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Biomedical subjects

A L Mehl

Publications and source records attributed to A L Mehl.

13 recordsLinked to original sources

The Marion Downs National Center for Infant Hearing: developing comprehensive state systems.

The Marion Downs National Center for Infant Hearing was established in 1996 through a Maternal and Child Health Grant awarded to the University of Colorado. The goals of the grant are to implement statewide systems of newborn hearing screening, audiologic assessment, and early intervention in 19 states. Newborn hearing screening alone will not assure early identification or positive outcomes for the development of communication and language. Therefore, the staff at the Marion Downs National Center developed comprehensive goals for all participating states. These goals are described in this article.

Child Health Services↗

Newborn hearing screening: the great omission.

OBJECTIVE: The advent of technologic improvements in assessing the hearing of newborn infants has made possible the implementation of universal newborn hearing screening. Furthermore, selective screening based on high-risk criteria fails to detect half of all infants with congenital hearing loss. Although universal screening has been recommended by the National Institutes of Health and the Joint Committee on Infant Hearing Screening, data to support this recommendation have been incomplete, and the recommendation has been seen as without solid foundation by many in the pediatrics field. This study was designed to assess the feasibility, accuracy, and cost-effectiveness of a hospital-based hearing screening program for all newborns. METHODOLOGY: Between 1992 and 1996, hospitals in Colorado with 100 or more births per year were targeted to participate in universal hearing screening of newborns. To date, 26 of 52 targeted hospitals, ranging in size from 40 to 3500 births per year, have implemented universal screening. A total of 41 796 infants were screened between 1992 and 1996. Screening was performed using automated auditory brainstem response, otoacoustic emission testing, or conventional auditory brainstem response, with follow-up testing performed on those infants who failed initial screening. RESULTS: Of 41 796 infants screened at birth, 2709 failed initial screening, and of 1296 who have completed reevaluation, 94 have been identified with congenital sensorineural hearing loss (75 bilateral) and an additional 32 identified with conductive hearing loss (14 bilateral). The frequency of bilateral congenital hearing loss requiring amplification therefore is shown to be at least 1 in every 500 newborns. During the study period, an additional 17 children with significant hearing loss not identified until >/=18 months of age were reported voluntarily; all 17 had been born at hospitals not participating in newborn hearing screening. The false-positive rate for the screening program to date in Colorado is calculated to be 6%, but evolving technology has resulted in improvements to as low as 2%. Positive predictive value of an abnormal screen result is shown to be at least 5%, and as high as 19%, with improving technology. The sensitivity of newborn screening is demonstrated to be at or near 100%. Costs of screening are compared with other screened congenital diseases; although the true cost per child for newborn hearing screening is significantly higher than screening tests performed on blood, the much higher incidence of congenital hearing loss results in a comparable cost per case diagnosed when compared with hypothyroidism or phenylketonuria, for example. The feasibility of early intervention is demonstrated, with amplification by the use of hearing aids being the catalyst for effective treatment. Finally, the costs of screening and early intervention are compared with the monetary savings in avoiding delayed and therefore intensive therapy and intervention for children not diagnosed at birth. The true cost of screening for one newborn is shown to be between $18 and $33, with an average cost of $25 per infant. The cost per case of congenital hearing loss diagnosed is approximately $9600. A model for cost predictions and subsequent intervention savings is presented, and recovery of all screening costs is demonstrated after only 10 years of universal screening in Colorado. CONCLUSIONS: Universal newborn hearing screening is feasible, beneficial, and justified, as indicated by the frequency of the disease, the accuracy of screening tests, the ability to provide early intervention, the improved outcomes attributable to early amplification, and the recovery of all screening costs in the prevention of future intervention costs. Furthermore, the incidence of bilateral congenital hearing loss is alarming, and is, in fact, many times greater than the combined incidence of all newborn screening tests currently performed on blood samples.

