In der veterinärmedizinischen Wissenschaft spielt das equine akustische Organ sowie dessen Erkrankungen und Funktionsstörungen bislang eine stark untergeordnete Rolle. Mangelnde Visualisierungs- und Untersuchungsmöglichkeiten, geringe Patienten- Compliance sowie fehlende Referenzen erschweren die Diagnose aurikulärer Erkrankungen (SARGENT et al. 2006; SOMMERAUER et al. 2012). Das übergeordnete langfristige Ziel dieser Forschungsarbeit ist es, humanmedizinische objektive audiometrische Messtechnik an das Pferdeohr anzupassen. Von speziellem Interesse ist dabei die Messung otoakustischer Emissionen zur objektiven Überprüfung der Innenohrfunktion. Die grundlegende Voraussetzung jeglicher Messungen und Adaptierungen ist zunächst die otoskopische Kontrolle des externen Gehörkanales und Trommelfelles. So können die Messung behindernde Faktoren, beispielsweise ein hoher Verschmutzungsgrad oder Fremdkörper im externen Gehörkanal, ausgeschlossen werden. Mit Hilfe herkömmlicher Videobronchoskope oder Videogastroskope (Durchmesser von 7 mm bzw. 9 mm) und der Anwendung eines standardisierten Protokolls konnten im Rahmen der Basisstudie die externen Gehörkanäle und Trommelfelle von 38 sedierten Pferden bilateral endoskopisch untersucht werden. Aus praktischer Sicht ist dabei hervorzuheben, dass die bislang obligatorische Leitungsanästhesie der Ohrnerven und das damit verbundene Risiko einer Fazialisparese vollständig umgangen werden konnte. Im Zuge dieses optimierten Verfahrens wurden physiologische und pathologische endoskopische Referenzen des externen Gehörkanales und Trommelfelles erstellt. Pathologische otoskopische Befunde (z.B. Tympanosklerose) sowie mangelnde veterinärmedizinische Fachliteratur verdeutlichen den Bedarf der histologischen Aufarbeitung des equinen akustischen Organs. Im Rahmen der Folgestudie wurden die Ohren von zehn Schlachtpferden für die detaillierte histologische Aufarbeitung herangezogen. Die Ergebnissedieser Arbeit beschreiben und verbildlichen erstmalig das vollständige equine akustische Organ. Im Folgenden sind nun die wesentlichen Ergebnisse der Basis- und Folgestudie zusammengefasst. Der physiologische kartilaginöse externe Gehörkanal ist pigmentiert, mit Haaren sowie mit cerumenproduzierenden Talg- und Schweißdrüsen ausgekleidet. Im Vergleich zum ossären externen Gehörkanal weist der kartilaginöse Anteil einen deutlich höheren Verschmutzungsgrad auf. Der Übergang zwischen dem kartilaginösen und ossären äußeren Gehörgang ist histologisch gekennzeichnet durch einen abrupten Wechsel zu einem unpigmentierten, haarlosen und drüsenfreien mehrschichtig verhornten Epithel. Endoskopisch ist dieser Übergang anhand kranzartig angeordneter beigefarbener Keratinschuppen erkennbar, welche Produkte des Selbstreinigungsmechanismus des knöchernen Gehörganges darstellen. Letzterer besitzt eine rund-ovale Form, ein trockenes zartrosafarbenes Epithel mit konzentrischen Keratinringen und schwach durchscheinender Gefäßzeichnung. Das physiologische equine Trommelfell stellt sich endoskopisch als eine klar in ihre Bestandteile (Pars tensa, Pars flaccida, Stria mallearis) differenzierte semitransparente Membran ohne positiven Lichtreflex dar. Auf der Grundlage der etablierten physiologischen Referenzen konnten pathologische Befunde bei sieben Pferden (vier Pferde mit Aural Plaques, drei Pferde mit Otitis externa) nachgewiesen werden. Zu den typischen Kennzeichen einer Otitis externa zählen die Schwellung und Rötung des ossären Epithels, das Verstreichen der konzentrischen Keratinringe und/oder die Ablösung der schützenden Keratinschicht im ossären Gehörkanal sowie ein positiver Lichtreflex im Bereich des Trommelfelles. Bei einem der an Otitis externa erkrankten Pferde konnte ein möglicher Zusammenhang zu einer Temporohyoidosteoarthropathie (THO) hergestellt werden. Darüber hinaus konnte bei zwei weiteren Pferden erstmalig eine Tympanosklerose diagnostiziert werden. Die Resultate dieser Dissertation liefern die Grundlage für weitere Forschungsansätze auf dem Gebiet des equinen akustischen Organs. Die Ohrendoskopie am stehenden sedierten Pferd ist eine praktikable, schonende sowie diagnostisch wertvolle Untersuchungsmöglichkeit. Sie sollte insbesondere bei der Abklärung einer THO, Fazialisparese, Vestibularsyndrom, Headshaking, Kopfscheue, parasitären Infektionen oder bei Kopftraumata zum Einsatz kommen. Die Ohrendoskopie ist zudem der Ausgangspunkt für die Anpassung und Anwendung humanmedizinischer audiometrischer Messsonden an das Pferdeohr. Die gewonnenen histologischen Erkenntnisse bilden die Basis für weiterführende Untersuchungen hinsichtlich angeborener oder erworbener Mittel- und Innenohrerkrankungen, welche Einfluss auf die Messung der otoakustischen Emissionen haben.:Inhaltsverzeichnis Einleitung ...................................................................................................................... 1 Literaturübersicht .......................................................................................................... 4 Anatomie des equinen akustischen Organs ................................................................. 4 8 Danksagung 2.4.1 2.4.2 2.4.3 2.4.4 Otoskopie ........................................................................................................ 10 Tympanometrie ............................................................................................... 11 Messung otoakustischer Emissionen (OAE) ................................................... 