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Tomlin D, Rance G. Maturation of the Central Auditory Nervous System in Children with Auditory Processing Disorder. Semin Hear 2016; 37:74-83. [PMID: 27587924 DOI: 10.1055/s-0035-1570328] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
Neurodevelopmental delay has been proposed as the underlying cause of the majority of cases of auditory processing disorder (APD). The current study employs the cortical auditory evoked potential (CAEP) to assess if maturational differences of the central auditory nervous system (CANS) can be identified between children who do and do not meet the diagnostic criterion for APD. The P1-N1 complex of the CAEP has previously been used for tracking development of the CANS in children with hearing impairment. Twenty-seven children (7 to 12 years old) who failed an APD behavioral test battery were age-matched (within 3 months) to children who had passed the same battery. CAEP responses to 500-Hz tone burst stimuli were recorded and analyzed for latency and amplitude measures. The P1-N1 complex of the CAEP, which has previously been used for tracking development of the CANS in children with hearing impairment, showed significant group differences. The children diagnosed with APD showed significantly increased latency (∼10 milliseconds) and significantly reduced amplitude (∼10 μV) of the early components of the CAEP compared with children with normal auditory processing. No significant differences were seen in the later P2 wave. The normal developmental course is for a decrease in latency and increase in amplitude as a function of age. The results of this study are, therefore, consistent with an immaturity of the CANS as an underlying cause of APD in children.
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Rance G, Chisari D, Edvall N, Cameron F. Functional hearing deficits in children with Type 1 diabetes. Diabet Med 2016; 33:1268-74. [PMID: 26823194 DOI: 10.1111/dme.13086] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 10/27/2015] [Accepted: 01/25/2016] [Indexed: 12/17/2022]
Abstract
AIM Hearing loss (as reflected by abnormal sound detection) is a frequently reported consequence of Type 1 diabetes mellitus. We sought to evaluate sound detection, auditory neural function and binaural processing ability in a group of school-aged participants with Type 1 diabetes and to assess their functional hearing and general communication ability. METHODS A range of electroacoustic, electrophysiological and behavioural test techniques were used to evaluate both cochlear and auditory neural function in 19 affected children. A cohort of matched controls was also assessed. RESULTS Although all of the participants with Type 1 diabetes enjoyed normal sound detection, 9 of the 19 (47%) showed evidence of auditory pathway abnormality with evoked potential latencies and/or amplitudes beyond age-related norms. Auditory brainstem response interpeak latencies (wave I-V) were longer than in matched controls [ 95% confidence interval (95% CI); 0.10, 0.28 ms: P < 0.001] and wave V amplitudes were reduced (95% CI; -0.21, 0.00 μV: P = 0.02). Binaural speech perception in noise was also impaired (95% CI; 0.82, 3.17 dB: P = 0.002) and perceptual ability was correlated with degree of neural disruption in the auditory brainstem (r = 0.662, P = 0.003). CONCLUSIONS Hearing deficits severe enough to restrict communication and threaten academic progress were common on our group of school-aged children with Type 1 diabetes. Evaluation of both cochlear and auditory neural function may form an important part of the standard management regime for children with diabetes.
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Rance G, Starr A. Pathophysiological mechanisms and functional hearing consequences of auditory neuropathy. Brain 2015; 138:3141-58. [PMID: 26463676 DOI: 10.1093/brain/awv270] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 08/05/2015] [Indexed: 01/19/2023] Open
Abstract
The effects of inner ear abnormality on audibility have been explored since the early 20th century when sound detection measures were first used to define and quantify 'hearing loss'. The development in the 1970s of objective measures of cochlear hair cell function (cochlear microphonics, otoacoustic emissions, summating potentials) and auditory nerve/brainstem activity (auditory brainstem responses) have made it possible to distinguish both synaptic and auditory nerve disorders from sensory receptor loss. This distinction is critically important when considering aetiology and management. In this review we address the clinical and pathophysiological features of auditory neuropathy that distinguish site(s) of dysfunction. We describe the diagnostic criteria for: (i) presynaptic disorders affecting inner hair cells and ribbon synapses; (ii) postsynaptic disorders affecting unmyelinated auditory nerve dendrites; (iii) postsynaptic disorders affecting auditory ganglion cells and their myelinated axons and dendrites; and (iv) central neural pathway disorders affecting the auditory brainstem. We review data and principles to identify treatment options for affected patients and explore their benefits as a function of site of lesion.
