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PubMedDate not supplied

[Giant cell arteritis, bilateral anterior ischemic optic neuropathy and anticardiolipin antibodies].

CLINICAL CASE: We report a case of giant cell arteritis (GCA) that developed acute bilateral amaurosis secondary to anterior ischemic optic neuropathy (AION), without other symptoms and with a normal erythrocyte sedimentation rate (ESR). Physical examination revealed painless and pulseless temporal arteries, ophthalmoscopic findings were blurring of margins, hyperaemia and elevation of both optic discs. Visual acuity was limited to hand motion perception and light-darkness discrimination. Six months before of this syndrome, the patient was diagnosed of polymyalgia rheumatica and was maintained asymptomatic with 6 mg/day of deflazacort. Temporal artery biopsy was diagnostic. An elevated IgG type anticardiolipin antibodies (ACA) rate was detected in serum. The remaining laboratory studies were normal. CONCLUSIONS: In old people with uni or bilateral acute visual loss, even with normal erythrocyte sedimentation rate and without other symptoms associated, it is necessary to have a high index of suspicion in order to detect giant cell arteritis. This can facilitate an early diagnosis and immediate initiation of treatment with high doses of corticosteroids. An elevated level of IgG type anticardiolipin antibodies may be a risk factor to thrombotic complications, as anterior ischemic optic neuropathy, in patients with giant cell arteritis.

Acute Disease↗
PubMed2000

The effects of scopolamine and cyclizine on visual-vestibular interaction in humans.

The aim of the present study was to investigate the effects of scopolamine (1.5 mg, transdermal patch) and cyclizine (50 mg tablet), at the doses usually used for the relief of motion sickness, on postural sway, optokinetic nystagmus (OKN) and circularvection (CV) in humans, using a within-subjects, double-blind, placebo-controlled design. Scopolamine and cyclizine were found to have no significant suppressive effect on these aspects of visual-vestibular interaction. Postural sway and CV were not significantly affected by either drug treatment; OKN SPV was significantly increased (p < 0.05), although OKN amplitude and frequency were unaffected. These results suggest that scopolamine and cyclizine, at doses used for the relief of motion sickness, may have minimal suppressive effects on these aspects of visual-vestibular interaction.

Administration, Cutaneous↗
PubMed1975

Developmental changes in the understanding of implied motion in two-dimensional pictures.

The power of various pictorial movement cues in eliciting a reading of movement was studied to determine the relationship between the ease with which a picture is interpreted and the degree to which the picture retains the structure of reality. Movement was indicated in 2 ways: pictorial conventions indicated movement by lines, blurs, and vibration marks; and pictorial postures indicated movement by figures which were isomorphic with the postures involved in real movement. Preschoolers, first graders, sixth graders, and college students were asked to label and sort pictures of human figures as "moving" or "still". Members of the 2 young groups did not classify pictures with conventional cues as "moving" as often as they did pictures with postural cues. Members of the 2 older groups classified both types of pictures as "moving". Since postural cues for movement are recognized at an earlier age than conventional cues, those that are more similar to reality may be easier to understand.

Adult↗
PubMed1975

[Responses of squirrel visual cortex neurons to patterned visual stimuli].

The responses of visual cortical neurons to patterned visual stimuli were studied in squirrel Sciurus vulgaris. The direction selective, orientation-selective and non-selective neurons were observed. Most direction-selective and non-selective neurons were sensitive to high speeds of stimulus movement--hundreds deg/s. The direction-selective neurons exhibited their selectivity at such high speeds in spite of the short time of the stimulus movement through the receptive field. Orientation-selective neurons (with simple or complex receptive fields) were sensitive to lower speeds of the stimulus movement (tens deg/s). Some mechanisms of the properties described are discussed.

Animals↗
PubMed1976

Physiological effects induced by antiorthostatic hypokinesia.

