Contrary to general belief, 95% of children with hearing impairment have residual hearing, and with early detection and intervention, they can learn to listen and speak.
At birth, most of the neural circuitry is in place, but functional connections are awaiting stimulation. Within the first 2 years, a child has double the number of neural connections, as compared to an adult brain, and there are significant changes in behaviour and performance. The capacity of the brain to change with learning (stimulation) is plasticity.
Learning is " the ability to acquire new knowledge or skills through instruction or experience. Memory is the process by which that knowledge is retained over time" There are four critical 'windows of Learning' - Vision, Emotions, Speech and Language and Logic. The development of speech and language is interdependent on the other three windows' to reach its maximum potential.
The period of most dramatic plasticity is during the first two years of life, as the infant's brain becomes organized in response to its environment.
Recent research indicates that the critical period of 'Learning' starts from the 6th month of pregnancy, up to 2 years and therefore early diagnosis and intervention is essential. Children with significant hearing loss who receive hearing aids before the age of 6 months, and a cochlear implant between the age of 7 months- 1 year, can develop language skills similar to those children with normal hearing. Those who receive implants between 18-24 months of age, acquire only two thirds of language skills in comparison.
However, just by fitting hearing devices, the child will not develop listening skills and spoken language. Once the child is diagnosed with hearing loss, immediate audiological management and fitting of appropriate amplification devices i.e. Hearing Aids or a Cochlear Implant, along with skilled and effective Aural Habilitation is required.
In the first two years of life, the brain concentrates on the phonemes that make up syllables and words, and builds connections that allow us to recognise those sounds as words. If the child is not exposed to language during this time, either due to hearing impairment or lack of auditory stimuli, speech will not develop properly. Reduced auditory input adversely affects the developing auditory nervous system and can have harmful effects on social, emotional, cognitive and academic development, plus on a person's vocational and economic potential. Hearing Impairment should be recognized as early in life as possible, so that the remediation process can begin well in time to take advantage of the critical periods of plasticity of the brain.