The effect of hemodialysis on hearing using pure-tone audiometry and distortion-product otoacoustic emissions

Patients under treatment of hemodialysis (HD) frequently exhibit some degree of sensorineural hearing loss. Fifteen subjects and 10 controls were tested by using pure-tone audiometry (PTA) and distortion-product otoacoustic emissions (DPOAEs) before and after a HD treatment. Other parameters (blood pressure, body weight, blood chemistries) were also evaluated before and after HD: The purpose of this study was to determine the acute effect of HD on hearing level by measuring PTA and DPOAE before and after one HD session. The results from PTA and DPOAE testings showed that hearing was unaffected by HD. However, all 15 subjects revealed significantly poorer hearing, especially in the higher frequencies, compared to that of the controls (p < 0.0001). It was concluded then that HD is a safe treatment, and that the sensorineural hearing loss in these patients may be attributed to the preexisting renal disease.     

Histopathological findings in clinical gentamicin ototoxicity

The temporal bone histopathological findings in a case of gentamicin sulfate-induced hearing loss and vertigo in an anephric patient undergoing hemodialysis are presented. A study of the sensory neuroepithelium of the cristae and maculae disclosed the presence of vacuoles with clubbing of the sensory cells. In the cochlea, loss of the innermost row of outer hair cells in the basal turn was the most prominent feature. These findings are discussed in light of reports of similar morphological changes in laboratory studies of gentamicin ototoxicity.     

Neuronal codes: reading them and learning how their structure influences network organization

Antioxidant enzymes together with trace elements in 26 patients with chronic renal failure treated with hemodialysis and 25 healthy subjects were investigated. Superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSHPx) in plasma and erythrocytes were examined immediately before and after hemodialysis. The results are summarized as follows: 1. A significant decrease in plasma SOD, CAT, and GSHPx and erythrocyte GSHPx were found in patients before hemodialysis. 2. Erythrocyte CAT and GSHPx were significantly lower in the patients after hemodialysis than in the controls. 3. Plasma GSHPx was significantly higher after a single hemodialysis than before hemodialysis. 4. A good correlation between erythrocyte SOD and copper (Cu) in patients before hemodialysis was found. 5. A good correlation of GSHPx in erythrocytes and plasma was found before hemodialysis, whereas an even better correlation was found after hemodialysis. 6. Abnormalities of trace elements were found in hemodialyzed patients. 7. There is indirect evidence for increased oxidizing stress in uremic patients with hemodialysis. Dialysis treatment may improve some abnormalities (e.g., Hb, P), but may also induce some deleterious effects of free radicals or lipid peroxidation.     

Recovery of free ADP, Pi, and free energy of ATP hydrolysis in human skeletal muscle

BACKGROUND: Recent studies have demonstrated that a high concentration of phosphate directly stimulates parathyroid hormone (PTH) secretion. High serum levels of phosphate are usually observed in patients with end-stage renal disease. The aim of the present study was to evaluate whether serum phosphate concentration had an acute effect on PTH secretion in hemodialysis patients. The levels of serum phosphate were manipulated during the hemodialysis session by using a phosphate free dialysate or a dialysate with a high content of phosphate. METHODS: Ten stable hemodialysis patients with PTH values above 300 pg/ml were included in the study. A PTH-calcium curve was obtained during both high phosphate and phosphate free hemodialysis. RESULTS: The serum phosphate concentration remained high (2.17 +/- 0.18 mM) throughout the high phosphate hemodialysis and decreased progressively to normal levels (1.02 +/- 0.06 mM) during the phosphate free hemodialysis. The serum PTH levels at maximal inhibition by hypercalcemia (minimal PTH) were greater during the high phosphate than the phosphate free hemodialysis (413 +/- 79 vs. 318 +/- 76 pg/ml, P < 0.003). In all patients the values of minimum PTH were greater during the high phosphorus than the phosphorus free hemodialysis. The values of maximally stimulated PTH during hypocalcemia and the set point of the PTH-calcium curve were similar during the high phosphate and the phosphate free hemodialysis. CONCLUSION: The maintenance of high serum phosphorus levels during hemodialysis prevented, in part, the inhibition of PTH secretion by calcium, which strongly suggests that in hemodialysis patients high serum phosphate contributes directly to the elevation of PTH levels despite normal or high serum calcium concentration.     

