Mattheus Vischer - Academia.edu (original) (raw)
Papers by Mattheus Vischer
Die Verfügbarkeit von Hinter-dem-Ohr (HdO) Sprachprozessoren für Cochlea-Implantate (CI) mehrerer... more Die Verfügbarkeit von Hinter-dem-Ohr (HdO) Sprachprozessoren für Cochlea-Implantate (CI) mehrerer Hersteller hat die Palette der Wahlmöglichkeiten für CI-Träger entscheidend und in attraktiver Weise erweitert. Trotz dieses wichtigen technischen Fortschritts sind HdO-Sprachprozessoren für CI-Systeme aber immer noch grösser und schwerer als gängige Hörgeräte und zeichnen sich durch einen hohen Batterieverbrauch aus, was von einigen Benutzern als störend empfunden wird. Verschiedene Stimulationsstrategien wie beispielsweise CIS, ACE oder SPEAK (Kiefer et al. 2001) kommen bei CI-Systemen zur Anwendung. Gewicht und Batterieverbrauch von HdO-Sprachprozessoren sind unter anderem von der verwendeten Stimulationsstrategie abhängig: schnelle Stimulationstrategien wie CIS oder ACE benötigen mehr Batterieleistung als die langsamere SPEAK-Strategie. Kenntnisse der Vor-und Nachteile verschiedener Systeme bilden eine wichtige Entscheidungsgrundlage für CI-Kandidaten. In dieser Untersuchung wird der subjektive und objektive Nutzen von CI-Systeme mit zwei verschiedenen HdO-Sprachprozessoren miteinander verglichen.
Zusammenfassung Die Möglichkeit, eine beidseitige Innenohrschwerhörigkeit mit Steroiden oder Cycl... more Zusammenfassung Die Möglichkeit, eine beidseitige Innenohrschwerhörigkeit mit Steroiden oder Cyclophosphamid zu heilen, erregte durch die Mitteilung McCabes (1979) einiges Aufsehen, wenngleich ähnliche Beobachtungen im Einzelfall auch vorher schon angestellt worden waren. Seine pathomechanistische Vorstellung einer «Autoimmun-Innenohrschwerhörigkeit» wurde begeistert aufgegriffen, und viele experimentelle und klinische Arbeitsgruppen sind seitdem darum bemüht, den Beweis für die Existenz einer Autoimmunerkrankung des Innenohres zu erbringen. Bis heute ist es jedoch nicht gelungen, die strengen Kriterien, welche von den Immunologen und Immunpathologen für die Definition einer Autoimmunerkrankung gefordert werden, auf bestimmte Innenohrer-krankungen zu übertragen. An einigen exemplarischen klinischen Fallbeispielen werden eindrückliche Hörverbesserungen sowohl mit als auch ohne Steroidtherapie aufgezeigt. Es scheint tatsächlich eine Gruppe von Innenohr-schwerhörigkeiten zu existieren,...
HNO
From 1989-1993 we performed rigid bronchoscopies in 86 children in whom foreign body aspirations ... more From 1989-1993 we performed rigid bronchoscopies in 86 children in whom foreign body aspirations were suspected. In 72 cases, foreign bodies were identified in the tracheobronchial tree. In the remaining 14, no foreign body was found. Boys outnumbered girls. The most common type of foreign body was a peanut. The predilection of the foreign body was to fall into the right main bronchus. If the history indicated foreign body aspiration, a chest x-ray was not found to be necessary except for forensic interest.
Departementale Einheit Hals-, Nasen-und Ohrenkrankheiten, Hals-und Kopfchirurgie Einführung Die E... more Departementale Einheit Hals-, Nasen-und Ohrenkrankheiten, Hals-und Kopfchirurgie Einführung Die Erfolge der Cochlea-Implantation in der Be-handlung der höchstgradigen Schwerhörigkeit sind hinreichend bekannt. Ersten eigenen Untersuchungen zufolge kann durch eine bilateralen Cochlea-Implantation (=CI) eine weitere Verbesserung des Sprachverständnisse erwartet werden, insbesondere im Lärm. Zudem sollte räumliches Hören möglich sein [1]. Unsere Studie hat zum Ziel, das Sprachverständnis und die Schalllokalisation nach bilateraler Implantation systematisch zu untersuchen und darüber Auskunft zu geben, ob die bilaterale der unilateralen Implantation in Bezug auf verschiedene Parameter des Hörvermö-gens überlegen ist. Material und Methoden Bis im Dezember 2001 wurden in Bern 12 Patien-ten, 10 prä-oder perilingual ertaube Kinder (Alter: durchschnittlich 8 Jahre, 4 – 13 Jahre) und zwei post-lingual ertaubte Erwachsene, beide 49-jährig, bilateral implantiert. Ein, drei und sechs Monate nach ...
