A hypnic jerk, hypnagogic jerk, sleep start, or night start, is a myoclonic twitch which occurs during hypnagogia, just as a person is beginning to fall asleep, often causing them to awaken suddenly for a moment. Physically, hypnic jerks resemble the "jump" experienced by a person when startled, often accompanied by a falling sensation. A higher occurrence is reported in people with irregular sleep schedules.
Famous quotes containing the word jerk:
“One farmer says to me, “You cannot live on vegetable food solely, for it furnishes nothing to make bones with;” and so he religiously devotes a part of his day to supplying his system with the raw material of bones; walking all the while he talks behind his oxen, which, with vegetable-made bones, jerk him and his lumbering plow along in spite of every obstacle.”
—Henry David Thoreau (1817–1862)