| 1. |
- Juhola, M, et al.
(author)
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An identification technique for the spike artefact of saccadic eye movements
- 1987
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In: Biological Cybernetics. - 0340-1200. ; 57:6, s. 20-415
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Journal article (peer-reviewed)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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| 2. |
- Juhola, M, et al.
(author)
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Detection of saccadic eye movements using a non-recursive adaptive digital filter
- 1985
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In: Computer Methods and Programs in Biomedicine. - 0169-2607. ; 21:2, s. 8-81
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Journal article (peer-reviewed)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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| 3. |
- Magnusson, M, et al.
(author)
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Effect of alertness and visual attention on optokinetic nystagmus in humans
- 1985
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In: American Journal of Otolaryngology - Head and Neck Medicine and Surgery. - 0196-0709. ; 6:6, s. 25-419
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Journal article (peer-reviewed)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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| 4. |
- Pyykkö, I., et al.
(author)
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A reduction of vestibulo-visual integration during transdermally administered scopolamine and dimenhydrinate. A presentation of gain control theory in motion sickness
- 1984
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In: Acta Oto-Laryngologica, Supplement. - : Informa UK Limited. - 0365-5237 .- 0001-6489 .- 1651-2251. ; 406, s. 73-167
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Journal article (other academic/artistic)abstract
- The effect of transdermally administered scopolamine (TTS scopolamine) (release rate 5 micrograms/h) and dimenhydrinate (100 mg) was examined on optovestibular nystagmus in 16 volunteers in a randomized double-blind trial. A statistically significant decrease in the optokinetic part of nystagmus was observed during all treatments. Most profound reduction was found during treatment with two TTS scopolamine. The vestibular part was reduced by treatment with two TTS scopolamine, only. The results indicate that scopolamine and dimenhydrinate exert their effect in motion sickness by reducing the vestibular and visual influx and by partly inhibiting the integrative functioning of the vestibular nuclei. In their action, the motion sickness drugs seem to assist the cerebellum by diminishing impulses from various orientation reflexes in order to preserve the functional capacity of the central nervous system. Different symptoms in motion sickness seem to arise when the vestibular gain operates beyond the normal range of the cerebellar control mechanisms.
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| 5. |
- Schalén, L, et al.
(author)
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Intra-individual variation in oculomotor performance in man
- 1984
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In: Acta Oto-Laryngologica, Supplement. - : Informa UK Limited. - 0365-5237 .- 0001-6489 .- 1651-2251. ; 96:S406, s. 7-212
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Journal article (peer-reviewed)abstract
- Peak velocity of saccade, maximum velocity of smooth pursuit, and peak velocity of slow phase of vestibular and optovestibular nystagmus were measured three times daily on three separate days in 6 healthy subjects in order to estimate the intra-individual variation of the results of oculomotor tests. Analysis of variance revealed that the oculomotor performance of the individual subjects varied systematically, depending on whether the tests were performed in the morning, at noon, or late in the afternoon. In particular, the velocity of saccade displayed lowest values in the afternoon. The present results indicate that oculomotor performance may depend on the individual biological rhythm of fatigue; however, it is also possible that eye motor behaviour is coupled to an independent rhythm of motor activity. Circadian rhythmicity of oculomotor performance should be considered in follow-up studies and in examination of patients with reduced vigilance.
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