From the Guidelines
The hearing arc in development refers to the sequence of auditory development in infants and children, beginning with the ability to detect sounds, then discriminate between different sounds, and finally comprehend and produce language. This developmental progression starts before birth, as fetuses can hear sounds from about 20 weeks gestation, and continues through childhood. The hearing arc includes milestones such as:
- startling to loud noises in newborns
- turning toward familiar voices at 3-4 months
- babbling at 6 months
- and understanding simple words around 12 months. This development is critical for language acquisition and social communication, as noted in the 2007 position statement on principles and guidelines for early hearing detection and intervention programs 1. The process relies on both intact hearing structures and appropriate auditory stimulation from the environment. Parents can support this development by talking, reading, and singing to their children regularly, creating a language-rich environment that fosters communication skills, especially in cases where children may have hearing loss due to congenital cytomegalovirus (cCMV) 1. Any concerns about a child's hearing or auditory development should prompt immediate evaluation, as early intervention for hearing issues significantly improves outcomes, and the use of well-fit hearing technology, such as hearing aids or cochlear implants, can provide auditory access and support language development 1. The hearing arc represents the foundation upon which more complex communication skills are built throughout childhood, and its importance is highlighted in guidelines for early hearing detection and intervention programs 1.
From the Research
Auditory Development
The development of the auditory system is a complex process that involves changes in the peripheral and central nervous system along the auditory pathways 2. This process occurs naturally and in response to stimulation, and it can last for decades.
Key Features of Auditory Development
- The auditory system constructs a perceptual space that takes information from objects and groups, segregates sounds, and provides meaning and access to communication tools such as language 2.
- Auditory signals are processed in a series of analysis stages, from peripheral to central, and coding of information has been studied for features of sound, including frequency, intensity, loudness, and location 2.
- The ability of the auditory system to adapt in response to novel stimuli is a key feature of development throughout the nervous system, known as neural plasticity 2.
Factors Influencing Auditory Development
- The absence of early and prolonged acoustic stimulation can delay neuronal maturation, affecting the central auditory nervous system and leading to atypical development 3.
- Non-auditory changes, such as attention, memory, and cognition, play an important role in auditory development 2.
- Exposure to noise during the developmental period can have a significant impact on the function of the auditory system, and can lead to persistent impairments in auditory function 4.
Stages of Auditory Development
- The peripheral auditory system is structurally and functionally adult-like at birth, while the central auditory system exhibits progressive anatomical and physiologic changes until early adulthood 3.
- The development of auditory functions can be divided into several stages, including the embryonic period, the perinatal period, early childhood, and later childhood 5.
- Each stage is characterized by specific anatomical and physiological changes, and is influenced by a combination of genetic and environmental factors 5.