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1.
Health Policy Open ; 6: 100117, 2024 Dec.
Article in English | MEDLINE | ID: mdl-38510780

ABSTRACT

Government subsidised funding arrangements serve as an essential medium for families to access private speech-language pathology (SLP) services in Australia. This study aimed to investigate whether, from a provider perspective, contemporary public funding models (PFMs) align with best-available scientific evidence for management of children and young persons with swallowing and communication disorders within Australian private-practice settings. This exploratory study was distributed to paediatric speech-language pathologists throughout Australia via an online survey. A total of 121 valid surveys were completed by Australian speech-language pathologists with divergent career experiences. In comparing three familiar PFMs using mixed effects logistic regression models to estimate odds ratios, results indicated that perceived congruence with recommended scientific evidence for SLP management varied across PFMs: the odds of failing to align with scientific evidence was 4.92 times higher for Medicare's Chronic Disease Management Plan (MBS_CDMP) than for the National Disability Insurance Scheme; and 7.40 times higher in comparison to Medicare's Helping Children with Autism initiative. This study is the first to report on (in)congruence between PFMs that provide access to independent Australian SLP services for children and young persons and best available scientific evidence to inform clinical practice. Participants identified that: (a) four out of seven contemporary PFMs were unfamiliar to speech-language pathologists; and (b) MBS_CDMP initiative failed to align with the evidence-base for best scientific SLP management.

2.
J Laryngol Otol ; 137(11): 1248-1255, 2023 Nov.
Article in English | MEDLINE | ID: mdl-37016895

ABSTRACT

OBJECTIVE: This study aimed to determine if pre-operative radiological scoring can reliably predict intra-operative difficulty and final cochlear electrode position in patients with advanced otosclerosis. METHOD: A retrospective cohort study of advanced otosclerosis patients who underwent cochlear implantation (n = 48, 52 ears) was compared with a larger cohort of post-lingually deaf adult patients (n = 1414) with bilateral hearing loss and normal cochlear anatomy. Pre-operative imaging for advanced otosclerosis patients and final electrode position were scored and correlated with intra-operative difficulty and speech outcomes. RESULTS: Advanced otosclerosis patients benefit significantly from cochlear implantation. Mean duration of deafness was longer in the advanced otosclerosis group (19.5 vs 14.3 years; p < 0.05). CONCLUSION: Anatomical changes in advanced otosclerosis can result in increased difficulty of surgery. Evidence of pre-operative cochlear luminal changes was associated with intra-operative difficult insertion and final non-scala tympani position. Nearly all electrodes implanted in the advanced otosclerosis cohort were peri-modiolar. No reports of facial nerve stimulation were observed.


Subject(s)
Cochlear Implantation , Cochlear Implants , Otosclerosis , Adult , Humans , Cochlear Implantation/methods , Retrospective Studies , Otosclerosis/complications , Otosclerosis/diagnostic imaging , Otosclerosis/surgery , Treatment Outcome
3.
J Laryngol Otol ; 137(4): 373-389, 2023 Apr.
Article in English | MEDLINE | ID: mdl-35698817

ABSTRACT

OBJECTIVE: Chronic suppurative otitis media is a major global disease disproportionately affecting low- and middle-income countries, but few studies have explored access to care for those with ear and hearing disorders. METHOD: In a tertiary hospital in Cambodia providing specialist ear services, a mixed method study was undertaken. This study had three arms: (1) quantitative analysis of patients undergoing ear surgery, (2) a questionnaire survey and (3) semi-structured in-depth interviews. RESULTS: Patients presented with advanced middle-ear disease and associated hearing loss at rates that are amongst the highest per capita levels globally. Patients reported several structural, financial and socio-cultural barriers to treatment. This study showed a significant burden of ear disease in Cambodia, which reflects a delay in receiving timely and effective treatment. CONCLUSION: This study highlights the opportunity to integrate effective ear and hearing care into primary care service provision, strengthening the package of activities delivered at government facilities.


