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Fundamental research on electrical stimulation of the auditory pathways resulted in the Multiple Channel Cochlear Implant, a device which provides understanding of speech to severely-toprofoundly deaf people. The device, a miniaturized receiverstimulator with multiple electrodes fed with power and speech data through two separate aerials was first implanted in a patient in 1978 as a prototype, and since 1982, was commercially produced by Cochlear Limited, Australia. Speech processing is based on the discovery that the sensation at each electrode is "vowel-like". Initially, the second formant was coded as a place of stimulation, the sound pressure was coded as a current level, and the voicing frequency as a pulse rate. Further research showed that there were progressively better open-set word and sentence scores for the extraction of the first formant in addition to the second formant (the F0/F1/F2 processor), the addition of high fixed filter outputs (MULTIPEAK) and then finally 6 to 8 maximal filter outputs at low rates (SPEAK) and high rates (ACE). All the frequencies were coded on a place basis. World trials completed for the US FDA on late-deafened adults in 1985 and in 1990 on children from two years to 17 years proved that a 22-channel cochlear implant was safe and effective in enabling them to understand speech both with and without lip-reading.