Acrophobia
Encyclopedia
Acrophobia is an extreme
Extremism
Extremism is any ideology or political act far outside the perceived political center of a society; or otherwise claimed to violate common moral standards...

 or irrational fear
Fear
Fear is a distressing negative sensation induced by a perceived threat. It is a basic survival mechanism occurring in response to a specific stimulus, such as pain or the threat of danger...

 of height
Height
Height is the measurement of vertical distance, but has two meanings in common use. It can either indicate how "tall" something is, or how "high up" it is. For example "The height of the building is 50 m" or "The height of the airplane is 10,000 m"...

s. It belongs to a category of specific phobia
Specific phobia
A specific phobia is a generic term for any kind of anxiety disorder that amounts to an unreasonable or irrational fear related to exposure to specific objects or situations...

s, called space and motion discomfort that share both similar etiology and options for treatment.

Most people experience a degree of natural fear when exposed to heights, especially if there is little or no protection. Those who are confident in such situations may be said to have a head for heights.

Acrophobia sufferers can experience a panic attack
Panic attack
Panic attacks are periods of intense fear or apprehension that are of sudden onset and of relatively brief duration. Panic attacks usually begin abruptly, reach a peak within 10 minutes, and subside over the next several hours...

 in a high place and become too agitated to get themselves down safely. Between 2 and 5 percent of the general population suffer from acrophobia, with twice as many women affected than men.

"Vertigo
Vertigo (medical)
Vertigo is a type of dizziness, where there is a feeling of motion when one is stationary. The symptoms are due to a dysfunction of the vestibular system in the inner ear...

" is often used (incorrectly) to describe a fear of heights, but it is more accurately a spinning sensation that occurs when one is not actually spinning. It can be triggered by looking down from a high place, or by looking straight up at a high place or tall object, but this alone does not describe vertigo. True vertigo can be triggered by almost any type of movement (e.g. standing up, sitting down, walking) or change in visual perspective (e.g. squatting down, walking up or down stairs, looking out of the window of a moving car or train). Vertigo is qualified as height vertigo when referring to dizziness triggered by heights.

Causes

Traditionally, acrophobia has been attributed, like other phobias, to conditioning
Classical conditioning
Classical conditioning is a form of conditioning that was first demonstrated by Ivan Pavlov...

 or a traumatic
Psychological trauma
Psychological trauma is a type of damage to the psyche that occurs as a result of a traumatic event...

 experience involving heights. Recent studies have cast doubt on this explanation; fear of falling, along with fear of loud noises
Ligyrophobia
Phonophobia is a fear of loud sounds. It can also mean a fear of voices, or a fear of one's own voice.For example, listening to a CD that starts with a minute of silence and then suddenly goes into loud rock music would be extremely startling for most people, assuming they had no prior knowledge...

, is one of the most commonly suggested inborn or non-associative fears. The newer non-association theory is that fear of heights is an evolved adaptation to a world where falls posed a significant danger. The degree of fear varies and the term phobia is reserved for those at the extreme end of the spectrum. It has been argued by researchers that fear of heights is an instinct found in many mammals, including domestic animals and human beings. Experiments using visual cliff
Visual cliff
The visual cliff apparatus was created by psychologists Eleanor J. Gibson and R.D. Walk to investigate depth perception in human and animal species. This apparatus allowed them to experimentally adjust the optical and tactical stimuli associated with a simulated cliff while protecting the subjects...

s have shown human infant
Infant
A newborn or baby is the very young offspring of a human or other mammal. A newborn is an infant who is within hours, days, or up to a few weeks from birth. In medical contexts, newborn or neonate refers to an infant in the first 28 days after birth...

s and toddler
Toddler
A toddler is a young child, usually defined as being between the ages of one and three. Registered nurse, midwife and author, Robin Barker, states 'Any time from eight months onwards your baby will begin to realise he is a separate person from you...

s, as well as other animals of various ages, to be reluctant in venturing onto a glass floor with a view of a few meters of apparent fall-space below it. While an innate cautiousness around heights is helpful for survival, an extreme fear can interfere with the activities of everyday life, such as climbing up a flight of stairs
Stairs
-People:* Scott Kannberg , guitarist of Pavement* A. Edison Stairs , New Brunswick politician* Denis Stairs , engineer, Montreal businessman* Ernest W. Stairs , New Brunswick politician...

 or a ladder
Ladder
A ladder is a vertical or inclined set of rungs or steps. There are two types: rigid ladders that can be leaned against a vertical surface such as a wall, and rope ladders that are hung from the top. The vertical members of a rigid ladder are called stringers or stiles . Rigid ladders are usually...

 or even standing on a chair.

A possible contributing factor is dysfunction in maintaining balance. In this case the anxiety is both well founded and secondary. The human balance system integrates proprioceptive, vestibular
Vestibular system
The vestibular system, which contributes to balance in most mammals and to the sense of spatial orientation, is the sensory system that provides the leading contribution about movement and sense of balance. Together with the cochlea, a part of the auditory system, it constitutes the labyrinth of...

 and nearby visual cues to reckon position and motion. As height increases, visual cues recede and balance becomes poorer even in normal people. However, most people respond by shifting to more reliance on the proprioceptive and vestibular
Vestibular system
The vestibular system, which contributes to balance in most mammals and to the sense of spatial orientation, is the sensory system that provides the leading contribution about movement and sense of balance. Together with the cochlea, a part of the auditory system, it constitutes the labyrinth of...

 branches of the equilibrium system.

An acrophobic, on the other hand, continues to over-rely on visual signals whether because of inadequate vestibular function or incorrect strategy. Locomotion at a high elevation requires more than normal visual processing. The visual cortex becomes overloaded resulting in confusion. Some proponents of the alternative view of acrophobia warn that it may be ill-advised to encourage acrophobics to expose themselves to height without first resolving the vestibular issues. Research is underway at several clinics.

Treatment

There have been a number of promising studies into using virtual reality as a treatment for acrophobia.

External links

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