Unilateral Hearing Impairment in Children: Age of Diagnosis

The Hearing Center, Children's Hospital of Pittsburgh
The University of Pittsburgh
Pittsburgh, Pennsylvania

Multiple reports have suggested that early onset, severe unilateral sensorineural hearing impairment (USNHI) in children is associated with significant deficits in auditory and psycholinguistic skills and school performance (Bess, 1982; Bess and Tharpe, 1984; Brookhouser, Worthington, & Kelly, 1991). Additionally, USNHI is known to cause problems with sound localization and decreases the ability to understand speech-in-noise.

While much of the literature on USNHI in children addresses communication and educational issues, age of diagnosis has not been previously evaluated as a significant, independent and important factor. In this brief report, we present our findings related to the age of diagnosis.

Typically, children with USNHI are not identified as having hearing impairment until they reach school age. Often, children with one normal hearing ear will appear to have normal hearing in day-to-day, non-challenging situations. Further, the ability to hear normally in one ear will often trick the parents and the non-hearing healthcare professional into a false sense of security regarding the child's hearing.

Once the child reaches school age, routine school-based screenings are performed, and USNHI is sometimes identified. The average reported age of diagnosis, for children with all degrees (mild, moderate, severe and profound) of USHNHI is 8.78 years (Brookhouser, et al., 1991).

Our experience at the Hearing Center at Children's Hospital of Pittsburgh, indicates that children with varying degrees of USNHI are identified at a younger age. Early identification and management of hearing impairment in children is pivotal to the successful management of hearing impaired children.

Through our chart review and examination of seventy-seven children with USNHI, not acquired through trauma or infection, the average age of diagnosis was four years, eleven months, (standard deviation equal to two years, six months).

Children with mild USNHI (pure tone average equal to 20-40 dB nHL, n=12) were diagnosed on average by age six years, nine months (standard deviation equal to two years, four months). All children in this group were diagnosed after entering school. This result is not unexpected as children with mild USNHI typically evidence fewer symptoms than those with moderate, severe or profound degrees of impairment.

For children with moderate or worse degrees of USNHI (moderate: PTA = 41-70 dB nHL, n = 27; severe: PTA = 71-90 dB nHL, n = 6; profound: PTA> 90 dB nHL, n = 32) the average age of diagnosis was found to be four years, three months (standard deviation equal to two years, five months). Approximately half of these children were identified prior to entering school. As hearing impairment increases, the likelihood of behavioral signs and symptoms consistent with hearing loss increase. Therefore, children with more significant hearing losses are arguably more likely to receive earlier audiometric evaluation, diagnosis and management.

The methods of diagnosis yielding the largest number of identified children included routine school or pediatrician screenings, parental concern for hearing loss, and newborn hearing screenings. These results lend support for continuation of these programs and increased attention to them.

School and/or pediatrician screenings accounted for over half (54.5%) of all identifications. Parental concern was a catalyst for diagnosis in 22% of all cases. Newborn hearing screening accounted for 26.7% of all children identified before age six years and 10% of all identifications. The percentage of children identified this way is likely to increase with implementation of universal newborn hearing screening programs.
This study involves children diagnosed in years prior to state mandated universal newborn hearing screening was mandated in Pennsylvania.

The etiology of USNHI was unknown for the majority of these children (55.5%). However, inner ear anomalies were identified in 26% of this group. Large vestibular aqueduct (LVA) was the most commonly identified anomaly, seen in 14.5% of these patients with USNHI.

Counseling for patients with LVA includes consideration for limited participation in sports and other activities that involve possible head contact, trauma or injury. Additionally, periodic audiometric monitoring to rule out progression of hearing loss is advisable. Given the possibility for additional hearing loss related to LVA, early identification of USNHI and an appreciation of the etiology are very important in this population.

The need for amplification among children with USNHI remains a controversial issue among hearing healthcare professionals. As the degree of hearing loss of the worse ear varies, and as the status of the better ear varies, amplification options and alternatives vary for each child. Ideally, management of each child should be based on their unique history, presentation, and their specific needs (audiometric, medical, social, educational, familial etc).

Investigation into the benefits obtained from the use of various types of amplification, such as; hearing aids, various assistive listening devices, sound field systems, FM systems and other alternatives, with respect to hearing, localization, speech-in-noise issues and educational opportunities and achievements, requires further attention.
References:

Bess, F.H. (1982). Children with unilateral hearing loss. Journal of the Academy of Rehabilitative Audiology, 15, 206-216.

Bess, F. H. & Tharpe, A. (1984). Unilateral hearing impairment in children. Pediatrics, 74, 206-216.

Brookhouser, P., Worthington, D., & Kelly, W. (1991). Unilateral hearing loss in children. Laryngoscope, 101, 1264-1272.


Acknowledgements:

This paper is based on a poster presentation from the American Academy of Audiology in San Antonio, Texas, April 2003.

This work was supported in part by the Eberly Family Endowed Chair in Pediatric Otolaryngology at Children's Hospital of Pittsburgh in Pittsburgh, Pennsylvania.