RESUMO
The influence of spatial-selective attention on the direction of the optokinetic nystagmus (OKN) was investigated in normal humans. During horizontal optokinetic stimulation of the peripheral retina, the central visual field was neutralized by ambivalent stimulation. The results showed that the direction of the OKN was modulated by the direction of the attention. A central mechanism that processes the optic information according to spatial-selective attention is proposed.
Assuntos
Atenção/fisiologia , Percepção de Movimento/fisiologia , Nistagmo Fisiológico/fisiologia , Ilusões Ópticas/fisiologia , Orientação/fisiologia , Eletronistagmografia , Humanos , Estimulação Luminosa/instrumentação , Acompanhamento Ocular Uniforme/fisiologia , Retina/fisiologia , Vias Visuais/fisiologiaRESUMO
Ninety patients were studied who had been admitted to Dijkzigt Hospital in Rotterdam between January 1980 and April 1987 with subarachnoid haemorrhage (SAH) due to an aneurysm at or near the junction of the internal carotid artery with the posterior communicating artery (IC-PC). An evaluation was made of the early neuro-opthalmological symptoms and the mortality in patients with paresis of the oculomotor nerve (N.III). The importance of early recognition of the condition is emphasized and a prospective investigation of the early symptoms of SAH in ophthalmological practices in the Netherlands is proposed.
Assuntos
Oftalmopatias/etiologia , Aneurisma Intracraniano/complicações , Hemorragia Subaracnóidea/diagnóstico , Adulto , Idoso , Artéria Carótida Interna , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Hemorragia Subaracnóidea/etiologiaRESUMO
Optokinetic nystagmus (OKN) was studied in patients with central visual field defects. Apart from a classic OKN, an inverted nystagmus was observed in some cases. A prerequisite for eliciting this paradoxic OKN was that the attention of the subject was directed to the field defect. Although other factors seem to be co-determining, a central mechanism is thought to process the visual information according to spatial-selective attention.
Assuntos
Nistagmo Fisiológico , Campos Visuais , Adulto , Idoso , Eletroculografia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Transtornos da Visão/fisiopatologiaRESUMO
Electrophysiological studies showed that a patient with Aland eye disease had no misrouting of the optic pathways which is always found in all forms of albinism as a consequence of the retino-geniculate anomaly. Also the spontaneous and optokinetic nystagmus did not resemble that of the large majority of human albinos. The marked asymmetry found in this patient seems to be typical for humans with a defective development of foveal binocular vision. These findings are in agreement with clinical, nystagmographic and EM findings that Aland eye disease is distinct from the Nettleship-Falls type of X-linked ocular albinism. Furthermore, Aland eye disease is different from X-chromosomal congenital stationary night blindness with myopia by the fact that the scotopic functions are only moderately affected and there is no restriction of the peripheral photopic visual fields. In addition, there is latent nystagmus of extraocular type that appears also in female carriers. There is no ophthalmoplegia, there is a progression of the myopia and the dyschromatopsia is of secondary type.
Assuntos
Albinismo/genética , Ligação Genética , Cromossomo X , Adulto , Albinismo/complicações , Albinismo/fisiopatologia , Eletronistagmografia , Potenciais Evocados Visuais , Oftalmopatias/genética , Oftalmopatias/fisiopatologia , Fundo de Olho , Humanos , Masculino , Nistagmo Patológico/complicações , Nistagmo Patológico/genética , Nistagmo Patológico/fisiopatologia , Síndrome , Campos VisuaisRESUMO
In the last ten to fifteen years refinements in the registration techniques for ocular movements have allowed a more precise definition of nystagmus forms and have thus brought new insight into their pathophysiology. As a result we can distinguish four types of disturbances of the subsystem for the slow movements, which are fundamental to nystagmus. This and other discoveries also have consequences for the practical diagnostics of neuro-ophthalmological diseases. In this article, with the help of a simple practical scheme, extra attention will be given to the clinically relevant new information needed to make the diagnosis or differential diagnosis of conditions in which nystagmus is one of the most important signs.
Assuntos
Encefalopatias/complicações , Movimentos Oculares , Doenças do Labirinto/complicações , Nistagmo Patológico/diagnóstico , Adulto , Malformação de Arnold-Chiari/complicações , Astrocitoma/complicações , Criança , Pré-Escolar , Humanos , Neoplasias Hipotalâmicas/complicações , Lactente , Recém-Nascido , Miastenia Gravis/complicações , Neuroma Acústico/complicações , Nistagmo Patológico/etiologia , Nistagmo Patológico/fisiopatologiaAssuntos
Esclerose Múltipla/diagnóstico , Córtex Visual/fisiopatologia , Diagnóstico Diferencial , Potenciais Evocados , Paralisia Facial/diagnóstico , Feminino , Humanos , Masculino , Esclerose Múltipla/fisiopatologia , Doenças do Nervo Óptico/diagnóstico , Estimulação Luminosa/métodos , Tempo de Reação , Doenças do Nervo Vestibulococlear/diagnósticoRESUMO
In 33 methyl bromide users, slight electroencephalographic changes (in 10 subjects) and a small increase in serum transaminases were found which could be related to bromine concentration in blood. No relationship was found with subjective symptoms, general neurological examination or the results of serum protein electrophoresis.