Subject(s)
Hearing Loss , Hearing , Humans , Cambodia/epidemiology , Hearing Loss/epidemiology , Hearing Loss/therapy , Hearing Disorders , Patient Outcome Assessment
4.
J Laryngol Otol ; : 1-11, 2022 Sep 26.
Article in English | MEDLINE | ID: mdl-36154944

ABSTRACT

OBJECTIVE: In Cambodia, little is known about the state of ear and hearing care, or the roles providers or key stakeholders play in delivering services. METHOD: This was an exploratory study using semi-structured qualitative interviews and a questionnaire addressed to key stakeholders to explore their perceptions and experiences in providing services to people suffering from ear disease or hearing loss in Cambodia. RESULTS: Several challenges were described including a lack of hearing services to meet the demand, especially outside Phnom Penh in primary care and aural rehabilitation. Supply-side challenges include a shortage of trained professionals, facilities and resources, poor co-ordination between providers, unclear referral pathways, and long wait times. CONCLUSION: Now is an opportune time to build on the positive trend in providing integrated care for non-communicable diseases in Cambodia, through the integration of effective ear and hearing care into primary care and strengthening the package of activities delivered at government facilities.

5.
J Econ Entomol ; 104(5): 1514-24, 2011 Oct.
Article in English | MEDLINE | ID: mdl-22066180

ABSTRACT

The light brown apple moth, Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae), is a highly successful biological invader. It was accidentally introduced to several countries including New Zealand, Hawaii, England, and California. Light brown apple moth attacks a wide range of crop plants and other woody and herbaceous plants, but a more comprehensive analysis of its host range is needed for risk assessments, to evaluate the likely economic and environmental impacts, and to enable targeting of particular plant species for detection surveys and treatments. We reviewed and synthesized the host range and host selection behavior of light brown apple moth by using information from Australia and invaded countries. The host range of light brown apple moth is determined by the behavior of both adult females and larvae. Females use visual, chemical and physical cues to choose host plants. Larvae are capable of limited active dispersal by walking and longer range dispersal by ballooning on silken strands; therefore, larvae also may need to select host plants. We review larval performance indicators across a range of plants. Based on our review, there are at least 545 plant species in 363 genera from 121 families that have been reported as hosts of light brown apple moth. Some plants were reported only once and need verification. Nevertheless, many host plant species and their wide phylogenetic range (from ferns to higher dicotyledons) indicates that light brown apple moth is one of the most polyphagous insects known. This information and our categorization of frequency of host use are valuable for incursion response and pest management activities.


Subject(s)
Diet/veterinary , Moths/physiology , Plants/classification , Animals , Diet/classification , Female , Larva/physiology , Male , Moths/growth & development , Phylogeny
6.
Audiol Neurootol ; 16(5): 289-303, 2011.
Article in English | MEDLINE | ID: mdl-21150199

ABSTRACT

This prospective, double-blind controlled, randomized clinical trial of 43 adults showed that topical methylprednisolone applied to the round window during cochlear implantation was effective in protecting inner ear function. Postoperative vestibular disturbance was significantly lower in the steroid group (5%) than the control group (29%). Electrode impedances from the middle portion of the electrode array (electrodes 10-13) were significantly reduced in steroid-treated recipients compared to controls. Hearing and vestibular function analyses were under-powered to detect any drug changes due to limited participant data.


Subject(s)
Cochlear Implantation/adverse effects , Dizziness/drug therapy , Glucocorticoids/therapeutic use , Methylprednisolone/therapeutic use , Round Window, Ear/drug effects , Adolescent , Adult , Aged , Aged, 80 and over , Dizziness/etiology , Double-Blind Method , Female , Glucocorticoids/administration & dosage , Humans , Male , Methylprednisolone/administration & dosage , Middle Aged , Prospective Studies , Round Window, Ear/surgery , Treatment Outcome
7.
J Vestib Res ; 13(2-3): 113-9, 2003.
Article in English | MEDLINE | ID: mdl-14757914