Effect of a hearing aid on progressive hearing loss

A group of 72 children with hearing aids followed in 4 different clinical settings presented progressive increase in sensorineural hearing loss. The mean hearing loss over time, the duration of hearing aid use and the gain were studied to test the hypothesis that continued progression in hearing loss was due to overly powerful amplification. No correlation was found between the progressive increased gain levels were associated with less progression in hearing loss than at lower gain levels. Therefore, the use of hearing aids was not directly and significantly related to the increase in hearing loss in the population studied. However according to the above criteria a few cases (4%) of progressive hearing loss did seem to be associated with hearing aid use.     

Communicative interactions of deaf and hearing children in a day care center. An exploratory study

Interactions were observed in a day care center serving deaf and hearing children. Observations focused on eight children (two deaf with deaf parents, two deaf with hearing parents, two hearing with deaf parents and two hearing with hearing parents) between 2 and 3 years of age. Center classes included deaf and hearing teachers and all children were encouraged to sign. Deaf and hearing children alike frequently interacted with other children and teachers whose hearing status differed from their own. However, each group showed a stronger tendency to initiate communication with same hearing status peers. Hearing children displayed the ability to modify their communications modes to match the hearing status of their intended communication partner. Language ability, not hearing status, was associated with the frequency of communication experienced by each child.     

A clinical study of persistent hypotension in patients on chronic hemodialysis

In order to clarify the pathogenesis of hypotension seen in the patients on chronic hemodialysis, we studied the vascular reactivity to exogenous vasoactive substances and the change of plasma ANP level during hemodialysis treatment. The vascular responsiveness to intravenously infused norepinephrine was decreased in hemodialysis patients, particularly in hypotensive group, compared with healthy controls (< 0.05). The blood pressure response to angiotensin II was also diminished significantly in hypotensive patients, compared with normotensive patients (p < 0.05). The plasma ANP concentration before and after each hemodialysis treatment was not different statistically between hypotensive and normotensive patients. Furthermore, the change of plasma ANP concentration was not correlated with the blood pressure change during each hemodialysis procedure. These findings suggest that the decrease of vascular responsiveness may be a factor for causing persistent hypotension in patients on chronic hemodialysis, and that the plasma ANP level is not responsible for the pathogenesis of hypotension.     

Hearing and Sj?gren's syndrome

Immune sensorineural hearing loss is manifested in several systemic immune diseases. Although hearing loss has been previously documented in patients with Sj?gren's syndrome (SS), the effect of SS on hearing is unclear. This prospective study was designed to assess the presence of hearing loss in 14 patients with SS and, if sensorineural hearing loss was present, to determine if the hearing loss was immune-mediated. Patients were evaluated with basic audiologic tests as well as for cellular immune inner ear reactivity as measured by the lymphocyte transformation test (LTT). Three patients had evidence of sensorineural hearing loss. Two patients had a positive LTT without evidence of sensorineural hearing loss. This preliminary study suggests that SS may not directly cause sensorineural hearing loss, immuno-mediated or otherwise.     