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Yiu EM, Tai G, Peverill RE, Lee KJ, Croft KD, Mori TA, Scheiber-Mojdehkar B, Sturm B, Praschberger M, Vogel AP, Rance G, Stephenson SEM, Sarsero JP, Stockley C, Lee CYJ, Churchyard A, Evans-Galea MV, Ryan MM, Lockhart PJ, Corben LA, Delatycki MB. An open-label trial in Friedreich ataxia suggests clinical benefit with high-dose resveratrol, without effect on frataxin levels. J Neurol 2015; 262:1344-53. [PMID: 25845763 DOI: 10.1007/s00415-015-7719-2] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Revised: 03/20/2015] [Accepted: 03/21/2015] [Indexed: 12/11/2022]
Abstract
Friedreich ataxia (FRDA) is due to a triplet repeat expansion in FXN, resulting in deficiency of the mitochondrial protein frataxin. Resveratrol is a naturally occurring polyphenol, identified to increase frataxin expression in cellular and mouse models of FRDA and has anti-oxidant properties. This open-label, non-randomized trial evaluated the effect of two different doses of resveratrol on peripheral blood mononuclear cell (PBMC) frataxin levels over a 12-week period in individuals with FRDA. Secondary outcome measures included PMBC FXN mRNA, oxidative stress markers, and clinical measures of disease severity. Safety and tolerability were studied. Twenty-four participants completed the study; 12 received low-dose resveratrol (1 g daily) and 12 high-dose resveratrol (5 g daily). PBMC frataxin levels did not change in either dosage group [low-dose group change: 0.08 pg/μg protein (95% CI -0.05, 0.21, p = 0.21); high-dose group change: 0.03 pg/μg protein (95% CI -0.10, 0.15, p = 0.62)]. Improvement in neurologic function was evident in the high-dose group [change in Friedreich Ataxia Rating Scale -3.4 points, 95% CI (-6.6, -0.3), p = 0.036], but not the low-dose group. Significant improvements in audiologic and speech measures, and in the oxidative stress marker plasma F2-isoprostane were demonstrated in the high-dose group only. There were no improvements in cardiac measures or patient-reported outcome measures. No serious adverse events were recorded. Gastrointestinal side-effects were a common, dose-related adverse event. This open-label study shows no effect of resveratrol on frataxin levels in FRDA, but suggests that independent positive clinical and biologic effects of high-dose resveratrol may exist. Further assessment of efficacy is warranted in a randomized placebo-controlled trial.
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Rance G, Rickards FW, Cohen LT, Burton MJ, Clark GM. Steady state evoked potentials: a new tool for the accurate assessment of hearing in cochlear implant candidates. Adv Otorhinolaryngol 2015; 48:44-8. [PMID: 8273498 DOI: 10.1159/000422556] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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Cowan RS, Dowell RC, Pyman BC, Dettman SJ, Dawson PW, Rance G, Barker EJ, Sarant JZ, Clark GM. Preliminary speech perception results for children with the 22-electrode Melbourne/cochlear hearing prosthesis. Adv Otorhinolaryngol 2015; 48:231-5. [PMID: 8273486 DOI: 10.1159/000422589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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Abstract
Neural disorders of the auditory nerve are associated with particular disorders of auditory perceptions dependent on processing of acoustic temporal cues. These include: (1) speech perception; (2) localizing a sound's origin in space; and (3) identifying sounds in background noise. Auditory neuropathy (AN) is a consequence of: (1) presynaptic disorders affecting inner hair cell ribbon synapses; (2) postsynaptic disorders of auditory nerve dendrites; and (3) postsynaptic disorders of auditory nerve axons. The etiologies of these disorders are diverse, similar to other cranial or peripheral neuropathies. The pathologies cause attenuated and dyssynchronous auditory nerve discharges. Therapies and management of patients with AN are reviewed.