ABSTRACT

This study considered whether the monothermal (MT) caloric test could predict the normality of the full conventional bithermal (BT) caloric test, and therefore be an alternative to full caloric investigation. This would have the advantages of reducing test time and patient discomfort as only two caloric tests would be needed instead of four. 744 BT caloric investigations were examined, and the unilateral weakness and directional preponderance calculated for the BT and the MT stimuli. By defining the BT results as the standard, the false-positive and false-negative results of the MT test were derived. Overall using very strict MT difference criteria of less than 5% and no spontaneous nystagmus, false-negative rates for the cool MT were very low (< 1%) and better than the warm MT (< 7.1%) suggesting that the cool MT was a reliable screen test. However, unacceptably high false-positive rates were produced reflecting more than 3/4 of normal BT results failing the MT criterion. This unacceptable false-positive rate decided against implementing the MT test at our facility. The results of this study however have guided the use of the cool air-stimulus first during BT testing and, when completion of the BT is not possible or inadvisable, satisfying the stringent MT criterion confidently indicates with a probability of > 99% the absence of an abnormal BT result.


Subject(s)
Caloric Tests/methods , Cold Temperature , Hot Temperature , Vestibular Diseases/diagnosis , Caloric Tests/standards , False Negative Reactions , False Positive Reactions , Humans , Predictive Value of Tests , Retrospective Studies
8.
BMC Bioinformatics ; 2: 7, 2001.
Article in English | MEDLINE | ID: mdl-11667947

ABSTRACT

BACKGROUND: Currently, most genome annotation is curated by centralized groups with limited resources. Efforts to share annotations transparently among multiple groups have not yet been satisfactory. RESULTS: Here we introduce a concept called the Distributed Annotation System (DAS). DAS allows sequence annotations to be decentralized among multiple third-party annotators and integrated on an as-needed basis by client-side software. The communication between client and servers in DAS is defined by the DAS XML specification. Annotations are displayed in layers, one per server. Any client or server adhering to the DAS XML specification can participate in the system; we describe a simple prototype client and server example. CONCLUSIONS: The DAS specification is being used experimentally by Ensembl, WormBase, and the Berkeley Drosophila Genome Project. Continued success will depend on the readiness of the research community to adopt DAS and provide annotations. All components are freely available from the project website http://www.biodas.org/.


Subject(s)
Computational Biology/methods , Base Sequence/physiology , Computational Biology/instrumentation , Computer Terminals , Databases, Genetic/standards , Genome, Human , Humans , Internet , Reference Values , Software
9.
Ear Hear ; 22(1): 18-28, 2001 Feb.
Article in English | MEDLINE | ID: mdl-11271973

ABSTRACT

OBJECTIVE: The objective of this study was to identify common factors affecting speech perception scores in children with cochlear implants. DESIGN: Speech perception data for 167 implanted children were collected at two cochlear implant centres in Melbourne and Sydney. The data comprised audition-alone scores on open-set word and sentence tests. Children were selected on the basis that they had a Nucleus 22-electrode cochlear implant. The average age of the children was 5 yr. Information was also collected about 12 factors that may have influenced speech perception scores for each child. Analysis of covariance was used to identify factors that significantly affected speech perception scores. Pearson pairwise correlation coefficients were also calculated for all factors analyzed. RESULTS: The analyses in this study identified factors that accounted for 51%, 34%, and 45% of the variance in phoneme, word and sentence perception scores. Scores decreased by 1.4 to 2.4% per year of profound deafness prior to implantation. Children who normally use oral communication scored significantly higher than children normally using sign or simultaneous oral and sign communication. Children implanted in Sydney scored higher on average than children implanted in Melbourne. CONCLUSIONS: The results show that a significant part of the variation in speech perception scores is systematically related to audiological and environmental factors for each child. The reasons for significant differences between children using different communication modes or from different clinics were not identified.


