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De Pascalis R, Parnell WJ, Abrahams ID, Shearer T, Daly DM, Grundy D. The inflation of viscoelastic balloons and hollow viscera. Proc Math Phys Eng Sci 2018; 474:20180102. [PMCID: PMC6237490 DOI: 10.1098/rspa.2018.0102] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 09/19/2018] [Indexed: 10/13/2023] Open
Abstract
For the first time, the problem of the inflation of a nonlinear viscoelastic thick-walled spherical shell is considered. Specifically, the wall has quasilinear viscoelastic constitutive behaviour, which is of fundamental importance in a wide range of applications, particularly in the context of biological systems such as hollow viscera, including the lungs and bladder. Experiments are performed to demonstrate the efficacy of the model in fitting relaxation tests associated with the volumetric inflation of murine bladders . While the associated nonlinear elastic problem of inflation of a balloon has been studied extensively, there is a paucity of studies considering the equivalent nonlinear viscoelastic case. We show that, in contrast to the elastic scenario, the peak pressure associated with the inflation of a neo-Hookean balloon is not independent of the shear modulus of the medium. Moreover, a novel numerical technique is described in order to solve the nonlinear Volterra integral equation in space and time originating from the fundamental problem of inflation and deflation of a thick-walled nonlinear viscoelastic shell under imposed pressure.
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Affiliation(s)
- Riccardo De Pascalis
- Dipartimento di Matematica e Fisica ‘E. De Giorgi’, Università del Salento, Via per Arnesano, 73100 Lecce, Italy
- School of Mathematics, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - William J. Parnell
- School of Mathematics, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - I. David Abrahams
- Isaac Newton Institute, University of Cambridge, 20 Clarkson Road, Cambridge CB3 0EH, UK
| | - Tom Shearer
- School of Materials, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Donna M. Daly
- School of Pharmacy and Biomedical Science, University of Central Lancashire, Preston PR1 2HE, UK
| | - David Grundy
- Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, UK
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Grundy L, Daly DM, Chapple C, Grundy D, Chess-Williams R. TRPV1 enhances the afferent response to P2X receptor activation in the mouse urinary bladder. Sci Rep 2018; 8:197. [PMID: 29317663 PMCID: PMC5760578 DOI: 10.1038/s41598-017-18136-w] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 11/29/2017] [Indexed: 11/09/2022] Open
Abstract
Both TRPV1 and P2X receptors present on bladder sensory nerve fibres have been implicated in mechanosensation during bladder filling. The aim of this study was to determine possible interactions between these receptors in modulating afferent nerve activity. In wildtype (TRPV1+/+) and TRPV1 knockout (TRPV1-/-) mice, bladder afferent nerve activity, intravesical pressure, and luminal ATP and acetylcholine levels were determined and also intracellular calcium responses of dissociated pelvic DRG neurones and primary mouse urothelial cells (PMUCs). Bladder afferent nerve responses to the purinergic agonist αβMethylene-ATP were depressed in TRPV1-/- mice (p ≤ 0.001) and also in TRPV1+/+ mice treated with the TRPV1-antagonist capsazepine (10 µM; p ≤ 0.001). These effects were independent of changes in bladder compliance or contractility. Responses of DRG neuron to αβMethylene-ATP (30 µM) were unchanged in the TRPV1-/- mice, but the proportion of responsive neurones was reduced (p ≤ 0.01). Although the TRPV1 agonist capsaicin (1 µM) did not evoke intracellular responses in PMUCs from TRPV1+/+ mice, luminal ATP levels were reduced in the TRPV1-/- mice (p ≤ 0.001) compared to wildtype. TRPV1 modulates P2X mediated afferent responses and provides a mechanistic basis for the decrease in sensory symptoms observed following resiniferatoxin and capsaicin treatment for lower urinary tract symptoms.
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Affiliation(s)
- Luke Grundy
- Centre for Urology Research, Faculty of Health Science and Medicine, Bond University, Gold Coast, Queensland, 4229, Australia
- Visceral Pain Group, University of Adelaide, SAHMRI, Adelaide, Australia
| | - Donna M Daly
- Department of Pharmacy and Biomedical Science, University of Central Lancashire, Preston, PR1 2HE, UK
| | | | - David Grundy
- Department of Biomedical Science, University of Sheffield, Sheffield, S10 2TN, UK
| | - Russ Chess-Williams
- Centre for Urology Research, Faculty of Health Science and Medicine, Bond University, Gold Coast, Queensland, 4229, Australia.