The main purpose of the present investigation was to reproduce some physiological reactions in the sensory system which are similar to those observed during the first day of the adaptation to weightlessness. This was achieved by a 5-day bed rest experiment during which the test subjects were kept in the antiorthostatic position at angles of 0 degrees, -4 degrees, -8 degrees, -12 degrees. Our investigations allowed simulation of the acute stage of adaptation to weightlessness and assessment of gravity-induced blood redistribution in the development of the above physiological reactions.

Adaptation, Physiological↗
PubMed2003

Optokinetic drum tilt hastens the onset of vection-induced motion sickness.

BACKGROUND: Under optokinetic drum conditions, a stationary participant views the patterned interior of a rotating drum. Quickly, most participants perceive illusory self-rotation in the direction opposite to the drum's true rotation (vection). It has been documented that up to 60% of participants experience motion sickness-like symptoms under optokinetic conditions perhaps because of conflicting sensory information from the visual and vestibular systems. METHODS: Keeping rotation speed constant (10 RPM), drum tilt relative to the axis of rotation was systematically manipulated (0 degrees, 5 degrees, 10 degrees), producing a wobble effect. Overall well-being and eight motion sickness symptoms were assessed every 2 min using subjective scales. RESULTS: Participants reported 1) a complex type of circular vection that included a "wobble" or "sway" component and 2) a quicker onset of motion sickness-like symptoms as tilt increased. CONCLUSION: In a tilted drum, the vestibular system correctly indicates that the participant is stationary while the visual system indicates a complex type of self-rotation. This type of sensory conflict is more severe than what takes place under typical optokinetic drum conditions (no tilt). Results suggest that as visual/vestibular sensory conflict increases, so does the speed at which motion sickness symptoms occur.

Humans↗
PubMed2003

Eye movement, vection, and motion sickness with foveal and peripheral vision.

BACKGROUND: Both motion sickness and the illusion of self-motion (i.e., vection) can be induced by moving visual scenes. The results of a previous study imply that motion sickness is primarily dependent on visual motion in foveal vision while vection is primarily dependent on motion in peripheral vision. HYPOTHESIS: It was hypothesized that similar motion sickness would be produced when tracking a single moving dot and a full screen of moving dots, but that vection would be greater when tracking multiple moving dots. METHOD: Sixteen subjects viewed moving images presented on a virtual reality head-mounted display. In one condition a single dot moved from left to right at 27 degrees x s(-1) over a distance of 18 degrees before returning instantly to its starting point. This motion was repeated continuously. In a second condition, five horizontal rows of dots, each 18 degrees apart, moved continuously across the screen at 27 degrees x s(-1); subjects were instructed to track each dot in the central row as it passed. RESULTS: In both conditions, there were nystagmic eye movements with an approximate amplitude of 18 degrees at 27 degrees x s(-1). Vection differed significantly between the two conditions, with more vection in the condition with five rows of dots. Subjects experienced motion sickness symptoms with both the single moving dot and the five rows of dots, with no significant difference in sickness between the two conditions. Subject ratings of motion sickness and vection were not correlated with each other in either of the two conditions. CONCLUSIONS: Motion sickness and vection can vary independently. Vection appears to be influenced by peripheral vision, as there was an increase in vection with full-field stimulation. Motion sickness induced by moving visual scenes may be influenced by foveal visual stimulation or by eye movements, as these were the same in both conditions.

Eye Movements↗
PubMed1992

The influence of age on susceptibility to motion sickness in monkeys.