Subject(s)
Cochlear Implants , Deafness/surgery , Speech Perception/physiology , Adolescent , Child , Child, Preschool , Female , Humans , Infant , Male , Phonetics , Speech Reception Threshold Test , Vocabulary
10.
Neurotoxicol Teratol ; 22(3): 357-68, 2000.
Article in English | MEDLINE | ID: mdl-10840179

ABSTRACT

The intravenous route of administration, accessed via a subcutaneous vascular access port, has been recently suggested as an animal model for studying the developmental effects of maternal cocaine abuse in the pregnant and/or group-housed rat. The present study (1) assessed the cardiovascular effects of intravenous (IV) cocaine, delivered via bolus injection, in chronically catheterized near-term pregnant rats, and (2) compared the IV cardiovascular responses to those following cocaine delivered via the commonly employed subcutaneous (SC) and intragastric (IG) routes of administration. Pregnant gestation day 15 (GD15) young adult female Sprague-Dawley rats (n = 21) were anesthetized and catheters surgically implanted into the carotid artery, jugular vein, fundus of the stomach, and a subcutaneous pouch. On GD17-19, heart rate (HR) and mean arterial pressure (MAP) were assessed, using a within-subjects design, prior and subsequent to IV (3 mg/kg), IG (60 mg/kg), and SC (40 mg/kg) cocaine. An interval of 6 h separated IV and IG cocaine administration and an interval of 18 h separated IG and SC cocaine administration. The peak responses of HR (23% downward arrow) and MAP (37% upward arrow) following IV cocaine were noted within 0.5 min. In contrast, the peak responses of HR (4% downward arrow, 6% downward arrow) and MAP (2% upward arrow, 15% downward arrow) after IG (23 min) or SC (26 min) cocaine, respectively, were significantly smaller and markedly delayed. No significant change in aortic blood flow velocity was detected following cocaine via any route of administration, although phasic flow velocities (PFV) were differentially sensitive to route of administration (PFV(dias) not PFV(sys)); IV cocaine increased (55% upward arrow) whereas IG or SC cocaine decreased approximately 35% downward arrow) PFV(dias). The pressor effects of an equimolar dose of IV cocaine methiodide (3.9 mg/kg) were indistinguishable from those of IV cocaine (38% upward arrow vs. 37% upward arrow), as were the effects on PFV(dias) (83% upward arrow vs. 55% upward arrow). The lack of an effect of cocaine methiodide on HR was consistent with the bradycardia effect of cocaine attributable to central mediation of the baroreflex. Finally, the pressor effects of IV cocaine paralleled the rapidly peaking arterial plasma levels of cocaine noted within 30 s after the initiation of drug injection. In sum, prominent effects of IV cocaine on maternal cardiovascular physiology are noted; as such, the recent reports of a lack of maternal/fetal toxicity following daily (3-6mg/kg) IV cocaine during GD8-21 are not due to use of an ineffective drug dose. It was equally clear that the SC and IG routes of exposure did not reproduce the cardiovascular component(s) of the expected physiological response to cocaine.


Subject(s)
Cocaine/administration & dosage , Cocaine/toxicity , Dopamine Uptake Inhibitors/administration & dosage , Dopamine Uptake Inhibitors/toxicity , Hemodynamics/drug effects , Pregnancy, Animal/physiology , Animals , Blood Flow Velocity/drug effects , Blood Pressure/drug effects , Cocaine/analogs & derivatives , Cocaine/blood , Cocaine/pharmacokinetics , Cocaine/pharmacology , Dopamine Uptake Inhibitors/blood , Female , Heart Rate/drug effects , Injections, Intravenous , Injections, Subcutaneous , Intubation, Gastrointestinal , Male , Pregnancy , Rats , Rats, Sprague-Dawley
11.
J Lipid Res ; 41(4): 605-12, 2000 Apr.
Article in English | MEDLINE | ID: mdl-10744781

