squatting down, walking up or down stairs, looking out of the window of a moving car or train). Vertigo is called height vertigo when the sensation of vertigo is triggered by heights. Height vertigo is caused by a conflict between vision, vestibular and somatosensory senses. This occurs when vestibular and somatosensory systems sense a body movement that is not detected by the eyes. More research indicate that this conflict leads to both motion sickness and anxiety. Causes
Traditionally, acrophobia has been attributed, like other phobias, to conditioning or a traumatic experience. Recent studies have cast doubt on this explanation. Individuals with acrophobia are found to be lacking in traumatic experiences. Nevertheless, this may be due to the failure to recall the experiences, as memory fades as time passes. To address the problems of self report and memory, a large cohort study with 1000 participants was conducted from birth; the results showed that participants with less fear of heights had more injuries because of falling.
As such, they also have a tendency to calcify and are highly vascularized.Meningiomata often are considered benign tumors that can be removed by surgery, but most recurrent meningiomata correspond to histologic benign tumors. The metabolic phenotype of these benign recurrent meningiomata indicated an aggressive metabolism resembling that observed for atypical meningioma. Diagnosis
Meningiomata are visualized readily with contrast CT, MRI with gadolinium, and arteriography, all attributed to the fact that meningiomata are extra-axial and vascularized. CSF protein levels are usually found to be elevated when lumbar puncture is used to obtain spinal fluid. On T1-weighted contrast-enhanced MRI, they may show a typical dural tail sign absent in some rare forms of meningiomas.Although the majority of meningiomata are benign, they may have malignant presentations. Classification of meningiomata are based upon the WHO classification system. Benign (Grade I) – (90%) – meningothelial, fibrous, transitional, psammomatous, angioblastic
Atypical (Grade II) – (7%) – chordoid, clear cell, atypical (includes brain invasion)
Anaplastic/malignant (Grade III) – (2%) – papillary, rhabdoid, anaplastic (most aggressive)In a 2008 review of the latter two categories, atypical and anaplastic-meningioma cases, the mean overall survival for atypical meningiomata was found to be 11.9 years vs. 3.3 years for anaplastic meningiomata. Mean relapse-free survival for atypical meningiomata was 11.5 years vs. 2.7 years for anaplastic meningiomata.Malignant anaplastic meningioma is aggressive. Although anaplastic meningioma has higher chances of distant metastasis than the other two types, the overall incidence of meningioma metastasis is only 0.18%; which is considered rare.