PloS one, 2015
Cochlear implants (CIs) are standard treatment for postlingually deafened individuals and preling... more Cochlear implants (CIs) are standard treatment for postlingually deafened individuals and prelingually deafened children. This human cadaver study evaluated diagnostic usefulness, image quality and artifacts in 1.5T and 3T magnetic resonance (MR) brain scans after CI with a removable magnet. Three criteria (diagnostic usefulness, image quality, artifacts) were assessed at 1.5T and 3T in five cadaver heads with CI. The brain magnetic resonance scans were performed with and without the magnet in situ. The criteria were analyzed by two blinded neuroradiologists, with focus on image distortion and limitation of the diagnostic value of the acquired MR images. MR images with the magnet in situ were all compromised by artifacts caused by the CI. After removal of the magnet, MR scans showed an unequivocal artifact reduction with significant improvement of the image quality and diagnostic usefulness, both at 1.5T and 3T. Visibility of the brain stem, cerebellopontine angle, and parieto-occip...
International journal of pediatric otorhinolaryngology, 2009
With more children receiving cochlear implants during infancy, there is a need for validated asse... more With more children receiving cochlear implants during infancy, there is a need for validated assessments of pre-verbal and early verbal auditory skills. The LittlEARS Auditory Questionnaire is presented here as the first module of the LittlEARS test battery. The LittlEARS Auditory Questionnaire was developed and piloted to assess the auditory behaviour of normal hearing children and hearing impaired children who receive a cochlear implant or hearing aid prior to 24 months of age. This paper presents results from two studies: one validating the LittlEARS Auditory Questionnaire on children with normal hearing who are German speaking and a second validating the norm curves found after adaptation and administration of the questionnaire to children with normal hearing in 15 different languages. Scores from a group of 218 German and Austrian children with normal hearing between 5 days and 24 months of age were used to create a norm curve. The questionnaire was adapted from the German orig...
International journal of pediatric otorhinolaryngology, Jan 11, 2002
The different speech sounds are formed by the primary voice signal and by the shape of the articu... more The different speech sounds are formed by the primary voice signal and by the shape of the articulation tract. With this mechanism, specific overtones, the formants, are generated for each vowel. The objective of this study was to investigate the fundamental frequency (F0) of the voice signal and the first three formants (F1-F3) as a parameter of the articulation in prelingually deafened children at different timepoints after cochlear implantation (CI) compared with children with normal speech development. Using the Kay CSL 4300B, the fundamental frequency and the formants F1-F3 of the Swiss-German vowel /a/ were investigated at different timepoints after CI in 20 prelingually deafened children aged 3.8-10.2 years by means of spectrographic and linear predictive coding (LPC) analysis. Children who had been operated before their fourth birthday showed no significant deviation in their fundamental frequency from age- and sex-matched peers, whereas a significant difference was document...
Schweizerische medizinische Wochenschrift, 2000
A Swiss study group was formed in summer 1998 with the aim of establishing a universal hearing sc... more A Swiss study group was formed in summer 1998 with the aim of establishing a universal hearing screening programme in newborns following the recommendations of the "European Consensus Statement on Neonatal Hearing Screening" (Milan 1998). The aim of the group was to standardise and to introduce universal hearing screening in all infants born in Switzerland. Starting in June 1999, several hospitals in Switzerland began the screening programme using commercially available equipment for easy and highly automated measurement of transient evoked otoacoustic emissions. Up to March 2000, 6262 children were born in these hospitals and 5656 (90%) underwent neonatal hearing screening. 88 children of the 5656 did not pass the screening test. The measurement of otoacoustic emissions was repeated in a follow-up examination within 6 weeks. If otoacoustic emissions were again absent, evoked auditory brainstem potentials were measured. 48 children were found to have hearing within normal ...
Journal für Hirnforschung, 1998
The distribution of Fos-like immunoreactivity (FLI) in the auditory pathway was analyzed and quan... more The distribution of Fos-like immunoreactivity (FLI) in the auditory pathway was analyzed and quantified in two groups of rats subjected to a similar electric stimulation of the cochlea, but the brains of the two groups were treated with a different antibody against Fos. The brains of control (unstimulated) rats were processed and analyzed in the same way. In a given auditory nucleus, for the same paradigm of stimulation, a very different density of FLI can be found depending on the antibody used to process the tissue. There are auditory nuclei which exhibited a significant activation of FLI as compared to control animals when one antibody was used whereas there was no difference when using the other antibody. In other cases, for both antibodies, a significant FLI increase was observed in relation to the stimulus. However, the increase of FLI density was significantly greater in some auditory nuclei with one antibody, while it was the reverse in other auditory nuclei. The present dat...