Low prevalence of hearing aid use among older adults with hearing loss: the Epidemiology of Hearing Loss Study

OBJECTIVES: To measure the prevalence of hearing aid use among older adults with hearing loss and to identify factors associated with those currently using hearing aids. DESIGN: Population-based cohort study. SETTING: The south-central Wisconsin community of Beaver Dam. PARTICIPANTS: A total of 1629 adults, aged 48 to 92 years, who have hearing loss and are participating in the Epidemiology of Hearing Loss Study and the Beaver Dam Eye Study. MEASUREMENTS: A hearing-related risk factor and medical history questionnaire, the Hearing Handicap Inventory for the Elderly (screening version), screening tympanometry, pure-tone air- and bone-conduction audiometry, and word recognition tests were administered by trained examiners using standard protocols. RESULTS: The prevalence of current hearing aid use among those with a hearing loss (pure-tone average > 25 decibels hearing level over 500, 1000, 2000, and 4000 Hertz, worse ear) was 14.6%. The prevalence was 55% in a subset of the most severely affected participants. In univariate analyses, current hearing aid use was associated with age, severity of loss, word recognition scores, self-reported hearing loss, self-perceived hearing handicap, and history of noise exposure. Factors associated with current hearing aid use in multivariate logistic regression models were age, severity of loss, education, word recognition scores, Hearing Handicap Inventory for the Elderly (screening version) score, and self-report of a hearing loss. CONCLUSIONS: Few older adults with hearing loss are currently utilizing hearing aids. Improved screening and intervention programs to identify older adults who would benefit from amplification are needed to improve hearing-related quality of life for this large segment of the population.     

Hemodialysis versus cross hemodialysis in experimental hepatic coma

In this study, the effects of conventional hemodialysis on experimental hepatic coma have been compared with those of hemodialysis against blood from a normal donor which allows exchanges without mixing of blood. cuprophan and polyacrylonitrile membranes were compared. Cross hemodialysis with a donor resulted in rpompt but transient recovery of consciousness, whichever membrane was used. Cuprophan hemodialysis without donor had no effect. Polacrylonitrile hemodialysis without donor allowed progressive and prolonged improvement in the consciusness level and the electroencephalograms. Therefore, clearance of middle molecular weight substances was more effective than exchange with a donor. Preliminary results in man showed total recovery of consciousness in six of ten patients with acute liver failure and coma and partial recovery from complete grade IV coma to grade II encephalopathy in two patients. These two patients reacted when called by their name by opening their eyes and obeying simple orders.     

Hearing preservation in acoustic tumor surgery: results and prognostic factors

A retrospective study was conducted to assess the hearing results in patients who underwent acoustic neuroma removal via the middle fossa approach. A statistical correlation of results with preoperative clinical and audiological data determined if any prognostic indicators could be associated with successful hearing preservation. Of 93 patients included in the study, useful hearing was preserved in 54 (58%), and hearing was preserved near preoperative levels in 42 (45%). The potential for hearing preservation appeared to be inversely related to the size of the acoustic tumor, with hearing preserved in 39 (60%) of 65 patients with tumors less than or equal to 0.5 cm extension into the cerebellopontine angle. Preoperative hearing levels and electronystagmography seemed to have no prognostic value. However, auditory brainstem response showed that a wave V latency of less than 6.8 msec was associated with an increased chance of hearing preservation, and the presence of vertigo as a preoperative complaint appeared to be a good prognostic indicator of successful hearing preservation.     

On being a medical student in the 1930s

The obstetrical management of women with renal disease is complicated and associated with increased fetal and maternal morbidity. However, maternal serum screening is an integral part of obstetrical care and should be offered to all women. We found that maternal serum levels of a-fetoprotein and human chorionic gonadotropin did not significantly change as a result of hemodialysis, whereas levels of unconjugated estriol were markedly decreased following hemodialysis. Maternal serum screening should be limited to alpha-fetoprotein analysis in women undergoing hemodialysis until the effects of hemodialysis on all serum analytes are better delineated.     

