Home Use of Remote Microphone Systems by Children with Hearing Loss

We have long known the benefits of high-quality, clear speech for optimum development of receptive and expressive language in typically developing children.¹ Primary factors that contribute to language quality include whether caregiver talk is child-directed,^2,3 whether the caregiver(s) is responsive to the child during conversations,⁴ and whether the topics of communication are relevant to the child's attention.⁵ In addition, the number of words to which children are exposed is linked positively to their subsequent vocabularies.⁶ However, children with hearing loss have difficulty hearing in noisy and reverberant environments, and thus, their speech and language development can suffer.⁷ Despite the use of well-fit hearing aids, these devices do not always ameliorate the negative impact of background noise. As such, it is common for these children to use remote microphone (RM) systems in classroom settings where there are high levels of background noise and reverberation and where the speaker of interest is likely to be distant from the listener.

Shutterstock/fizkes, audiology, telehealth, hearing aids.

Figure 1: Data averaged across families for both conditions, with and without the use of RM systems illustrating (a) the percentage of caregiver words produced from a distance and (b) the percentage of recorded intervals containing child-directed speech (CDS), as coded from caregivers’ LENAs. *p <.05. Audiology, telehealth, hearing aids.

Figure 2: Data averaged across families for both conditions, with and without the use of RM systems, displaying a frequency count of alerting behaviors (e.g., the use of verbal repetitions) by caregivers. *p <.05. Audiology, telehealth, hearing aids

RM systems are known for improving the signal-to-noise ratio in classrooms, and can help combat the detrimental effects of background noise, reverberation, and distance ubiquitous in many listening environments. Less common is the use of RM systems in home environments where high noise levels can also exist and negatively impact the speech perception of children with hearing loss.⁸ Most studies that have examined the use of RM systems in homes have involved the use of parental reports to determine the effectiveness and feasibility of these systems. Such reports have generally been positive, citing the benefits of improved child access to speech, overhearing, and incidental learning.^9,10 In addition, anecdotal reports suggest improved attention and receptive language and reduced listening effort and fatigue among children with hearing loss who use RM systems in their homes.¹¹

To expand on these prior studies and objectively quantify the possible communication benefits of RM system use in the homes of children with hearing loss, our laboratory investigated the effects of home use of RM systems on several aspects of caregiver and child communication. These communication measures focused on both the quantity and quality of communication. Specifically, we examined the impact of RM system use in the home on the amount of caregiver talk, including child-directed speech, both produced and received at the level of the child, and the caregiver's production of repetitions or other talk intended to alert or secure the child's attention.^12,13,14

STUDY METHODS

We provided nine families of pre-school-age children who have bilateral, permanent hearing loss with Language Environmental Analysis (LENA™) technology¹⁵ and Phonak Roger™ Inspiro RM systems to determine the efficacy of home use of RM systems. Participants included nine adult caregiver-child dyads with children being between 2 and a half and 6 and a half years of age. Children were full-time users of some type of hearing amplification (hearing aids, cochlear implants, and/or bone-anchored device) for at least one year and were not previous users of RM systems at home or school.

The RM systems were set with the hearing aid or cochlear implant microphones activated; thus, the environmental microphones were active even when the RM system microphone was active. The RM system provided a 10 dB advantage relative to the incoming signal. LENA technology is designed to record up to 16 hours of continuous data that can subsequently be downloaded and automatically analyzed by the LENA software, which yields an estimate of the amount of speech produced near (i.e., within approximately 6-8 feet) the recorders.¹⁶ Because we were interested not only in caregiver talk produced near the child but in all caregiver talk that was accessible or potentially accessible to the child via the RM system, we had the child and the caregiver wear LENA recorders while participating in the study; thus, two LENA recorders were simultaneously used (i.e., the child's LENA recorder and the caregiver's LENA recorder). Both the child and the caregiver wore LENA recorders for two consecutive weekends, including one weekend with and one weekend without RM system use, and recorded data were compared across weekends.

RESULTS

Across the nine participating families, RM system use at home provided children with access to approximately 11 words per minute more than when not wearing the RM system. Assuming a child is wearing an RM system for eight hours a day,¹⁷ this would result in exposure to 5,300 more caregiver words (approximate 42% increase) daily. Moreover, caregivers spoke more from a distance (i.e., far talk) while using the RM system than when not.¹² That is, on average, caregivers produced a higher proportion of far talk when using the RM system (47% of words) than when not using the RM system (37% of words; Fig. 1a).

Recall that we were interested not only in determining whether RM system use influenced the quantity of caregiver talk available to the children but also the quality of caregiver talk.¹³ Therefore, we executed human coding of the audio recordings from the nine families, and found that caregivers produced the same amount of child-directed speech when using and when not using the RM system. Specifically, 57 percent of caregiver talk produced during a typical weekend at home was child-directed in nature (see Fig. 1b), and 12 percent of this child-directed talk was produced from a considerable distance away from the child. Thus, this 12 percent of child-directed speech produced at a relatively far distance from the child reflects some high-quality caregiver talk that would likely only be heard by the child while using an RM system.

Finally, we sought to determine if RM system use influenced caregiver-child communication, such as child responsiveness.¹⁴ Specifically, audio samples from LENA recorders were manually coded to quantify the frequency of verbal repetitions and alerting phrases caregivers utilized in communicating with their children. These caregiver phrases were characterized as intentional repetitions, casual or informal repetitions, or other utterances intended to capture their child's attention (e.g., “Hey Julie! Come here!”). Results revealed significant between-condition differences for all categories of caregiver communication examined in this study. That is, on average, when using an RM system, caregivers produced 67 percent fewer verbal clarifying behaviors per sample than when not using an RM system,¹⁰ as presented in Figure 2. This reduction in the caregiver's repetition and alerting phrases was interpreted as an index of increased child responsiveness while wearing an RM system.

DISCUSSION

These results offer confirmation of prior parental reports of advantages to using RM systems in the homes of children with hearing loss. The use of RM system technology in the home is likely to increase children's access to caregivers’ clear, linguistic input during verbal interactions, even from a distance.¹² In addition, providing children with hearing loss access to 12 percent more child-directed speech through RM system use could increase the amount of quality language available in their home environments.¹³

Furthermore, the reduction in caregivers’ verbal repetitions and alerting phrases when using RM systems to communicate with their children might have encouraged caregivers to talk more from a distance.¹² In other words, the use of RM systems might result in caregivers talking more from a distance because of the decreased need to repeat themselves as frequently as when they were not using an RM system. Collectively, our findings suggest that RM system use in home settings results in enhanced child attentiveness and engagement in daily activities and family dialogues, thereby easing communication. Moreover, the findings suggest that children have access to a greater amount of caregiver talk (including child-directed speech) when using this technology; thus, potentially promoting language development. These findings support the recommendation of using RM system technology at home for young children with hearing loss.