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Rance G, Chisari D, O'Hare F, Roberts L, Shaw J, Jandeleit-Dahm K, Szmulewicz D. Auditory neuropathy in individuals with Type 1 diabetes. J Neurol 2014; 261:1531-6. [PMID: 24846202 DOI: 10.1007/s00415-014-7371-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 05/08/2014] [Accepted: 05/09/2014] [Indexed: 12/29/2022]
Abstract
Peripheral neuropathy is a major consequence of diabetes mellitus with up to 50 % of patients showing clinically significant neural injury during the disease course. Hearing loss (as defined by impaired sound detection thresholds) is a recognized symptom of DM, but the possibility of auditory neuropathy (AN) has not been explored in this population. This pilot study investigated peripheral auditory function, auditory processing and speech perception in individuals with Type 1 diabetes mellitus (T1DM) and compared the findings with measures of vestibular function, ocular pathology/visual acuity and overall neurologic profile. Ten adults with T1DM and ten matched controls underwent a battery of tests which included: audiometry, otoacoustic emissions, auditory brainstem responses, temporal processing measures and speech perception. Six of the ten T1DM participants showed electrophysiologic evidence of AN and impaired functional hearing. Furthermore, auditory capacity was correlated with both visual acuity and degree of somatic peripheral neuropathy. This pilot investigation revealed functional-hearing deficits severe enough to impact upon everyday communication. Should the findings be confirmed by larger studies, auditory evaluation may form an important part of the management regimen for individuals with T1DM. This may be especially important for those with DM-related eye conditions, as deficits across multiple sensory modalities can have multiplicative detrimental effects on quality-of-life.
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Rance G, Saunders K, Carew P, Johansson M, Tan J. The use of listening devices to ameliorate auditory deficit in children with autism. J Pediatr 2014; 164:352-7. [PMID: 24183205 DOI: 10.1016/j.jpeds.2013.09.041] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Revised: 08/14/2013] [Accepted: 09/18/2013] [Indexed: 10/26/2022]
Abstract
OBJECTIVES To evaluate both monaural and binaural processing skills in a group of children with autism spectrum disorder (ASD) and to determine the degree to which personal frequency modulation (radio transmission) (FM) listening systems could ameliorate their listening difficulties. STUDY DESIGN Auditory temporal processing (amplitude modulation detection), spatial listening (integration of binaural difference cues), and functional hearing (speech perception in background noise) were evaluated in 20 children with ASD. Ten of these subsequently underwent a 6-week device trial in which they wore the FM system for up to 7 hours per day. RESULTS Auditory temporal processing and spatial listening ability were poorer in subjects with ASD than in matched controls (temporal: P = .014 [95% CI -6.4 to -0.8 dB], spatial: P = .003 [1.0 to 4.4 dB]), and performance on both of these basic processing measures was correlated with speech perception ability (temporal: r = -0.44, P = .022; spatial: r = -0.50, P = .015). The provision of FM listening systems resulted in improved discrimination of speech in noise (P < .001 [11.6% to 21.7%]). Furthermore, both participant and teacher questionnaire data revealed device-related benefits across a range of evaluation categories including Effect of Background Noise (P = .036 [-60.7% to -2.8%]) and Ease of Communication (P = .019 [-40.1% to -5.0%]). Eight of the 10 participants who undertook the 6-week device trial remained consistent FM users at study completion. CONCLUSIONS Sustained use of FM listening devices can enhance speech perception in noise, aid social interaction, and improve educational outcomes in children with ASD.
