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Biomedical subjects

J W Thelin

Publications and source records attributed to J W Thelin.

13 recordsLinked to original sources

Evaluation of a behavioral audiometry simulator for teaching visual reinforcement audiometry.

Eight audiology students with little or no visual reinforcement audiometry (VRA) experience each performed a VRA test on an infant. Four of the students received approximately 5 hours of behavioral audiometry simulator (BAS) training, and 1 week later, after the first VRA test, all eight students tested a second infant. Student performance was rated by three audiologists who were experienced in performing VRA with infants. The performance of the group that received BAS training improved significantly while the performance of the control group did not. Among the students who received BAS training, those who improved the most during stimulated testing also showed the greatest improvement in VRA with real infants.

Audiology

Mixed hearing loss in Larsen syndrome.

A mixed bilateral hearing loss is described in a child with classical Larsen syndrome. The presence of a residual conductive loss after successful placement of ventilating tubes suggests that the conductive loss is due to an ossicular abnormality. In Larsen syndrome, characterized by multiple joint dislocations and bony malformations, the ossicular joints may also be affected.

Abnormalities, Multiple

Skin tolerance and adaptation following implantation of the Xomed Audiant bone conductor.

Placement of the Xomed Audiant implantable bone conduction hearing prosthesis was initially restricted to a limited number of investigators. It was introduced to other otolaryngologists in a workshop on August 15-16, 1986. There have since been several workshops offered by Xomed and Dr. Hough, who developed the device, to train otolaryngologists how to implant this device. The literature thus far is limited to the experience of Hough and others involved with his initial trials. He has not reported any significant complications associated with this device. The purpose of this paper is to communicate a complication resulting from the use of this device. Skin ulceration over the implant resulted from excessive use of the hearing prosthesis within 2 weeks of the initial fitting. Other contributing factors in the breakdown of skin will be discussed along with suggestions regarding prevention.

Aged

CHARGE syndrome. Part I. External ear anomalies.

Ear anomalies and hearing loss are major components of CHARGE Syndrome. This paper describes the external ear anomalies found in this syndrome: short wide pinnae, often cupped and asymmetrical; distinctive triangular concha; discontinuity between the antihelix and antitragus; and 'snipped-off' portions of the helical folds. The patterns of anomalies are so distinctive that a preliminary diagnosis of CHARGE Syndrome can often be made on the basis of ear shape alone. Part II of this communication describes hearing loss in this syndrome.

Abnormalities, Multiple

CHARGE syndrome. Part II. Hearing loss.

CHARGE is a mnemonic for a syndrome with multiple congenital anomalies that occurs with normal chromosomes. The unique external ear anomalies have been described in CHARGE Syndrome Part I in this journal. This report describes the distinctive middle ear and sensorineural losses that occur in the syndrome, both of which can be progressive and, in most cases, are moderate to severe. There is evidence to indicate that these losses are due to congenital ossicular anomalies, eustachian tube dysfunction from craniofacial malformation, and cochlear involvement that is greatest for high frequencies.

Abnormalities, Multiple

Partial trisomy 6p and partial monosomy 9p from a de novo translocation 46,XY, -9, +DER(9)T(6:9)(p211:p24).

This report describes an adult male with a partial trisomy 6p(p211-pter) and a partial monosomy 9p(9p24-pter) resulting from a de novo unbalanced translocation. This patient does not show the classical featured of the 9p partial monosomy syndrome, thus disputing the claim of Hoo et al. (1982) that 9p24 is the critical segment for the monosomy syndrome. Partial trisomy for 6p has only been previously reported in children. In addition to the chromosomal anomalies, the patient has autosomal recessive spinal muscular atrophy with a different age of onset than two affected sibs. Finally, he shows unusual audiologic and ophthalmologic signs nor previously reported as part of the 9p monosomy or 6p trisomy syndromes.

Abnormalities, Multiple

The earplug procedure.

In the measurement of hearing, a masking dilemma is a situation in which it is not possible to use masking to determine if the signal is crossing the head and activating the opposite cochlea. A nonmasking procedure, called the earplug procedure, was developed to rule out crossover for air-conducted signals in patients with a masking dilemma. In the procedure, an earplug is inserted in the suspect ear in an attempt to increase the loss in that ear. If the loss is increased significantly, then thresholds were obtained from the test ear and crossover is ruled out. If there was no significant threshold shift with the earplug, crossover is not ruled out and the uncertainty remains. Threshold shift criteria were developed for five test frequencies and for single test frequencies. The procedure correctly rules out crossover for a majority of unmaskable ears.