ABSTRACT

We have previously shown (Mansbach, C. M. and P. J. Nevin, 1998. J. Lipid Res. 39: 963;-968) that after the development of a mass steady state with respect to triacylglycerol absorption in rats, the introduction of radiolabeled trioleoylglycerol, while maintaining the input rate of trioleoylglycerol constant at 135 micromol/h, was followed by a slow (60 min) achievement of a radiolabel steady state in the intestinal endoplasmic reticulum (ER). We hypothesized that this was due to the large input load and that the time to steady state would be shorter at lower lipid loads. Rats were infused intraduodenally with 22.5, 45, 90, or 135 micromol trioleoylglycerol/h for 6 h to obtain a mass steady state in the intestine. [(3)H]trioleoylglycerol was added to the infusate and the ER and Golgi were isolated from the proximal intestine after 5;-60 min of radiolabel infusion. The time required to reach a radiolabel steady state in the ER lengthened from 10 min at the 22.5 micromol/h infusion rate to 60 min at the 135 micromol/h rate. Similar data were obtained for the Golgi. Incubation of the ER with lipase reduced the ER;-triacylglycerol amount by 43% and increased its specific activity by 73%. The amount of [(3)H]TG-dpm in the ER was not reduced unless taurocholate, 10 mm, and colipase were added. We conclude that as the rate of triacylglycerol infusion is increased, TG movement from the ER to the Golgi progressively lengthens until finally all the triacylglycerol infused cannot be transported. A portion of this triacylglycerol is disposed on the cytoplasmic face of the ER and thus able to be attacked by lipase whereas another fraction is sequestered in the ER lumen and immune to lipase attack unless the ER membrane is solubilized.


Subject(s)
Dietary Fats/metabolism , Endoplasmic Reticulum/metabolism , Golgi Apparatus/metabolism , Intestinal Mucosa/metabolism , Lipid Metabolism , Triolein/metabolism , Animals , Biological Transport , Duodenum/surgery , Infusions, Parenteral , Rats , Rats, Sprague-Dawley
12.
Am J Otol ; 21(1): 57-61, 2000 Jan.
Article in English | MEDLINE | ID: mdl-10651436

ABSTRACT

HYPOTHESIS: Speech perception outcomes for cochlear implantation of children vary over a wide range, and it is hypothesized that central pathologic states associated with certain causes of hearing impairment account for a substantial part of the variance. STUDY DESIGN: A retrospective analysis was carried out to ascertain the relationships between speech perception, etiologic factors, and central pathologic states as indicated by preoperative delayed motor milestones and/or cognitive delays. SETTING: Data were obtained from the pre- and postoperative records of patients attending a hospital cochlear implant clinic. PATIENTS: Results for 75 consecutive patients up to age 5 years who underwent implantation were included in the study. INTERVENTION: Patients received a 22-electrode cochlear prosthesis and were seen by the clinic for regular tune-up and assessments. Home- and school-based habilitation was recommended by the clinic. MAIN OUTCOME MEASURES: Speech perception measures were classified on a five-point scale to allow for different evaluation procedures at different ages and developmental stages. RESULTS: The incidence of motor and cognitive delays were fairly evenly spread across etiologic factors, except for cytomegalovirus, which had a much higher than average incidence. Children with motor and/or cognitive delays were significantly slower than other children in the development of speech perception skills after implantation. Etiologic factors did not have a statistically significant effect on speech perception outcome. CONCLUSIONS: It is likely that central pathologic states account for a substantial part of the variance among children using cochlear implants. Specific indicators of central pathologic states should be used to assess a child's prognosis in preference to less specific information based on etiologic factors alone.


Subject(s)
Cochlear Implantation , Cognition Disorders/etiology , Developmental Disabilities/etiology , Motor Skills Disorders/etiology , Speech Perception/physiology , Child, Preschool , Cognition Disorders/diagnosis , Deafness/surgery , Developmental Disabilities/diagnosis , Humans , Incidence , Motor Skills Disorders/diagnosis , Preoperative Care , Retrospective Studies
13.
J Speech Lang Hear Res ; 42(3): 540-52, 1999 Jun.
Article in English | MEDLINE | ID: mdl-10391621

ABSTRACT

By diminishing the role of communicative context, traditional tests of speech perception may underestimate or misrepresent the actual speech perception abilities of adults with a hearing impairment. This study investigates this contention by devising an assessment that may better simulate some aspects of "real-life" speech perception. A group of 31 participants with a severe-to-profound hearing impairment took part in a series of speech perception tests while wearing their hearing aids. The tests used question/answer or adjacency pairs, where the stimulus sentence was preceded by a question spoken by the participant. Four conditions were included: (a) where there was no initiating sentence, as in a traditional open-set speech perception test; (b) where the initiating question was neutral (e.g. "Why?"); (c) where there was a disruptive semantic relationship between the question and answer; and (d) where there was a strong contextual relationship between the question and answer. The time delay between the question and answer was also varied. Results demonstrated that in all conditions where there was a preceding question speech perception improved, and increasing the cohesion between the question and the reply improved speech perception scores. Additionally, time delay and the relatedness of the reply interacted. The effects of semantic context appeared to diminish over a 10-s period while other linguistic effects remained more constant. These results indicate the utility of simulating communicative environments within speech perception tests.


