RESUMO
Seesaw nystagmus is characterized by cyclic eye movements with a conjugate torsional component and a dissociated vertical component. In the first half of the cycle, one eye elevates and intorts, whereas the other eye depresses and extorts. The pattern is reversed in the remaining half of the cycle. We describe a patient with a giant pituitary adenoma who developed pendular seesaw nystagmus. Disturbance in the visuovestibular system is postulated to contribute to this form of seesaw nystagmus. Lesions compressing the optic chiasm and the accessory optic system could interrupt the transmission of retinal error signals to the inferior olivary nucleus and the interstitial nucleus of Cajal, thus interfering with the adaptive mechanism of the vestibulo-ocular reflex and leading to pendular seesaw nystagmus.
Assuntos
Adenoma/fisiopatologia , Movimentos Oculares/fisiologia , Nistagmo Patológico/fisiopatologia , Neoplasias Hipofisárias/fisiopatologia , Tegmento Mesencefálico/fisiologia , Adenoma/diagnóstico por imagem , Eletronistagmografia , Feminino , Humanos , Imageamento por Ressonância Magnética , Pessoa de Meia-Idade , Nistagmo Patológico/diagnóstico , Neoplasias Hipofisárias/diagnóstico por imagemRESUMO
BACKGROUND/OBJECTIVE: Tai Chi Chuan (TCC) is suggested to have beneficial effects on the musculoskeletal system. The aim of this systematic review is to evaluate the evidence of the effect of TCC on bone mineral density (BMD) and its potential for prevention of osteoporosis. METHODS: A literature search was conducted using PubMed, Embase, and Cochrane databases from inception to January 2017. Randomized controlled studies, case-control trials, prospective cohort studies, and cross-sectional studies which evaluated the effect of TCC on BMD were selected without any subject or language restriction. RESULTS: Nine articles met the inclusion criteria, including seven randomized controlled trials (RCTs), one case-control trial (CCT), and one cross-sectional study, encompassing a total of 1222 participants. Five studies showed statistically significant improvements in BMD after TCC, three studies showed nonsignificant intergroup differences, and one study provided no statistical evaluation of results. The studies with nonsignificant results tended to have a shorter total duration of TCC practice. Apart from dual-energy X-ray absorptiometry (DXA), two studies additionally used peripheral quantitative computed tomography (pQCT) which showed statistically significant positive effects of TCC on preventing osteoporosis. CONCLUSION: TCC is beneficial to BMD and may be a cost-effective and preventive measure of osteoporosis. This beneficial effect is better observed in long-term TCC practice. THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE: The beneficial effect of TCC on BMD is suggested to be clinically translated to its potential for early rehabilitation and prevention of secondary osteoporosis in patients after surgical treatment of common osteoporotic fractures. The length of practicing TCC, the form and style of TCC, and the types of patient suitable for TCC are to be investigated in future studies.