Pub Date : 2009-01-01DOI: 10.1080/16513860802638752
H. Thai-Van, B. Philibert, E. Veuillet, L. Collet
Anatomical and physiological changes may occur under different circumstances, reflecting the plasticity of the human central and peripheral auditory system: deprivation of peripheral auditory input (plasticity induced by hearing deprivation), chronic exposition to sound in deaf subjects (plasticity induced by auditory rehabilitation), or auditory learning (learning-induced plasticity). In this review, we focus on auditory deprivation and rehabilitation-induced plasticity. We first describe some perceptual correlates of cortical plasticity induced by sensory deprivation, and then we present some of our original results showing the influence of hearing aids on perceptual performances of sensorineural hearing impaired listeners. These results are in line with the auditory acclimatization phenomenon (i.e. in monaurally fitted listeners, the aided ear performs better than the unaided ear for fine processing of high-intensity sounds). They also suggest that the auditory acclimatization phenomenon is lateralized with, in right-handed subjects, a more pronounced effect observed on the right side.
{"title":"Assessment of auditory plasticity using psychoacoustic and electrophysiological measurements","authors":"H. Thai-Van, B. Philibert, E. Veuillet, L. Collet","doi":"10.1080/16513860802638752","DOIUrl":"https://doi.org/10.1080/16513860802638752","url":null,"abstract":"Anatomical and physiological changes may occur under different circumstances, reflecting the plasticity of the human central and peripheral auditory system: deprivation of peripheral auditory input (plasticity induced by hearing deprivation), chronic exposition to sound in deaf subjects (plasticity induced by auditory rehabilitation), or auditory learning (learning-induced plasticity). In this review, we focus on auditory deprivation and rehabilitation-induced plasticity. We first describe some perceptual correlates of cortical plasticity induced by sensory deprivation, and then we present some of our original results showing the influence of hearing aids on perceptual performances of sensorineural hearing impaired listeners. These results are in line with the auditory acclimatization phenomenon (i.e. in monaurally fitted listeners, the aided ear performs better than the unaided ear for fine processing of high-intensity sounds). They also suggest that the auditory acclimatization phenomenon is lateralized with, in right-handed subjects, a more pronounced effect observed on the right side.","PeriodicalId":88223,"journal":{"name":"Audiological medicine","volume":"2000 1","pages":"55 - 66"},"PeriodicalIF":0.0,"publicationDate":"2009-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78099371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Otitis media with effusion (OME) is one of the most common disorders in childhood. Several investigators have reported central auditory processing disorders in children with recurrent attacks of OME. The aim was to study PSI in children with normal hearing and those with a history of recurrent OME. The study group consisted of 40 children, age range 5–8 years, with a previous history of three to five attacks of otitis media with effusion (OME). The average length of OME was 8.3 weeks/attack. The study group was divided into two equal subgroups, A and B; subgroup A had recently recovered from OME while subgroup B had recovered from OME at an earlier time. The control group consisted of 20 children with normal hearing. The control and study groups had matched age and gender distribution. A t-test was carried out to compare the different listening conditions of the PSI test in the control and the two study subgroups (CCM 0, CCM −20, ICM 0 and ICM +4). Non-statistically significant differences were found in all listening conditions when comparing the control group and subgroup B. Comparing the results of PSI testing of subgroup A to either control group or subgroup B, there were statistically high differences in all of the different testing conditions (p<0.01). Recurrent attacks of OME during the early years of life affect figure-ground ability as indicated by the significantly reduced PSI scores. However, this affection is reversed within a few months of recovery from OME.
