<p>Barn med Down syndrom har ofta återkommande hörselproblem som exempelvis vaxpropp och sekretorisk mediaotit. Vanligt förekommande hörselnedsättning bland dessa barn är en fluktuerande konduktiv hörselnedsättning. Den utvecklingsstörning som syndromet orsakar kan leda till att barnen ej kan medverka aktivt vid konventionella hörselmätningar. Metoder för hörselutredning av små barn och barn som ej kan medverka adekvat är BRA, OAE och tympanometri. Syftet med arbetet är att belysa resultaten från BRA, OAE och tympanometri hos barn med DS. Vidare syftar studien till att belysa tänkbara habiliterande insatser för att bibehålla eller förbättra hörseln hos barn med Down syndrom. Som metod används systematisk litteraturstudie. Resultatet från föreliggande studie visar att mätresultat skiljer sig mellan barn med Down syndrom och barn utan Down syndrom. Strukturella avvikelser i hörselsystemet hos barn med Down syndrom påverkar resultaten från dessa mätningar. Det är därför av vikt att resultaten tolkas utifrån kunskaper om hur olika faktorer i hörselsystemet orsakade av syndromet kan påverka resultaten. Barn med DS behöver regelbundna och återkommande hörselhabiliterande insatser för att förebygga konduktiva hörselnedsättningar.</p>

High resolution sampling was performed along the &Uuml / z&uuml / ml&uuml / Formation exposed near the YeniceSihlar village of Mudurnu (Bolu). Field and thin-section analyses showed that the &Uuml / z&uuml / ml&uuml / Formation is composed of cm to m scale cycles of 4th and 5th order. The 4th order cycles are equivalencies of parasequences and have 0.4 Ma average duration. 5th order cycles are interpreted as episodic. Upper Albian (OAE1c or OAE1d) and Cenomanian/Turonian (OAE2) anoxic events are observed as black shale levels in the studied section. Position of black shale levels is interpreted using cyclostratigraphy and sequence stratigraphy. Four types of cycle are determined. A and B-type cycles are placed in transgressive and Highstand System Tract. C and D-type cycles are placed in Lowstand System Tract. Two type 3 and one type 1 sequence boundaries are recorded. The boundary between the Soguk&ccedil / am Limestone and the &Uuml / z&uuml / ml&uuml / Formation is interpreted as the first type 3 sequence boundary. The second one separates the &Uuml / z&uuml / ml&uuml / Formation and the Yenipazar Formation and is observed at the top of the section. Type 1 boundary is represented by a conglomeratic level in the middle of the succession. Provenance analysis of sandstones indicates that during the Cenomanian the source area changed from magmatic arc setting to continental setting.

Professional research project (Au.D.)--University of SouthFlorida, 2000. / Title from PDF of title page. / Document formatted into pages; contains 17 pages. / Includes bibliographical references. / Text (Electronic thesis) in PDF format. / ABSTRACT: The difference in otoacoustic emission (OAE) hearing screening failure rates as a function of ethnic category was investigated in a population of newborns at Tampa General Hospital, Tampa, Florida. Clinical observation led to a concern that due to a higher incidence of outer and middle ear dysfunction in Hispanic newborns and children, screening could result in disparate failure rates, with a larger number of these infants requiring further testing. This result would warrant changes in current protocols, as well as screener training,and parent counseling practices. Between January and July of 2000, 1407 newborns were tested utilizing distortion product otoacoustic emission screening protocols. Of those infants,only 68 failed, yeilding a higher than average overall program referral rate of 5%. It is hypothesized that since later reported referral rates for this program fall below 1%, the individuals performing the screenings had not yet become experienced enough to yield low refer rates. In addtion, initial screens are not repeated in this program due to staffing and funding issues, which may contribute to higher than average fail rates. More important, however, results indicated that there is indeed a difference in failure rates as a funciton of ethnicity, with a greater proportion of Hispanic and African-American and "Other" newborn referrals that Caucasian or Asian newborns. This difference, however, was not significantly reliable. It is hypothesized that this difference may be the result of a generally lower socioeconomic status and access to medical care within urban minority populations in Hillsborough County, Florida. Implications are discussed. / System requirements: World Wide Web browser and PDF reader. / Mode of access: World Wide Web.

Otoacoustic Emissions (OAE) are minute acoustic responses originating from the cochlea as a result of an external acoustic stimulus and are recorded using a sensitive microphone placed in the ear canal. OAEs are acquired by synchronous stimulation with an acoustic click or tone burst and recording of the post-stimulus responses. This method of acquiring OAEs is known as transient evoked otoacoustic emissions (TEAOE) and is commonly used in clinics as a screening method for hearing and cochlear functionality in infants. Recently, a novel method of acquiring OAEs utilizing a swept-tone, or chirp, as a stimulus was developed. This method used a deconvolution process to compress the swept tone response into an impulse or click-like response. Because the human ear does not hear all frequencies (pitches) at equal loudness the swept-tone stimulus was equalized in amplitude with respect to frequency. This equalized stimulus will be perceived by the ear as equally loud in all frequencies. In this study a new hearing level equalized stimulus was designed and the OAE responses were analyzed and compared to conventional click evoked OAEs. The equalized swept-tone stimulus evoked greater magnitude OAE responses when compared to the conventional methods. It was also able to evoke responses in subjects that had little TEOAEs which might fail conventional hearing screening.

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