A common concern reported by parents at the Paediatric Audiology Department is: “I think my son has a hearing problem because I always have to call him many times. His teacher noticed the same behavior at school”. The child is then referred for a hearing test. However, the result confirms that his hearing is normal, and the parents, understandably, feel frustrated for not getting answers.
The answer might be related to differences between hearing sensitivity and listening. Hearing tests are designed to test the sense of hearing or the simple ability to detect sounds, the so-called hearing sensitivity. Babies are born with this ability as it relies on the peripheral part of the auditory system, the part that is functionally mature shortly after birth (Moore, 2002). To test this sense and detect a possible hearing loss, a hearing test is performed in an acoustically isolated environment through simple tasks that require minimum thinking (low cognitive demand) to avoid interferences. In addition, the test is adapted to be as child-friendly as possible; the child is conditioned to do some activity every time he hears sounds. Thus, he waits attentively for those sounds to complete the given task.
Most of the time, the situations reported by parents are more complex than the one described above in regard to different aspects. Firstly, they might consist of acoustically challenging conditions due to the presence of competing sounds or background noise. Those situations often occur at school, where several children usually speak simultaneously. The ability to successfully hear in those situations relies not only on the absence of a hearing loss but also on more complex auditory skills such as speech in noise perception and spatial processing skills. Unlike hearing sensitivity, those skills are not fully mature at birth. In fact, they gradually develop during childhood (Moore, 2015). For instance, performance in speech in noise perception tests improves from 5 to 12 years old (Wilson et al., 2010; Myhrum et al., 2016; Murphy et al., 2019), probably due to the gradual maturation of the binaural processing combined with the development of language and cognitive skills.
Attention also plays an important role in listening. For instance, selective auditory attention, which is related to the ability to prioritize stimuli, selecting the relevant one while suppressing irrelevant distractors (background noise), is required in those situations where background noise is unpredictable. This skill is another one that is not fully developed until the age of 11 years, approximately (Jones et al., 2015). Sustained attention is also relevant. A typical example is story time or “carpet time” at school, when the child is asked to pay attention to a story or any other auditory message during a prolonged period of time. Sustained attention also develops significantly until approximately ten years old (Betts et al, 2006).
Concerns regarding hearing in children should be primarily investigated through a hearing assessment to rule out any possible issue involving hearing sensitivity. A normal result might indicate problems in developing those listening skills, with symptoms mirroring the symptoms presented by children with a hearing loss.
Those listening skills can be assessed from 7 years old through an Auditory Processing Assessment, which is an in-depth hearing assessment using tests that simulate those specific challenging situations in which the child struggles to hear. This assessment is suggested when the child is suspected of having a Developmental Auditory Processing Disorder, condition mainly characterized by problems in processing speech and non-speech sounds in the presence of normal hearing sensitivity.
References:
Betts J, McKay J, Maruff P, Anderson V. The development of sustained attention in children: the effect of age and task load. Child Neuropsychol. 2006 Jun;12(3):205-21
Moore DR. (2002). Auditory development and the role of experience, British Medical Bulletin. 63 (1):171–181.
Moore DR. (2015). Sources of pathology underlying listening disorders in children. Int J Psychophysiol. 95(2):125-34
Murphy CFB, Hashim E, Dillon H, Bamiou DE. (2019). British children's performance on the listening in spatialised noise-sentences test (LISN-S). Int J Audiol. 58(11):754-760.
Myhrum M., Tvete O. E., Heldahl M. G., Moen I., Soli S. D. (2016). The Norwegian hearing in noise test for children. Ear Hear. 37 80–92.
Wilson R. H., Farmer N. M., Gandhi A., Shelburne E., Weaver J. (2010). Normative data for the words-in-noise test for 6-to 12-year-old children. J. Speech Lang. Hear Res. 53 1111–1121.
Jones PR, Moore DR, Amitay S. Development of auditory selective attention: why children struggle to hear in noisy environments. Dev Psychol. 2015 Mar;51(3):353-69.