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Hornsby J, Daly DM, Grundy D, Cheng F, Robertson AM, Watton PN, Thompson MS. Quantitative multiphoton microscopy of murine urinary bladder morphology during in situ uniaxial loading. Acta Biomater 2017; 64:59-66. [PMID: 28951123 DOI: 10.1016/j.actbio.2017.09.029] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 09/18/2017] [Accepted: 09/21/2017] [Indexed: 10/18/2022]
Abstract
Urodynamic tests are the gold standard for the diagnosis of bladder dysfunction, and the mechanical compliance of the bladder is an important parameter in these tests. The bladder wall has a layered structure, differentially affected by pathology, so knowledge of the contribution and role of these layers and their constituents to overall bladder compliance will enhance interpretation of these clinical tests. In this study we document the functional morphology of the detrusor and lamina propria of the murine bladder wall using a custom in-situ tensile loading system under multiphoton microscopy (MPM) observation in unloaded state and under incremental uniaxial stretch. Features in the stress-stretch curves of bladder samples were then directly related to corresponding MPM images. Collagen organisation across wall depth was quantified using image analysis techniques. The hypothesis that the lamina propria deformed at low strain by unfolding of the rugae and rearranging collagen fibrils was confirmed. A novel 'pocket' feature in the detrusor was observed along with extensive rearrangement of fibrils in two families at different depths, providing higher stiffness at high stretches in the detrusor. The very different deformations of detrusor and lamina propria were accommodated by the highly coiled structure of collagen in the lamina propria. Imaging and mechanical studies presented here allow gross mechanical response to be attributed to specific components of the bladder wall and further, may be used to investigate the impact of microstructural changes due to pathology or aging, and how they impair tissue functionality. STATEMENT OF SIGNIFICANCE This article reports the first in-situ multiphoton microscopy observations of microstructural deformation under uniaxial tensile loading of ex vivo bladder. We describe collagen rearrangement through the tissue thickness and relate this directly to the stress-stretch behaviour. We confirm for the first time the unfolding of rugae and realignment of fibrils in the lamina propria during extension and the rapid stiffening as two fibril families in the detrusor are engaged. This technique provides new insight into microstructure function and will enhance understanding of the impact of changes due to pathology or aging.
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Nocchi L, Daly DM, Chapple C, Grundy D. Induction of oxidative stress causes functional alterations in mouse urothelium via a TRPM8-mediated mechanism: implications for aging. Aging Cell 2014; 13:540-50. [PMID: 24593692 PMCID: PMC4326884 DOI: 10.1111/acel.12208] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/05/2014] [Indexed: 12/18/2022] Open
Abstract
The incidence of bladder conditions such as overactive bladder syndrome and its associated urinary incontinence is highly prevalent in the elderly. However, the mechanisms underlying these disorders are unclear. Studies suggest that the urothelium forms a ‘sensory network’ with the underlying innervation, alterations in which, could compromise bladder function. As the accumulation of reactive oxygen species can cause functional alterations with age, the aim of this study was to investigate whether oxidative stress alters urothelial sensory signalling and whether the mechanism underlying the effect of oxidative stress on the urothelium plays a role in aging. Five-month-old(young) and 24-month-old (aged) mice were used. H2O2, used to induce oxidative stress, resulted in an increase in bladder afferent nerve activity and urothelial intracellular calcium in preparations from young mice. These functional changes were concurrent with upregulation of TRPM8 in the urothelium. Moreover, application of a TRPM8 antagonist significantly attenuated the H2O2-induced calcium responses. Interestingly, an upregulation of TRPM8 was also found in the urothelium from aged mice, where high oxidative stress levels were observed, together with a greater calcium response to the TRPM8 agonist WS12. Furthermore, these calcium responses were attenuated by pretreatment with the antioxidant N-acetyl-cysteine. This study shows that oxidative stress affects urothelial function involving a TRPM8-mediated mechanism and these effects may have important implications for aging. These data provide an insight into the possible mechanisms by which oxidative stress causes physiological alterations in the bladder, which may also occur in other organs susceptible to aging.