Quality of hearing preservation in acoustic neuroma surgery

OBJECTIVE: This study aimed to investigate the factors affecting the quality of postoperative hearing in acoustic neuroma. STUDY DESIGN: The study was designed as a retrospective case review. SETTING: The study was performed at the Department of Otolaryngology, School of Medicine, Keio University, Tokyo, Japan. PATIENTS: The subjects were 94 patients with unilateral acoustic neuroma. INTERVENTION: Hearing preservation surgery was performed in the subjects via the extended cranial fossa approach or the middle cranial fossa approach. MAIN OUTCOME MEASURES: The outcome measures included patient's age and gender, hearing level, speech discrimination score, tumor size, and surgical approach. The relationship between the qualities of preoperative and postoperative hearing and the long-term prognosis of preserved hearing also was investigated. RESULTS: In 94 subjects, there were 47 patients whose hearing was preserved (HP group) and 47 patients whose hearing was not preserved (non-HP group). Overall, hearing preservation rate was 50%. There were no significant differences in age, gender, and tumor size between the two groups. The hearing preservation rate was significantly higher in patients with an intracanalicular tumor than that with a larger tumor. The better the preoperative quality of hearing was, the higher the postoperative one. Although the preserved hearing deteriorated after surgery in 4 patients, no significant hearing deterioration was observed in the other 43 patients. CONCLUSIONS: The results of this study indicated that the diagnosis for acoustic neuroma in the early stage with serviceable hearing is the most important to improve the quality of postoperative hearing.     

Temporal analysis and stimulus fluctuation in listeners with normal and impaired hearing

The first experiment investigated the effects of mild to moderate sensorineural hearing impairment on temporal analysis for noise stimuli of varying bandwidth. Tasks of temporal gap detection, amplitude modulation (AM) detection, and AM discrimination were examined. Relatively high levels of stimulation were used in order to reduce the possibility that the results of the listeners with hearing impairment would be influenced strongly by audibility. A general summary of results was that there was relatively great interlistener variation among the listeners with hearing impairment, with most listeners showing normal performance and some showing degraded performance, regardless of the bandwidth of the stimulus carrying the temporal information. A second experiment investigated the hypothesis that listeners with sensorineural hearing impairment might have poor gap detection due to loudness recruitment. Here, gap markers were presented at levels where loudness growth was steeper for the listeners with hearing impairment than for the listeners with normal hearing. Although gap detection was sometimes poorer in listeners with hearing impairment than in listeners with normal hearing, there was no clear relation between gap detection performance and loudness recruitment in listeners with mild to moderate sensorineural hearing impairment.     

Active electronic cochlear implants for middle and inner ear hearing loss--a new era in ear surgery. I: Basic principles and recommendations on nomenclature

Hearing aids have fundamental disadvantages: (1) stigmatization of the patient; (2) the sound is often found to be unsatisfactory due to the limited frequency range and undesired distortion; (3) in many patients, the ear canal fitting device generally necessary leads to an occlusion effect; (4) acoustic feedback when amplification is high. Conventional hearing aids transmit sound into the ear canal via a small microphone. Sound has the disadvantage of requiring high output sound pressure levels for its transmission. This along with the necessary miniaturization of the loudspeaker as well as the resonances and reflections in the closed ear canal contribute to the disadvantages mentioned. In contrast, implantable hearing aids do not make sound signals but micromechanical vibrations. An implantable hearing aid has an electromechanical transducer instead of the loudspeaker of a conventional hearing aid. The hearing signal does not leave the transducer as sound but as a mechanical vibration which is directly coupled to the auditory system bypassing the air. This implantable hearing aid is either coupled to the tympanic membrane, the ossicular chain, the perilymph of the inner ear, or the skull. An implantable hearing aid is expected to have: 1 Better sound fidelity than a hearing aid 2 No ear canal fitting device, free ear canal 3 No feedback 4 Invisibility Requirements on electronic hearing implants designed for patients with conductive hearing loss differ from those on implants for sensorineural hearing loss. Conductive hearing loss requires the implant to replace the impedance transformation, thus being an impedance transformation implant (ITI). In various respects, the demands on an ITI are lower than the demands on an electronic hearing aid for patients with sensorineural hearing loss. The latter are mostly patients with a failure of the cochlea amplifier (CA). A damage to the CA is clinically discernible by a positive recruitment and loss of otoacoustic emissions (OAE). Since these patients form the majority of cases with sensorineural hearing loss, an active hearing implant for such patients should partially replace the function of the CA. Therefore, the suggestion is to refer to a CAI (cochlea amplifier implant). The implant expressions ITI (for patients with conductive hearing loss) and CAI (for patients with sensorineural hearing loss) used in this context allow nomenclatural association with the CI (cochlear implant) for complete inner ear failure as well as with the BSI (brainstem implant) in the case of hearing nerve failure.     

