Use of Amplification in Children With Unilateral Hearing Loss
Condition: Unilateral Hearing Loss
MeSH terms: Hearing Loss; Deafness; Hearing Loss, Unilateral
Study type: Interventional

Summary: 
      Unilateral hearing loss (UHL) in children has been demonstrated to have a negative impact on
      quality of life, school performance and behavior. Despite this knowledge, it remains unclear
      how to best manage this common problem. There has been much debate regarding this issue with
      many programs recommending preferential seating in the classroom and use of a
      frequency-modulated (FM) system to amplify the teacher's voice in the classroom (conventional
      measures), and others recommending these accommodations in addition to use of a hearing aid
      for amplification (amplification). There is very limited research to support or refute the
      efficacy of a hearing aid in improving measurable academic, behavioral, or quality-of-life
      (QOL) outcomes in children with UHL. We propose a study evaluating the impact of hearing aid
      use in school-aged children (ages 6-12 years) with mild to moderately severe UHL. In this
      study, subjects will be randomized to receive either conventional measures or conventional
      measures plus amplification. After a three month period, the groups will be reversed, with
      each subject serving as their own control. Outcome measurements will include patient reported
      disease-specific QOL reported by patients, parents, and teachers using validated survey
      instruments at regular intervals throughout the study period.
    

Detailed description: 
      Unilateral hearing loss (UHL) is defined as decreased hearing in one ear, with normal hearing
      thresholds in the contralateral ear. Approximately 0.83/1000 newborn children are found to
      have UHL. It is estimated that about 3-5% of all children in the United States are eventually
      diagnosed with UHL. When the cutoff for normal hearing is placed at 15 decibels (dB), this
      incidence is as high as 6.3%, which corresponds to a prevalence of 6.2 million children
      nationally. The management of UHL continues to be an area of debate, as the handicap
      associated with UHL is often underestimated. In fact, those with UHL often go without
      assistance due to lack of recognition of the disability by some health and educational
      professionals, who have claimed that this hearing loss "attracts little attention from either
      patient or parent" and that "these children experience few communicational or educational
      problems." However, in evaluation of children with permanent hearing loss, rates of children
      who need speech/language intervention and aural rehabilitation are not significantly
      different between those with bilateral permanent hearing loss and those with unilateral
      permanent hearing loss. Unfortunately, children with UHL are half as likely to be referred
      for hearing testing as those with bilateral hearing loss.

      Studies have demonstrated the negative impact of unilateral hearing impairment in children.
      Educational and behavioral difficulties have been clearly shown, with a number of studies
      demonstrating increased rates of failure of at least one grade in children with UHL when
      compared to their classmates with normal hearing (24-35% vs. 3.5%). Additionally, increase in
      special educational needs (12-41%) and frequent problems with behavior have also been noted
      in this population. In several studies, Lieu and colleagues have shown poorer performance for
      children with UHL. In a study looking at oral and written language scores, children with UHL
      did significantly worse than their siblings, who served as matched controls, on language
      comprehension, oral expression, and oral composite scores. In addition, these children were
      four times more likely to have Individualized Education Plans (IEPs) and twice as likely to
      have received speech-language therapy.

      Despite these findings regarding the impact of UHL on children, there is a paucity of
      literature to support or refute the efficacy of hearing aid use in improving measurable
      academic, behavioral, or quality-of-life (QOL) outcomes. While hearing related
      disease-specific quality of life measures for children were not developed until very
      recently, previous studies in adults with UHL reported decreased quality of life, with
      increased frustration and shame due to hearing disability. The Hearing Environments and
      Reflection on Quality of Life questionnaire, or HEAR-QL, an instrument developed and
      validated at Washington University in St. Louis for young children with hearing loss
      initially (2011) and then later for adolescents (2013), examined effects on environments,
      activities, and feelings of children with both unilateral and bilateral hearing loss.
      Significantly lower scores, indicating poorer quality of life, were seen in patients with
      both UHL and bilateral hearing loss. Interestingly, differences in quality of life between
      children with UHL and children with bilateral hearing loss were found to be significant in
      only 1 out of 3 subdomains.

      A 2010 study by Johnstone et al. demonstrated that children with UHL who used amplification
      at a young age (6-9 years) had improvement in localization acuity, while those who received
      amplification at an older age (10-14 years) noted impairment in localization. This may
      indicate that the timing of initiation of amplification in UHL may play an important role in
      whether the intervention is beneficial. In addition, Noh and Park's study in 2012
      demonstrated that children with UHL needed to sit 3.5 meters closer to the teacher to obtain
      the same speech discrimination scores as children with binaural hearing. While this can be
      accomplished in a small room setting, this may not be possible at all times in all classes,
      and it is certainly not translatable to hearing environments outside of the classroom. It is
      not clear whether adding amplification to would eliminate this handicap and improve quality
      of life, behavior, or academic performance.

