In the Netherlands, each year around 180 children are born with a permanent bilateral hearing loss (HL) and around 50% of them have a moderate hearing loss (MHL; Zoutenbier et al., 2016). Children with MHL have a loss in sound sensitivity between 40 and 70 decibel (dB) and often use hearing aids (HAs) to increase their access to sounds and speech. Despite the use of a HA, however, these children still encounter challenges while growing up in a sound-dominated society. Yet, we do not have a complete picture of the acoustic environments and linguistic input for this specific group of children, as most research is focused on children with severe and profound HL, often using cochlear implants (CIs). As a result, the knowledge on the potential challenges and potential solutions to these challenges remain limited for this group of children with MHL.
Few recent studies that have been performed indicated that children with MHL are at risk for language difficulties (Hammer & Coene, 2016; Tomblin et al., 2015) and that the consistent use of HAs and high-quality linguistic input by caregivers could positively affect the language outcomes (McCreery et al., 2015; Ambrose et al., 2015). Hence, in order to fully participate in our hearing society, it is important that the daily environments in which children grow up are acoustic-friendly and that the linguistic development is stimulated to their full potential. The first years of life are crucial for language learning and especially the home environment of young children is relevant (Golinkhof et al., 2019). Therefore, we need to start from early on and in the home environment of children with MHL to promote their linguistic development (Dirks, 2018).
In the proposed project, we will focus on the understudied MHL group at this sensitive age range for linguistic development (0-4 years of age). Since these children cannot yet fully communicate, we will use the newest technology combined with caregivers’ reports to gain a clear and comprehensive overview of the amount of time young children with MHL spend in optimal and suboptimal situations for language learning. We will not only assess this in the home environment but also in other daily environments such as day care.
Based on the model of “inconsistent access” (Moeller & Tomblin, 2015) and the expansion of this model by Dirks (2018), we distinguish three key factors that are essential for promoting linguistic development in young children with MHL: 1) hearing technology, 2) the auditory environment and 3) caregivers’ linguistic input. The first factor, the use of hearing technology (e.g., HA), increases children’s access to linguistic input and its consistent use can be effective in promoting linguistic development in children with MHL (McCreery et al., 2015). However, considering the second factor, despite the use of HAs children with MHL still have difficulties in understanding speech in noisy environments (playground, daycare, but also the home environment; Benítez-Barrera et al., 2020). Therefore, children should be optimally equipped to function in auditory-challenging environments and the environments should be modified to make them as acoustically accessible as possible. The third factor concerns caregivers’ talking with children that should be of a high amount and high-quality, since the exposure to a larger number of words and conversational turns is related to better linguistic outcomes (Ambrose et al., 2015; Golinkhof et al., 2019).
In this project we will use; 1) new HA software allowing for daily remote datalogging (amount of time a HA is used during a specific day) and auditory scene analysis (e.g., amount of time a child is in noisy situations), 2) LENA (Language ENvironment Analysis), a small device attached to a child’s clothes providing all-day recordings of children’s auditory and linguistic environments. Hence, LENA allows for both qualitative analyses of the linguistic input and for automated analyses on the number of words a child is exposed to, how many conversational turns they had during the day and an overview of the different acoustic scenes (noise or no-noise situations).
The above described technology allows us to combine daily ecological measures concerning the use of hearing technology, the auditory environment and the linguistic input to children with MHL in one and the same study, which has not been done before. Collecting these measures simultaneously enables us to relate the obtained measures (between themselves) to the child’s language outcomes, for example, identifying acoustically poor or supportive environments for children and identifying which tools could be used reliably (such as a smartphone app). Hence, the outcomes of this project will be relevant for caregivers, clinicians, family-centered early interventionists, day care centers and society in general, and will lead to clinical and practical tools for family-centered intervention programs for children with MHL.