TAILIEUCHUNG - Chapter 022. Dizziness and Vertigo (Part 2)

Physiologic Vertigo This occurs in normal individuals when (1) the brain is confronted with an intersensory mismatch among the three stabilizing sensory systems; (2) the vestibular system is subjected to unfamiliar head movements to which it is unadapted, such as in seasickness; (3) unusual head/neck positions, such as the extreme extension when painting a ceiling; or (4) following a spin. Intersensory mismatch explains carsickness, height vertigo, and the visual vertigo most commonly experienced during motion picture chase scenes; in the latter, the visual sensation of environmental movement is unaccompanied by concomitant vestibular and somatosensory movement cues. Space sickness, a. | Chapter 022. Dizziness and Vertigo Part 2 Physiologic Vertigo This occurs in normal individuals when 1 the brain is confronted with an intersensory mismatch among the three stabilizing sensory systems 2 the vestibular system is subjected to unfamiliar head movements to which it is unadapted such as in seasickness 3 unusual head neck positions such as the extreme extension when painting a ceiling or 4 following a spin. Intersensory mismatch explains carsickness height vertigo and the visual vertigo most commonly experienced during motion picture chase scenes in the latter the visual sensation of environmental movement is unaccompanied by concomitant vestibular and somatosensory movement cues. Space sickness a frequent transient effect of active head movement in the weightless zero-gravity environment is another example of physiologic vertigo. Pathologic Vertigo This results from lesions of the visual somatosensory or vestibular systems. Visual vertigo is caused by new or incorrect eyeglasses or by the sudden onset of an extraocular muscle paresis with diplopia in either instance central nervous system CNS compensation rapidly counteracts the vertigo. Somatosensory vertigo rare in isolation is usually due to a peripheral neuropathy or myelopathy that reduces the sensory input necessary for central compensation when there is dysfunction of the vestibular or visual systems. The most common cause of pathologic vertigo is vestibular dysfunction involving either its end organ labyrinth nerve or central connections. The vertigo is associated with jerk nystagmus and is frequently accompanied by nausea postural unsteadiness and gait ataxia. Since vertigo increases with rapid head movements patients tend to hold their heads still. Labyrinthine Dysfunction This causes severe rotational or linear vertigo. When rotational the hallucination of movement whether of environment or self is directed away from the side of the lesion. The fast phases of nystagmus beat away from the .

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• Dizziness and Vertigo
• bệnh học và điều trị
• bài giảng bệnh học
• tài liệu học ngành y
• Harrisons Internal Medicine
• BMC Geriatrics
• Benign paroxysmal positional vertigo
• Retirement home
• Supine roll maneuvers
• Somatosensory disorders
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• Obstetrics
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• Preventing Morbidity
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