Audiometry, Evoked Response↗

Language of early- and later-identified children with hearing loss.

OBJECTIVE: To compare the language abilities of earlier- and later-identified deaf and hard-of-hearing children. METHOD: We compared the receptive and expressive language abilities of 72 deaf or hard-of-hearing children whose hearing losses were identified by 6 months of age with 78 children whose hearing losses were identified after the age of 6 months. All of the children received early intervention services within an average of 2 months after identification. The participants' receptive and expressive language abilities were measured using the Minnesota Child Development Inventory. RESULTS: Children whose hearing losses were identified by 6 months of age demonstrated significantly better language scores than children identified after 6 months of age. For children with normal cognitive abilities, this language advantage was found across all test ages, communication modes, degrees of hearing loss, and socioeconomic strata. It also was independent of gender, minority status, and the presence or absence of additional disabilities. CONCLUSIONS: Significantly better language development was associated with early identification of hearing loss and early intervention. There was no significant difference between the earlier- and later-identified groups on several variables frequently associated with language ability in deaf and hard-of-hearing children. Thus, the variable on which the two groups differed (age of identification and intervention) must be considered a potential explanation for the language advantage documented in the earlier-identified group.

Age Factors↗

Munchausen syndrome by proxy: a family affair.

Munchausen syndrome by proxy is an unusual form of child abuse: a child presents with an illness that has been factitiously produced by a parent, typically the mother. A case of chronic illicit insulin administration to a one-year-old girl is described. Despite temporary separation of the child from the mother and long-term psychiatric intervention, factitious illnesses continued, including urine specimen contamination, laxative-induced diarrhea, suspected bladder catheterization, and suspected poisoning. Retrospective review of the medical records of the mother and two siblings demonstrated previously unrecognized evidence of factitious illnesses. The medical records contained evidence of 30 separate episodes of suspected or documented factitious illness in these four members of the same family. This unique family illustrates the significant morbidity of Munchausen syndrome by proxy and a poor response to psychiatric treatment.

Child Abuse↗

Interpretation of traumatic lumbar puncture. A prospective experimental model.

Contamination of cerebrospinal fluid (CSF) with blood at the time of collection interferes with the interpretation of laboratory studies. Twenty-four children with normal CSF were studied prospectively using an experimental model. Blood was added to clear CSF, producing red cell counts from 1,000 to 600,000 cells per cubic millimeter. The expected values for white blood cell count, protein, percent neutrophils, and glucose were calculated, using the results from uncontaminated CSF, peripheral blood cell counts, blood protein, and the red blood cell count of the contaminated specimen. The ratio of observed values to expected values ranged from 0.13 to 3.00 for CSF white blood cell count (mean 0.96, standard deviation 0.56), from 0.55 to 1.63 for CSF protein (mean 0.97, standard deviation 0.23), and from 0.10 to 2.25 for percent neutrophils in the CSF (mean 1.17, standard deviation 0.41). CSF glucose was unchanged by the addition of blood. Guidelines for interpretation of laboratory studies following traumatic lumbar puncture are suggested.

Blood↗

Interpretation of traumatic lumbar puncture. Predictive value in the presence of meningitis.

Contamination of cerebrospinal fluid (CSF) with blood was studied prospectively in nine children with aseptic meningitis as the second phase of a study reported in this volume last month. Using criteria defined in the first phase, four of nine patients had recognizably abnormal CSF after experimental contamination with blood. As a third phase of the study, 53 children with bacterial meningitis were reviewed retrospectively to assess if hypothetical contamination of CSF with blood would have disguised their abnormal CSF studies. All but one of these 53 patients had either an abnormal CSF glucose or a positive gram stain (indicators independent of contamination with blood), and none would have gone undiagnosed with hypothetical contamination of up to 200,000 red cells per cubic millimeter. Guidelines for interpretation of laboratory studies following traumatic lumbar puncture are reviewed.

Bacterial Infections↗