12 Hirnstammaudiometrie (BERA) ....................................................................... 14 Äußeres Ohr...................................................................................................... 4 Mittelohr ............................................................................................................ 4 Innenohr ............................................................................................................ 5 Hörbahn ............................................................................................................ 7 Gleichgewichtsbahn .......................................................................................... 7 2.1.1 2.1.2 2.1.3 2.1.4 2.1.5 Physiologie des Hörvorganges ..................................................................................... 8 Physiologie des Vestibularorgans................................................................................. 9 Untersuchungsmethoden des akustischen Organs .................................................... 10 Ergebnisse .................................................................................................................. 15 Publikation 1: Endoscopic findings of the external ear canal in a group of clinically normal horses and horses with head shaking or vestibular disease .......................... 15 Publikation 2: Histological Study of the External, Middle and Inner Ear of Horses .... 25 Diskussion .................................................................................................................. 44 Otoskopie.................................................................................................................... 45 Der physiologische equine externe Gehörkanal und das Trommelfell ....................... 46 Pathologische Befunde des equinen externen Gehörkanales und Trommelfelles ..... 48 Histologie des equinen akustischen Organs............................................................... 50 Diagnostische Möglichkeiten - OAE ........................................................................... 51 Zusammenfassung ..................................................................................................... 53 Summary .................................................................................................................... 55 Literaturverzeichnis..................................................................................................... 57 Anhang ....................................................................................................................... 64 / The equine acoustic organ, including its diseases and disorders, still plays a minor role in veterinary science. Due to insufficient visualization and examination equipment, little patient compliance and sparse references the diagnosis of auricular diseases is rather difficult (SARGENT et al. 2006; SOMMERAUER et al. 2012). The overall aim of this research project is to adapt human objective audiometric testing devices onto the equine acoustic organ. Particularly, the measurement of so-called otoacoustic emissions is of importance for an objective evaluation of the inner ear function. The otoscopic examination of the external ear canal and tympanic membrane is the fundamental precondition for the adaption of probes and every audiometric testing. Circumstances that may prevent us from having successful measurements, like a high degree of ceruminous and cellular debris or even foreign bodies within the external ear canal, can be identified and eliminated by otoscopy. By the use of common veterinary videobronchoscopes or videogastroscopes (calibre 7 mm/9 mm) the external ear canal and tympanic membrane of 38 standing sedated horses were bilaterally examined following a standardized protocol. Special emphasis should be placed on the fact that the obligatory local nerve block anaesthesia of the auricular nerves and the associated risk of a facial nerve paralysis were completely eliminated. With the help of this simplified procedure physiological and pathological references could be established. Pathological findings and a lack of relevant veterinary literature prompted us to take a closer look at histological aspects of the equine acoustic organ. In this context, the ears of ten slaughter horses were histologically examined in detail. The results of this follow-up study describe and illustrate the complete histology of the equine acoustic organ for the first time. In the following the essential results of the basic- and follow-up study are summarized. The physiological cartilaginous external ear canal is pigmented and contains hair, as well as ceruminous and sebaceous glands. In comparison to the osseous external ear canal, the cartilaginous part has higher degree of ceruminous and cellular debris. The intersection between both- the cartilaginous and osseous portion- is histologically characterized by an abrupt change to a non-pigmented, hairless, aglandular keratinized stratified squamous epithelium. Endoscopically, the intersection can be identified by a rim of beige keratin scales, which are products of the self-cleaning mechanism of the osseous epithelium. The osseous ear canal is round to oval shaped and lined with pale pink coloured epithelium that contains concentric keratin formations and visible capillary drawing. The physiological equine tympanic membrane is endoscopically characterized by a well-differentiated semi- transparent membrane, which shows no positive light reflex. On basis of the established physiological