To answer this question, we offer you an excerpt from the book "Why Mozart?".
"The listening pedagogy thus implemented uses sound material that contains either the mother's voice or music. And that music is always Mozart. Of course, I have experimented with everything that can be recorded acoustically: noises, musical messages, classical or modern, traditional or contemporary. I have also tried to integrate music from other continents, especially from the Far East, India and Africa. The results concerning the effects of music on the body and the psyche have never reached, in terms of dynamism, what Mozart brings us. This does not mean that I have given up any investigation, because every time an unknown piece falls into my hands, I submit it to experimentation.
Thus, Mozart remains almost alone in the competition throughout the process undertaken in the treatment of deficiencies in listening, oral or written language, spoken or sung voice. His music is, in my opinion, one of the universals. It affects everyone and everywhere."
"To live, to vibrate, Mozart was especially gifted. He was ready to lead others, to take them to where only the beautiful, the transcendent, the joy of life exists."