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Kennerson ML, Yiu EM, Chuang DT, Kidambi A, Tso SC, Ly C, Chaudhry R, Drew AP, Rance G, Delatycki MB, Züchner S, Ryan MM, Nicholson GA. A new locus for X-linked dominant Charcot-Marie-Tooth disease (CMTX6) is caused by mutations in the pyruvate dehydrogenase kinase isoenzyme 3 (PDK3) gene. Hum Mol Genet 2013; 22:1404-16. [PMID: 23297365 PMCID: PMC3596851 DOI: 10.1093/hmg/dds557] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Revised: 12/16/2012] [Accepted: 12/27/2012] [Indexed: 01/30/2023] Open
Abstract
Hereditary motor and sensory disorders of the peripheral nerve form one of the most common groups of human genetic diseases collectively called Charcot-Marie-Tooth (CMT) neuropathy. Using linkage analysis in a three generation kindred, we have mapped a new locus for X-linked dominant CMT to chromosome Xp22.11. A microsatellite scan of the X chromosome established significant linkage to several markers including DXS993 (Zmax = 3.16; θ = 0.05). Extended haplotype analysis refined the linkage region to a 1.43-Mb interval flanked by markers DXS7110 and DXS8027. Whole exome sequencing identified a missense mutation c.G473A (p.R158H) in the pyruvate dehydrogenase kinase isoenzyme 3 (PDK3) gene. The change localized within the 1.43-Mb linkage interval, segregated with the affected phenotype and was excluded in ethnically matched control chromosomes. PDK3 is one of the four isoenzymes regulating the pyruvate dehydrogenase complex (PDC), by reversible phosphorylation, and is a nuclear-coded protein located in the mitochondrial matrix. PDC catalyzes the oxidative decarboxylation of pyruvate to acetyl CoA and is a key enzyme linking glycolysis to the energy-producing Krebs cycle and lipogenic pathways. We found that the R158H mutation confers enzyme hyperactivity and binds with stronger affinity than the wild-type to the inner-lipoyl (L2) domain of the E2p chain of PDC. Our findings suggest a reduced pyruvate flux due to R158H mutant PDK3-mediated hyper-phosphorylation of the PDC as the underlying pathogenic cause of peripheral neuropathy. The results highlight an important causative link between peripheral nerve degeneration and an essential bioenergetic or biosynthetic pathway required for the maintenance of peripheral nerves.
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Rance G, Ryan M, Carew P, Corben L, Yiu E, Tan J, Delatycki M. Binaural speech processing in individuals with auditory neuropathy. Neuroscience 2012; 226:227-35. [DOI: 10.1016/j.neuroscience.2012.08.054] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2012] [Revised: 08/20/2012] [Accepted: 08/26/2012] [Indexed: 10/27/2022]
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Rance G, Corben LA, Delatycki MB. Auditory pathway changes mirror overall disease progress in individuals with Friedreich ataxia. J Neurol 2012; 259:2746-8. [DOI: 10.1007/s00415-012-6679-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2012] [Revised: 09/11/2012] [Accepted: 09/12/2012] [Indexed: 10/27/2022]
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O'Hare F, Rance G, Crowston JG, McKendrick AM. Auditory and visual temporal processing disruption in open angle glaucoma. Invest Ophthalmol Vis Sci 2012; 53:6512-8. [PMID: 22879422 DOI: 10.1167/iovs.12-10188] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Open angle glaucoma (OAG) is increasingly being viewed as an age-related neurodegenerative condition that may occur in individuals who are innately susceptible to global (autonomic) neural injury. Recent data support the plausibility of auditory neural impairment in a proportion of individuals with OAG, with results showing a key disruption to processing temporal properties of sound. This study tested the hypothesis that temporal processing deficits consistent with central (cortical) processing abnormalities are present in both the visual and auditory domains in individuals with glaucoma. METHODS A series of tasks designed to test progressively more complex aspects of temporal processing were conducted in 25 OAG individuals and 25 age- and sex-matched controls. For audition, baseline measurement of hearing sensitivity was followed by functional assessment of amplitude modulation detection, frequency discrimination at two reference levels, and speech perception. For vision, measures of foveal temporal contrast detection at two flicker rates, speed discrimination at two reference velocities, and coherent global motion detection were assessed. RESULTS A significant proportion of the OAG cohort displayed an impairment in auditory low-frequency discrimination, speech perception, visual speed discrimination for slow velocities and/or visual global motion detection, compared to controls (36%, 25%, 39%, and 34% respectively, were outside the 90th percentile of control performance; P < 0.05). CONCLUSIONS A subgroup of individuals with OAG displayed impaired auditory temporal processing concurrent with signs of visual temporal processing impairment. These temporal processing deficits were in the presence of normal sound detection and normal central luminance increment thresholds.