HNO, 1996
From 1989-1993 we performed rigid bronchoscopies in 86 children in whom foreign body aspirations ... more From 1989-1993 we performed rigid bronchoscopies in 86 children in whom foreign body aspirations were suspected. In 72 cases, foreign bodies were identified in the tracheobronchial tree. In the remaining 14, no foreign body was found. Boys outnumbered girls. The most common type of foreign body was a peanut. The predilection of the foreign body was to fall into the right main bronchus. If the history indicated foreign body aspiration, a chest x-ray was not found to be necessary except for forensic interest.
Advances in oto-rhino-laryngology, 1995
ORL, 1995
The activity elicited by electrical stimulation of the cochlea in the auditory pathway was assess... more The activity elicited by electrical stimulation of the cochlea in the auditory pathway was assessed in an animal model of cochlear implants on the basis of the induction of the immediate early gene c-fos and single neuron recordings. Electrical stimulation of the cochlea induced Fos-like immunoreactivity in the cochlear nucleus, mainly in its dorsal nucleus, in the superior olivary complex, in the lateral lemniscus, but not in the central nucleus of the inferior colliculus, the main relay nucleus in the auditory midbrain. However, single unit recordings from the inferior colliculus, ipsilateral and contralateral to the electrically stimulated cochlea, showed clear responses of single neurons, reminiscent of those elicited by acoustic stimulation. These findings provide immunocytochemical and electrophysiological evidence that the various nuclei of the auditory pathway are activated by electrical stimulation of the cochlea.
The Laryngoscope, 2012
Postmeningitic basal turn ossification is a challenge for successful cochlear implantation despit... more Postmeningitic basal turn ossification is a challenge for successful cochlear implantation despite the availability of sophisticated implants and advanced drill-out procedures. A less complex concept consisting of a cochleostomy near the apex with retrograde array insertion is evaluated clinically and experimentally with emphasis on imaging of intracochlear array morphology. Retrospective case-control study. Outcome, hearing performance, and radiological findings including three-dimensional (3D) reconstructions were assessed in the long term in eight retrograde implanted ears of seven postmeningitic deaf patients and compared to an etiology- and device-matched control group of 17 basal turn implanted ears of 14 patients. Experimental insertions into three autopsy-derived human temporal bones were evaluated using high-resolution microtomography, 3D reconstruction, and histology. No complications occurred. At the long-term follow-up, the average monosyllabic word test scores were 41% for the study group and 67% for the control group (P = .03). Radiological follow-up revealed insertion sites into either the apical or middle turn and frequent intracochlear array direction changes (n = 5). Experimental implantations in temporal bones resulted in folding-free, retrograde, middle turn insertions (n = 3). The retrograde cochlear implantation is a safe and efficient alternative approach in basal turn ossification. Despite a high occurrence of intracochlear array direction changes, open set speech discrimination was achieved in all patients. Postoperative computed tomography is recommended for fitting the speech processor according to intracochlear array positions. The experimental insertion in temporal bones helped to optimize the approach.
Neuroscience Research, 1994
Fos-like immunoreactivity (FLI) was mapped in the auditory pathway of Sprague-Dawley rats in resp... more Fos-like immunoreactivity (FLI) was mapped in the auditory pathway of Sprague-Dawley rats in response to unilateral electrical stimulation of the cochlea implanted with two stimulating electrodes. Densely packed FLI neurons were widely distributed in the dorsal cochlear nucleus (more ipsilaterally than contralaterally), while FLI neurons were rare in the posteroventral cochlear nucleus and virtually absent in the anteroventral cochlear nucleus. Sparse FLI was detected in the superior olivary complex, the pontine nuclei and the ipsilateral dorsal nucleus of the lateral lemniscus, whereas the contralateral dorsal nucleus of the lateral lemniscus was moderately labeled. In the inferior colliculus, the pattern of FLI was similar on both sides, restricted mainly to its dorsal and external cortices. At the thalamic level, FLI neurons were seen in the dorsal and medial divisions of the medial geniculate body as well as in the peripeduncular nucleus. A significant increase of FLI was observed in the temporal cortex. This study demonstrates the presence of selective functional changes along the auditory pathway elicited by electrical stimulation of the cochlea, as revealed by FLI.