Hearing evaluation in children with bacterial meningitis

Twenty four children with bacterial meningitis were studied prospectively to ascertain the incidence, type and severity of hearing loss. The incidence of sensorineural hearing loss was 20.8%. Patients with hearing loss were followed-up audiologically for six months to find out the progress of hearing impairment. Of the five patients with sensorineural hearing loss only one showed partial recovery while the other three did not show any improvement. Of the five patients with sensorineural hearing loss only one showed partial recovery while the other three did not show any improvement. One patient was lost to follow-up, therefore, recovery was not known. The degree of hearing loss varied form mild to moderate. Antibiotic treatment and laboratory data were analysed to identify the high risk factors predisposing to hearing impairment. The presence of low CSF sugar level, high protein at the initial lumbar puncture and presence of neurological deficits was associated with a significantly higher risk of hearing loss. However, the nature of antibiotic therapy, duration of illness, age and sex of the patients were not significant risk factors in the development of hearing impairment.     

Ambulatory blood pressure monitoring in dialysis patients and estimation of mean interdialytic blood pressure

To define blood pressure (BP) patterns and control in dialysis patients, 48-hour ambulatory BP monitoring was performed in 36 hemodialysis and 18 peritoneal dialysis patients. Monitoring began during a dialysis session for hemodialysis patients. Data revealed significantly lower diastolic BP (DBP) and lower diastolic load (percentage of diastolic values > 90 mm Hg) in hemodialysis patients compared with peritoneal dialysis patients (80.6 mm Hg v 88.8 mm Hg, respectively, [P < 0.03] and 26% v 45%, respectively [P < 0.03]) for the 48-hour period. When the 2 days were analyzed separately, the difference in diastolic pressures and loads was significant only for the first (dialysis) day. Similarly, trends toward lower systolic BP (SBP) and systolic load in hemodialysis patients existed throughout monitoring and were greater in magnitude during the first day. BP data were fit to a random-coefficient growth curve model to detect periodicity. This sensitive model did not detect diurnal variation of BP in either group. The incidence of hypotension did not differ between the two groups (2.0% v 1.0% of total observations, hemodialysis v peritoneal dialysis). In the hemodialysis group, the proportion of hypotensive observations was significantly greater during the 4 hours postdialysis compared with other periods (5.6% v 1.6%; P < 0.02), a finding that likely reflects the practice of holding antihypertensives until after hemodialysis. However, patient diaries did not reflect hypotensive symptoms during this time. In the hemodialysis group, mean BP and predialysis BP did not correlate with interdialytic sodium load or weight gain. Predialysis and postdialysis BP (recorded by dialysis nurses) correlated significantly with mean BP. Predialysis SBP overestimated mean SBP by an average of 10 mm Hg, while postdialysis SBP underestimated mean SBP by an average of 7 mm Hg. To create formulas to estimate mean SBP and DBP in hemodialysis patients, multiple linear regression was used to model these variables against age, sex, race, and average prehemodialysis/posthemodialysis BP. The model achieved a high degree of fit (r2 = 0.72 for SBP; r2 = 0.65 for DBP), demonstrating that prehemodialysis and posthemodialysis BP can be used to predict mean BP in hemodialysis patients. In summary, our data show the absence of a diurnal variation of BP in dialysis patients and lower BP in hemodialysis patients compared with peritoneal dialysis patients. Among hemodialysis patients, more hypotension occurred after dialysis compared with other periods, and predialysis and postdialysis BP can be used to model mean BP levels.     