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Abstract
Friedreich ataxia is a neurodegenerative disease with an average age of onset of 10 years. The authors sought to investigate the presence and functional consequences of auditory neuropathy in a group of affected children and to evaluate the ability of personal FM-listening systems to improve perception. Nineteen school-aged individuals with Friedreich ataxia and a cohort of matched control subjects underwent a battery of auditory function tests. Sound detection was relatively normal, but auditory temporal processing and speech understanding in noise were severely impaired, with children with Friedreich ataxia typically able to access less than 40% of the information available to controls. Use of FM-listening devices did, however, improve the speech perception performance of those with Friedreich ataxia to the level of their unaffected peers in conditions designed to replicate the listening environment of the average school classroom.
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O'Hare F, Rance G, McKendrick AM, Crowston JG. Is primary open-angle glaucoma part of a generalized sensory neurodegeneration? A review of the evidence. Clin Exp Ophthalmol 2012; 40:895-905. [DOI: 10.1111/j.1442-9071.2012.02812.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Rance G, Ryan MM, Bayliss K, Gill K, O'Sullivan C, Whitechurch M. Auditory function in children with Charcot-Marie-Tooth disease. Brain 2012; 135:1412-22. [PMID: 22522939 DOI: 10.1093/brain/aws085] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The peripheral manifestations of the inherited neuropathies are increasingly well characterized, but their effects upon cranial nerve function are not well understood. Hearing loss is recognized in a minority of children with this condition, but has not previously been systemically studied. A clear understanding of the prevalence and degree of auditory difficulties in this population is important as hearing impairment can impact upon speech/language development, social interaction ability and educational progress. The aim of this study was to investigate auditory pathway function, speech perception ability and everyday listening and communication in a group of school-aged children with inherited neuropathies. Twenty-six children with Charcot-Marie-Tooth disease confirmed by genetic testing and physical examination participated. Eighteen had demyelinating neuropathies (Charcot-Marie-Tooth type 1) and eight had the axonal form (Charcot-Marie-Tooth type 2). While each subject had normal or near-normal sound detection, individuals in both disease groups showed electrophysiological evidence of auditory neuropathy with delayed or low amplitude auditory brainstem responses. Auditory perception was also affected, with >60% of subjects with Charcot-Marie-Tooth type 1 and >85% of Charcot-Marie-Tooth type 2 suffering impaired processing of auditory temporal (timing) cues and/or abnormal speech understanding in everyday listening conditions.
