Meditation
Marcia Montenegro: “…Eastern and New-Age influences in our culture, the word meditation has come to mean a technique to enter another state of consciousness, to go beyond thinking, or to realize spiri­tual enlightenment. We cannot read these techniques and purposes into the Biblical word translated as meditation which originates from several different Hebrew words. The contexts of these words indicate an active pondering, thinking and learning, neither a technique nor a disengagement from the mind.
Winter 2005 MCOI Journal www.midwestoutreach.org

Breath Prayers
Richard Foster: "Christians ... have developed two fundamental expressions of Unceasing Prayer. The first ... is usually called aspiratory prayer or breath prayer. The most famous of the breath prayers is the Jesus Prayer. It is also possible to discover your own individual breath prayer.... Begin praying your breath prayer as often as possible."
Prayer: Finding the Heart's True Home, p. 122

Mantra
Ray Yungen: “Since mantras are central to New Age meditation, it is important to understand a proper definition of the word. The translation from Sanskrit is man, meaning to think and tra, meaning to be liberated from. Thus, the word literally means to escape from thought. By repeating the mantra, either out loud or silently, the word or phrase begins to lose any meaning it once had. The conscious thinking process is gradually tuned out until an altered state of consciousness is achieved.” http://www.lighthousetrailsresearch.com/meditationexcerptbyray.htm

Marcia Montenegro: “In Hinduism, Tibetan Buddhism, Transcendental Meditation, and sometimes in New-Age meditation, a word—called a man­tra—is given to the meditator to repeat. This is often the name of a deity, or sometimes a phrase meaning, “I am That,” “Not this, not that,” or simply, “I am.” The purpose of this mantra is self-purifi­cation, and to become open to spiritual truths.”
Winter 2005 MCOI Journal www.midwestoutreach.org

Gary Thomas: “Choose a word (Jesus or Father, for example) as a focus for contemplative prayer. Repeat the word silently in your mind for a set amount of time (say, twenty minutes) until your heart seems to be repeating the word by itself, just as naturally and involuntarily as breathing. But centering prayer is a contemplative act in which you don’t do anything; you’re simply resting in the presence of God.” Sacred Pathways, p. 185

Altered state/Alpha state
Richard Foster: "If you feel we live in a purely physical universe, you will view meditation as a good way to obtain a consistent alpha brain wave pattern" Celebration of Discipline, p.

Dr. Lee Warren: "Mystical states of consciousness happen in the alpha state ... The Alpha State also occurs voluntarily during light hypnosis, meditation, biofeedback, day dreaming, hypnogogic and hypnapompic states." , B.A., D.D.

Laurie Cabot: "The science of witchcraft is based upon our ability to enter altered states of consciousness we call "alpha"... This is a state associated with relaxation, meditation and dreaming...In alpha the mind opens up to non ordinary forms of communication...Here we also experience out-of-body sensations and psychokinesis and receive mystical, visionary information" Power Of the Witch, Delta Books, 1989

"Chanting or meditating silently on mantras helps one to attain an altered state of consciousness ..."
From an online encyclopedia of mysticism and the occult

True Self
Thomas Keating: “God and our true Self are not separate. Though we are not God, God and our true Self are the same thing.” Open Mind, Open Heart, p. 127.

Thomas Merton: “ex­ternal, everyday self….fabrication… our true self….is not easy to find. It is hidden in obscurity and ‘nothingness,’ at the center, where we are in direct depen­dence on God.”, Contemplative Prayer, p. 70.

Desert Fathers
The first appearance of something approximating contemplative prayer arises in the 4th century writings of the monk St. John Cassian, who wrote of a practice he learned from the Desert Fathers (specifically from Isaac). Cassian's writings remained influential until the medieval era, when monastic practice shifted from a mystical orientation to scholasticism. http://en.wikipedia.org/wiki/Centering_prayer

Centering Prayer is drawn from ancient prayer prac­tices of the Christian contemplative heritage, notably the Fathers and Mothers of the Desert, Lectio Divina, (praying the scriptures), The Cloud of Unknowing, St. John of the Cross and St. Teresa of Avila.
www.contemplativeoutreach.org