A longitudinal study on the effects of age on the susceptibility to motion sickness in the squirrel monkey was carried out over a 10-year period (1982 to 1991). The typical life span of squirrel monkeys is 15 years. Ten mature male squirrel monkeys of the Bolivian subspecies were found to be susceptible to motion sickness induced by a combination of vertical oscillation at 0.5 Hz and rotation in the horizontal plane at 25 rotations per minute (RPM) in a visually unrestricted environment. Signs of motion sickness were quantified according to a rating scale based on Graybiel's diagnostic criteria. Latency to vomiting/retching and severity of sickness obtained from year 1 (baseline), 3, 5, 7 and 10 were subjected to repeated-measures design analysis. There were no significant differences in the susceptibility level (as measured by latency to vomiting/retching and cumulative sickness scores) in the monkeys throughout the 10-year period. The habituation to 7 consecutive daily exposures remained the same throughout the same period. We conclude that, in the squirrel monkeys from maturity to near the end of their life span, there is no change in susceptibility to motion sickness with aging.

Aging↗
PubMed2003

[Effects of microgravity on human cognitive function in space flight].

In researches of space flight, studies on the effects of microgravity on cognitive function were relatively few. This paper reviews recent progress on this topic. It was shown that under the condition of microgravity, spatial orientation, motion perception and early process of object recognition were impaired to a certain degree. Capability of muscle movement and coordination was lowered, while higher cognitive functions, such as logic reasoning task, the speed and accuracy of short-term memory retrieval were less affected by microgravity. But long-term memory tasks and performance in which attention processes were needed (e.g., tracking task, selective response task), were impaired during space flight or under simulated weightlessness condition.

Cognition↗
PubMed1992

The effects of perceived motion on sound-source lateralization.

Lateralization of dichotic click pairs differing in time of onset was studied under conditions of angular acceleration, optokinetic stimulation, and gaze fixation. Data obtained from 20 subjects with normal hearing indicate poorer left-right judgment performance for small time differences, as well as shifts in subjective simultaneity, for all experimental conditions relative to control conditions. In addition, response times increased for the experimental conditions. The results suggest that real or apparent motion may affect an individual's ability to process one of the major cues for sound-source localization--binaural time difference--under conditions similar to those encountered in vehicular motion.

Acceleration↗
PubMed2004

Sopite symptoms in the optokinetic drum.

UNLABELLED: Sopite syndrome is a disturbance caused by motion characterized by drowsiness and mood changes that may occur without the classic symptoms of motion sickness. Because sopite symptoms are often subtle, it is important to assess for their presence, and to distinguish true sopite symptoms from changes in mood and drowsiness that are due to non-motion related factors such as fatigue and boredom. We compared sopite symptoms in the optokinetic drum (OKD) with symptoms in a control condition in which the drum's motion cues were removed. METHODS: There were 48 Introductory Psychology students who were randomly assigned to 1 of 2 groups: the rotating stripes group (RS) sat inside a drum lined with black and white stripes. The drum rotated at 5 rpm. The control group (Ctrl) sat inside the same drum without stripes or rotation. All participants completed the Positive and Negative Affect Scale (PANAS), the Motion Sickness Assessment Questionnaire (MSAQ), and the Epworth Sleepiness Scale (ESS) at pre- and post-drum exposures. RESULTS: The RS, but not the Ctrl, showed increases on all four MSAQ subscales (gastric, peripheral, central, sopite). The groups showed equivalent decreases in positive and negative affect. These findings show that some sopite-related symptoms were due specifically to the motion stimuli, while others could be attributed to non-motion aspects of the experimental situation. DISCUSSION: The findings have implications for the use of control conditions in the study of sopite syndrome, and for methods of assessing the changes in mood and drowsiness that are the cardinal symptoms of sopite.

Adolescent↗
PubMed2004

Vestibular coriolis effect differences modeled with three-dimensional linear-angular interactions.

