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Mild Bilateral and Unilateral Hearing Loss in Childhood: A 20-Year View of Hearing Characteristics, and Audiologic Practices Before and After Newborn Hearing Screening

Fitzpatrick, Elizabeth M.1,2; Whittingham, JoAnne2; Durieux-Smith, Andrée1,2

doi: 10.1097/AUD.0b013e31829e1ed9
Research Articles

Objectives: There is some evidence that the presence of even mild degrees of hearing loss and unilateral loss in early childhood can negatively affect typical development. Consequently, the identification of all children with permanent hearing loss including those with milder degrees of hearing loss is currently targeted through some newborn hearing screening initiatives. The objectives of this study were to document the proportion of children identified with mild bilateral or unilateral hearing loss (MBUHL) before and after the implementation of a universal newborn hearing screening program (UNHS). A second objective was to examine the clinical characteristics and audiologic management of this population of children.

Design: This population-based study involved an analysis of data on children with hearing loss; these data had been collected prospectively over a 20-year period from 1990 to 2010 in a publicly funded pediatric teaching hospital in Canada, which provided diagnostic audiology services for all children in the region. The proportion of all children with hearing loss identified with MBUHL before and after implementation of UNHS and their clinical profiles were documented. Data related to amplification use were also retrospectively extracted from detailed medical chart reviews to investigate clinical recommendations regarding amplification and subsequent use of hearing devices. Factors affecting amplification decisions and amplification use were examined.

Results: A total of 381 of 823 children (46.3%) aged 0 to 18 years who were identified with permanent nonacquired hearing loss presented with MBUHL. The proportions identified were similar in the pre- and post-UNHS periods (p = 0.207). Before UNHS children were identified at a median age of 5.0 years (interquartile range: 3.6 to 7.0) compared with a median of 0.8 years, (interquartile range: 0.3 to 2.3) post-UNHS. Progression of hearing loss was documented for 22% of all children, and for the group identified since UNHS, 32.4% experienced deterioration in hearing thresholds. Although 87.2 % of children received recommendations for amplification, more than 50% experienced considerable delay from identification to amplification. Age at identification and severity of hearing loss in the better ear were associated with amplification decisions for bilateral but not unilateral loss.

Conclusions: MBUHL constitutes almost half of childhood hearing loss. UNHS has lowered age of confirmation of MBUHL by 4 to 5 years. Delay to amplification suggests uncertainty of the benefit of intervening early for these losses. Further research is required to determine the effects of early-identified MBUHL on children’s development and to document the benefits of early amplification.

This study examined prevalence and practices related to mild bilateral and unilateral hearing loss in children identified over a 20-year period from 1990 to 2010 before and after universal newborn hearing screening. Almost half of 831 children with hearing loss presented with a mild bilateral or unilateral impairment. Before universal newborn hearing screening, children were identified at a median age of 5 years but at age 9.5 months after screening, resulting in a new clinical population. Although amplification was recommended for 87% of children, more than half experienced delays between diagnosis and amplification, suggesting considerable clinical uncertainty about their potential hearing difficulties.

1Audiology and Speech-Language Program, Faculty of Health Sciences, University of Ottawa, Ontario, Canada; and 2Child Hearing Laboratory, Children’s Hospital of Eastern Ontario Research Institute, Ottawa, Ontario, Canada.

ACKNOWLEDGMENTS: The authors thank Dr. Nicholas Barrowman for assistance with statistical analysis.

This study was supported through a research grant from the Canadian Institutes of Health Research. E. Fitzpatrick holds a Canadian Institutes of Health Research New Investigator award and a Canadian Child Health Clinician Scientist Award, which also supported the research. Funding for the Child Hearing Laboratory at the Children’s Hospital of Eastern Ontario Research Institute is gratefully acknowledged from the Masonic Foundation of Ontario.

The authors declare no conflict of interest.

Address for correspondence: Elizabeth M. Fitzpatrick, University of Ottawa, 451 Smyth Road, Ottawa, Ontario, K1H 8M5, Canada. E-mail: elizabeth.fitzpatrick@uottawa.ca

© 2014 by Lippincott Williams & Wilkins