NeuroReport, 1999
USING guinea-pig isolated whole brain preparation in vitro, synaptic responses to electrical stim... more USING guinea-pig isolated whole brain preparation in vitro, synaptic responses to electrical stimulation of auditory nerves were examined in intracellularly recorded and stained neurons of posteroventral and dorsal divisions of the cochlear nucleus. Stimulation of the contralateral auditory nerve evoked exclusively IPSPs in 70% of neurons, with amplitude of 2.3 AE 1.2 mV. Neurons of all major cell types were inhibited from the contralateral side. In the majority of responding cells (78%) IPSPs were induced at latencies of 3± 9 ms suggesting di-and trisynaptic connections from contralateral auditory afferents or, respectively, monoand disynaptic connections from the contralateral cochlear nucleus. Few cells responded with long-latency IPSPs (13.5±23 ms), indicating involvement of polysynaptic pathways. These data demonstrate the existence of functional, direct and indirect inhibitory connections between the cochlear nuclei.
Neurogastroenterology and Motility, 2004
The aim of this study was to investigate the effect of gastric electrical stimulation (GES) on ga... more The aim of this study was to investigate the effect of gastric electrical stimulation (GES) on gastric myoelectric activity (GMA) and to identify possible mechanisms that could help explain how high-frequency GES is effective in treating nausea and vomiting associated with gastroparesis. Fifteen gastroparetic patients who received high-frequency GES were enrolled. Two pairs of temporary pacing wires were implanted on the serosa of the stomach along the greater curvature during surgery for placement of the permanent stimulation device. Two-channel serosal recordings of GMA before and during GES were measured. A gastric emptying test and severity of nausea and vomiting were assessed at baseline and at 3 months of GES. Power spectral and cross correlation analyses revealed that impaired propagation of slow waves (50%), tachygastria (30%) and abnormal myoelectric responses to a meal (50%) were the main abnormalities observed at baseline. GES with a high frequency significantly enhanced the slow wave amplitude and propagation velocity, and resulted in a significant improvement in nausea and vomiting but did not entrain the gastric slow wave or improve gastric emptying after 3 months of GES.
The Journal of Infectious Diseases, 2007
Early exposure of infants and long-term immunity suggest that colonization with Moraxella catarrh... more Early exposure of infants and long-term immunity suggest that colonization with Moraxella catarrhalis is more frequent than is determined by routine culture. We characterized a reservoir of M. catarrhalis in pharyngeal lymphoid tissue. Tissue from 40 patients (median age, 7.1 years) undergoing elective tonsillectomy and/or adenoidectomy was analyzed for the presence of M. catarrhalis by culture, real-time DNA and RNA polymerase chain reaction (PCR), immunohistochemical analysis (IHC), and fluorescent in situ hybridization (FISH). Histologic sections were double stained for M. catarrhalis and immune cell markers, to characterize the tissue distribution of the organism. Intracellular bacteria were identified using confocal laser scanning microscopy (CLSM). Twenty-nine (91%) of 32 adenoids and 17 (85%) of 20 tonsils were colonized with M. catarrhalis. Detection rates for culture, DNA PCR, RNA PCR, IHC, and FISH were 7 (13%) of 52, 10 (19%) of 52, 21 (41%) of 51, 30 (61%) of 49, and 42 (88%) of 48, respectively (P<.001). Histologic analysis identified M. catarrhalis in crypts, intraepithelially, subepithelially, and (using CLSM) intracellularly. M. catarrhalis colocalized with macrophages and B cells in lymphoid follicles. Colonization by M. catarrhalis is more frequent than is determined by surface culture, because the organism resides both within and beneath the epithelium and invades host cells.
International Journal of Audiology, 2002
A patient with bilateral profound deafness was implanted with a Nucleus CI24M cochlear implant (C... more A patient with bilateral profound deafness was implanted with a Nucleus CI24M cochlear implant (CI) and used an Esprit behind-the-ear (BTE) speech processor. Thirteen months later, the implant had to be removed because of a cholesteatoma. As the same electrode could not be reinserted, a Medel combi40s CI was implanted in the same ear, and the patient used a Tempo+ BTE processor. After 1 year of use of the Combi40s/Tempo+ system, speech recognition was better and was rated better subjectively than with the CI24M/Esprit system. Speech recognition and subjective ratings were also assessed for two matched groups of nine CI users each, using either an Esprit or a Tempo+ processor. On average, speech recognition scores were higher for the group of Tempo+ users, but the difference was not statistically significant. Users of the Esprit processors rated their device higher in terms of cosmetic appearance and comfort of wearing.
