Falling (sensation)
Encyclopedia
A sensation
of falling occurs when the labyrinth or vestibular apparatus, a system of fluid-filled passages in the inner ear
, detects changes in acceleration. This sensation can occur when a person begins to fall, resulting in a sudden increase in acceleration from 0.0 m/s2 to 9.8 m/s2. However, once the body is in free fall
(for example, during skydiving), there is no falling sensation. Even though velocity continues to increase, the downward acceleration due to gravity remains constant and does not produce a sensation of falling.
The vestibular apparatus also detects spatial orientation with respect to visual input. A similar sensation of falling can be induced when the eyes detect rapid apparent motion with respect to the environment. This system enables us to keep our balance by signalling when a physical correction is necessary. Some medical conditions, known as balance disorder
s, also induce the sensation of falling. In the early stages of sleep
, a falling sensation may be perceived in connection with a hypnic jerk
, sometimes awaking the sleeper abruptly.
Sense
Senses are physiological capacities of organisms that provide inputs for perception. The senses and their operation, classification, and theory are overlapping topics studied by a variety of fields, most notably neuroscience, cognitive psychology , and philosophy of perception...
of falling occurs when the labyrinth or vestibular apparatus, a system of fluid-filled passages in the inner ear
Ear
The ear is the organ that detects sound. It not only receives sound, but also aids in balance and body position. The ear is part of the auditory system....
, detects changes in acceleration. This sensation can occur when a person begins to fall, resulting in a sudden increase in acceleration from 0.0 m/s2 to 9.8 m/s2. However, once the body is in free fall
Free fall
Free fall is any motion of a body where gravity is the only force acting upon it, at least initially. These conditions produce an inertial trajectory so long as gravity remains the only force. Since this definition does not specify velocity, it also applies to objects initially moving upward...
(for example, during skydiving), there is no falling sensation. Even though velocity continues to increase, the downward acceleration due to gravity remains constant and does not produce a sensation of falling.
The vestibular apparatus also detects spatial orientation with respect to visual input. A similar sensation of falling can be induced when the eyes detect rapid apparent motion with respect to the environment. This system enables us to keep our balance by signalling when a physical correction is necessary. Some medical conditions, known as balance disorder
Balance disorder
A balance disorder is a disturbance that causes an individual to feel unsteady, for example when standing or walking. It may be accompanied by feelings of giddiness or wooziness, or having a sensation of movement, spinning, or floating...
s, also induce the sensation of falling. In the early stages of sleep
Hypnagogia
Hypnagogia is the transitional state between wakefulness and sleep , originally coined in adjectival form as "hypnagogic" by Alfred Maury....
, a falling sensation may be perceived in connection with a hypnic jerk
Hypnic jerk
A hypnic jerk, hypnagogic jerk, sleep start, or night start, is an involuntary myoclonic twitch which occurs during hypnagogia, just as a person is beginning to fall asleep, often causing them to awaken suddenly. Physically, hypnic jerks resemble the "jump" experienced by a person when...
, sometimes awaking the sleeper abruptly.