Acrophobia and visual height intolerance: advances in epidemiology and mechanisms - PMC
Metadata
- Author: Doreen Huppert,1,3 Max Wuehr,2 and Thomas Brandt1
- Full Title: Acrophobia and visual height intolerance: advances in epidemiology and mechanisms - PMC
- Category: articles
- URL: https://omnivore.app/me/1efa279a-18d5-4b8d-93ba-8056a538fd0b
Highlights
- Neurophysiological analyses of stance, gait, and eye movements revealed an anxious control of postural stability, which entails a co-contraction of anti-gravity muscles that causes a general stiffening of the whole body including the oculomotor apparatus. (View Highlight)
- Irrational anxiety plays a major role in the condition of acrophobia and visual height intolerance, which Balaban and Jacob [1] stated in their seminal historical article “Background and history of the interface between anxiety and vertigo”. This vertigo-balance-anxiety interface has been an integral component of medical literature since antiquity. (View Highlight)
- Increased postural threat, for instance while walking on a modestly elevated support surface in the laboratory, causes gait changes especially in older people. These changes are characterized by a reduced speed of walking, shorter steps, decreased cadence, and longer times in double support [42–44]. (View Highlight)
- This finding suggests, that alterations in sensorimotor balance control at heights are primarily elicited by fear and anxiety rather than by the visual height stimulus alone. (View Highlight)
- Body sway alterations as well as leg- and neck-muscle co-contraction increased with increasing subjective anxiety (View Highlight)
- In accordance with the above-described laboratory-based findings in healthy controls, this observation was explained as a fear-induced lowering of the threshold for sensorimotor balance reflexes accompanied by an increased stiffening of the complete postural control apparatus. (View Highlight)
- Taken together, experimental evidence on behavioral changes of gaze, balance, and locomotion control in susceptible individuals during exposure to real heights reveals a stiffening strategy that encompasses the whole anti-gravity musculoskeletal apparatus, including the ocular-motor apparatus. (View Highlight)
- These alterations can best be described by the common expression of being ‘scared stiff’ by fear of heights—a behavioral response that results in tonic immobility. (View Highlight)
- Accordingly, anxiety appears to be the critical psychopathological symptom that causes the typical, but not specific eye and body motor responses to height exposure in subjects with visual height intolerance. (View Highlight)
- Interestingly, they observed that the mere postural threat by the knowledge of danger rather than the actual perception of height was responsible for the switch to a cautious gait pattern. (View Highlight)
- Furthermore, changes in balance control and locomotion in individuals susceptible to visual height intolerance were shown to scale with the severity of subjectively perceived anxiety (View Highlight)
- A recent study in a comprehensive cohort of individuals with different degrees of susceptibility (insusceptible or susceptible up to acrophobic) further suggests that the intensity of perceived anxiety at heights and the extent of corresponding behavioral alterations is directly proportional (Wuehr et al. 2019). (View Highlight)
- Based on this evidence, a hypothetical cascade on emergence of symptoms during height exposure has been proposed [54]. Accordingly, (1) anxiety of falling off or falling down at heights triggers a vicious circle with a (2) co-contraction of anti-gravity muscles that results in (3) increased sensitivity of sensorimotor balance reflexes and a rigid regulation of body sway, which (4) aggravates subjective imbalance and in turn intensifies the initial anxiety [54] (Fig. 3). (View Highlight)
- This difference in height-dependency suggests a dissociation between sensorimotor and emotional reactions when being confronted with heights. (View Highlight)
- Visual height intolerance and acrophobia are characterized by a dissociation between subjective fear and objective danger of falling. (View Highlight)
- falling. Although the thus affected individuals are able to recognize this discrepancy, they can typically overcome inappropriate avoidance behavior only with difficulty. (View Highlight)
- Whereas there is broad evidence that repeated confrontation with real or virtual fear-inducing height stimuli can results in a rapid remission of anxiety and autonomic responses in afflicted individuals, recent studies indicate that threat-induced changes in balance regulation may largely persist across repeated exposures to heights [61, 66]. (View Highlight)
- Finally, while a wide range of therapies has been proven to be effective in the short term, therapeutic improvements do not persist in the long term in most cases [67]. (View Highlight)
New highlights added 2024-06-10 at 4:18 PM
- Visual height intolerance and acrophobia are characterized by a dissociation between subjective fear and objective danger of falling. Although the thus affected individuals are able to recognize this discrepancy, they can typically overcome inappropriate avoidance behavior only with difficulty. (View Highlight)
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Acrophobia and visual height intolerance: advances in epidemiology and mechanisms - PMC
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Highlights
New highlights added 2024-06-10 at 4:18 PM