references pathological changes were found in seven horses (four horses with aural plaques, three horses with otitis externa). Typical sings of otitis externa were swelling and reddening of the osseous epithelium, the loss of the concentric keratin layer formation and/or detachment of the protective osseous keratin layer, as well as a positive light reflex on the tympanic membrane. In one diseased horse a possible correlation between the Otitis externa and severe temporohyoid osteoarthropathy (THO) could be revealed. Additionally, tympanosclerotic changes within two equine eardrums could be visualized for the first time. The results of this study provide a basis for further research on the equine acoustic organ. The otoscopic examination in standing sedated horses is a viable, safe, easy and quick to perform beneficial diagnostic procedure for a complete work-up of ear-related diseases, such as THO, facial nerve paralysis, vestibular disease, head shaking, parasitic infections or head trauma. In addition, the otoscopic examination is a basic requirement for the adaption and the use of human audiometric measuring probes in equine ears. The results obtained in the histological study can be employed as references for further research on equine congenital and acquired middle and inner ear diseases, which can influence the measurement results of otoacoustic emissions.:Inhaltsverzeichnis Einleitung ...................................................................................................................... 1 Literaturübersicht .......................................................................................................... 4 Anatomie des equinen akustischen Organs ................................................................. 4 8 Danksagung 2.4.1 2.4.2 2.4.3 2.4.4 Otoskopie ........................................................................................................ 10 Tympanometrie ............................................................................................... 11 Messung otoakustischer Emissionen (OAE) ................................................... 12 Hirnstammaudiometrie (BERA) ....................................................................... 14 Äußeres Ohr...................................................................................................... 4 Mittelohr ............................................................................................................ 4 Innenohr ............................................................................................................ 5 Hörbahn ............................................................................................................ 7 Gleichgewichtsbahn .......................................................................................... 7 2.1.1 2.1.2 2.1.3 2.1.4 2.1.5 Physiologie des Hörvorganges ..................................................................................... 8 Physiologie des Vestibularorgans................................................................................. 9 Untersuchungsmethoden des akustischen Organs .................................................... 10 Ergebnisse .................................................................................................................. 15 Publikation 1: Endoscopic findings of the external ear canal in a group of clinically normal horses and horses with head shaking or vestibular disease .......................... 15 Publikation 2: Histological Study of the External, Middle and Inner Ear of Horses .... 25 Diskussion .................................................................................................................. 44 Otoskopie.................................................................................................................... 45 Der physiologische equine externe Gehörkanal und das Trommelfell ....................... 46 Pathologische Befunde des equinen externen Gehörkanales und Trommelfelles ..... 48 Histologie des equinen akustischen Organs............................................................... 50 Diagnostische Möglichkeiten - OAE ........................................................................... 51 Zusammenfassung ..................................................................................................... 53 Summary .................................................................................................................... 55 Literaturverzeichnis..................................................................................................... 57 Anhang ....................................................................................................................... 64

The relationship between hearing sensitivity in the extended high-frequency region (8-16 kHz) and (1) the presence of synchronized spontaneous otoacoustic emissions (SSOAEs) and (2) the strength of click-evoked and distortion product otoacoustic emissions (CEOAEs and DPOAEs) was investigated in 104 ears of 57 young adults. The age range was confined to 16 to 19 years. All subjects had normal hearing in the conventional audiometric frequency range (0.5-8 kHz). Ears with detected SSOAEs had better hearing sensitivity in the extended high-frequency region and also higher levels of CEOAEs and DPOAEs than ears with undetected SSOAEs. The results support the hypothesis that the presence of SSOAEs is indicative of an ear with highly normal cochlear function over a broad frequency range.