{"title":"Paediatric speech intelligibility (PSI) in normal hearing children with history of recurrent otitis media with effusion (OME)","authors":"Hossam Sanyelbhaa Talaat, Abdelmagied Hasn Kabel, Etaf Qatanani","doi":"10.1080/16513860902949091","DOIUrl":"https://doi.org/10.1080/16513860902949091","url":null,"abstract":"Otitis media with effusion (OME) is one of the most common disorders in childhood. Several investigators have reported central auditory processing disorders in children with recurrent attacks of OME. The aim was to study PSI in children with normal hearing and those with a history of recurrent OME. The study group consisted of 40 children, age range 5–8 years, with a previous history of three to five attacks of otitis media with effusion (OME). The average length of OME was 8.3 weeks/attack. The study group was divided into two equal subgroups, A and B; subgroup A had recently recovered from OME while subgroup B had recovered from OME at an earlier time. The control group consisted of 20 children with normal hearing. The control and study groups had matched age and gender distribution. A t-test was carried out to compare the different listening conditions of the PSI test in the control and the two study subgroups (CCM 0, CCM −20, ICM 0 and ICM +4). Non-statistically significant differences were found in all listening conditions when comparing the control group and subgroup B. Comparing the results of PSI testing of subgroup A to either control group or subgroup B, there were statistically high differences in all of the different testing conditions (p<0.01). Recurrent attacks of OME during the early years of life affect figure-ground ability as indicated by the significantly reduced PSI scores. However, this affection is reversed within a few months of recovery from OME.","PeriodicalId":88223,"journal":{"name":"Audiological medicine","volume":"461 1","pages":"112 - 119"},"PeriodicalIF":0.0,"publicationDate":"2009-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79830553","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-01-01DOI: 10.1080/16513860902900136
A. Berto, D. Pellati, A. Castiglione, M. Busi, P. Trevisi, F. Gualandi, A. Ferlini, A. Martini
In many world populations, mutations in the GJB2 gene (codifying for Connexin 26) are the most common causes of autosomal recessive non-syndromic hearing loss and account for approximately 50% of cases. To date, more than 100 (dominant or recessive) mutations have been identified (The Connexin Deafness Homepage, 2009) and differences in frequency and distribution across the world are significant. In European and American Caucasian populations, the 35delG is the most common mutation found to account for nearly 70% of the pathological alleles. Mutations in the GJB6 gene (codifying for Connexin 30) can co-occur in some cases (we refer to the 342-kb truncating deletion, named as GJB6-D13S1830). Thus, these mutations have been associated with autosomal recessive and non-syndromic hearing loss, mostly as biallelic/digenic inheritance of the Cx26 and/or Cx30. Our objective in this study was to describe audiological features and genotypes in patients with GJB2 and/or GJB6 mutations. We performed a retrospective study on a deaf cohort of 566 patients who underwent specific genetic tests for Connexin 26 and 30; the latter was investigated in 385 cases. GJB2 mutations were found in 162 patients and GJB6 mutations in five. The most common mutation of GJB2 was 35delG, a truncating (T) mutation, although we also found other types of truncating (nine genotypes) and non-truncating (NT) (11 genotypes) mutations, such as M34T, L90P, R184P, IVS1 + 1G→A, V37I, and E47X. Even if more than 70% of patients with biallelic/digenic mutations exhibit a severe/profound hearing impairment (even between the simple heterozygotes), mild/moderate deafness is also possible. Other interesting clinical data, such as atypical history or phenotype, were considered. In accordance with the literature, all categories of HL were found. The severe-profound HL was predominant especially in T/T, T/NT forms. The 35delG is the most common mutation that we found, especially in profound hearing impairment. Mild-moderate HL was identified overall among NT/NT forms. Our findings confirm the importance of newborn screening, and the evaluation of genetic mutations to define genotype/phenotype correlation and clinical or audiological features useful to early diagnosis and improvement of therapeutic protocols.