International Journal of Audiology, 1997
Die Verfügbarkeit von Hinter-dem-Ohr (HdO) Sprachprozessoren für Cochlea-Implantate (CI) mehrerer... more Die Verfügbarkeit von Hinter-dem-Ohr (HdO) Sprachprozessoren für Cochlea-Implantate (CI) mehrerer Hersteller hat die Palette der Wahlmöglichkeiten für CI-Träger entscheidend und in attraktiver Weise erweitert. Trotz dieses wichtigen technischen Fortschritts sind HdO-Sprachprozessoren für CI-Systeme aber immer noch grösser und schwerer als gängige Hörgeräte und zeichnen sich durch einen hohen Batterieverbrauch aus, was von einigen Benutzern als störend empfunden wird. Verschiedene Stimulationsstrategien wie beispielsweise CIS, ACE oder SPEAK (Kiefer et al. 2001) kommen bei CI-Systemen zur Anwendung. Gewicht und Batterieverbrauch von HdO-Sprachprozessoren sind unter anderem von der verwendeten Stimulationsstrategie abhängig: schnelle Stimulationstrategien wie CIS oder ACE benötigen mehr Batterieleistung als die langsamere SPEAK-Strategie. Kenntnisse der Vor-und Nachteile verschiedener Systeme bilden eine wichtige Entscheidungsgrundlage für CI-Kandidaten. In dieser Untersuchung wird der subjektive und objektive Nutzen von CI-Systeme mit zwei verschiedenen HdO-Sprachprozessoren miteinander verglichen.
Zusammenfassung Die Möglichkeit, eine beidseitige Innenohrschwerhörigkeit mit Steroiden oder Cycl... more Zusammenfassung Die Möglichkeit, eine beidseitige Innenohrschwerhörigkeit mit Steroiden oder Cyclophosphamid zu heilen, erregte durch die Mitteilung McCabes (1979) einiges Aufsehen, wenngleich ähnliche Beobachtungen im Einzelfall auch vorher schon angestellt worden waren. Seine pathomechanistische Vorstellung einer «Autoimmun-Innenohrschwerhörigkeit» wurde begeistert aufgegriffen, und viele experimentelle und klinische Arbeitsgruppen sind seitdem darum bemüht, den Beweis für die Existenz einer Autoimmunerkrankung des Innenohres zu erbringen. Bis heute ist es jedoch nicht gelungen, die strengen Kriterien, welche von den Immunologen und Immunpathologen für die Definition einer Autoimmunerkrankung gefordert werden, auf bestimmte Innenohrer-krankungen zu übertragen. An einigen exemplarischen klinischen Fallbeispielen werden eindrückliche Hörverbesserungen sowohl mit als auch ohne Steroidtherapie aufgezeigt. Es scheint tatsächlich eine Gruppe von Innenohr-schwerhörigkeiten zu existieren,...
HNO
From 1989-1993 we performed rigid bronchoscopies in 86 children in whom foreign body aspirations ... more From 1989-1993 we performed rigid bronchoscopies in 86 children in whom foreign body aspirations were suspected. In 72 cases, foreign bodies were identified in the tracheobronchial tree. In the remaining 14, no foreign body was found. Boys outnumbered girls. The most common type of foreign body was a peanut. The predilection of the foreign body was to fall into the right main bronchus. If the history indicated foreign body aspiration, a chest x-ray was not found to be necessary except for forensic interest.
Departementale Einheit Hals-, Nasen-und Ohrenkrankheiten, Hals-und Kopfchirurgie Einführung Die E... more Departementale Einheit Hals-, Nasen-und Ohrenkrankheiten, Hals-und Kopfchirurgie Einführung Die Erfolge der Cochlea-Implantation in der Be-handlung der höchstgradigen Schwerhörigkeit sind hinreichend bekannt. Ersten eigenen Untersuchungen zufolge kann durch eine bilateralen Cochlea-Implantation (=CI) eine weitere Verbesserung des Sprachverständnisse erwartet werden, insbesondere im Lärm. Zudem sollte räumliches Hören möglich sein [1]. Unsere Studie hat zum Ziel, das Sprachverständnis und die Schalllokalisation nach bilateraler Implantation systematisch zu untersuchen und darüber Auskunft zu geben, ob die bilaterale der unilateralen Implantation in Bezug auf verschiedene Parameter des Hörvermö-gens überlegen ist. Material und Methoden Bis im Dezember 2001 wurden in Bern 12 Patien-ten, 10 prä-oder perilingual ertaube Kinder (Alter: durchschnittlich 8 Jahre, 4 – 13 Jahre) und zwei post-lingual ertaubte Erwachsene, beide 49-jährig, bilateral implantiert. Ein, drei und sechs Monate nach ...
