Exploring reasons for late identification of children with early-onset hearing loss

Abstract

Introduction

Several studies have shown that early identification of childhood hearing loss leads to better language outcomes. However, delays in the confirmation of hearing loss persist even in the presence of well-established universal newborn hearing screening programs (UNHS). The objective of this population-based study was to document the proportion of children who experienced delayed confirmation of congenital and early onset hearing loss in a UNHS program in one region of Canada. The study also sought to determine the reasons for delayed confirmation of hearing loss in children.

Methods

Population level data related to age of first assessment, age of identification and clinical characteristics were collected prospectively for all children identified through the UNHS program. We documented the number of children who experienced delay (defined as more than 3 months) from initial audiologic assessment to confirmation of hearing loss. A detailed chart review was subsequently performed to examine the reasons for delay to confirmation.

Results

Of 418 children identified from 2003 to 2013, 182 (43.5%) presented with congenital or early onset hearing loss, of whom 30 (16.5%) experienced more than 3 months delay from initial audiologic assessment to confirmation of their hearing disorder. The median age of first assessment and confirmation of hearing loss for these 30 children was 3.7 months (IQR: 2.0, 7.6) and 13.8 months (IQR: 9.7, 26.1) respectively. Close examination of the factors related to delay to confirmation revealed that for the overwhelming majority of children, a constellation of factors contributed to late diagnosis. Several children (n = 22; 73.3%) presented with developmental/medical issues, 15 of whom also had middle ear dysfunction at assessment, and 9 of whom had documented family follow-up concerns. For the remaining eight children, additional reasons included ongoing middle ear dysfunction for five children, complicated by family follow-up concerns (n = 3) and mild hearing loss (n = 1) and the remaining three children had isolated reasons related to family follow-up (n = 1) or mild hearing loss (n = 2).

Conclusion

Despite the progress made in the early detection of pediatric hearing loss since UNHS, a substantial number of children referred for early assessment can experience late confirmation and intervention. In particular, infants with developmental and/or medical issues including middle ear disorders are at particular risk for longer time to confirmation of hearing loss.

Introduction

Considerable attention has been accorded to the importance of early identification of hearing loss in early childhood during the last few decades. With a prevalence rate of approximately 2–4 per 1000 infants screened in infancy, permanent hearing loss (PHL) remains one of the most common congenital disorders [1], [2], [3]. Late detection of hearing loss results in delays in speech-language development and negatively impacts literacy, which has implications for social and academic functioning [4], [5], [6], [7].

In several investigations over almost two decades, early identification and/or early intervention has emerged as an important factor in achieving positive spoken language outcomes [4], [6], [8] Furthermore, knowing early about the presence of hearing loss has reported benefits for the family [9], [10]. For several decades, the Joint Committee on Infant Hearing (JCIH) [11] has promoted the need for well-developed comprehensive programs that include screening, diagnosis, and intervention. The widely promoted JCIH benchmarks of screening by 1 month, diagnosis by 3 months and intervention by 6 months have been adopted to reduce speech and language delays and to promote overall better quality of life in early childhood. Consequently, population-based newborn hearing screening and intervention programs with well-established protocols have been implemented as standard care in many developed countries [2], [12], [13].

Numerous reports confirm that age of diagnosis for children with congenital hearing loss has been substantially lowered across the spectrum of hearing disorders [14], [15] even for children with milder and unilateral loss when these degrees are included in the target disorder [16], [17]. Not all children with hearing loss can be detected shortly after birth including those with late onset and acquired loss [3], [18], [19]. Furthermore, not all programs screen for mild hearing loss of less than 40 dB HL [2] and when targeted, there are concerns about later identification due to difficulties of identifying very mild loss [20], [21]. Studies also suggest that some children with congenital hearing loss continue to experience delays in diagnosis or intervention despite the emphasis on early identification and management [15], [22], [23]. Despite well-defined UNHS protocols, the time of first audiologic assessment and subsequent intervention remains longer than recommended in some cases.

Investigations of age of diagnosis and characteristics of newborn screening cohorts have shed some light on factors affecting late diagnosis and/or late intervention with amplification. Key factors proposed include treatment in the neonatal intensive care unit (NICU) [1], [15], [24] as well as the presence of mild or unilateral hearing loss [16], [24], [25]. Other factors reported to affect loss to follow-up at various points in the screening to intervention process include socioeconomic challenges, maternal education, type of health insurance (private vs. public) and access to an audiology center. However, these studies were mostly interested in investigating benchmarks or the timeliness of the initial audiologic assessment after newborn screening [23] or on overall age of identification [15], [25]. Systematic examination of the reasons for late confirmation of hearing loss once children undergo the initial diagnostic assessment is lacking and the reasons remain unclear.

Given the lack of recent information about late identification and time to confirmation of hearing loss since UNHS, investigations of contemporary clinical cohorts are important to inform audiologic care. The purpose of the current population-based study was to examine late identification in a cohort of all children identified with congenital or early-onset hearing loss (i.e., onset determined to be <6 months of age) in one region of Canada. The primary goal was to identify reasons for late identification (defined as a gap of >3 months between first audiologic assessment and confirmation of permanent hearing loss). Specifically, we aimed to: 1) determine the number of children who experienced late confirmation of permanent hearing loss during an 11-year period, 2) describe their clinical characteristics, and 3) examine the reasons for late confirmation.