{"title":"Audiological profiles and gjb2, gjb6 mutations: A retrospective study on genetic and clinical data from 2003 to 2008","authors":"A. Berto, D. Pellati, A. Castiglione, M. Busi, P. Trevisi, F. Gualandi, A. Ferlini, A. Martini","doi":"10.1080/16513860902900136","DOIUrl":"https://doi.org/10.1080/16513860902900136","url":null,"abstract":"In many world populations, mutations in the GJB2 gene (codifying for Connexin 26) are the most common causes of autosomal recessive non-syndromic hearing loss and account for approximately 50% of cases. To date, more than 100 (dominant or recessive) mutations have been identified (The Connexin Deafness Homepage, 2009) and differences in frequency and distribution across the world are significant. In European and American Caucasian populations, the 35delG is the most common mutation found to account for nearly 70% of the pathological alleles. Mutations in the GJB6 gene (codifying for Connexin 30) can co-occur in some cases (we refer to the 342-kb truncating deletion, named as GJB6-D13S1830). Thus, these mutations have been associated with autosomal recessive and non-syndromic hearing loss, mostly as biallelic/digenic inheritance of the Cx26 and/or Cx30. Our objective in this study was to describe audiological features and genotypes in patients with GJB2 and/or GJB6 mutations. We performed a retrospective study on a deaf cohort of 566 patients who underwent specific genetic tests for Connexin 26 and 30; the latter was investigated in 385 cases. GJB2 mutations were found in 162 patients and GJB6 mutations in five. The most common mutation of GJB2 was 35delG, a truncating (T) mutation, although we also found other types of truncating (nine genotypes) and non-truncating (NT) (11 genotypes) mutations, such as M34T, L90P, R184P, IVS1 + 1G→A, V37I, and E47X. Even if more than 70% of patients with biallelic/digenic mutations exhibit a severe/profound hearing impairment (even between the simple heterozygotes), mild/moderate deafness is also possible. Other interesting clinical data, such as atypical history or phenotype, were considered. In accordance with the literature, all categories of HL were found. The severe-profound HL was predominant especially in T/T, T/NT forms. The 35delG is the most common mutation that we found, especially in profound hearing impairment. Mild-moderate HL was identified overall among NT/NT forms. Our findings confirm the importance of newborn screening, and the evaluation of genetic mutations to define genotype/phenotype correlation and clinical or audiological features useful to early diagnosis and improvement of therapeutic protocols.","PeriodicalId":88223,"journal":{"name":"Audiological medicine","volume":"20 1","pages":"105 - 93"},"PeriodicalIF":0.0,"publicationDate":"2009-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81831437","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-01-01DOI: 10.1080/16513860802628217
P. Gil-Loyzaga, M. Iglesias, F. Carricondo, M. Bartolomé, Fernando Rodríguez, J. Poch-Broto
Hearing loss clearly alters the function and connectivity in auditory pathways in the brain. The effects of an auditory receptor lesion on the auditory pathway might be linked to the absence of peripheral stimulation on the first level of the auditory pathway (cochlear nuclei, CN). Loss of stimulation affects the pathway connectivity, at least in the CN, inducing the reorganization of the neural circuits. This reorganization may reduce the efficiency of some deafness therapies, including cochlear implants. Cochlea removal has been shown to be a good model for analysing neuroplasticity in the CN. Three main periods of degeneration and regeneration were found after cochlea removal. During the first week after cochlea removal, early effects included auditory nerve fibre degeneration, and the progressive degeneration of nerve endings on CN neurons. Some CN neurons degenerate. From the second week after cochlea removal a very limited and diffuse expression of GAP-43, a protein linked to developing or regenerating axon growth cones, was found. Expression was observed in small nerve endings connecting cochlear nuclei neurons. One month after cochlea removal, CN were stabilized with a clear reduction of new neuron degeneration. At this time a very relevant expression of GAP-43 was found around remaining neurons, in particular in the ventral cochlear nuclei. Molecular aspects and control of neuroplasticity in cochlear nuclei still remains controversial, even though it is clear that trophic factors and many other substances (i.e. neurotransmitters) have been involved in neuroplasticity.