No description available.

Para avaliar a audição em crianças com paralisia cerebral foi realizada a avaliação comportamental, eletroacústica e eletrofisiológica em 61 sujeitos na faixa etária de três a seis anos e 11 meses, subdivididas em grupo experimental e controle. Foram observadas diferenças estatisticamente significantes na comparação entre os resultados obtidos nos dois grupos, bem como na comparação dos procedimentos no grupo experimental. Existe uma diversidade nos resultados dos procedimentos audiológicos em crianças com paralisia cerebral, o que torna importante a aplicação da bateria completa na determinação do perfil audiológico destas crianças. / In order to evaluate the hearing of children who have cerebral palsy disease the behavioral, eletroacoustical, electrophysiological evaluations were done in 61 people between three and six years and 11 months old, subdivided in experimental and control group. There were statistically significant differences when comparing the results obtained in both groups, as well as when comparing the procedures in the experimental group. There is diversity in the results of hearing procedures in children with Cerebral Palsy, which stresses the importance of a full battery of exams for determining the hearing profile of these children.

Com o objetivo de analisar o efeito de supressão das emissões otoacústicas transientes com a apresentação de ruído branco contralateral, foram avaliadas 51 crianças de 7 a 11 anos, sendo 15 sem queixas auditivas (grupo controle) e 36 com distúrbio de processamento auditivo (divididas em dois grupos experimentais). Foram determinados, para cada grupo, a média e o desvio padrão dos valores de supressão em cada condição de estímulo: clique linear e clique não linear. Verificou-se que a proporção de ausência do efeito de supressão foi significativamente maior nos grupos de crianças com distúrbio de processamento auditivo, comparados ao grupo controle / This study concerns the suppression of transient evoked otoacoustic emissions by contralateral white noise in children with auditory processing disorder. Fifty-one children between 7 and 11 years old were assessed, being 15 children without auditory complaints (control group) and 36 with auditory processing disorder (divided in two experimental groups). The mean suppression of otoacoustic emissions and standard deviation were determined for each group, both in linear and nonlinear acquisition mode. The results provided evidence that proportion of absence of otoacoustic emissions suppression was significantly higher in auditory processing disorder groups, when compared to control group

Objetivos: avaliar a prevalência de alterações auditivas em recém-nascidos de muito baixo peso na Unidade de Tratamento Intensivo Neonatal do Hospital de Clínicas de Porto Alegre e estudar as variáveis que possam estar relacionadas com as alterações da acui-dade auditiva. Métodos: foi realizado um estudo transversal que incluiu todos os recém-nascidos de muito baixo peso admitidos na Unidade de Tratamento Intensivo Neonatal do Hospital de Clínicas de Porto Alegre no período de 1o de setembro de 2001 a 31 de janeiro de 2002. To-dos os pacientes foram submetidos ao exame de otoemissão acústica evocada por produto de distorção no momento da alta hospitalar. O exame foi repetido em 30 dias quando havia alte-ração no primeiro exame. Quando o paciente apresentava o exame de otoemissão acústica al-terada em duas ocasiões, era realizado o potencial auditivo evocado cerebral, considerado al-terado a partir de 35 dB NA. Resultados: foram estudados 96 recém-nascidos. Seis tiveram tanto o exame de otoemissão acústica quanto o potencial auditivo evocado cerebral alterados. A média da idade gestacional foi de 31,5 ± 2,6 semanas, o peso de nascimento variou de 640 a 1.500 g e 57,3% dos pacientes eram do sexo feminino. A idade gestacional e o índice de Apgar no 5o minuto foram inferiores no grupo otoemissão acústica e potencial auditivo evocado cerebral alterados em relação aos demais grupos, atingindo significância limítrofe. Conclusões: a prevalência de perda auditiva nos recém-nascidos de muito baixo peso da Unidade de Tratamento Intensivo Neonatal do Hospital de Clínicas de Porto Alegre foi de 6,3%, tendo sido observadas associações de significância limítrofe com idade gestacional e índice de Apgar no 5o minuto. / Objectives: to evaluate the prevalence of hearing loss in very low birth weight patients in the Neonatal Intensive Care Unit of the Hospital de Clínicas de Porto Alegre and to study the variables that can be related to hearing loss. Methods: a transversal study was carried through including all very low birth weight neonates admitted in the Neonatal Intensive Care Unit of the Hospital de Clínicas de Porto Alegre during September 1, 2000 to January 31, 2002. All patients were undergone to the distortion evoked otoacoustic emission test in the hospital discharge. When the patient presented alteration in this test, it was repeated in 30 days. However, when the patient who presented pathologic otoacoustic emission on two ocasions was undergone to the auditory evoked brain response. This test was considered abnormal from 35 dB NA. Results: we studied 96 neonates. Six children presented alteration in the distortion evoked otoacoustic emission test as well in the auditory evoked brain response. The children age average was 31.5 ± 2.6 weeks, their birth weight was between 640 g and 1,500 g, and 57.3% of the patients were female. The gestational age and the Apgar score at 5 minutes were inferior in the otoacoustic emission and auditory evoked brain response abnormal group related to the other groups, reaching bordering significance. Conclusions: the hearing loss prevalence of the very low birth weight neonates from the Neonatal Intensive Care Unit of the HCPA was 6.3%, and it was observed bordering significance associations related to gestational age and 5 minutes Apgar score.