PloS one, 2015
Cochlear implants (CIs) are standard treatment for postlingually deafened individuals and preling... more Cochlear implants (CIs) are standard treatment for postlingually deafened individuals and prelingually deafened children. This human cadaver study evaluated diagnostic usefulness, image quality and artifacts in 1.5T and 3T magnetic resonance (MR) brain scans after CI with a removable magnet. Three criteria (diagnostic usefulness, image quality, artifacts) were assessed at 1.5T and 3T in five cadaver heads with CI. The brain magnetic resonance scans were performed with and without the magnet in situ. The criteria were analyzed by two blinded neuroradiologists, with focus on image distortion and limitation of the diagnostic value of the acquired MR images. MR images with the magnet in situ were all compromised by artifacts caused by the CI. After removal of the magnet, MR scans showed an unequivocal artifact reduction with significant improvement of the image quality and diagnostic usefulness, both at 1.5T and 3T. Visibility of the brain stem, cerebellopontine angle, and parieto-occip...
International journal of pediatric otorhinolaryngology, 2009
With more children receiving cochlear implants during infancy, there is a need for validated asse... more With more children receiving cochlear implants during infancy, there is a need for validated assessments of pre-verbal and early verbal auditory skills. The LittlEARS Auditory Questionnaire is presented here as the first module of the LittlEARS test battery. The LittlEARS Auditory Questionnaire was developed and piloted to assess the auditory behaviour of normal hearing children and hearing impaired children who receive a cochlear implant or hearing aid prior to 24 months of age. This paper presents results from two studies: one validating the LittlEARS Auditory Questionnaire on children with normal hearing who are German speaking and a second validating the norm curves found after adaptation and administration of the questionnaire to children with normal hearing in 15 different languages. Scores from a group of 218 German and Austrian children with normal hearing between 5 days and 24 months of age were used to create a norm curve. The questionnaire was adapted from the German orig...
International journal of pediatric otorhinolaryngology, Jan 11, 2002
The different speech sounds are formed by the primary voice signal and by the shape of the articu... more The different speech sounds are formed by the primary voice signal and by the shape of the articulation tract. With this mechanism, specific overtones, the formants, are generated for each vowel. The objective of this study was to investigate the fundamental frequency (F0) of the voice signal and the first three formants (F1-F3) as a parameter of the articulation in prelingually deafened children at different timepoints after cochlear implantation (CI) compared with children with normal speech development. Using the Kay CSL 4300B, the fundamental frequency and the formants F1-F3 of the Swiss-German vowel /a/ were investigated at different timepoints after CI in 20 prelingually deafened children aged 3.8-10.2 years by means of spectrographic and linear predictive coding (LPC) analysis. Children who had been operated before their fourth birthday showed no significant deviation in their fundamental frequency from age- and sex-matched peers, whereas a significant difference was document...
Schweizerische medizinische Wochenschrift, 2000
A Swiss study group was formed in summer 1998 with the aim of establishing a universal hearing sc... more A Swiss study group was formed in summer 1998 with the aim of establishing a universal hearing screening programme in newborns following the recommendations of the "European Consensus Statement on Neonatal Hearing Screening" (Milan 1998). The aim of the group was to standardise and to introduce universal hearing screening in all infants born in Switzerland. Starting in June 1999, several hospitals in Switzerland began the screening programme using commercially available equipment for easy and highly automated measurement of transient evoked otoacoustic emissions. Up to March 2000, 6262 children were born in these hospitals and 5656 (90%) underwent neonatal hearing screening. 88 children of the 5656 did not pass the screening test. The measurement of otoacoustic emissions was repeated in a follow-up examination within 6 weeks. If otoacoustic emissions were again absent, evoked auditory brainstem potentials were measured. 48 children were found to have hearing within normal ...
Journal für Hirnforschung, 1998
The distribution of Fos-like immunoreactivity (FLI) in the auditory pathway was analyzed and quan... more The distribution of Fos-like immunoreactivity (FLI) in the auditory pathway was analyzed and quantified in two groups of rats subjected to a similar electric stimulation of the cochlea, but the brains of the two groups were treated with a different antibody against Fos. The brains of control (unstimulated) rats were processed and analyzed in the same way. In a given auditory nucleus, for the same paradigm of stimulation, a very different density of FLI can be found depending on the antibody used to process the tissue. There are auditory nuclei which exhibited a significant activation of FLI as compared to control animals when one antibody was used whereas there was no difference when using the other antibody. In other cases, for both antibodies, a significant FLI increase was observed in relation to the stimulus. However, the increase of FLI density was significantly greater in some auditory nuclei with one antibody, while it was the reverse in other auditory nuclei. The present dat...