{"title":"Cochlear nuclei neuroplasticity after auditory nerve and cochlea removal","authors":"P. Gil-Loyzaga, M. Iglesias, F. Carricondo, M. Bartolomé, Fernando Rodríguez, J. Poch-Broto","doi":"10.1080/16513860802628217","DOIUrl":"https://doi.org/10.1080/16513860802628217","url":null,"abstract":"Hearing loss clearly alters the function and connectivity in auditory pathways in the brain. The effects of an auditory receptor lesion on the auditory pathway might be linked to the absence of peripheral stimulation on the first level of the auditory pathway (cochlear nuclei, CN). Loss of stimulation affects the pathway connectivity, at least in the CN, inducing the reorganization of the neural circuits. This reorganization may reduce the efficiency of some deafness therapies, including cochlear implants. Cochlea removal has been shown to be a good model for analysing neuroplasticity in the CN. Three main periods of degeneration and regeneration were found after cochlea removal. During the first week after cochlea removal, early effects included auditory nerve fibre degeneration, and the progressive degeneration of nerve endings on CN neurons. Some CN neurons degenerate. From the second week after cochlea removal a very limited and diffuse expression of GAP-43, a protein linked to developing or regenerating axon growth cones, was found. Expression was observed in small nerve endings connecting cochlear nuclei neurons. One month after cochlea removal, CN were stabilized with a clear reduction of new neuron degeneration. At this time a very relevant expression of GAP-43 was found around remaining neurons, in particular in the ventral cochlear nuclei. Molecular aspects and control of neuroplasticity in cochlear nuclei still remains controversial, even though it is clear that trophic factors and many other substances (i.e. neurotransmitters) have been involved in neuroplasticity.","PeriodicalId":88223,"journal":{"name":"Audiological medicine","volume":"15 1","pages":"29 - 39"},"PeriodicalIF":0.0,"publicationDate":"2009-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79710274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-01-01DOI: 10.3109/16513860903374646
Sudhagar Kuttva, P. Radomskij, E. Raglan
Abstract Objective: The aim of this study was to establish the impact of peer review on estimated ABR thresholds. Study design: The reported ABR thresholds of two groups of 38 babies tested over a period of six months when a system of formal peer review was in place, and another period of six months when it was not in place, were retrospectively analysed by expert clinicians. Results: The modal differences between experts and tester estimated threshold with and without peer review were 5dB (-10 to +20) and 0dB (-10 to +35), respectively. Wilcoxon's signed-rank test for paired samples revealed a small but significant difference in estimated thresholds between experts and tester irrespective of whether tester was subjected to peer review on the day of the test or not. Conclusion: Peer review provides opportunities for peer support and continuing professional development. A system of formal peer review is strongly advocated.
{"title":"Effect of peer review on accuracy of reported auditory brainstem response thresholds in newborn hearing screening programme referrals","authors":"Sudhagar Kuttva, P. Radomskij, E. Raglan","doi":"10.3109/16513860903374646","DOIUrl":"https://doi.org/10.3109/16513860903374646","url":null,"abstract":"Abstract Objective: The aim of this study was to establish the impact of peer review on estimated ABR thresholds. Study design: The reported ABR thresholds of two groups of 38 babies tested over a period of six months when a system of formal peer review was in place, and another period of six months when it was not in place, were retrospectively analysed by expert clinicians. Results: The modal differences between experts and tester estimated threshold with and without peer review were 5dB (-10 to +20) and 0dB (-10 to +35), respectively. Wilcoxon's signed-rank test for paired samples revealed a small but significant difference in estimated thresholds between experts and tester irrespective of whether tester was subjected to peer review on the day of the test or not. Conclusion: Peer review provides opportunities for peer support and continuing professional development. A system of formal peer review is strongly advocated.","PeriodicalId":88223,"journal":{"name":"Audiological medicine","volume":"1 1","pages":"205 - 210"},"PeriodicalIF":0.0,"publicationDate":"2009-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83542753","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-01-01DOI: 10.1080/16513860802630304
Anette Lykke Hindhede, A. Parving
This contribution briefly describes the history of Danish audiology during the last 50–60 years from the establishment of the National Hearing Health Services (NHHS). Progress within the field is framed according to the theory of Bourdieu which challenges the present concept of evidence based medicine and health technology assessment (HTA). The humanistic field has recently been re-introduced due to the international impact of the WHO-ICF, in contrast to the former exclusion of this field from the NHHS. The major impact from the political field, resulting in a partial privatization, is regarded as potentially leading to a reduction of future research and training within audiology. In contrast, the political field considers it as an improvement despite the substantial increase in costs for the state.