Subject(s)
Communication , Speech Perception/physiology , Adult , Aged , Aged, 80 and over , Female , Hearing Loss, Sensorineural/diagnosis , Humans , Male , Middle Aged , Severity of Illness Index , Surveys and Questionnaires , Time Factors
14.
Ear Hear ; 20(3): 238-52, 1999 Jun.
Article in English | MEDLINE | ID: mdl-10386850

ABSTRACT

OBJECTIVE: To examine the prevalence of auditory neuropathy in a group of infants at risk for hearing impairment and to present an overview of the clinical findings for affected children. DESIGN: Results for 20 subjects who showed repeatable cochlear microphonic potentials in the absence of click-evoked auditory brain stem responses are included in this study. Behavioral and steady state evoked potential thresholds were established in each case. Where possible, otoacoustic emission and speech perception results (unaided and aided) also were obtained. RESULTS: One in 433 (0.23%) of the children in our series had evidence of auditory neuropathy. The audiometric findings for these subjects varied significantly, with behavioral thresholds ranging from normal to profound levels. Discrimination skills were also variable. Approximately half of the subjects showed little understanding, or even awareness, of speech inputs in both the unaided and aided conditions. There were, however, a number of children who could score at significant levels on speech discrimination tasks and who benefited from the provision of amplification. CONCLUSION: The results suggest that auditory neuropathy is more common in the infant population than previously suspected. The effects of neuropathy on auditory function appear to be idiosyncratic, producing significant variations in both the detection and discrimination of auditory signals. As such, the management of children with this disorder must allow for individual differences.


Subject(s)
Evoked Potentials, Auditory, Brain Stem , Hearing Disorders/diagnosis , Hearing Disorders/etiology , Peripheral Nervous System Diseases/complications , Peripheral Nervous System Diseases/physiopathology , Vestibulocochlear Nerve/physiopathology , Audiometry, Evoked Response/methods , Child, Preschool , Hearing Disorders/epidemiology , Humans , Hyperbilirubinemia/complications , Infant , Male , Otoacoustic Emissions, Spontaneous/physiology , Peripheral Nervous System Diseases/epidemiology , Prevalence , Retrospective Studies , Speech Perception/physiology
15.
J Speech Lang Hear Res ; 41(2): 285-99, 1998 Apr.
Article in English | MEDLINE | ID: mdl-9570583

ABSTRACT

Adults with severe or severe-to-profound hearing losses constitute between 11% and 13.5% of the hearing-impaired population. A detailed investigation of the speech recognition of adults with severe (n = 20) or severe-to-profound (n = 14) hearing loss was conducted at The University of Melbourne. Each participant took part in a series of speech recognition tasks while wearing his or her currently fitted hearing aid(s). The assessments included closed-set tests of consonant recognition and vowel recognition, combined with open-set tests of monosyllabic word recognition and sentence recognition. Sentences were presented in quiet and in noise at +10 dB SNR to replicate an environment more typical of everyday listening conditions. Although the results demonstrated wide variability in performance, some general trends were observed. As expected vowels were generally well perceived compared with consonants. Monosyllabic word recognition scores for both the adults with a severe hearing impairment (M = 67.2%) and the adults with a severe-to-profound hearing impairment (M = 38.6%) could be predicted from the segmental tests, with an allowance for lexical effects. Scores for sentences presented in quiet showed additional linguistic effects and a significant decrease in performance with the addition of background noise (from 82.9% to 74.1% for adults with a severe hearing loss and from 55.8% to 34.2% for adults with a severe-to-profound hearing loss). Comparisons were made between the participants and a group of adults using a multiple-channel cochlear implant. This comparison indicated that some adults with a severe or severe-to-profound hearing loss may benefit from the use of a cochlear implant. The results of this study support the contention that cochlear implant candidacy should not rely solely on audiometric thresholds.