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Affiliation(s)
- Linda Nocchi
- Department of Biomedical Science; University of Sheffield; Western Bank; Sheffield S10 2TN UK
| | - Donna M. Daly
- Department of Biomedical Science; University of Sheffield; Western Bank; Sheffield S10 2TN UK
| | - Christopher Chapple
- Department of Urology; Royal Hallamshire Hospital; Glossop Road Sheffield S10 2JF UK
| | - David Grundy
- Department of Biomedical Science; University of Sheffield; Western Bank; Sheffield S10 2TN UK
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Daly DM, Nocchi L, Liaskos M, McKay NG, Chapple C, Grundy D. Age-related changes in afferent pathways and urothelial function in the male mouse bladder. J Physiol 2013; 592:537-49. [PMID: 24297847 PMCID: PMC3930438 DOI: 10.1113/jphysiol.2013.262634] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The prevalence of lower urinary tract storage disorders such as overactive bladder syndrome and urinary incontinence significantly increase with age. Previous studies have demonstrated age-related changes in detrusor function and urothelial transmitter release but few studies have investigated how the urothelium and sensory pathways are affected. The aim of this study was to investigate the effect of ageing on urothelial-afferent signalling in the mouse bladder. Three-month-old control and 24-month-old aged male mice were used. In vivo natural voiding behaviour, sensory nerve activity, urothelial cell function, muscle contractility, transmitter release and gene and protein expression were measured to identify how all three components of the bladder (neural, contractile and urothelial) are affected by ageing. In aged mice, increased voiding frequency and enhanced low threshold afferent nerve activity was observed, suggesting that ageing induces overactivity and hypersensitivity of the bladder. These changes were concurrent with altered ATP and acetylcholine bioavailability, measured as transmitter overflow into the lumen, increased purinergic receptor sensitivity and raised P2X3 receptor expression in the urothelium. Taken together, these data suggest that ageing results in aberrant urothelial function, increased afferent mechanosensitivity, increased smooth muscle contractility, and changes in gene and protein expression (including of P2X3). These data are consistent with the hypothesis that ageing evokes changes in purinergic signalling from the bladder, and further studies are now required to fully validate this idea.
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Affiliation(s)
- Donna M Daly
- Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield S10 2TN, UK.
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Collins VM, Daly DM, Liaskos M, McKay NG, Sellers D, Chapple C, Grundy D. OnabotulinumtoxinA significantly attenuates bladder afferent nerve firing and inhibits ATP release from the urothelium. BJU Int 2013; 112:1018-26. [PMID: 23937318 DOI: 10.1111/bju.12266] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
OBJECTIVE To investigate the direct effect of onabotulinumtoxinA (OnaBotA) on bladder afferent nerve activity and release of ATP and acetylcholine (ACh) from the urothelium. MATERIALS AND METHODS Bladder afferent nerve activity was recorded using an in vitro mouse preparation enabling simultaneous recordings of afferent nerve firing and intravesical pressure during bladder distension. Intraluminal and extraluminal ATP, ACh, and nitric oxide (NO) release were measured using the luciferin-luciferase and Amplex(®) Red assays (Molecular Probes, Carlsbad, CA, USA), and fluorometric assay kit, respectively. OnaBotA (2U), was applied intraluminally, during bladder distension, and its effect was monitored for 2 h after application. Whole-nerve activity was analysed to classify the single afferent units responding to physiological (low-threshold [LT] afferent <15 mmHg) and supra-physiological (high-threshold [HT] afferent >15 mmHg) distension pressures. RESULTS Bladder distension evoked reproducible pressure-dependent increases in afferent nerve firing. After exposure to OnaBotA, both LT and HT afferent units were significantly attenuated. OnaBotA also significantly inhibited ATP release from the urothelium and increased NO release. CONCLUSION These data indicate that OnaBotA attenuates the bladder afferent nerves involved in micturition and bladder sensation, suggesting that OnaBotA may exert its clinical effects on urinary urgency and the other symptoms of overactive bladder syndrome through its marked effect on afferent nerves.
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Affiliation(s)
- Donna M Daly
- University of Sheffield, Western Bank, Sheffield S10 2TN, UK.
