Robert Stenstrom

Exposure to environmental tobacco smoke as a risk factor for recurrent acute otitis media in children under the age of five years

Exposure to environmental tobacco smoke (ETS) has remained a controversial risk factor for otitis media in children. This study evaluates the association between exposure to ETS and recurrent acute otitis media (RAOM) in 85 cases and 85 age and gender matched controls under the age of 5 years. Cases and controls were obtained from outpatient otolaryngology and ophthalmology clinics, respectively, at the Childrens Hospital of Eastern Ontario. Cases were defined as having four or more physician documented AOM episodes in the preceding 12 months and controls were otitis free in the prior 12 months. Exposure status was assessed via parental questionnaire. Controlling for other risk factors (via conditional logistic regression), such as daycare attendance, socioeconomic status, prematurity and family history of otitis media, a significant association between ETS and RAOM was evident (odds ratio = 2.68, 95% CI = 1.27-5.65). When categorized, a significant exposure response relationship between increasing level of exposure to ETS and increased risk of RAOM was evident. The population etiologic fraction indicated that up to 34% of RAOM cases may be accounted for by ETS exposure. We conclude that exposure to ETS is an important and modifiable risk factor for RAOM in children under the age of 5 years.

Test-Retest Variability in Audiometric Threshold with Supraaural and Insert Earphones among Children and Adults

The effect of age and earphone condition on test-retest intrasubject variability in audiometric threshold was investigated. Ten subjects in each of the following age groups were investigated: 6-9 years, 10-13 years and young adults. Test-retest audiometric thresholds were collected at six frequencies (250, 500, 1,000, 2,000, 4,000 and 8,000 Hz) under three earphone conditions (Telephonics TDH-50P supraaural and Etymotic Research ER-3A insert earphone coupled to an immittance probe cuff or a foam insert). No statistically significant differences were found in variability of test-retest differences as a function of age, earphone condition or test frequency (p greater than 0.05). The clinical application of the insert earphone is recommended with children and adults as it affords no greater test-retest variability and at the same time provides a solution to a number of limitations incurred with the use of the supraaural earphone.

Effect of temporal area bone vibrator placement on auditory brain stem response in newborn infants

The effect of bone conduction vibratory placement on the temporal area, revealed by the auditory brain stem response (ABR), in newborn infants, was investigated. Twenty-five full term neonates were tested at 48 to 72 hours postparturition. ABR wave V latencies were obtained from three different temporal area postauricular vibrator placements at 15 and 30 dB nHL stimulus intensity levels. Results showed that significant ABR wave V latency shifts were observed with changes in the three vibrator placements (p less than 0.05). It is suggested that, with ABR testing in newborn infants using bone conducted stimuli, bone vibrator placement on the temporal area remain consistent.

Effect of vibrator to head coupling force on the auditory brain stem response to bone conducted clicks in Newborn infants

The effect of vibrator to head coupling force on the auditory brain stem response (ABR) to bone conducted clicks in newborn infants was investigated. Twenty full term newborn infants were tested. ABRs to bone conducted clicks were obtained with four different coupling forces (225, 325, 425, and 525 g) at stimulus intensities of 15 and 30 dB nHL. ABRs to air conducted clicks were also obtained at 30 dB nHL. The results of this study indicated that ABR wave V latencies to bone conducted clicks in newborn infants were affected significantly when the vibrator to head coupling force shift exceeded 200 g. It is recommended that the coupling force be controlled and remain consistent when implementing ABR to bone conducted stimuli in newborn infants.

Test-Retest Variability of the Auditory Brainstem Response to Bone-Conducted Clicks in Newborn Infants

The variability of the auditory brainstem response (ABR) to bone- and air-conducted clicks was investigated utilizing a test-retest paradigm with 20 normal full-term newborn infants. ABRs to bone-conducted clicks at 15 and 30 dB nHL and air-conducted clicks at 30 dB nHL were obtained. The delivery of the bone-conducted signal was controlled. ABR wave V latencies were measured from each test-retest stimulus condition. The results indicated no statistically significant difference in test-retest variability of ABR wave V latencies or amplitudes between bone- and air-conducted clicks. ABRs to bone-conducted clicks, under controlled clinical conditions, are as reproducible and reliable as ABRs to air-conducted clicks in newborn infants.

