaH et .la (1977) elihw data morf
M21 were deliated yb snibbetS et .la (1969). ehT
thgir ear margoelhcocotyc dna tnenamrep
dlohserht tfihs noitcnuf of M62, treated htiw 100
/gm yad/gk DHSM for 75 ,syad are nees ni .giF
9. Less naht 20% of sCHI or OHCs were tneserp
ni the lacipa 20% of the ,aelhcoc elihw on riah
sllec were tneserp ni the gniniamer 80% of the
.aelhcoc gniraeH was detcirtser ot seicneuqerf of
0.5 kHz dna .woleb
ehT thgir ear margoelhcocotyc dna tnenamrep
dlohserht tfihs noitcnuf of M91, a patas yeknom
0.125 0.5 2.0 8.0 32.0
treated htiw 20 yad/gk/gm DHSM for 100 ,syad
ycneuqerF )zHk(
.giF .8 tfeL rae margoelhcocotyc dna etulosba dlohserht tfihs are detciped ni .giF 10. oreZ ot ytrof tnecrep of
snoitcnuf fo ,89HC a allihcnihc hcihw dah a eborpoyrc deilppa
ot eht xepa fo eht ynob llaw fo eht aelhcoc ,eciwt htiw
noitacilppa snoitarud fo 5.1 nim dna na noitacilpparetni -retni Percent Distance from Apex
lav fo 3 .nim PTS atad refer ot eht dlohserht tfihs derusaem ni 0 10 20 30 40 50 60 70 80 90 100
r
eht ecnesba fo a ,reksam elihw -74 dna Bd-75 reksam atad refer
I
ot eht dlohserht tfihs derusaem ni eht ecneserp fo a 17.0 zHk
ssap-hgih reksam tes ot 74 dna 75 Bd LPS (C .)elacs ycneuqerF
)
dna ecnatsid sexa era dengila gnidrocca ot eht dohtem fo
egderdlE et .la .)1891(
1
I
creased at lla seicneuqerf yb 04-02 ;Bd the
dlohserht tfihs for 1.0 kHz dna woleb was ylthgils
1
ssel (23 dB) naht that for 0.61-0.1 kHz (30 dB).
sihT gnidnif of a rellams tfihs for seicneuqerf-wol ) ’
naht for seicneuqerf-hgih was detacilpud ni the
data of CH118, the driht puorG 4 ,tcejbus elihw
the nrettap of riah llec ssol was ralimis for CH98
dna CH118. ssap-hgiH gniksam data morf CH98,
nees ni .giF 8, mrifnoc the sisehtopyh that -nu
degamad lasab sllec dednopser ot ycneuqerf-wol
;ilumits ni the ecneserp of the Bd-75 ,reksam
sdlohserht at lla seicneuqerf were detavele yb
02-ol .Bd 0.125 0.5 2.0 8.0 32.0
tuohguorhT siht ,tnemirepxe a laitnatsbus Frequency (kHz)
(greater naht 30 dB) ycneuqerf-wol dlohserht tfihs .giF .9 thgiB rae margoelhcocotyc dna etulosba dlohserht tfihs
noitcnuf fo ,26M a yeknom acacaM( )anirtsemen detaert htiw
was decudorp ylno nehw htob lacipa dna lasab
001 yad/gk&m nicymotpertsordyhid rof 57 .syad ycneuqerF
riah sllec were .degamad sihT ,gnidnif ni -cnujnoc
dna ecnatsid sexa era dengila sa debircsed yb snibbetS et .la
noit htiw the ssap-hgih gniksam data, stseggus .)7891( ataD( morf snikwaH et ..la .)7791
881
ecnatsiD
Percent from Apex noissucsiD
0 10 20 30 40 50 60 70 80 90 100
100 ehT tnetni of siht yduts was ot etaulave the
gniraeh hcihw deniamer gniwollof the laitnereffid
noitcurtsed of lacipa riah .sllec ehT yteirav of
gninoisel seuqinhcet deyolpme decudorp tnereffid
snrettap of riah llec noitcurtsed hcihw were -tac
deziroge otni ruof .spuorg
Data morf puorG 1 stcejbus etacidni that htiw
50% lacipa OHC ,noitcurtsed sdlohserht desaercni
0 yb at tsom 10 .Bd esehT data are ni tsartnoc ot
data gnibircsed dlohserht stfihs gniwollof egamad
