To quote Prof. J.C. LAFON:
« The exact timing of the onset of deafness is crucial for the future of the child.
What is already assimilated when deafness arises remains both as a neurosensory organisation triggered by an acoustic excitation, and as some psychophysiological mechanisms, provided that other sensory pathways allow their continuation. For instance, the notion of depth – in which the acoustic aspect plays an important role in one year old-toddlers – is switched to the visual perception of perspective as part of a residual conditioned behaviour: the sight both recollects auditory signals and replaces them. However, perceptions that rely mostly and inherently on auditory signals – such as articulated speech supported by verbal speech – are much more fragile.
Prior birth, one can hardly assess the consequences of the timing of the onset of deafness, as determining this moment is complicated – except in case of rubella or other obvious diseases. In general, deafness caused by illnesses during the foetal life are not as severe as those occurring during the first few months after birth; its consequences on the neural system structure do not seem too severe. As for a so-called ‘gained memory’, this is just another fantasy about the mother-foetus relationship, in which everyone tend to project their own affectivity. I do not think it could be of major importance, on a specificity point of view, as the memory function that would be involved in this relationship is very unstable. This is more about the elaboration of the auditory system rather than a particular psychological relationship.
At birth, deafness affects a system whose innate reflexes have been in operation for a while although their specific effects did not have time to develop, just like elementary reflexes. It is the case of developed auditory reflexes that did not have time to achieve their final purpose. Beside anatomical differences found specifically in those children, based on statistical analysis – e.g. a decrease in skull circumference – no major differences have been found on an educational point of view: indeed, numerous other factors impact the development of a child’s personality and allow those with less capabilities to make a better use of them.
Before one year old, babies display acquired psychophysiological mechanisms, i.e. the new-born shows a more advanced affective relationship, a better understanding of its surrounding, a control of the voice and tunes… All this, provided that the parents manage to maintain these acquired but fragile mechanisms through the stimulation of other sensory pathways.
From one year old, although the major speech and verbal language capacities tend to disappear, so many functions and information have been acquired that there will always be some left: not necessarily immediately after they occurred, but rather in the long term. Hearing devices are efficient on a developed system, with better symbolisation capacities. Indeed, reports show that group 2 and group 3 severely death students who pursue their studies beyond A-levels are often suffering from a deafness that developed during the earliest age, just as group 1 severe deafness or severe, congenital deafness.
At the age of three, deafness and its educational consequences have a different, stronger impact. Some acquired mechanisms that are perfectly developed tend to be employed less often, the most elaborated parts of which even tend to disappear. The social and affective consequences of deafness, such as a feeling of losing their personalities and a social and affective isolation play a key role in the issues children are facing at this stage. Wearing hearing devices -equipment is usually provided almost immediately (and should be in all cases), does compensate some of these issues. However, very strong feelings of unfairness and frustration remain and do require a targeted management of the child’s emotions – without being overprotective nor causing a rupture – down to all aspects of everyday life. In a reported case of severe, bilateral, rubella deafness, closing the eyes at night was so isolating from the surrounding world – and from the parents in particular – that the affected child also suffered from sleeplessness. It took months to overcome this feeling of complete abandon and isolation. Within a few years, considerable speech deterioration and language regression were observed, all the more so as the onset of deafness occurred at an early stage and that speech therapy was not initiated immediately.
From five years old, the major issue is learning how to read. What remains of oral signals must be associated with written signs as soon as possible in order to maintain relevant mechanisms of memory fixation. At that age, the language development is at a sufficiently advanced stage to ensure that deafness will not jeopardise the child’s level of abstraction and symbolism. Speech, on the other hand, requires a thorough management, as the control of the automatic – and well established – mechanisms involved does rely on hearing.
From eight years old, deafness is almost similar to acquired deafness in adults, provided that the educational management allows the continuation of a regular curriculum in the same social and affective environments as before »(1).
(1) Prof. J.C. LAFON « hearing-impaired children » pp. 106-107.