Kunigunde Welzl-Müller

Post-operative Stapedius Reflex Tests with Simultaneous Loudness Scaling in Patients Supplied with Cochlear Implants

The estimation of the maximum comfort loudness levels (MCL) by measurements of the electrically elicited stapedius reflex was examined in six experienced cochlear implant users supplied with the COMBI 40 implant system. The stapedius reflex was tested and loudness scaling was performed simultaneously using an up/down stimulation protocol close to the reflex threshold with automated recording of both test procedures. The electrical stapedius reflex threshold (ESRT) and loudness scaling were evaluated separately. Scaling at the reflex threshold ranged between normal and loud. The range of stimulus intensities corresponding to ESRT is much smaller than that at a particular loudness category. The overall correlation between ESRT and MCL was high (r=0.92), with a similar dependence of ESRT and MCL on the channel stimulated. Thus, when the stapedius reflex can be detected post-op-eratively, the ESRT can be applied successfully for the fitting procedure of the speech processor. Simultaneous loudness scaling during the entire reflex test showed that overstimulation via the implant can be avoided effectively.

Stapedius Reflex Threshold in Cochlear Implant Patients

The contralateral stapedius reflex elicited by sinusoidal electrostimulation via cochlear implant was investigated in 12 patients. Contraction of the middle ear muscle was monitored by time-resolved synchronized digital sampling of the impedance change in the contralateral ear. The reflex was detected in all patients in whom the uncomfortable loudness level (UCLL) could be reached and who had intact middle ear function. Generally, the reflex threshold is located in the upper part of the dynamic range between the most comfortable loudness (MCL) and the UCLL. The demonstrated method may provide suitable assistance in speech processor adjustment in difficult-to-test patients.

Confirmation of Transiently Evoked Otoacoustic Emissions Based on User-Independent Criteria

Transiently evoked otoacoustic emissions (TEOAEs) were recorded from 525 ears (children, 3-11 years). Based on visual evaluation, the recordings were classified as TEOAEs present, absent or uncertain. Within each group the distribution of response level and reproducibility as well as of four derived parameters were calculated. The latter comprised: (1) corrected response level (difference between response level and approximated noise), (2) weighted response level (product of response level and correlation), (3) weighted sound pressure of the response (product of sound pressure and correlation) and (4) level of the weighted sound pressure of the response (weighted sound pressure of the response transformed to decibels). Based on these distributions, criteria to separate recordings with TEOAEs from recordings without TEOAEs were established. In this study the cutoff point is the parameter value where the amount of incorrectly identified recordings with TEOAEs is equal to the amount of correctly identified recordings without TEOAEs. The corresponding limiting values are: (a) response level 7.3 dB with 7.6% incorrect identifications for each group, (b) reproducibility 56% with 4.2% incorrect identifications, (c) corrected response level 2.4 dB with 5% incorrect identifications, (d) weighted response level 3.7 dB with 3.2% of incorrect identifications, (e) sound pressure of the response 0.027 mPa with 2% incorrect identifications and (f) level of the weighted sound pressure of the response 1.22 dB with 2% incorrect identifications.

Epidemiology of permanent childhood hearing impairment in the Tyrol, 1980-94

In recent years the need for reliable data on permanent childhood hearing impairment (PCHI) has increased, owing to both scientific interest and practical aspects such as implementation of neonatal hearing screening. In order to obtain data about the epidemiology of PCHI in the Austrian state of Tyrol, the medical records of all hearing-impaired Tyrolean children born between 1980 and 1994 were researched. A total of 165 children with at least moderate hearing impairment in the better ear were registered, of whom 52.7% were found to be moderately hearing-impaired, 24.2% severely hearing-impaired and 23.0% profoundly hearing-impaired. Sensorineural hearing loss was observed in 87.3%, conductive hearing loss in 6.7% and mixed hearing loss in 6.1%. As for aetiology, non-syndromic hereditary hearing loss was diagnosed in 22% of the children and syndromic hearing loss in 8%. Congenital malformation of the ear was found in 3%. In 19% of the children, perinatal risk factors were seen, and in 10% a pre-, peri- or postnatal infection had occurred. Aetiology remained unknown in 36% of the children. The prevalence rate of newborn hearing impairment was 1.27/1000 newborns. The results are considered to fit well to the PCHI findings reported from other European regions.

