Avtor/Urednik		Butinar, Dušan; Gros, Anton
Naslov		Predoperacijska elektrofiziološka obravnava otrok, kandidatov za polžkov vsadek
Prevedeni naslov		Preoperative neurophysiological assessment of children, candidates for cochlear implantation
Tip		članek
Vir		Med Razgl
Vol. in št.		Letnik 39, št. Suppl 3
Leto izdaje		2000
Obseg		str. 191-4
Jezik		slo
Abstrakt		Background: For electrophysiological assessment of children with profound cochlear hearing loss - candidates for cochlear implantation, electrocochleography (EcochG) and recording of electrically evoked auditory brain-stem responses (EABR) are used. They provide an objective measure of the inner ear cell damage and preservation of auditory nerve fibers which is a prerequisite for a successful cochlear implantation. Setting: the operating room. Patients: Since November 1998 we have tested 22 children, 14 girls and 8 boys, aged 8 months to 16 years, in general anaesthesia and muscular relaxation Methods: 100 micro s alternating click stimuli were presented via the headphones to each ear. Electrocochleograms were recorded with needle electrode at the promontorium and surface electrode on the vertex. Stimuli consisting of 200 micro s inversed biphasic current pulses with intensity increasing from 600 microA to 1mA were provided by transtympanically placed promontory needle electrode. EABR were recorded with surface electrodes on the vertex and contralateral mastoid. The ground electrode was placed on the forehead at the beginning of the study, but was later moved to the ipsilateral mastoid, since this position was found associated with a substantially smaller artefact. Results: As expected, no electrocochleograms could be recorded in our children. EABR were obtained from 12 of the 22 patients tested. Mean EABR threshold was 690 microA (SD=110.3), mean wave V latency at the treshold was 4.8ms, and mean wave V amplitude was 0.25 micro V. Conclusion: Since one year, EcochG and EABR have been an integral component of the preoperative selection process for children who are candidates for cochlear implants. The ear with no EcochG and hogher EABR amplitude and lower threshold is chosen for implantation.
Izvleček		Namen: Z elektrokohleografijo (ECochG) in preiskavo električnih potencialov slušne poti v možganskem deblu (EABR) elektrofiziološko preverjamo, kdo izmed gluhih otrok je lahko kandidat za polžkov vsadek. Preiskavi namreč pokažeta prizadetost notranjega ušesa in koliko so ohranjena vlakna slušnega živca, kar je pogoj za uspešno delovanje polžkovega vsadka. Metode in bolniki: Preiskavi delamo v operacijski dvorani, ko so otroci v splošni anesteziji in mišično relaksirani. Pri ECochG smo dražili vsako uho posebej s klikom jakosti 100 dB HL, aktivnost polžka pa odjemali z igelno elektrodo na promontoriju, z referenčno površinsko elektrodo na temenu glave. Za EABR smo dražili vlakna slušnega živca z isto igelno elektrodo na promontoriju, in sicer z obrnjenimi dvofaznimi električnimi dražljaji, trajajočimi 200ps, njihovo jakost pa smo večali od 600 mikroA do 1 mA. EABR smo odjemali na temenu glave in na mečici nasprotnega ušesa. Ozemljitveno elektrodo smo sprva nameščali na čelo, vendar se je izkazalo, da je pri tem položaju dražilni artefakt prevelik, in smo jo zato kasneje pritrjevali na bradavičar na strani električnega draženja. Od novembra 1998 smo pregledali 22 otrok, 14 deklic in 8 dečkov, starih od 8 mesecev do 16 let. Rezultati: Kot smo pričakovali, elektrokohleograma nismo dobili pri nobenem, EABR pa pri 12 od 22 pregledanih otrok. Srednja vrednost za prag za EABR je bila 690 mikroA (SD = 110,3), srednja vrednost latence vrha NV ob pragu je bila 4,8 ms, srednja vrednost amplitude vrha NV pa 0,25 mikroV. Zaključki: Elektrokohleografija in EABR sta sestavna dela presejalnega testiranja za otroke, ki so kandidati za polžkove vsadke. Za vsadek izberemo uho brez kohleograma, ki ima nižji prag izvabljanja EABR oziroma višjo amplitudo EABR.
Deskriptorji		AUDIOMETRY, EVOKED RESPONSE EVOKED POTENTIALS, AUDITORY, BRAIN STEM AUDITORY PERCEPTION COCHLEAR IMPLANT PATIENT SELECTION ACOUSTIC NERVE ANESTHESIA, GENERAL