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Henshall KR, Sergejew AA, McKay CM, Rance G, Shea TL, Hayden MJ, Innes-Brown H, Copolov DL. Interhemispheric transfer time in patients with auditory hallucinations: an auditory event-related potential study. Int J Psychophysiol 2012; 84:130-9. [PMID: 22342240 DOI: 10.1016/j.ijpsycho.2012.01.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Revised: 01/25/2012] [Accepted: 01/26/2012] [Indexed: 11/26/2022]
Abstract
Central auditory processing in schizophrenia patients with a history of auditory hallucinations has been reported to be impaired, and abnormalities of interhemispheric transfer have been implicated in these patients. This study examined interhemispheric functional connectivity between auditory cortical regions, using temporal information obtained from latency measures of the auditory N1 evoked potential. Interhemispheric Transfer Times (IHTTs) were compared across 3 subject groups: schizophrenia patients who had experienced auditory hallucinations, schizophrenia patients without a history of auditory hallucinations, and normal controls. Pure tones and single-syllable words were presented monaurally to each ear, while EEG was recorded continuously. IHTT was calculated for each stimulus type by comparing the latencies of the auditory N1 evoked potential recorded contralaterally and ipsilaterally to the ear of stimulation. The IHTTs for pure tones did not differ between groups. For word stimuli, the IHTT was significantly different across the 3 groups: the IHTT was close to zero in normal controls, was highest in the AH group, and was negative (shorter latencies ipsilaterally) in the nonAH group. Differences in IHTTs may be attributed to transcallosal dysfunction in the AH group, but altered or reversed cerebral lateralization in nonAH participants is also possible.
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Rance G, O'Hare F, O'Leary S, Starr A, Ly A, Cheng B, Tomlin D, Graydon K, Chisari D, Trounce I, Crowston J. Auditory processing deficits in individuals with primary open-angle glaucoma. Int J Audiol 2011; 51:10-5. [DOI: 10.3109/14992027.2011.609185] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Rance G, Corben L, Barker E, Carew P, Chisari D, Rogers M, Dowell R, Jamaluddin S, Bryson R, Delatycki MB. Auditory perception in individuals with Friedreich's ataxia. Audiol Neurootol 2009; 15:229-40. [PMID: 19893304 DOI: 10.1159/000255341] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2009] [Accepted: 08/21/2009] [Indexed: 11/19/2022] Open
Abstract
INTRODUCTION Friedreich's ataxia (FRDA) is an inherited ataxia with a range of progressive features including axonal degeneration of sensory nerves. The aim of this study was to investigate auditory perception in affected individuals. METHODS Fourteen subjects with genetically defined FRDA participated. Two control groups, one consisting of healthy, normally hearing individuals and another comprised of subjects with sensorineural hearing loss, were also assessed. Auditory processing was evaluated using structured tasks designed to reveal the listeners' ability to perceive temporal and spectral cues. Findings were then correlated with open-set speech understanding. RESULTS Nine of 14 individuals with FRDA showed evidence of auditory processing disorder. Gap and amplitude modulation detection levels in these subjects were significantly elevated, indicating impaired encoding of rapid signal changes. Electrophysiologic findings (auditory brainstem response, ABR) also reflected disrupted neural activity. Speech understanding was significantly affected in these listeners and the degree of disruption was related to temporal processing ability. Speech analyses indicated that timing cues (notably consonant voice onset time and vowel duration) were most affected. CONCLUSION The results suggest that auditory pathway abnormality is a relatively common consequence of FRDA. Regular auditory evaluation should therefore be part of the management regime for all affected individuals. This assessment should include both ABR testing, which can provide insights into the degree to which auditory neural activity is disrupted, and some functional measure of hearing capacity such as speech perception assessment, which can quantify the disorder and provide a basis for intervention.
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Leigh J, Rance G, Dettman S, Dowell R. Cochlear Implant Outcomes for Children With Auditory Neuropathy Spectrum Disorder. ACTA ACUST UNITED AC 2009. [DOI: 10.1044/hhdc19.2.75] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
AbstractCochlear implantation is currently the intervention option of choice for many children with auditory neuropathy spectrum disorder (ANSD) who are unable to obtain benefit from conventional amplification. The aim of this study was to review the speech perception and language outcomes for children with ANSD who had received a cochlear implant and highlight specific clinical considerations for working with this population of children with hearing impairment who are being considered for implantation. Finds for the group of 17 children with ANSD using cochlear implants were compared to previously reported outcomes for children with sensori-neural (SN) type hearing loss using cochlear implants.Two children, identified with cochlear nerve deficiency pre-operatively, received no useful auditory percepts from their cochlear implant and discontinued device use. The remaining children demonstrated speech perception and language outcomes comparable to those observed for SN hearing loss peers using cochlear implants.This paper highlights a number of considerations for clinicians to be aware of and the importance of careful counseling pre-operatively regarding the potential for less-than-optimal outcomes, particularly for those children identified with cochlear nerve deficiency.