Paediatric hearing loss in rural Pakistan

OBJECTIVE: The present study was designed to generate population-based data on the prevalence and causes of hearing loss in rural Pakistani children. A community screening programme was utilized to identify and evaluate the hearing impaired. METHODS: The study was performed in conjunction with the Ministry of Population Welfare in Sialkot District, Punjab Province. School-aged children between the ages of 5 and 15 years were screened and examined for hearing impairment according to World Health Organization (WHO) protocols. Case-control analysis of audiometric, physical examination, and risk factors for hearing loss were performed, followed by chi-square analyses. RESULTS: A total of 607 children comprised the study population, with an overall point prevalence of hearing impairment of 7.9%. Fifty percent of all hearing loss was conductive in nature, amenable to either medical or surgical therapy. The risk factors most associated with conductive hearing loss were otorrhea and multiple ear infections greater than 5. In cases of severe hearing loss, 70% were the result of consanguinous marriages. Almost no cases of hearing loss were attributable to measles, mumps, rubella, and the TORCH infections. CONCLUSION: This study has generated some badly needed population-based data on the magnitude of the problem of hearing loss in rural Pakistan. It is hoped that the results of this work will stress the importance of hearing health in Pakistan and to encourage other professionals to pursue similar projects.     

Hearing and occupation

Not only does the environment play a role as a source of risk factors for a hearing impairment, but a hearing impairment itself can adversely affect interaction with family members, workmates and friends, thus reducing social well-being. The number of work-related hearing impairments has been decreasing for last five years, but noise-induced sensorineural hearing loss is still the second most common work-related disease in Finland. The financial burden related to occupational hearing impairments includes costs of compensation, salaries of screening personnel, equipment, maintenance costs, costs resulting from loss of work for the employer and referrals to specialist clinics etc, which until now have not been calculated in Finland. Numerous questions still remain to be answered regarding the association of age, socioacousis, occupation and leisure activities with the development of sensorineural hearing impairment. Can hearing impairment acquired in childhood or in early adolescence predict the development of occupational hearing loss? What is the interactive role of such factors as ageing, chemicals, diet, environmental noise, genetic susceptibility and the individual's other diseases in the development of noise-induced hearing impairment?     

Pharmacokinetic study of an oral cephalosporin, cefdinir, in hemodialysis patients

The pharmacokinetics of cefdinir were investigated in six hemodialysis patients. For the present study, two tests were carried out, one with 4 h of hemodialysis and the other without hemodialysis. Cefdinir was given orally to each patient in a dose of 100 mg, and blood was collected serially for 48 h after dosing in the test without dialysis and for 72 h in the test with dialysis. In the test without dialysis, the maximum plasma concentration (Cmax) was 2.36 +/- 0.53 micrograms/ml (mean +/- standard deviation) and the time to Cmax was 9.00 +/- 2.45 h. The terminal elimination half-life (t1/2) and area under the concentration-time curve (AUC) were 16.95 +/- 1.20 h and 69.05 +/- 14.84 micrograms.h/ml, respectively. In the test with dialysis, t1/2 during hemodialysis decreased approximately to one-sixth of that obtained in the test without dialysis, although t1/2 in the latter elimination phase did not differ from that in the nondialysis test. AUC was reduced to 43% of that in the test without dialysis. The fractional removal of cefdinir by hemodialysis was 61%. These findings indicate that clearance of cefdinir is prolonged in patients with renal failure, and cefdinir is well removed by introduction of hemodialysis, although t1/2 (during hemodialysis) and AUC were two and eight times higher than the data previously reported for healthy volunteers, respectively. The pharmacokinetic data suggest that 100 mg of oral cefdinir once a day would result in a sufficient concentration in plasma in hemodialysis patients, but this remains to be confirmed by multiple-dose studies.