Objetivos: avaliar a prevalência de alterações auditivas em recém-nascidos de muito baixo peso na Unidade de Tratamento Intensivo Neonatal do Hospital de Clínicas de Porto Alegre e estudar as variáveis que possam estar relacionadas com as alterações da acui-dade auditiva. Métodos: foi realizado um estudo transversal que incluiu todos os recém-nascidos de muito baixo peso admitidos na Unidade de Tratamento Intensivo Neonatal do Hospital de Clínicas de Porto Alegre no período de 1o de setembro de 2001 a 31 de janeiro de 2002. To-dos os pacientes foram submetidos ao exame de otoemissão acústica evocada por produto de distorção no momento da alta hospitalar. O exame foi repetido em 30 dias quando havia alte-ração no primeiro exame. Quando o paciente apresentava o exame de otoemissão acústica al-terada em duas ocasiões, era realizado o potencial auditivo evocado cerebral, considerado al-terado a partir de 35 dB NA. Resultados: foram estudados 96 recém-nascidos. Seis tiveram tanto o exame de otoemissão acústica quanto o potencial auditivo evocado cerebral alterados. A média da idade gestacional foi de 31,5 ± 2,6 semanas, o peso de nascimento variou de 640 a 1.500 g e 57,3% dos pacientes eram do sexo feminino. A idade gestacional e o índice de Apgar no 5o minuto foram inferiores no grupo otoemissão acústica e potencial auditivo evocado cerebral alterados em relação aos demais grupos, atingindo significância limítrofe. Conclusões: a prevalência de perda auditiva nos recém-nascidos de muito baixo peso da Unidade de Tratamento Intensivo Neonatal do Hospital de Clínicas de Porto Alegre foi de 6,3%, tendo sido observadas associações de significância limítrofe com idade gestacional e índice de Apgar no 5o minuto. / Objectives: to evaluate the prevalence of hearing loss in very low birth weight patients in the Neonatal Intensive Care Unit of the Hospital de Clínicas de Porto Alegre and to study the variables that can be related to hearing loss. Methods: a transversal study was carried through including all very low birth weight neonates admitted in the Neonatal Intensive Care Unit of the Hospital de Clínicas de Porto Alegre during September 1, 2000 to January 31, 2002. All patients were undergone to the distortion evoked otoacoustic emission test in the hospital discharge. When the patient presented alteration in this test, it was repeated in 30 days. However, when the patient who presented pathologic otoacoustic emission on two ocasions was undergone to the auditory evoked brain response. This test was considered abnormal from 35 dB NA. Results: we studied 96 neonates. Six children presented alteration in the distortion evoked otoacoustic emission test as well in the auditory evoked brain response. The children age average was 31.5 ± 2.6 weeks, their birth weight was between 640 g and 1,500 g, and 57.3% of the patients were female. The gestational age and the Apgar score at 5 minutes were inferior in the otoacoustic emission and auditory evoked brain response abnormal group related to the other groups, reaching bordering significance. Conclusions: the hearing loss prevalence of the very low birth weight neonates from the Neonatal Intensive Care Unit of the HCPA was 6.3%, and it was observed bordering significance associations related to gestational age and 5 minutes Apgar score.