Subject(s)
Cochlear Implantation , Hearing Aids , Hearing Loss, Sensorineural/rehabilitation , Speech Perception , Adolescent , Adult , Child , Female , Hearing Loss, Sensorineural/diagnosis , Humans , Male , Middle Aged , Phonetics , Prosthesis Fitting , Severity of Illness Index
16.
Mol Cell Biochem ; 178(1-2): 87-94, 1998 Jan.
Article in English | MEDLINE | ID: mdl-9546586

ABSTRACT

The degree to which developmentally related alterations in cardiac creatine kinase (CK) activity reflect modification of CK isoenzyme gene expression remains uncertain. The present studies addressed this question by assessing multiple aspects of CK in rat heart during the perinatal to adult transition. In addition to whole tissue, isolated and purified muscle and nonmuscle cells were studied, as well as myofibrillar, mitochondrial, and cytosolic subcellular fractions. Whole homogenate CK enzyme specific activity nearly doubled during the weanling to adult developmental period. Muscle cell CK activity increased by a similar magnitude. Nonmuscle cell activity decreased. In the adult heart, both myofibrillar and mitochondrial CK activities were augmented versus the weanling heart. The cytoplasmic fraction activity held constant during development. Electrophoretic isoenzyme analyses of both weanling and adult cardiac muscle cells indicated the presence of mitochondrial CK and MM-CK isoforms. Weanling heart nonmuscle cells contained mitochondrial, MM, MB, and BB isoforms; however, BB isoform was not detected in the adult heart nonmuscle cells. Arrhenius plots provided information regarding heart muscle and nonmuscle cell alterations during development. CK activation energies were also determined for whole tissue, muscle/nonmuscle cells, myofibrils, mitochondria, and cytosol. Results demonstrate that heterogeneous muscle/nonmuscle cellular composition and differential myofibrillar/mitochondrial subcellular composition account for normal, developmentally related changes in heart CK enzyme activity. CK isoenzyme gene expression changes were not detected in cardiac muscle cells, and transition of CK-B to CK-M gene expression is limited to nonmuscle cells during normal, weanling to adult development in the rat heart.


Subject(s)
Creatine Kinase/metabolism , Heart/growth & development , Myocardium/enzymology , Animals , Creatine Kinase/genetics , Enzyme Activation , Gene Expression Regulation, Developmental , Gene Expression Regulation, Enzymologic , Isoenzymes , Male , Rats , Rats, Sprague-Dawley
17.
Ear Hear ; 19(1): 48-61, 1998 Feb.
Article in English | MEDLINE | ID: mdl-9504272

ABSTRACT

OBJECTIVE: 1) To examine the distribution of behavioral hearing thresholds in a group of children who had shown no click-evoked auditory brain stem response (ABR) at maximum presentation levels. 2) To describe the relationship between the 90 Hz steady-state evoked potential (SSEP) and behavioral thresholds in these subjects. DESIGN: A retrospective study based on clinical findings obtained from 108 infants and young children. Each of these children had shown no recordable ABR to clicks presented at maximum levels (100 dB nHL). SSEP audiograms were obtained using AM/FM tones at the octave frequencies 250 to 4000 Hz. The results of these evoked potential assessments were compared with hearing thresholds established behaviorally. RESULTS: Click-ABR assessment could not differentiate between the subjects in our sample with total hearing losses and those with useful residual hearing. Although some of the ears were anacusic, more than a quarter showed residual hearing at each of the audiometric frequencies. Furthermore, at least 10% of the behavioral thresholds at each frequency fell within the moderate/severe hearing loss range. A far closer relationship was observed between SSEP and hearing thresholds. On occasions where the SSEP was absent at maximum levels, 99.5% of the ears showed either a total loss or a behavioral threshold within 10 dB of that level. When an SSEP was obtained, the hearing threshold was typically within 5 dB of the SSEP threshold. CONCLUSION: The results suggested that in our group of selected subjects, the SSEP technique was able to assess ears with only minimal amounts of residual hearing. Where the brevity of the acoustic click limits both its frequency specificity and its presentation level, the modulated tones used for SSEP testing allow accurate, frequency-specific assessment at high presentation levels.