Stapedius reflex growth function in cochlear implant patients

The growth function of the contralateral stapedius reflex elicited by analog electrostimulation via cochlear implant was investigated in 9 patients and compared to reflex functions obtained for acoustic stimulation in 3 normal-hearing subjects. Sinusoidal signal bursts with the same time pattern were used for the two stimulation modes, the contraction of the middle ear muscle was monitored by sampling the compliance change in the contralateral ear. The reflex amplitudes were found to increase with increasing stimulus intensity in all individuals except in 1 with electrical stimulation. The slope of the intensity function for electrostimulation ranged between 5 and 85%/dB and in the acoustical mode between 2 and 4%/dB. In case of electrostimulation a frequency effect was observed.

Hörscreening an Kindergärten: Ergebnisse einer Evaluierungsstudie

SummaryObjectiveThis study aimed to evaluate the hearing screening of pre-school children at nursery schools in Tyrol, Austria.Methods and sample47 nursery schools with a total of 2199 enrolled children participated in the study. At the screening, the children were presented a series of tones at frequencies 0.5 kHz (25 dB), 1 kHz, 2 kHz, 3 kHz, and 4 kHz (20 dB each) from portable audiometers. The tones were presented over headphones for each ear separately and at irregular intervals. Failure to respond to any of the frequencies was considered failure of the screening. Parents were then advised in written form to have the child examined by an ENT-specialist.Results1832 individuals were screened (coverage: 83% of nursery school children; corresponding to at least 63% of all Tyrolean children aged 3 to 5 years). Of these, 390 failed the test (referral rate: 21% of all screened). Examination through an ENT-specialist occurred with 217 children, and this confirmed the positive test in 139 children (hit rate: 64%). In most cases, a temporary conductive hearing loss due to external or middle ear problems (glue ear, tube dysfunction, cerumen, otitis media) was diagnosed. A sensorineural hearing loss was found in 4 children (in 3 of them bilateral). The need for therapy was recognized in 81 children (4% of all screened).ConclusionPre-school hearing screening identifies children with ear and hearing problems that need therapeutical intervention. Although the hearing problems are mostly of a temporary nature, some may require monitoring over some period. Also some children with permanent sensorineural hearing loss may be detected through this measure. Hearing screening is an efficient means of assessing ear and hearing problems in pre-school children. However, the follow-up rate needs to be improved for optimizing the efficacy.ZusammenfassungFragestellungZweck der Studie war die Evaluierung des Hörscreenings im Vorschulalter an den Tiroler Kindergärten.Methode und StichprobeDie Studie wurde in zwei Bezirken durchgeführt, es nahmen 47 Kindergärten mit insgesamt 2199 eingeschriebenen Kindern teil. Beim Screening werden den Kindern mittels portabler Audiometer Töne der Frequenzen 0,5 kHz (25 dB), 1 kHz, 2 kHz, 3 kHz und 4 kHz (je 20 dB) für jedes Ohr getrennt über Kopfhörer angeboten. Gibt das Kind auf mindestens eine Frequenz keine antwort, gilt das Testergebnis als auffällig. In diesem Fall werden die Eltern schriftlich aufgefordert, das Kind HNO-fachärztlich untersuchen zu lassen. Die Ergebnisse der fachärztlichen Untersuchung wurden zur Validierung des Hörscreenings herangezogen.ErgebnisseDas Screening erfasste 1832 Kindergartenkinder (83%), dies entspricht mindestens 63% der Population der Drei- bis Fünfjährigen (coverage). Von den Getesteten bestanden 390 das Screening nicht (referral rate: 21%). Das Ergebnis der fachärztlichen Abklärung lag von 217 Kindern vor (follow-up rate: 56%). In 139 Fällen hat der HNO-ärztliche Befund den positiven Screeningtest bestätigt (Trefferrate: 64%), wobei meist eine Schalleitungsstörung diagnostiziert wurde (Seromukotympanon, Tubenventilationsstörung, Cerumen, Otitis media). Eine Innenohrschwerhörigkeit wurde bei 4 Kindern gefunden (davon 3 beidseitig). Die Notwendigkeit einer Therapie wurde von den Fachärzten in 81 Fällen (37% der Kinder mit auffälligem Screeningergebnis bzw. 4% der Getesteten) angegeben.SchlussfolgerungenDurch das Hörscreening in Kindergärten werden Vorschulkinder mit therapiebedürftigen ohrbefunden oder/und Hörproblemen entdeckt. Es über-wiegen passagere Hörstörungen, in diesen Fällen sind oft primär Kontrollen bzw. “Überwachung” von Ohrbefund oder/und Hörvermögen notwendig. Es werden aber auch Kinder mit permanenten Hörschäden entdeckt, die bisher noch nicht erfasst sind. Diese Vorsorgeuntersuchung ist daher eine effiziente Maßnahme, um Kinder mit Hör-/Ohrproblemen noch vor Schuleintritt zu erfassen. Dringend erforderlich ist es jedoch, die Abklärungsrate (follow-up rate) zu verbessern.OBJECTIVEnThis study aimed to evaluate the hearing screening of pre-school children at nursery schools in Tyrol, Austria.nnnMETHODS AND SAMPLEn47 nursery schools with a total of 2199 enrolled children participated in the study. At the screening, the children were presented a series of tones at frequencies 0.5 kHz (25dB), 1 kHz, 2 kHz, 3 kHz, and 4 kHz (20 dB each) from portable audiometers. The tones were presented over headphones for each ear separately and at irregular intervals. Failure to respond to any of the frequencies was considered failure of the screening. Parents were then advised in written form to have the child examined by an ENT-specialist.nnnRESULTSn1832 individuals were screened (coverage: 83% of nursery school children; corresponding to at least 63% of all Tyrolean children aged 3 to 5 years). Of these, 390 failed the test (referral rate: 21% of all screened). Examination through an ENT-specialist occurred with 217 children, and this confirmed the positive test in 139 children (hit rate: 64%). In most cases, a temporary conductive hearing loss due to external or middle ear problems (glue ear, tube dysfunction, cerumen, otitis media) was diagnosed. A sensorineural hearing loss was found in 4 children (in 3 of them bilateral). The need for therapy was recognized in 81 children (4% of all screened).nnnCONCLUSIONnPre-school hearing screening identifies children with ear and hearing problems that need therapeutical intervention. Although the hearing problems are mostly of a temporary nature, some may require monitoring over some period. Also some children with permanent sensorineural hearing loss may be detected through this measure. Hearing screening is an efficient means of assessing ear and hearing problems in pre-school children. However, the follow-up rate needs to be improved for optimizing the efficacy.