ni the lasab .aelhcoc iksokilY (1974) reported that
ni the aeniug ,gip after noitcurtsed of row 1 lasab
OHCs, sdlohserht detfihs yb 18 ,Bd of row 2
OHCs, yb 38 ;Bd dna lla 3 rows of OHCs, yb 42
.Bd ,ylralimiS htiw laitnatsbus lasab OHC ssol
dna good lasab CHI .noitneter snikwaH et .la
(1977) nesorP et .la (1978), dna snibbetS et .la
(1987) reported a 06-04 Bd ycneuqerf-hgih -raeh
gni .ssol
.giF .01 thgiR rae margoelhcocotyc dna etulosba dlohserht gniksaM data morf the stcejbus htiw laitrap
tfihs noitcnuf fo .19M a yeknom subecorhtyrE( )satap detaert lacipa riah llec ssol detseggus that the gniniamer
htiw 02 yad/gk/gm nicymotpertsordyhid rof 001 .syad -nwoD lacipa sllec nac detect ycneuqerf-wol slangis at wol
draw sworra sa ni .giF .4 ycneuqerF dna ecnatsid sexa era
,slevel gnirrucnoc htiw the gnidnif of kralC dna
dengila sa debircsed yb snibbetS et .la .)7891(
enhoB (1986) that a lluf tnemelpmoc of lacipa riah
sllec si ton yrassecen for ylraen lamron dlohserht
noitceted of wol ycneuqerf .ilumits ehT lasab
OHCs were tneserp ni the lacipa 40% of the aelhcoc does ton evaheb ni siht ;noihsaf laitrap
,aelhcoc elihw %52-O of sCHI deniamer ni the riah llec ssol si syawla deinapmocca yb a -arusaem
lacipa 50% of the .aelhcoc No riah sllec were elb gniraeh .ssol
tneserp ni the lasab flah of the .aelhcoc -erroC nehW the level of the erusopxe-esion was -ni
gnidnops ot siht nrettap of gniniamer riah ,sllec creased ot 120 Bd for the aeniug sgip ni puorG 1.
M91 dednopser ot ilumits morf 0.063 ot 4.0 kHz gniraeh netfo degnahc at elddim dna hgih -erf
after gurd .tnemtaert ehT data tseggus that ni the seicneuq ni the ecnesba of a gnidnopserroc riah
ecneserp of evissam lacipa dna etelpmoc lasab llec .ssol sihT nrettap of laitnatsbus gniraeh ssol
riah llec ,ssol ycneuqerf-wol sdlohserht yam tfihs deinapmoccanu yb riah llec noitcurtsed has neeb
yb ylno 04-02 .Bd debircsed ni seiduts gnisu hgih slevel of esion
eviF lanoitidda sets of smargoelhcocotyc dna ivlaS( et ,.la ;2891 Shaddock dna Borszcz, ;6891
smargoidua were elbaliava morf the puorG 4 -bus Borg, ;7891 dna xeniS et ,.la 1987). namrebiL dna
.stcej Of these, eno set was ylbakramer ralimis ot lieB )7891( detseggus that ailicoerets snoitaretla
data morf M62, htiw gniraeh detimil ot -neuqerf devresbo htiw the thgil epocsorcim were the tseb
seic 0.5 kHz dna woleb dna riah sllec gniniamer .rotacidni ni noitidda ot llec death, of the dlohserht
ylno ni the lacipa 10% of the .aelhcoc ehT -niamer noitavele derusaem ni elgnis yrotidua evren .srebif
gni ruof detartsnomed gniraeh pu ot 4.0 kHz (3 Shaddock dna Borszcz (1986) debircsed eltbus
)slamina or 8.0 kHz (1 ;)lamina sdlohserht at these segnahc ni OHCs detacol ni the redluohs of a
hgih seicneuqerf had detfihs yb 09-06 .Bd ehT decudni-esion noisel 3 shtnom ;erusopxe-tsop -erp
ytirojam of gniniamer riah sllec ni lla -oelhcocotyc ,ylbamus these .sllec hcihw had tcatni ,ailicoerets
smarg was detimil ot the lacipa 25% of the .aelhcoc dluow evah neeb detnuoc tneserp nehw gnisu the