Why then, for this patient, is this prognosis wrong in terms of speech understanding in quiet and noisy situations ?
Professor J.C. LAFON answers that question in his explanation of how the auditory integration list was developed: « … having young children among my patients, I encountered severe cases of spatial distortions that could only originate from speech identification difficulties, as tonal was normal and no damage had been detected in the ear. Incidentally, I then noticed that those distortions would come up more easily and to a higher extend in noisy situations. That fact sounded interested to me, as it could help distinguish between what should be assigned to cochlea and what should be interpreted as speech discrimination impairment. Allthere was to do was to perform a comparative measurement of two elements from a wordlist, in silence, and of two others, with a noisy background. Noise intensities were selected so that noise was almost as loud as speech, both measurements being performed at a same intensity: similar acoustic intensities would overcome the effects of cochlea impairments, since this was a comparative measurement. I had chosen a high level, 90 dB, in order to set the message at a higher level than the hearing treshold in cases of heraing loss. This measurement could thus be performed on deaf as well as hearing patients. »(1) Continuer la lecture de « LAFON 50A THE PRIMARY HEARING (road to language) part 10 »