Zehn Jahre Neugeborenen-Hörscreening in Österreich: Eine Evaluierung

SummaryBACKGROUND: Universal neonatal hearing screening (UNHS) has been gradually implemented since the mid-nineties in Austrian maternity wards and neonatal intensive care units. This study evaluated the effect of UNHS on reducing age at identification as well as age of intervention for children with congenital and perinatal sensorineural hearing impairment. METHODS: This was a retrospective analysis of clinical data of 394 Austrian children diagnosed with an at least mild degree (>20dB hearing level) of permanent sensorineural hearing loss. Age at identification and age at intervention were compared between children who underwent UNHS (with UNHS) and those who did not undergo UNHS (without UNHS). RESULTS: The median of age of identification was 37.6 months in children without UNHS, and 3.9 months in children with UNHS. By six months of age, 69% of hearing-impaired children who underwent UNHS were identified but only 6% of those without UNHS. At one year, the corresponding percentages are 80% and 12%, respectively. In children without UNHS, the degree of hearing loss was the most predictive factor of age at identification (median of age at diagnosis for profound hearing loss, 15 months; severe, 26 months; moderate, 52 months; mild, 73 months). In children with UNHS, age of identification was unrelated to degree of hearing loss (medians between 3.7 and 4.4 months). In the majority of children intervention, began within one month after diagnosis, regardless of whether or not the child was identified by UNHS. DISCUSSION: UNHS greatly increases the proportion of children whose hearing impairment is diagnosed before six months of age. However, in some 20% of children, hearing impairment was diagnosed later than one year of age, despite having failed the screening. Additionally, data from this study suggest that about 15% of childhood hearing losses manifest themselves after the hearing screening period. Efforts are thus required for the early detection of these children as well.ZusammenfassungFRAGESTELLUNG: Ab Mitte der 90er Jahre wurde das Neugeborenen-Hörscreening an österreichischen Geburten- und neonatologischen Stationen zunehmend eingeführt. Seit 2003 ist es im Mutter-Kind-Pass verankert. Ziel dieser Studie war es zu überprüfen, ob das universelle Neugeborenen-Hörscreening (UNHS) eine relevante Absenkung des Alters bei Erkennung der frühkindlichen Hörstörungen bewirkt. METHODE UND STICHPROBE: Retrospektive Analyse der Daten von 394 Kindern mit prä/perinataler permanenter sensorineuraler Hörstörung, die seit 1990 in österreichischen Einrichtungen erfasst wurden. Das Alter bei Diagnose der Hörstörung und bei Beginn der Intervention wurde verglichen zwischen Kindern, bei denen ein Hörscreening durchgeführt wurde (mit UNHS), und Kindern, bei denen keines durchgeführt wurde (ohne UNHS). ERGEBNIS: Bei Kindern mit UNHS liegt der Median des Alters bei Diagnose der Hörstörung bei 3,9 Monaten, bei Kindern ohne UNHS bei 37,6 Monaten. Bis zum Alter von 6 Monaten wurden mit UNHS 69 % der hörgestörten Kinder erfasst, ohne UNHS nur 6 %. Bis zum Alter von 1xa0Jahr sind die entsprechenden Werte 