HNO, 1996
From 1989-1993 we performed rigid bronchoscopies in 86 children in whom foreign body aspirations ... more From 1989-1993 we performed rigid bronchoscopies in 86 children in whom foreign body aspirations were suspected. In 72 cases, foreign bodies were identified in the tracheobronchial tree. In the remaining 14, no foreign body was found. Boys outnumbered girls. The most common type of foreign body was a peanut. The predilection of the foreign body was to fall into the right main bronchus. If the history indicated foreign body aspiration, a chest x-ray was not found to be necessary except for forensic interest.
Advances in oto-rhino-laryngology, 1995
ORL, 1995
The activity elicited by electrical stimulation of the cochlea in the auditory pathway was assess... more The activity elicited by electrical stimulation of the cochlea in the auditory pathway was assessed in an animal model of cochlear implants on the basis of the induction of the immediate early gene c-fos and single neuron recordings. Electrical stimulation of the cochlea induced Fos-like immunoreactivity in the cochlear nucleus, mainly in its dorsal nucleus, in the superior olivary complex, in the lateral lemniscus, but not in the central nucleus of the inferior colliculus, the main relay nucleus in the auditory midbrain. However, single unit recordings from the inferior colliculus, ipsilateral and contralateral to the electrically stimulated cochlea, showed clear responses of single neurons, reminiscent of those elicited by acoustic stimulation. These findings provide immunocytochemical and electrophysiological evidence that the various nuclei of the auditory pathway are activated by electrical stimulation of the cochlea.
The Laryngoscope, 2012
Postmeningitic basal turn ossification is a challenge for successful cochlear implantation despit... more Postmeningitic basal turn ossification is a challenge for successful cochlear implantation despite the availability of sophisticated implants and advanced drill-out procedures. A less complex concept consisting of a cochleostomy near the apex with retrograde array insertion is evaluated clinically and experimentally with emphasis on imaging of intracochlear array morphology. Retrospective case-control study. Outcome, hearing performance, and radiological findings including three-dimensional (3D) reconstructions were assessed in the long term in eight retrograde implanted ears of seven postmeningitic deaf patients and compared to an etiology- and device-matched control group of 17 basal turn implanted ears of 14 patients. Experimental insertions into three autopsy-derived human temporal bones were evaluated using high-resolution microtomography, 3D reconstruction, and histology. No complications occurred. At the long-term follow-up, the average monosyllabic word test scores were 41% for the study group and 67% for the control group (P = .03). Radiological follow-up revealed insertion sites into either the apical or middle turn and frequent intracochlear array direction changes (n = 5). Experimental implantations in temporal bones resulted in folding-free, retrograde, middle turn insertions (n = 3). The retrograde cochlear implantation is a safe and efficient alternative approach in basal turn ossification. Despite a high occurrence of intracochlear array direction changes, open set speech discrimination was achieved in all patients. Postoperative computed tomography is recommended for fitting the speech processor according to intracochlear array positions. The experimental insertion in temporal bones helped to optimize the approach.
Neuroscience Research, 1994
Fos-like immunoreactivity (FLI) was mapped in the auditory pathway of Sprague-Dawley rats in resp... more Fos-like immunoreactivity (FLI) was mapped in the auditory pathway of Sprague-Dawley rats in response to unilateral electrical stimulation of the cochlea implanted with two stimulating electrodes. Densely packed FLI neurons were widely distributed in the dorsal cochlear nucleus (more ipsilaterally than contralaterally), while FLI neurons were rare in the posteroventral cochlear nucleus and virtually absent in the anteroventral cochlear nucleus. Sparse FLI was detected in the superior olivary complex, the pontine nuclei and the ipsilateral dorsal nucleus of the lateral lemniscus, whereas the contralateral dorsal nucleus of the lateral lemniscus was moderately labeled. In the inferior colliculus, the pattern of FLI was similar on both sides, restricted mainly to its dorsal and external cortices. At the thalamic level, FLI neurons were seen in the dorsal and medial divisions of the medial geniculate body as well as in the peripeduncular nucleus. A significant increase of FLI was observed in the temporal cortex. This study demonstrates the presence of selective functional changes along the auditory pathway elicited by electrical stimulation of the cochlea, as revealed by FLI.
