| 1. |
- Boniver, R, et al.
(författare)
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Medico-legal in ORL
- 1988
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Ingår i: Acta Oto-Rhino-Laryngologica Belgica. - 0001-6497. ; 42:6, s. 722-771
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Tidskriftsartikel (refereegranskat)
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| 2. |
- Enbom, Håkan, et al.
(författare)
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Presentation of a posturographic test with loading of the proprioceptive system
- 1988
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Ingår i: Acta Oto-Laryngologica, Supplement. - 0365-5237. ; 455, s. 58-61
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Postural control is maintained by sensory feedback from visual, vestibular and somatosensory receptors. Recently several methods for evaluating postural control have been devised, utilizing an imposed perturbation. Most of these methods use stimuli which simultaneously affect more than one of the sensory feedback loops. In the present paper a posturographic technique is presented with specific loading of the proprioceptive system, using a computer controlled vibratory stimulus and computerized analysis of the results.
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| 3. |
- Juhola, M, et al.
(författare)
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An identification technique for the spike artefact of saccadic eye movements
- 1987
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Ingår i: Biological Cybernetics. - 0340-1200. ; 57:6, s. 20-415
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Tidskriftsartikel (refereegranskat)abstract
- Many subjects have a negative spike in the beginning of a saccade in electro-oculographic signals. The amplitude of the spike depends on the location of the electrodes. The spike distorts the saccades and causes errors in the parameters. The saccade spike can assist in the identification of small saccades. A syntactic technique based on formal languages and parsing is presented which looks for spikes from the electro-oculographic signal. For calculation of the algorithm, saccades from the photoelectric signal have been concurrently recorded and compared with the electro-oculographic signal.
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| 4. |
- Juhola, M, et al.
(författare)
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Detection of saccadic eye movements using a non-recursive adaptive digital filter
- 1985
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Ingår i: Computer Methods and Programs in Biomedicine. - 0169-2607. ; 21:2, s. 8-81
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Tidskriftsartikel (refereegranskat)abstract
- Saccadic eye movements provide important information about the neuron system at several levels. In recent years computer analysis of saccades has been adapted for use in clinical work. The most common detection methods do not always function without the user's control and aid. In the present paper a digital filter is described for the detection of saccades. This non-recursive filter unscrambles saccade data which has been collected during the execution of an algorithm. The method is suitable for use with microcomputers. The filter is adaptive. Two concise experiments using the method are described.
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| 5. |
- Magnusson, M, et al.
(författare)
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Clinical considerations concerning horizontal optokinetic nystagmus
- 1988
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Ingår i: Acta Oto-Laryngologica, Supplement. - 0365-5237. ; 455, s. 7-53
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- During recent decades a vast amount of literature concerning horizontal optokinetic nystagmus has emerged, regarding which--and especially as regards our own work--this report is intended to consider the clinical value of optokinetic nystagmus.
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| 6. |
- Magnusson, M, et al.
(författare)
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Dynamic Performance of Vibration Induced Anterior-Posterior Sway during Upright Posture in Normal Subjects
- 1989
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Ingår i: Acta Oto-Laryngologica. - : Informa UK Limited. - 1651-2251 .- 0001-6489. ; 468:S468, s. 227-230
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Tidskriftsartikel (refereegranskat)abstract
- Human postural control works as a dynamic feedback control system. The dynamic performance of postural control for anterior-posterior movements during upright posture are defined by three parameters. These parameters reflect the stiffness, the damping and the swiftness of a response to an induced perturbation. In the present study 23 normal subjects were investigated. Both with open and closed eyes, there was a negative correlation between swiftness and stiffness. With open eyes there was also a weak correlation between swiftness and damping. When the subjects were tested with open eyes there was a prominent and highly significant increase of stiffness and a reduction of swiftness of the responses. It was found that proprioceptive information from the calf muscles contributes in postural control of movements up to 1 Hz and visual information is important for movements up to 0.05 Hz. The present findings suggest that postural control changes dynamic strategies depending on the available sensory feedback.
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| 7. |
- Magnusson, M, et al.
(författare)
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Effect of alertness and visual attention on optokinetic nystagmus in humans
- 1985
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Ingår i: American Journal of Otolaryngology - Head and Neck Medicine and Surgery. - 0196-0709. ; 6:6, s. 25-419
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Tidskriftsartikel (refereegranskat)abstract
- The effect of alertness and visual attention on optokinetic nystagmus (OKN) and optokinetic after-nystagmus (OKAN) was studied in 20 volunteers. Electroencephalographic (EEG) activity was recorded over the occipital lobe. Exposure to sound and vibration caused a significant increase in the mean slow-phase velocity of OKN, whereas its maximum slow-phase velocity remained unaffected. Vibration tended to increase the mean slow-phase velocity of OKN more than sound did, though the difference was not statistically significant. Vibration also significantly increased the OKAN. When alpha rhythm appeared in the occipital EEG during OKN, the velocity of concurrent slow phases was reduced. However, the periods of alpha rhythm did not differ between the different stimulus conditions. The findings suggest that sound and vibration activate the subcortical optokinetic mechanism, thus causing an increase in the mean velocity of OKN. Abatement of visual attention is reflected in temporary reduction of OKN in conjunction with the appearance of alpha waves and is to be interpreted as transient quiescence of the cortical optokinetic mechanism.
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| 8. |
- Magnusson, M
(författare)
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Effect of alertness on the vestibulo-ocular reflex and on the slow rise in optokinetic nystagmus in rabbits
- 1986
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Ingår i: American Journal of Otolaryngology - Head and Neck Medicine and Surgery. - 0196-0709. ; 7:5, s. 9-353
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Tidskriftsartikel (refereegranskat)abstract
- The effect of alertness on the time constant of the vestibulo-ocular reflex (VOR) and the time constant of the slow rise of the optokinetic nystagmus (OKN) was studied in nine pigmented rabbits. When the rabbits were alerted by vibration, the time constant of the VOR was prolonged, and that of the slow rise in OKN was shortened, whereas the gain of VOR and OKN remained largely unaffected. These findings agree with the suggestion that the state of alertness affects the vestibular system by way of the so-called velocity storage mechanism.
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| 9. |
- Magnusson, M, et al.
(författare)
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Reduction of the time constant in the VOR as a protective mechanism in acute vestibular lesions
- 1989
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Ingår i: Acta Oto-Laryngologica, Supplement. - 0365-5237. ; 468, s. 32-329
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Fourteen patients with vestibular neuritis were examined at onset of symptoms and after one year. Postrotatory time constant and gain in the vestibulo-ocular reflex (VOR) were measured after rotation with a velocity step of 150 deg/s. There was no significant difference in gain towards the healthy side at onset of the disease compared to recordings after one year. The time constant towards the healthy side was significantly shorter at onset compared to measurements after one year. The results reflect the loss of unilateral vestibular function on the velocity storage mechanism, both in the acute situation and after compensation. The findings indicate that reduction of the time constant in the VOR is not only due to unilaterally vestibular impairment but it is also an effect of the generally reduced activity in the vestibular system after a lesion and may act as protective mechanism in acute vertigo.
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| 10. |
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