80 % bzw. 12 %. Wird kein UNHS durchgeführt, dann bestimmt der Grad der Hörstörung den Zeitpunkt bei Diagnose (Median des Diagnosealters für resthörig bzw. gehörlos, 15xa0Monate; hochgradig, 26xa0Monate; mittelgradig, 52xa0Monate; geringgradig, 73xa0Monate). Bei Kindern mit UNHS ist das Diagnosealter unabhängig vom Grad der Hörstörung (Mediane zwischen 3,7 und 4,4 Monaten). Die Intervention erfolgt – unabhängig, ob ein Hörscreening erfolgte – bei der Mehrzahl der Kinder innerhalb eines Monats nach Diagnose. DISKUSSION: Das UNHS führt zu einer enormen Erhöhung des Anteils der Kinder, deren Hörstörung vor dem 6. Lebensmonat bzw. innerhalb des ersten Lebensjahres erkannt wird. Unbefriedigend ist, dass bei ca. 20 % der Kinder trotz auffälligem Ergebnis im Hörscreening die Diagnose erst nach dem 1. Lebensjahr gestellt wird. Unsere Daten legen zudem nahe, dass ca. 15 % aller hörgestörten Kinder einen Beginn der Hörstörung nach dem Hörscreening aufweisen, was die Wichtigkeit zusätzlicher Maßnahmen zur Früherkennung auch dieser Fälle anzeigt.FRAGESTELLUNG: Ab Mitte der 90er Jahre wurde das Neugeborenen-Horscreening an osterreichischen Geburten- und neonatologischen Stationen zunehmend eingefuhrt. Seit 2003 ist es im Mutter-Kind-Pass verankert. Ziel dieser Studie war es zu uberprufen, ob das universelle Neugeborenen-Horscreening (UNHS) eine relevante Absenkung des Alters bei Erkennung der fruhkindlichen Horstorungen bewirkt. METHODE UND STICHPROBE: Retrospektive Analyse der Daten von 394 Kindern mit pra/perinataler permanenter sensorineuraler Horstorung, die seit 1990 in osterreichischen Einrichtungen erfasst wurden. Das Alter bei Diagnose der Horstorung und bei Beginn der Intervention wurde verglichen zwischen Kindern, bei denen ein Horscreening durchgefuhrt wurde (mit UNHS), und Kindern, bei denen keines durchgefuhrt wurde (ohne UNHS). ERGEBNIS: Bei Kindern mit UNHS liegt der Median des Alters bei Diagnose der Horstorung bei 3,9 Monaten, bei Kindern ohne UNHS bei 37,6 Monaten. Bis zum Alter von 6 Monaten wurden mit UNHS 69 % der horgestorten Kinder erfasst, ohne UNHS nur 6 %. Bis zum Alter von 1 Jahr sind die entsprechenden Werte 80 % bzw. 12 %. Wird kein UNHS durchgefuhrt, dann bestimmt der Grad der Horstorung den Zeitpunkt bei Diagnose (Median des Diagnosealters fur resthorig bzw. gehorlos, 15 Monate; hochgradig, 26 Monate; mittelgradig, 52 Monate; geringgradig, 73 Monate). Bei Kindern mit UNHS ist das Diagnosealter unabhangig vom Grad der Horstorung (Mediane zwischen 3,7 und 4,4 Monaten). Die Intervention erfolgt – unabhangig, ob ein Horscreening erfolgte – bei der Mehrzahl der Kinder innerhalb eines Monats nach Diagnose. DISKUSSION: Das UNHS fuhrt zu einer enormen Erhohung des Anteils der Kinder, deren Horstorung vor dem 6. Lebensmonat bzw. innerhalb des ersten Lebensjahres erkannt wird. Unbefriedigend ist, dass bei ca. 20 % der Kinder trotz auffalligem Ergebnis im Horscreening die Diagnose erst nach dem 1. Lebensjahr gestellt wird. Unsere Daten legen zudem nahe, dass ca. 15 % aller horgestorten Kinder einen Beginn der Horstorung nach dem Horscreening aufweisen, was die Wichtigkeit zusatzlicher Masnahmen zur Fruherkennung auch dieser Falle anzeigt.