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Daly DM, Park SJ, Valinsky WC, Beyak MJ. Impaired intestinal afferent nerve satiety signalling and vagal afferent excitability in diet induced obesity in the mouse. J Physiol 2011; 589:2857-70. [PMID: 21486762 DOI: 10.1113/jphysiol.2010.204594] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Gastrointestinal vagal afferents transmit satiety signals to the brain via both chemical and mechanical mechanisms. There is indirect evidence that these signals may be attenuated in obesity. We hypothesized that responses to satiety mediators and distension of the gut would be attenuated after induction of diet induced obesity. Obesity was induced by feeding a high fat diet (60% kcal from fat). Low fat fed mice (10% kcal from fat) served as a control. High fat fed mice were obese, with increased visceral fat, but were not hyperglycaemic. Recordings from jejunal afferents demonstrated attenuated responses to the satiety mediators cholecystokinin (CCK, 100 nm) and 5-hydroxytryptamine (5-HT, 10 μm), as was the response to low intensity jejunal distension, while responses to higher distension pressures were preserved. We performed whole cell patch clamp recordings on nodose ganglion neurons, both unlabelled, and those labelled by fast blue injection into the wall of the jejunum. The cell membrane of both labelled and unlabelled nodose ganglion neurons was less excitable in HFF mice, with an elevated rheobase and decreased number of action potentials at twice rheobase. Input resistance of HFF neurons was also significantly decreased. Calcium imaging experiments revealed reduced proportion of nodose ganglion neurons responding to CCK and 5-HT in obese mice. These results demonstrate a marked reduction in afferent sensitivity to satiety related stimuli after a chronic high fat diet. A major mechanism underlying this change is reduced excitability of the neuronal cell membrane. This may explain the development of hyperphagia when a high fat diet is consumed. Improving sensitivity of gastrointestinal afferent nerves may prove useful to limit food intake in obesity.
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Affiliation(s)
- Donna M Daly
- Departments of Medicine and Physiology, Gastrointestinal Diseases Research Unit (GIDRU) Wing, Kingston General Hospital, 76 Stuart Street, Kingston, Ontario, Canada K7L2V7
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Daly DM, Chess-Williams R, Chapple C, Grundy D. The Inhibitory Role of Acetylcholine and Muscarinic Receptors in Bladder Afferent Activity. Eur Urol 2010; 58:22-8; discussion 31-2. [DOI: 10.1016/j.eururo.2009.12.030] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2009] [Accepted: 12/25/2009] [Indexed: 11/25/2022]
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Daly DM, Chess-Williams R, Chapple C, Grundy D. Reply from Authors re: Delphine Behr-Roussel, François A. Giuliano. Sensory Effects of Antimuscarinics: Still a Matter of Debate. Eur Urol 2010;58:29–30. Eur Urol 2010. [DOI: 10.1016/j.eururo.2010.01.037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Abstract
BACKGROUND Glucagon-like peptide-1 (GLP-1) is a major hormone known to regulate glucose homeostasis and gut function, and is an important satiety mediator. These actions are at least in part mediated via an action on vagal afferent neurons. However, the mechanism by which GLP-1 activates vagal afferents remains unknown. We hypothesized that GLP-1 acts on nodose ganglion neuron voltage-gated potassium (KV) channels, increasing membrane excitability. METHODS Employing perforated patch clamp recordings we examined the effects of GLP-1 on membrane properties as well as voltage-gated potassium currents. Extracellular recordings of jejunal afferents were performed to demonstrate the functional relevance of these effects at the nerve terminal. KEY RESULTS Glucagon-like peptide-1 depolarized a subpopulation of nodose neurons. This membrane depolarization was used to identify neurons containing functional GLP-1 receptors. In these neurons, GLP-1 decreased rheobase and broadened the action potential, and increased the number of action potentials elicited at twice rheobase. We identified a GLP-1 sensitive current whose reversal potential shifted in a depolarizing direction when extracellular potassium was increased. We identified two macroscopic K currents, IA, an inactivating current and IK a sustained current. GLP-1 caused inhibition of these currents, IK by 45%, P < 0.05 and IA currents by 52%P < 0.01, associated with a hyperpolarizing shift of steady-state inactivation curves for both currents. In extracellular recordings of jejunal afferents, GLP-1 increased firing rate, the effect blocked by the K(+) channel antagonist 4-AP. CONCLUSIONS & INFERENCES These experiments indicate that GLP-1 receptor activation results in vagal afferent excitation, due at least in part to inhibition of sustained and inactivating potassium currents. This mechanism may be important in satiety and glucose homeostatic signals arising from the gastrointestinal tract.