Probe tube microphone measures of loudness discomfort levels in children

Loudness discomfort levels (LDLs) have been advocated as a means for selecting the SSPL90 setting of an individuals hearing aid. Kawell, Kopun, and Stelmachowicz (Ear Hear 1988; 9: 133-136) recently developed a procedure to measure LDLs in children. Several procedural cautions, involving the hearing aid stimulus delivery and sound field calibration, have been noted with this method. As a means of overcoming these problems, a new method utilizing insert earphone derived stimuli delivered to a childs ear-mold with probe tube microphone monitoring of real-ear sound pressure level was explored. Twenty children, aged 7 to 14 years, served as subjects. The advantage of the present method lies in the procedural conveniences and the ability to compare real-ear audiometric measures and hearing aid performance.

Fluctuating hearing losses in children can be migraine equivalents

Fluctuation of hearing thresholds in an already severely to profoundly deaf child constitutes a stressing condition and a therapeutic challenge. Thorough medical inquiries revealed strong histories of migraine headaches in the parents of 13 severely deaf children (mean age: 7 years) and two of them also presented symptoms of migraine. This disease is viewed as a form of a relatively benign cerebral vasospasm causing an intense transitory vasodilatation of the small vessels of the brain and a subsequent sterile inflammatory reaction. Liberation of histamine, serotonin and plasma kinins appear to interfere with the metabolism of nerve cells. All children in our study had suffered from anoxia at birth, a condition related to a depopulation of cochlear brainstem nuclei. Migraines may therefore produce obvious hearing symptoms when vasomotor disturbances occur in already damaged nervous structures. Treatment with propranolol hydrochloride (HCl), a potent beta-blocker, resulted in cessation of hearing fluctuations in all patients and in an improvement of thresholds in two of them. We presented our results, as well as preliminary studies on asphyxiated rats shortly after birth, with transitory artificially induced cerebral vasodilatation.

Real Ear Sound Pressure Levels Developed by Three Portable Stereo System Earphones

Differences in real ear sound pressure levels (SPLs) with three portable stereo system (PSS) earphones (supraaural [Sony Model MDR-44], semiaural [Sony Model MDR-A15L], and insert [Sony Model MDR-E225]) were investigated. Twelve adult men served as subjects. Frequency response, high frequency average (HFA) output, peak output, peak output frequency, and overall RMS output for each PSS earphone were obtained with a probe tube microphone system (Fonix 6500 Hearing Aid Test System). Results indicated a significant difference in mean RMS outputs with nonsignificant differences in mean HFA outputs, peak outputs, and peak output frequencies among PSS earphones. Differences in mean overall RMS outputs were attributed to differences in low-frequency effects that were observed among the frequency responses of the three PSS earphones. It is suggested that one cannot assume equivalent real ear SPLs, with equivalent inputs, among different styles of PSS earphones.

Probe-Tube Microphone Measures of Vent Effects With In-the-Canal Hearing Aid Shells

The acoustic effects of three different configurations of vented in-the-canal (ITC) hearing aid shells were investigated. Real-ear sound pressure level measures (200-2000 Hz) were obtained from unvented and vented ITC shells from 12 adult subjects. In general, with increasing vent size, an increase in the amount of low-frequency reduction and an upward shift in vent kneepoints and vent-associated resonance occurred. The use of venting may be considered clinically for low-frequency reduction in ITC hearing aid frequency responses.

Prevalence of hypertension in children with primary vesicoureteral reflux

This study was undertaken to determine the prevalence of hypertension in children with primary, uncomplicated vesicoureteral reflux (VUR) and to evaluate the relationship between blood pressure (BP), grade and duration of reflux, and renal scarring. Subjects were identified retrospectively during a 17-year period; of 146 subjects who agreed to participate, 129 (88.4%) were female. Mean age at diagnosis was 5.0 years (range, 1 month to 16 years), and at follow-up was 14.4 years (range, 5 months to 21 years). Mean duration of follow-up was 9.6 years. Renal scarring was detected in 34.3% of patients by intravenous pyelogram, ultrasonography, or both. The BP at diagnosis was linearly related to the grade of reflux, but values were not higher than expected norms for age. At follow-up, mean systolic and diastolic BP were at the 41.6 percentile and the 18.7 percentile, respectively. No patients BP was above the 55th percentile. After a mean follow-up period of 10 years, we conclude that primary, uncomplicated VUR, regardless of the number of documented urinary tract infections, duration and severity of reflux, modality of therapy, presence of renal scarring, and duration of follow-up, is not associated with the development of hypertension. Hypertension does not appear to be a complication of VUR and urinary tract infection unless there is preexisting dysplasia.