Dynamic Range of the Contralateral Stapedius Reflex in Cochlear Implant Patients

The dynamic range of the contralateral Stapedius reflex elicited by analog electrostimulation via cochlear implant was investigated in 8 subjects supplied with a Vienna prosthesis. The study comprised patients fitted with intracochlear devices as well as patients with extracochlear devices. Sinusoidal bursts of 125, 500, 1,000 and 2,000 Hz were used as stimulation signals. Only in one patient was saturation of reflex amplitude observed. The dynamic range of the Stapedius reflex was defined either by the difference in stimulus level for reflex saturation or individual uncomfortable loudness level and reflex threshold. Two different methods were used, yielding values between 0.1 and 12 dB, with a median of 4 dB. The individual results were compared with individual psychoacoustic quantities, i.e. subjective dynamic range (difference between sensation threshold and uncomfortable loudness level) and residual dynamic range (difference between most comfortable loudness level and uncomfortable loudness level). The reflex dynamic range is located within the residual dynamic range of electrostimulation. Thus the Stapedius reflex dynamic range can be applied as a rough estimate of minimum residual dynamic range.

Examples of implemented neonatal hearing screening programs in Austria

In order to improve early detection of congenital permanent childhood hearing impairment the Austrian ENT society recommended in 1995 that universal neonatal hearing screening be introduced (Millstätter Concept). Coverage is presently about 67% for full-term healthy neonates and 86% for neonates from intensive care units. For maternity units, referral rates between 1% and 3.7% have been reported (2.7- 15% for intensive care units). The results of the screening test and follow-up in cases of failure have been documented in 37 543 neonates. Of this population, 91 infants (2.4 per 1000) showed bilateral permanent hearing loss. In these children intervention and management of the family started within the first months of life. These results justify the effort involved in introducing universal neonatal hearing screening.

The Benefit of Hearing Aids: Influence of Hearing Loss and Age

The relation between accessible benefit and hearing loss in combination with age of the patient is analysed. The degree of hearing loss and improvement derived by hearing aid use as found in this work is based on the individually determined speech reception threshold (SRT) for the condition with and without hearing aid in a noiseless environment. It was found that a significant correlation exists between hearing loss and SRT gain by the hearing aid (difference between unaided and aided speech reception threshold) for a pure-tone hearing loss of less than 40 dB at 500 Hz, irrespective of age, whereas for a hearing impairment of 40-60 dB, the gain by using the hearing aid is dependent on the age of the patient. A multiple regression analysis was performed to study the relation between benefit and hearing loss for the two groups of hearing impairment and different age groups.