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Affiliation(s)
- G G Gaisano
- Gastrointestinal Diseases Research Unit (GIDRU), Department of Medicine, Queen's University, Kingston, ON, Canada
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Gopal KV, Daly DM, Daniloff RG, Pennartz L. Effects of selective serotonin reuptake inhibitors on auditory processing: case study. J Am Acad Audiol 2000; 11:454-63. [PMID: 11012241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Auditory sensitivity and processing ability were evaluated in a patient who suffered from hyperacusis, difficulty understanding speech, withdrawn depression, lethargy, and hypersensitivity to touch, pressure, and light. Treatment with fluvoxamine and fluoxetine (selective serotonin reuptake inhibitors) reversibly alleviated complaints. Testing while medicated and unmedicated (after voluntary withdrawal from medication for several weeks) revealed no difference in pure-tone thresholds, speech thresholds, word recognition scores, tympanograms, or acoustic reflex thresholds. Medicated SCAN-A (a screening test for central auditory processing disorders) results were normal, and unmedicated results were abnormal. Unmedicated transient otoacoustic emissions and auditory brainstem response waves I, III, and V were significantly larger bilaterally. Uncomfortable loudness levels indicated greater tolerance during the medicated condition. Central processing and vigilance were evaluated with analog-synthesized three-formant consonant-vowel syllables. While medicated, responses to stimuli at each ear revealed well-defined, labeling crossovers of about 90 msec. Vowel identification matched normal subject responses; labeling of /gE/jE/ and /bE/wE/ continua was well defined but all crossover points differed from normals (p < .0001). During unmedicated testing, responses to /gE/jE/ began at medicated levels but approached chance levels for the entire continuum within 10 min; labeling of /bE/wE/ was consistent with medicated responses throughout with earlier than normal crossover points.
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Affiliation(s)
- K V Gopal
- Department of Speech and Hearing Sciences, University of North Texas, Denton 76203, USA
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Ameratunga R, Lambert T, Daly DM, Caughey DE. Reactive arthritis caused by Yersinia enterocolitica. N Z Med J 1987; 100:725. [PMID: 3452177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Drane JW, Daly DM, Daly DD. Analysis of the perception and classification of synthetic sounds. Comput Biomed Res 1979; 12:351-77. [PMID: 487776 DOI: 10.1016/0010-4809(79)90046-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Abstract
Using clicks with varying interstimulus intervals and coherent tone-bursts, early components of the auditory evoked potential (brain stem responses) were studied in four patients with confirmed acoustic neuroma. Abnormalities in responses appeared with shorter interstimulus intervals and with tone-bursts delivered monaurally to the involved ear; bilateral alterations occurred in one patient with brain stem displacement. The results indicate that BSR can provide a stable, independent, noninvasive measure of auditory nerve function useful in the early detection of acoustic neuroma. The results contribute to the understanding of the so-called human FFR.
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Daly DM, Roeser RJ, Moushegian G. The frequency-following response in subjects with profound unilateral hearing loss. Electroencephalogr Clin Neurophysiol 1976; 40:132-42. [PMID: 55354 DOI: 10.1016/0013-4694(76)90158-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Frequency-following responses (FFRs) evoked by 500 c/sec tone bursts 14 msec in duration, presented at 50 dB SL were recorded from Cz--A1 and Cz--A2 electrode derivations using eight subjects with normal bilateral hearing, and eight subjects with profound unilateral hearing loss. Monaural stimulation of either ear in normal subjects, and of the unimpaired ear in hearing-loss subjects, evoked larger responses from the ipsilateral electrode derivation than from the contralateral electrode derivation. Stimulation of the impaired ear in hearing-loss subjects evoked no response. Binaural stimulation in normal-hearing subjects evoked Cz--A1 and Cz--A2 responses of equal magnitude, each larger than either the ipsilateral or contralateral monaural response, but each slightly smaller than the sum of the ipsilateral and contralateral monaural responses. Binaural stimulation in hearing-loss subjects evoked responses equivalent to those obtained monaurally. The results provide evidence of binaural interaction in normal-hearing subjects and indicate that FFR arises from at least two separate symmetric neural sources, possibly by iterative activation of brainstem evoked response (BER) generators.
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