NeuroReport, 1999
USING guinea-pig isolated whole brain preparation in vitro, synaptic responses to electrical stim... more USING guinea-pig isolated whole brain preparation in vitro, synaptic responses to electrical stimulation of auditory nerves were examined in intracellularly recorded and stained neurons of posteroventral and dorsal divisions of the cochlear nucleus. Stimulation of the contralateral auditory nerve evoked exclusively IPSPs in 70% of neurons, with amplitude of 2.3 AE 1.2 mV. Neurons of all major cell types were inhibited from the contralateral side. In the majority of responding cells (78%) IPSPs were induced at latencies of 3± 9 ms suggesting di-and trisynaptic connections from contralateral auditory afferents or, respectively, monoand disynaptic connections from the contralateral cochlear nucleus. Few cells responded with long-latency IPSPs (13.5±23 ms), indicating involvement of polysynaptic pathways. These data demonstrate the existence of functional, direct and indirect inhibitory connections between the cochlear nuclei.
Neurogastroenterology and Motility, 2004
The aim of this study was to investigate the effect of gastric electrical stimulation (GES) on ga... more The aim of this study was to investigate the effect of gastric electrical stimulation (GES) on gastric myoelectric activity (GMA) and to identify possible mechanisms that could help explain how high-frequency GES is effective in treating nausea and vomiting associated with gastroparesis. Fifteen gastroparetic patients who received high-frequency GES were enrolled. Two pairs of temporary pacing wires were implanted on the serosa of the stomach along the greater curvature during surgery for placement of the permanent stimulation device. Two-channel serosal recordings of GMA before and during GES were measured. A gastric emptying test and severity of nausea and vomiting were assessed at baseline and at 3 months of GES. Power spectral and cross correlation analyses revealed that impaired propagation of slow waves (50%), tachygastria (30%) and abnormal myoelectric responses to a meal (50%) were the main abnormalities observed at baseline. GES with a high frequency significantly enhanced the slow wave amplitude and propagation velocity, and resulted in a significant improvement in nausea and vomiting but did not entrain the gastric slow wave or improve gastric emptying after 3 months of GES.
The Journal of Infectious Diseases, 2007
Early exposure of infants and long-term immunity suggest that colonization with Moraxella catarrh... more Early exposure of infants and long-term immunity suggest that colonization with Moraxella catarrhalis is more frequent than is determined by routine culture. We characterized a reservoir of M. catarrhalis in pharyngeal lymphoid tissue. Tissue from 40 patients (median age, 7.1 years) undergoing elective tonsillectomy and/or adenoidectomy was analyzed for the presence of M. catarrhalis by culture, real-time DNA and RNA polymerase chain reaction (PCR), immunohistochemical analysis (IHC), and fluorescent in situ hybridization (FISH). Histologic sections were double stained for M. catarrhalis and immune cell markers, to characterize the tissue distribution of the organism. Intracellular bacteria were identified using confocal laser scanning microscopy (CLSM). Twenty-nine (91%) of 32 adenoids and 17 (85%) of 20 tonsils were colonized with M. catarrhalis. Detection rates for culture, DNA PCR, RNA PCR, IHC, and FISH were 7 (13%) of 52, 10 (19%) of 52, 21 (41%) of 51, 30 (61%) of 49, and 42 (88%) of 48, respectively (P<.001). Histologic analysis identified M. catarrhalis in crypts, intraepithelially, subepithelially, and (using CLSM) intracellularly. M. catarrhalis colocalized with macrophages and B cells in lymphoid follicles. Colonization by M. catarrhalis is more frequent than is determined by surface culture, because the organism resides both within and beneath the epithelium and invades host cells.
International Journal of Audiology, 2002
A patient with bilateral profound deafness was implanted with a Nucleus CI24M cochlear implant (C... more A patient with bilateral profound deafness was implanted with a Nucleus CI24M cochlear implant (CI) and used an Esprit behind-the-ear (BTE) speech processor. Thirteen months later, the implant had to be removed because of a cholesteatoma. As the same electrode could not be reinserted, a Medel combi40s CI was implanted in the same ear, and the patient used a Tempo+ BTE processor. After 1 year of use of the Combi40s/Tempo+ system, speech recognition was better and was rated better subjectively than with the CI24M/Esprit system. Speech recognition and subjective ratings were also assessed for two matched groups of nine CI users each, using either an Esprit or a Tempo+ processor. On average, speech recognition scores were higher for the group of Tempo+ users, but the difference was not statistically significant. Users of the Esprit processors rated their device higher in terms of cosmetic appearance and comfort of wearing.
International Journal of Audiology, 1997