{"title":"The field of Danish audiology: A historical perspective","authors":"Anette Lykke Hindhede, A. Parving","doi":"10.1080/16513860802630304","DOIUrl":"https://doi.org/10.1080/16513860802630304","url":null,"abstract":"This contribution briefly describes the history of Danish audiology during the last 50–60 years from the establishment of the National Hearing Health Services (NHHS). Progress within the field is framed according to the theory of Bourdieu which challenges the present concept of evidence based medicine and health technology assessment (HTA). The humanistic field has recently been re-introduced due to the international impact of the WHO-ICF, in contrast to the former exclusion of this field from the NHHS. The major impact from the political field, resulting in a partial privatization, is regarded as potentially leading to a reduction of future research and training within audiology. In contrast, the political field considers it as an improvement despite the substantial increase in costs for the state.","PeriodicalId":88223,"journal":{"name":"Audiological medicine","volume":"21 1","pages":"84 - 92"},"PeriodicalIF":0.0,"publicationDate":"2009-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77920763","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-01-01DOI: 10.3109/16513860903364050
D. Stephens, I. Pyykkő, Kirsi Varpa, E. Kentala
Abstract Objective: Patient enablement in a disease or disorder comprises the alleviation of medical symptoms, reduced participation restriction and reinforcement of the positive aspects of the condition. The aim of this study was to determine the aspects of positive experiences related to the impact of Ménière's disorder on the individuals’ lives. Study design: A postal survey of the members of the Finnish Ménière's Association included a structured questionnaire on positive experiences that have been reported by people with Ménière's disorder. Results: Detailed analyses revealed 10 questions that loaded on three factors related to the impact of the condition. Five questions loaded on two factors – ‘Relaxation’ and ‘Perspective on Ménière's disorder', which accounted for 58% in the variance in the psychological impact of the condition. Eight questions loaded on three factors: ‘Relaxation’ and ‘Perspective on Ménière's disorder’ and ‘Appreciation of support', which accounted for 56% in the variance in the global impact measures. Conclusions: Aspects of self-reported positive experience in Ménière's disorder can predict the impact of the condition describing ways in which it can be improved, its acceptance, and appreciation of those around the individual.
{"title":"The relationship between positive experiences in people with Ménière's disorder and the impact of the condition","authors":"D. Stephens, I. Pyykkő, Kirsi Varpa, E. Kentala","doi":"10.3109/16513860903364050","DOIUrl":"https://doi.org/10.3109/16513860903364050","url":null,"abstract":"Abstract Objective: Patient enablement in a disease or disorder comprises the alleviation of medical symptoms, reduced participation restriction and reinforcement of the positive aspects of the condition. The aim of this study was to determine the aspects of positive experiences related to the impact of Ménière's disorder on the individuals’ lives. Study design: A postal survey of the members of the Finnish Ménière's Association included a structured questionnaire on positive experiences that have been reported by people with Ménière's disorder. Results: Detailed analyses revealed 10 questions that loaded on three factors related to the impact of the condition. Five questions loaded on two factors – ‘Relaxation’ and ‘Perspective on Ménière's disorder', which accounted for 58% in the variance in the psychological impact of the condition. Eight questions loaded on three factors: ‘Relaxation’ and ‘Perspective on Ménière's disorder’ and ‘Appreciation of support', which accounted for 56% in the variance in the global impact measures. Conclusions: Aspects of self-reported positive experience in Ménière's disorder can predict the impact of the condition describing ways in which it can be improved, its acceptance, and appreciation of those around the individual.","PeriodicalId":88223,"journal":{"name":"Audiological medicine","volume":"34 1","pages":"233 - 240"},"PeriodicalIF":0.0,"publicationDate":"2009-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78292093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-01-01DOI: 10.1080/16513860802628225
P. Gil-Loyzaga
The adult auditory receptor and pathway are organized by highly complex circuits that appear during embryonic development. Several different neuroplasticity processes during development and maturation have clearly contributed to its final structural and functional organization. It seems especially interesting that an important over-sprouting of nerve fibres is first observed and later re-accommodates until reaching the final structure. During earlier development stages afferent nerve fibres from type I spiral ganglion cells reach all of the immature hair cells, before their differentiation into inner (IHCs) and outer (OHCs) hair cells. They were all recognized by the precocious ability to respond to glutamate agonists, which means an early high degree of maturation. Later, only type I afferent nerve fibres (kainic acid sensitive), connecting OHCs, will degenerate and disappear. The recent finding of some molecular differences between both types could justify this dissimilar maturation. In addition, an over-sprouting affects the olivary efferent fibres. In the same way as the afferents, these efferent nerve fibres promptly begin to express neurotransmitters even though a relevant number will degenerate during maturation and after the onset of hearing. Two types of nerve fibres must be considered: stable fibres, which remain into adult life, and transitory ones that reach a high degree of maturation but then disappear. All these neurotransmitters, and transitory nerve fibres, could be involved in neuroplasticity.