Adolescent

Dominant CHARGE association.

We had the opportunity to examine eight individuals in four generations of a family with dominant CHARGE association. In three generations there were five affected individuals. The 25-year old male proband had coloboma of the iris, retina and optic disc, mental retardation, hypogonadism, malformed ears, and mixed hearing loss. His 19-year old sister had colobomas of the retina, choroid, and disc, mental retardation and malformed ears. The mother of these two individuals had coloboma of the retina, choroid, and optic disc, dull mentality, and mixed hearing loss. The proband's maternal grandmother had peripapillary staphylomatous changes of the disc, mixed hearing loss, and malformed protruding ears. The proband's maternal uncle had mental retardation, hypogonadism, mixed hearing loss, protruding ears, but no colobomas. All of the affected individuals had a distinct configuration to the midface, including malar hypoplasia, prominent nasal columnella and a long nasal philtrum. The inheritance of the CHARGE association in this family would appear to be autosomal dominant. However, as the males have not reproduced, it is not possible to rule out X-linked dominant inheritance.

Abnormalities, Multiple

Erythromycin ototoxicity: analysis and conclusions based on 22 case reports.

Although the majority of patients receiving erythromycin experience no hearing loss, certain patients are susceptible. Erythromycin ototoxicity data were analyzed on 20 patients from 13 reports in the English language literature as well as on two patients from the University of Missouri-Columbia. Patients were classified with respect to age, sex, premorbid diagnosis, renal/hepatic function, type of erythromycin used, dosage, duration of therapy, and route of administration. The following auditory effects were considered: onset of symptoms, degree and configuration of hearing loss, and recovery of hearing. The factors which, when combined with the use of high-dose erythromycin (greater than or equal to 2 gm/day), might place patients at risk for erythromycin ototoxicity are preexisting renal or hepatic disease, age (elderly), and perhaps being female. With knowledge of the predisposing factors and auditory effects, the clinician can more easily recognize hearing loss caused by erythromycin and properly counsel referring physicians and affected patients.

Adult

Effect of middle-ear dysfunction and disease on hearing and language in high-risks infants.

The effect of middle-ear dysfunction and disease on hearing and language development at one year of age was evaluated for 143 high-risk infants. These infants were categorized as normal or abnormal based on otologic history, otoscopic examinations, and on tympanometric examinations. Language was significantly related to gestational age, being delayed by approximately the amount of prematurity. Language scores were therefore adjusted for gestational age. Speech-detection threshold was not related to gestational age, and was used as the measure of hearing. Hearing levels were negatively correlated with adjusted language quotients. Infants with abnormal otologic histories reported were not different from infants with normal histories in either hearing or language development. Infants with bilateral otoscopic abnormalities had significantly higher speech-detection thresholds, but did not differ in language development from those with bilaterally normal otoscopy. Infants who were abnormal bilaterally by tympanometric examination had significantly higher speech-detection thresholds as well as significantly delayed language development. A significant effect on both hearing and language was found among those infants bilaterally abnormal by tympanometry for whom evidence of middle-ear disease was not visualized by otoscopic examination. Implications of these findings are discussed.

Hearing Disorders

High-frequency hearing loss in male farmers of Missouri.

Farmers are exposed to noise that is potentially hazardous to hearing. We measured the hearing of 161 male farmers and 75 male nonfarmers at the 1979 Missouri Farmers Association Agri-Fair and compared it with the hearing of 129 office workers from central Missouri. Fixed-level screening tests were conducted in both ears at three stimulus frequencies: 1000 and 2000 hertz at 20 decibels hearing level and 4000 hertz at 25 decibels hearing level. Audiometers were calibrated in accordance with the ANSI-1969 standard. The results show that farmers are at risk for hearing loss at 2000 and 4000 hertz when compared with office workers. The prevalence of hearing loss was greater for farmers at both frequencies in every decade age group from 25 to 64 years. Using screening failure at 2000 and 4000 hertz in both ears as a criterion for a loss that would affect communication ability, we found that the failure rate was 16.8 percent for farmers and 6.2 percent for office workers. As other investigators have found, the prevalence of high-frequency hearing loss in male nonfarmers who associate with farmers was nearly as great as for farmers.

Adult