Subject(s)
Auditory Perception , Auditory Threshold , Evoked Potentials, Auditory, Brain Stem , Evoked Potentials, Auditory , Hearing Loss, Sensorineural/diagnosis , Acoustic Impedance Tests , Audiometry, Pure-Tone , Child, Preschool , Hearing Aids , Hearing Loss, Sensorineural/rehabilitation , Humans , Infant , Infant, Newborn , Retrospective Studies
18.
Am J Otol ; 18(6 Suppl): S125-6, 1997 Nov.
Article in English | MEDLINE | ID: mdl-9391629

ABSTRACT

OBJECTIVE: Many reports have established that hearing-impaired children using the Nucleus 22-channel cochlear implant may show both significant benefits to lipreading and significant scores on open-set words and sentences using electrical stimulation only. These findings have raised questions about whether severely or severely-to-profoundly deaf children should be candidates for cochlear implants. To study this question, postoperative results for implanted children with different levels of preoperative residual hearing were evaluated in terms of speech perception benefits. STUDY DESIGN/SETTING: A retrospective study of the first 117 children, sequentially, to undergo implantation in the Melbourne and Sydney Cochlear Implant Clinics was undertaken. All children had been assessed by and received their implants in a tertiary referral centre. MAIN OUTCOME MEASURES: To assess aided residual hearing, the children were grouped into four categories of hearing on the basis of their aided residual hearing thresholds measured preoperatively. To assess benefits, the scores of children on standard speech perception tests were reviewed. As different tests were used for children with different ages and language skills, children were grouped into categories according to the level of postoperative speech perception benefit. RESULTS: The results showed that children in the higher categories of aided preoperative residual hearing showed significant scores on open-set word and sentence perception tests using the implant alone. For children in lower categories of aided residual hearing, results were variable within the groups. More than 90% of children with implants with aided residual hearing thresholds in the speech range above 1 kHz achieved open-set understanding of words and sentences. CONCLUSION: While the results of this preliminary study confirm previous findings of differential outcomes for children with different levels of preoperative residual hearing, they suggest that children with severe to profound hearing impairments should be considered for cochlear implantation.


Subject(s)
Cochlear Implantation , Deafness/diagnosis , Deafness/surgery , Speech Perception , Auditory Threshold , Child , Humans , Retrospective Studies , Severity of Illness Index , Speech Discrimination Tests
19.
Otolaryngol Head Neck Surg ; 117(3 Pt 1): 236-42, 1997 Sep.
Article in English | MEDLINE | ID: mdl-9334771

ABSTRACT

A series of 73 postlinguistically deafened adults and 34 prelinguistically deafened children were evaluated with the Spectral Peak (SPEAK) coding strategy of the Nucleus 22-channel cochlear implant. The adults who received consecutive implants demonstrated rapid acquisition of open-set speech recognition skills in the initial postoperative period. Group mean sentence recognition improved to 53.5% (n = 52) after 2 weeks, 62.1% (n = 55) after 1 month, 69.8% (n = 57) after 3 months, and 74.4% (n = 42) after 6 months of use. At the 6-month evaluation interval, 43% of subjects scored greater than 90% on sound-alone sentence recognition in quiet and only one patient (2.4%) scored less than 10%. Mean monosyllabic word recognition was 35.6% after 6 months of use. The 34 prelinguistically deafened children were converted from the Multipeak strategy to Spectral Peak strategy at four large pediatric implant centers. After 6 months of using the new coding strategy, the children demonstrated significant improvements in their speech perception abilities.


Subject(s)
Cochlear Implants , Signal Processing, Computer-Assisted , Speech Perception/physiology , Adult , Aged , Aged, 80 and over , Child , Child, Preschool , Cochlear Implantation , Deafness/congenital , Deafness/physiopathology , Deafness/surgery , Evaluation Studies as Topic , Female , Follow-Up Studies , Hearing/physiology , Humans , Learning , Male , Middle Aged , Phonetics , Prosthesis Design , Time Factors
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