{"title":"Neurotransmitters and neuroplasticity during cochlear development: in vivo and in vitro studies","authors":"P. Gil-Loyzaga","doi":"10.1080/16513860802628225","DOIUrl":"https://doi.org/10.1080/16513860802628225","url":null,"abstract":"The adult auditory receptor and pathway are organized by highly complex circuits that appear during embryonic development. Several different neuroplasticity processes during development and maturation have clearly contributed to its final structural and functional organization. It seems especially interesting that an important over-sprouting of nerve fibres is first observed and later re-accommodates until reaching the final structure. During earlier development stages afferent nerve fibres from type I spiral ganglion cells reach all of the immature hair cells, before their differentiation into inner (IHCs) and outer (OHCs) hair cells. They were all recognized by the precocious ability to respond to glutamate agonists, which means an early high degree of maturation. Later, only type I afferent nerve fibres (kainic acid sensitive), connecting OHCs, will degenerate and disappear. The recent finding of some molecular differences between both types could justify this dissimilar maturation. In addition, an over-sprouting affects the olivary efferent fibres. In the same way as the afferents, these efferent nerve fibres promptly begin to express neurotransmitters even though a relevant number will degenerate during maturation and after the onset of hearing. Two types of nerve fibres must be considered: stable fibres, which remain into adult life, and transitory ones that reach a high degree of maturation but then disappear. All these neurotransmitters, and transitory nerve fibres, could be involved in neuroplasticity.","PeriodicalId":88223,"journal":{"name":"Audiological medicine","volume":"4 1","pages":"11 - 21"},"PeriodicalIF":0.0,"publicationDate":"2009-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73530242","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-01-01DOI: 10.1080/16513860903211731
E. Ulmer, A. Chays, L. Seidermann
Objective: In the vestibular system, many pathologies, particularly in children, decrease the canalar reactivity in such a way that high and low frequencies are simultaneously affected. Since Curthoys and Halmagyi (1) described the Head Impulse Test (HIT) in 1988 we know that we can check each semicircular canal individually with passive high frequency stimulation. Our aim is to quantify the VOR gain as measured during the HIT, in order to increase the sensitivity in such a way that we could, at least in some cases, replace the caloric test. Study design: To evaluate the sensitivity of the HIT combined with videography, we have measured the horizontal VOR gain in a population of 36 acoustic neuroma patients, and compared the results with unilateral weakness (UW) as measured with the Jongkees formula in the caloric test. A patient sitting in front of a camera is instructed to gaze continuously at a steady target. Their face is filmed at 25 FPS (frames per second) with a CCD (charge-coupled device) black and white camera located 1 metre in front. An infrared light source illuminates the face and creates a corneal reflection. Head rotation angle is calculated from variations in the grey scale image of the head, while gaze direction deflection is deduced from the coordinates of the corneal reflection referenced to pupillar centre. Results: Our results show good proportionality between UW(%) in the caloric test and the VOR gain weakness measured as a percentage in the HIT. However, we have found one case in which the caloric test indicated a significant UW of 38% while HIT remained in the normal range. Conclusion: The Head Impulse Test and caloric tests are different, but they are complementary. Using a camera, and automatic image processing, we are able to increase the sensitivity of the HIT in such a way that we are able to detect any VOR weakness of more than 40%.