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Rance G, Barker EJ. Speech and language outcomes in children with auditory neuropathy/dys-synchrony managed with either cochlear implants or hearing aids. Int J Audiol 2009; 48:313-20. [DOI: 10.1080/14992020802665959] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Tomlin D, Rance G, Graydon K, Tsialios I. A comparison of 40 Hz auditory steady-state response (ASSR) and cortical auditory evoked potential (CAEP) thresholds in awake adult subjects. Int J Audiol 2009; 45:580-8. [PMID: 17062499 DOI: 10.1080/14992020600895170] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Evoked potential thresholds using the 40 Hz auditory steady-state response (ASSR) and cortical auditory evoked potential (CAEP) were recorded at 500 Hz and 4000 Hz test frequencies in 36 subjects with normal acuity, and 30 subjects with sensorineural hearing loss. ASSR threshold sensation levels (SLs) were lower in ears with greater degrees of hearing loss, and for the 500 Hz stimulus. Mean SLs (maximum duration of a single recording: 89 seconds) were as follows at 500 Hz and 4000 Hz respectively: normal hearing group, 16.9+/-10.3 dB and 42.4+/-14.4 dB; mild-moderate group, 10.6+/-8.8 dB and 23.8+/-8.1 dB; severe-profound group, 10.0+/-13.2 dB and 21.5+/-18.9 dB. CAEP SLs showed no change with hearing level and CAEP/behavioural differences were similar at each test frequency. Mean SLs for CAEP threshold (single recording duration: 84 seconds) at 500 Hz and 4000 Hz respectively were: normal hearing group, 10.3+/-6.4 dB and 11.5+/-3.8 dB; mild-moderate group, 8.4+/-7.4 dB and 13.2+/-12.4 dB; severe-profound group, 11.0+/-6.6 dB and 15.9+/-16.4 dB. The results of this study suggest that while both 40 Hz ASSR and CAEP can reflect the behavioural audiogram, CAEPs may provide a more reliable estimate of hearing in awake adults.
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Quinn S, Rance G. The extent of hearing impairment amongst Australian Indigenous prisoners in Victoria, and implications for the correctional system. Int J Audiol 2009; 48:123-34. [DOI: 10.1080/14992020802516558] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Rance G, Fava R, Baldock H, Chong A, Barker E, Corben L, Delatycki MB. Speech perception ability in individuals with Friedreich ataxia. ACTA ACUST UNITED AC 2008; 131:2002-12. [PMID: 18515321 DOI: 10.1093/brain/awn104] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
The aim of this study was to investigate auditory pathway function and speech perception ability in individuals with Friedreich ataxia (FRDA). Ten subjects confirmed by genetic testing as being homozygous for a GAA expansion in intron 1 of the FXN gene were included. While each of the subjects demonstrated normal, or near normal sound detection, 3 of the 10 showed electrophysiological evidence of auditory pathway disorder [presenting with the auditory neuropathy/dyssynchrony (AN/AD) result pattern], and 9 of the 10 showed abnormal speech understanding when tested with levels of background noise typical of everyday listening conditions. Information transmission analyses of the speech perception findings for the three FRDA subjects with AN/AD type hearing loss when compared with those of a cohort of individuals with peripheral [sensorineural (SN)] hearing loss, showed a distinct pattern of perceptual disruption. Where the listeners with SN loss confused sounds on the basis of frequency (pitch) differences, the FRDA subjects with AN/AD made errors that reflected an inability to perceive temporal (timing) cues in the speech sounds.
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