Para avaliar a audição em crianças com paralisia cerebral foi realizada a avaliação comportamental, eletroacústica e eletrofisiológica em 61 sujeitos na faixa etária de três a seis anos e 11 meses, subdivididas em grupo experimental e controle. Foram observadas diferenças estatisticamente significantes na comparação entre os resultados obtidos nos dois grupos, bem como na comparação dos procedimentos no grupo experimental. Existe uma diversidade nos resultados dos procedimentos audiológicos em crianças com paralisia cerebral, o que torna importante a aplicação da bateria completa na determinação do perfil audiológico destas crianças. / In order to evaluate the hearing of children who have cerebral palsy disease the behavioral, eletroacoustical, electrophysiological evaluations were done in 61 people between three and six years and 11 months old, subdivided in experimental and control group. There were statistically significant differences when comparing the results obtained in both groups, as well as when comparing the procedures in the experimental group. There is diversity in the results of hearing procedures in children with Cerebral Palsy, which stresses the importance of a full battery of exams for determining the hearing profile of these children.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This research aims to verify the hearing condition of goers of support groups for former drug users. It was evaluated 17 individuals, all former drug users, being marijuana, crack and cocaine the most used drugs. The individuals were divided into two groups according to the kind of the most commonly used drug: Group 1 (G1) - 10 former users of marijuana, Group 2 (G2) - Seven former users of crack/cocaine. For the results analysis, they were also subdivided according to the time of drug use: one to five years, six to 10 years and more than 15 years. The subjects were submitted to anamnesis, pure tone audiometry (PTA), acoustic impedance measurements, transient evoked otoacoustic emissions (TEOAE), suppressive effect of TEOAE and brainstem evoked response audiometry (BERA). By comparing the results of PTA of the G1 and G2 with one to five years of drug use, G2 presented pure tone levels greater than 25 dB with a significant statistically difference in the pure tone levels for the frequencies of 250, 500, 6000 and 8000 Hz in the right ear. In the group of six to 10 years of drug use it was not found significant difference in pure tone levels for frequencies of 4000 and 8000 Hz in the left ear, with worse pure tone levels for the G2. For the group with more than 15 years of drug use, it was observed pure tone levels above 25 dB for the frequencies from 3000 to 8000 Hz in the right ear. In evaluations with TEOAE, TEOAE suppression effect and BERA, it was not observed a difference in the results when they were compared according to the time of drug use. G1 presented an average in the relation signal/noise of TEOAE greater than the average in the G2, but without a significant statistically difference. The two groups did not differ in the occurrence of suppressor effect of TEOAE and absolute latency and inter-peak interval of BERA. It is emphasized that only five individuals had adequate results for the age group in the BERA. As the time of drug use increases, more changes were observed in the G1 results in PTA and BERA, but it did not interfere in the results of the evaluations of the G2. The results suggest that the use of drugs can cause peripheral and central hearing loss, and that the use of crack/cocaine is more deleterious to the hearing that the use of marijuana. / O presente trabalho tem como objetivo verificar a condição auditiva de frequentadores de grupos de apoio a ex-usuários de drogas. Foram avaliados 17 indivíduos ex-usuários de drogas, estando entre as mais usadas a maconha, o crack e a cocaína. Os indivíduos foram divididos em dois grupos, conforme o tipo de droga mais consumida: Grupo 1 (G1) 10 ex-usuários de maconha; Grupo 2 (G2) sete ex-usuários de crack/cocaína. Para a análise dos resultados, houve uma subdivisão conforme o tempo de uso de drogas: um a cinco anos, seis a 10 anos e mais do que 15 anos. Os indivíduos foram submetidos à anamnese, audiometria tonal liminar (ATL), medidas de imitância acústica, emissões otoacústicas transientes (EOAT), efeito supressor das EOAT e potenciais evocados auditivos de tronco encefálico (PEATE). Ao comparar os resultados da ATL do G1 e G2 com um a cinco anos de uso de drogas, o G2 apresentou limiares tonais maiores que 25 dBNA com diferença estatisticamente significante nos limiares tonais para as frequências de 250, 500, 6000 e 8000 Hz na orelha direita. No grupo de seis a 10 anos de uso de drogas houve diferença estatisticamente significante nos limiares tonais para as frequências de 4000 e 8000 Hz da orelha esquerda, com limiares piores para o G2. Para o grupo com mais de 15 anos de uso de drogas, observou-se limiares tonais acima de 25 dBNA para as frequências de 3000 a 8000 Hz na orelha direita. Nas avaliações com EOAT, efeito supressor das EOAT e PEATE não se observou diferença nos resultados quando foram comparados conforme o tempo de uso de drogas. O G1 apresentou média da relação sinal/ruído das EOAT superior ao G2, porém sem diferença estatisticamente significante. Os dois grupos não diferiram quanto à ocorrência do efeito supressor das EOAT, bem como quanto às latências absolutas e aos intervalos interpicos do PEATE. Ressalta-se que apenas cinco indivíduos apresentaram resultados adequados para a faixa etária no PEATE. O tempo de uso da droga exerceu influência nos resultados do G1 na ATL e PEATE; observou-se que quanto maior o tempo, maiores as alterações. Porém, o tempo de uso não interferiu nos resultados das avaliações do G2. Os resultados encontrados sugerem que o uso de drogas pode provocar alterações auditivas periféricas e centrais, e que o uso de crack/cocaína é mais deletério para a audição que o uso de maconha.