The vestibular coriolis (or "cross-coupling") effect is traditionally explained by cross-coupled angular vectors, which, however, do not explain the differences in perceptual disturbance under different acceleration conditions. For example, during head roll tilt in a rotating chair, the magnitude of perceptual disturbance is affected by a number of factors, including acceleration or deceleration of the chair rotation or a zero-g environment. Therefore, it has been suggested that linear-angular interactions play a role. The present research investigated whether these perceptual differences and others involving linear coriolis accelerations could be explained under one common framework: the laws of motion in three dimensions, which include all linear-angular interactions among all six components of motion (three angular and three linear). The results show that the three-dimensional laws of motion predict the differences in perceptual disturbance. No special properties of the vestibular system or nervous system are required. In addition, simulations were performed with angular, linear, and tilt time constants inserted into the model, giving the same predictions. Three-dimensional graphics were used to highlight the manner in which linear-angular interaction causes perceptual disturbance, and a crucial component is the Stretch Factor, which measures the "unexpected" linear component.

Algorithms↗
PubMedDate not supplied

[Results of 13 hypoglosso-facial anastomoses].

BACKGROUND AND PURPOSE: Facial nerve paralysis significantly decreases the quality of life in patients after skull base tumors surgery. There are different options for surgical repair of the nerve. One of the most effective methods is the anastomosis of the distal trunk of the facial nerve with the proximal trunk of the hypoglossal nerve or with hypoglossal loop. MATERIAL AND METHODS: Thirteen hypoglosso-facial anastomoses had been performed in our department between 1999 and 2003. In all patients the facial nerve paralysis was due to the surgery in its proximity. In one case the patient suffered from petroclival chordoma, in one case ameloblastoma, one was with petroclival meningioma and the rest of cases were after vestibular schwannoma. The follow-up period lasted from 6 months to three years. The final result was expressed in House-Brackmann scale (HB) describing facial muscle strength. RESULTS: In two cases there was no improvement (HB 6), in two cases barely perceptible motion (HB 5), in five obvious weekness with disfiguring assymetry (HB 4) and in four obvious but not disfiguring dysfunction (HB 3). There was only one postoperative complication haematoma at the place of anastomosis requiring evacuation. CONCLUSION: Hypoglosso-facial anastomosis remains one of the most important techniques of the reanimation of the paralysed face. Its efficacy is limited, but it is a relatively safe procedure.

Anastomosis, Surgical↗
PubMed2006

Rotation velocity change and motion sickness in an optokinetic drum.

BACKGROUND: Stationary subjects who view the interior of an optokinetic drum often experience motion sickness (MS) symptoms, perhaps because visual and vestibular sensory inputs are in conflict. It was predicted that intermittently changing drum rotation velocity would cause an increase in sensory conflict, and subsequently lead to more MS. Visual input indicating frequent changes in self-motion would not be consistent with vestibular input indicating no self-motion. When drum rotation is steady, visual and vestibular inputs are more likely to agree given that the vestibular organs only respond to change. METHODS: There were 12 individuals who participated in the experiment (7 men, 5 women, mean age = 24.0 yr). In two conditions subjects viewed the interior of an optokinetic drum that steadily rotated at either 5 RPM or 10 RPM. In a third condition drum velocity alternated every 30 s between 5 RPM and 10 RPM (5/10 RPM condition). In all conditions the subject's head was immobilized in the center of the drum that rotated on an Earth-vertical axis. Subjects completed the Simulator Sickness Questionnaire (SSQ) designed by Kennedy and colleagues both before a trial and after 4 min of drum viewing. A total SSQ score and three SSQ sub-scores (nausea, oculomotor, and disorientation) were obtained. RESULTS: Mean post-treatment total SSQ scores (mean = 41) were significantly the highest in the 5/10 RPM condition followed by the conditions of steady rotation velocity at 10 RPM (mean = 36) and 5 RPM (mean = 24). Likewise, mean nausea sub-scores were also the highest (mean = 24) in the 5/10 RPM condition followed by the 10 RPM condition (mean = 19) and the 5 RPM condition (mean = 11). CONCLUSIONS: These results support the hypothesis that a conflict between sensed and expected effects of self-motion alone can lead to MS. Changing rotation velocity increases sensory conflict that in turn leads to more MS.

Adult↗