{"title":"Application of videography during head impulse test in children: A possible replacement for the caloric test?","authors":"E. Ulmer, A. Chays, L. Seidermann","doi":"10.1080/16513860903211731","DOIUrl":"https://doi.org/10.1080/16513860903211731","url":null,"abstract":"Objective: In the vestibular system, many pathologies, particularly in children, decrease the canalar reactivity in such a way that high and low frequencies are simultaneously affected. Since Curthoys and Halmagyi (1) described the Head Impulse Test (HIT) in 1988 we know that we can check each semicircular canal individually with passive high frequency stimulation. Our aim is to quantify the VOR gain as measured during the HIT, in order to increase the sensitivity in such a way that we could, at least in some cases, replace the caloric test. Study design: To evaluate the sensitivity of the HIT combined with videography, we have measured the horizontal VOR gain in a population of 36 acoustic neuroma patients, and compared the results with unilateral weakness (UW) as measured with the Jongkees formula in the caloric test. A patient sitting in front of a camera is instructed to gaze continuously at a steady target. Their face is filmed at 25 FPS (frames per second) with a CCD (charge-coupled device) black and white camera located 1 metre in front. An infrared light source illuminates the face and creates a corneal reflection. Head rotation angle is calculated from variations in the grey scale image of the head, while gaze direction deflection is deduced from the coordinates of the corneal reflection referenced to pupillar centre. Results: Our results show good proportionality between UW(%) in the caloric test and the VOR gain weakness measured as a percentage in the HIT. However, we have found one case in which the caloric test indicated a significant UW of 38% while HIT remained in the normal range. Conclusion: The Head Impulse Test and caloric tests are different, but they are complementary. Using a camera, and automatic image processing, we are able to increase the sensitivity of the HIT in such a way that we are able to detect any VOR weakness of more than 40%.","PeriodicalId":88223,"journal":{"name":"Audiological medicine","volume":"17 1","pages":"168 - 171"},"PeriodicalIF":0.0,"publicationDate":"2009-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87311943","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2009-01-01DOI: 10.1080/16513860902957466
D. Stephens
The 1970s were a period when many professionals from different parts of the world, who were interested in audiological enablement (rehabilitation), looked to Denmark for inspiration. They also marked the 25th anniversary of the establishment of the three State Hearing Centres in Århus, Copenhagen and Odense (1,2), established at the inception of the National Hearing Health Service of that country. Such visitors included physicians, audiological scientists and educationalists, covering the range of specialties described by Hindhede and Parving in this Journal (pp****). Among those from the UK who went to Denmark were Andreas Markides (educationalist), Denzil Brooks (audiological scientist) and myself as an audiological physician. We all derived much benefit from our visits, and our experiences which we described elsewhere (3,4). These led to us collaborating to produce a document for the British Society of Audiology on our recommendations for audiological enablement and, in particular, for hearing therapy, in the UK (5). Unfortunately, politics being what they are, our recommendations took some 30 years to be implemented in the UK, eventually with the recent establishment of the MSc course at Bristol University. Returning to Denmark, questions arise as to how such a service developed in Denmark and why the country no longer provides the model, even for other countries with broadly similar sociomedical systems. I shall attempt to address these questions below in a way to complement the interesting analysis offered by Hindhede and Parving. In their paper those authors discuss the dynamics of competing groups of professionals and lay interests in the provision of services for people with hearing difficulties. In addition, they present the background to the establishment of the hearing health care service in Denmark, but do not touch on the personalities involved. From the standpoint of the maintenance and development of the system they touch on the political ideology that has led to a fragmentation of the system, and this needs further emphasis.
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