      Current interventions: Multiple options exist for management of UHL. Preferential seating in
      the classroom is often the first line of treatment utilized, placing the child at the front
      of the classroom with the better hearing ear toward the teacher. Evaluation of the classroom
      by an educational audiologist or other specialist in the education of children with hearing
      loss in order to optimize the listening environment is another commonly utilized modality for
      managing UHL. Interventions such as carpeting, tennis balls placed on the legs of chairs, and
      selection of a classroom with lower ambient noise levels from outside traffic or air handling
      equipment can reduce significantly improve signal to noise ratios for the student. Another
      modality for improving signal to noise ration is use of a frequency-modulated (FM) system in
      the classroom, which specifically amplifies the teacher's voice via a microphone worn by the
      teacher. This increases the signal-to-noise ratio for the teacher's voice as it does not
      amplify background noise. Differentiating relevant sound signals from background noise a
      particularly challenging problem for children with UHL. Other options for management of UHL
      include various forms of amplification including a unilateral hearing aid, contralateral
      routing of sound (CROS) systems, and potentially cochlear implantation (though this practice
      has not been widely adopted in children with UHL in the United States).

      In the only study to date comparing the above modalities to one another, Updike compared
      speech perception measures in 6 children, ages 5 to 12 years, with mild to profound UHL with
      use of FM systems, CROS aids, and conventional hearing aids. He concluded that FM systems
      were beneficial in all hearing situations and in all degrees of hearing loss. In addition, he
      stated that neither hearing aids nor CROS aids provided benefit in speech understanding, and
      both may worsen speech perception in noisy situations. Multiple limitations exist with this
      study, including a small sample size and lack of a time period for the patients to adjust to
      the use of amplification.

      In studies looking at acceptance of hearing aid use in children with UHL, children with mild
      to moderately severe hearing loss tended to accept hearing aids, while those with severe to
      profound hearing loss were less accepting. Parental satisfaction with hearing aids in this
      population has been good, with many noticing improved hearing for their children. More
      recently, Briggs et al. published a study looking at 8 children, ages 7 to 12 years, with
      mild to moderately severe UHL, who were aided with digital hearing aids. Although speech
      perception scores did not show significant improvement, parents subjectively reported
      significant improvement in quality of life after 3 months of use. In one German study of 3
      children with severe to profound unilateral hearing loss, improvement in speech understanding
      in noise and sound localization following cochlear implantation was observed and subjective
      improvement was reported by parents.

      Compliance with use of amplification should also be considered in these cases, as Fitzpatrick
      et al. demonstrated in a study of 670 children with unilateral or bilateral hearing loss.
      While amplification was recommended in 90%, less than two-thirds of the children wore their
      hearing aids consistently.

      To date, only two studies exist which examine the use of amplification in children with
      unilateral hearing loss. Both studies are limited by small sample size. In addition, the
      earlier study evaluated analog hearing aids, whereas in the present day, digital hearing aids
      are widely used, and was further limited by a very short study period. Our study proposes to
      examine whether children with UHL note improved quality of life when using amplification via
      a hearing aid in conjunction with conventional classroom accommodations including an FM
      system.

      In our study we will compare the use of conventional measures to conventional measures plus a
      digital hearing aid on the affected ear using validated quality of life instruments
      administered to the subject, the subject's teacher, and the subject's parent. The instruments
      used will be the HEAR-QL, the CHILD, and the LIFE-R (See outcome measures for details).

      Each of the surveys will be administered five times in total: at the time of enrollment, once
      at the midpoint of the first treatment arm, once after completion of the first treatment arm,
      once at the midpoint of the second treatment arm, and once after completion of the second
      treatment arm. Comparisons will then be made among groups as described later in this
      proposal.

      Our practice is well suited to carrying out this study as we are a tertiary care center
      serving a large region. Our multidisciplinary pediatric hearing loss clinic allows children
      to be evaluated and longitudinally followed in conjunction with the audiology, speech and
      language pathology, neuropsychology, and medical genetics. In the past year, there were over
      300 visits coded for unilateral hearing loss based on ICD-9 codes, with 70 unique patients,
      making recruitment of our target sample size over the 3-year study period feasible. The
      potential impact of this study is great, as there is no consensus as to whether amplification
      should be recommended for children with unilateral hearing loss, and a study of this power
      would serve as a useful guide in this decision-making process.
    

Intervention name(s): Hearing aid
Intervention type(s): Device
Intervention description(s): The subject will wear a hearing aid at all times for a 3-month period. At school, he/she will wear this hearing aid in addition to using conventional measures (FM system and preferential seating).
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: None (Open Label)
Primary purpose: Treatment