Objetivos: avaliar a prevalência de alterações auditivas em recém-nascidos de muito baixo peso na Unidade de Tratamento Intensivo Neonatal do Hospital de Clínicas de Porto Alegre e estudar as variáveis que possam estar relacionadas com as alterações da acui-dade auditiva. Métodos: foi realizado um estudo transversal que incluiu todos os recém-nascidos de muito baixo peso admitidos na Unidade de Tratamento Intensivo Neonatal do Hospital de Clínicas de Porto Alegre no período de 1o de setembro de 2001 a 31 de janeiro de 2002. To-dos os pacientes foram submetidos ao exame de otoemissão acústica evocada por produto de distorção no momento da alta hospitalar. O exame foi repetido em 30 dias quando havia alte-ração no primeiro exame. Quando o paciente apresentava o exame de otoemissão acústica al-terada em duas ocasiões, era realizado o potencial auditivo evocado cerebral, considerado al-terado a partir de 35 dB NA. Resultados: foram estudados 96 recém-nascidos. Seis tiveram tanto o exame de otoemissão acústica quanto o potencial auditivo evocado cerebral alterados. A média da idade gestacional foi de 31,5 ± 2,6 semanas, o peso de nascimento variou de 640 a 1.500 g e 57,3% dos pacientes eram do sexo feminino. A idade gestacional e o índice de Apgar no 5o minuto foram inferiores no grupo otoemissão acústica e potencial auditivo evocado cerebral alterados em relação aos demais grupos, atingindo significância limítrofe. Conclusões: a prevalência de perda auditiva nos recém-nascidos de muito baixo peso da Unidade de Tratamento Intensivo Neonatal do Hospital de Clínicas de Porto Alegre foi de 6,3%, tendo sido observadas associações de significância limítrofe com idade gestacional e índice de Apgar no 5o minuto. / Objectives: to evaluate the prevalence of hearing loss in very low birth weight patients in the Neonatal Intensive Care Unit of the Hospital de Clínicas de Porto Alegre and to study the variables that can be related to hearing loss. Methods: a transversal study was carried through including all very low birth weight neonates admitted in the Neonatal Intensive Care Unit of the Hospital de Clínicas de Porto Alegre during September 1, 2000 to January 31, 2002. All patients were undergone to the distortion evoked otoacoustic emission test in the hospital discharge. When the patient presented alteration in this test, it was repeated in 30 days. However, when the patient who presented pathologic otoacoustic emission on two ocasions was undergone to the auditory evoked brain response. This test was considered abnormal from 35 dB NA. Results: we studied 96 neonates. Six children presented alteration in the distortion evoked otoacoustic emission test as well in the auditory evoked brain response. The children age average was 31.5 ± 2.6 weeks, their birth weight was between 640 g and 1,500 g, and 57.3% of the patients were female. The gestational age and the Apgar score at 5 minutes were inferior in the otoacoustic emission and auditory evoked brain response abnormal group related to the other groups, reaching bordering significance. Conclusions: the hearing loss prevalence of the very low birth weight neonates from the Neonatal Intensive Care Unit of the HCPA was 6.3%, and it was observed bordering significance associations related to gestational age and 5 minutes Apgar score.