| 1. |
- Hydén, Dag, et al.
(author)
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Broad frequency rotatory testing
- 1988
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In: Acta oto-laryngologica. Supplementum. - : Informa Healthcare. - 0365-5237 .- 1651-2464 .- 0001-6489 .- 1651-2251. ; 105:s455, s. 48-52
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Journal article (peer-reviewed)abstract
- The method of broad-frequency-band rotatory testing with results from normal subjects and patients with peripheral uni- and bilateral loss as well as central vestibular disorders are reviewed. The following conclusions are drawn: adequate testing of the vestibulo-ocular reflex including side detection of unilateral loss in light or in darkness can only be done with either random or high-frequency (2.5–3 Hz) sinusoidal stimulation. Measurements of compensatory eye movements at lower frequencies where vestibular and non-vestibular signals interact are of interest for central vestibular diagnosis. A decreased ability to suppress vestibular nystagmus is not an uncommon finding in patients with large acoustic neuromas or pathology in the brainstem or cerebellum.
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| 2. |
- Hydén, Dag, et al.
(author)
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Quantification of compensatory eye movements in light and darkness
- 1984
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In: Acta oto-laryngologica. Supplementum. - : Informa Healthcare. - 0365-5237 .- 1651-2464 .- 0001-6489 .- 1651-2251. ; 96:s406, s. 209-211
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Journal article (peer-reviewed)abstract
- A broad frequency-band rotatory test has been used to quantify compensatory eye movements in 13 healthy subjects during light and darkness conditions. Eye movements were recorded by EOG. Head movements were recorded either by a potentiometer attached to the chair's axis of rotation or by an angular rate sensor attached to a bite-board. Gain and phase values between eye and head velocity were calculated. A systematic error in the higher frequency range is introduced in the results by assuming head movement equal to chair movement. Different instructions in the dark can alter the gain values at lower frequencies (up to 2 Hz) during sinusoidal stimulation. During pseudorandom stimulation no such differences can be obtained. During all test conditions with the rate sensor the gain values approach unity at about 3 Hz.
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| 3. |
- Hydén, Dag, et al.
(author)
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Visual suppression tests in acoustic neuroma patients
- 1989
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In: Acta oto-laryngologica. Supplementum. - : Informa UK Limited. - 0365-5237 .- 1651-2464 .- 0001-6489 .- 1651-2251. ; 108:s468, s. 349-351
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Journal article (peer-reviewed)abstract
- Fifty-five patients with a unilateral acoustic neuroma were investigated preoperatively with visual suppression tests during rotatory oscillation and caloric irrigation. During a sinusoidal oscillation, 29% of the patients showed a reduced suppression compared to 9% during pseudo-random oscillation and 11 % in the caloric test. In the sinusoidal and caloric tests the majority of the patients with deficient suppression had large or medium-sized tumors. In a few patients with small tumors, pathology was observed in both sinusoidal and randomized tests, presumably as a sign of unconcentration. The study shows that the sinusoidal visual suppression test and to a lesser degree suppression during caloric irrigation are of value for identification of brainstem-cerebellum compression of acoustic neuromas.
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| 4. |
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| 5. |
- Larsby, Birgitta
(author)
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Pursuit eye movements. Methodological aspects
- 1988
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In: Acta oto-laryngologica. Supplementum. - : Informa Healthcare. - 0365-5237 .- 1651-2464 .- 0001-6489 .- 1651-2251. ; 105:s455, s. 24-27
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Journal article (peer-reviewed)abstract
- A reduced smooth pursuit ability is often a sign of central vestibular pathology. Methodological aspects of stimulation, recording of eye movements and analysis of results in the evaluation of the smooth pursuit function are discussed. A method for evaluation of the smooth pursuit function over a broad frequency range is presented and the effects of target predictability and age on recorded parameters are shown.
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| 6. |
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| 7. |
- Nilsson, P, et al.
(author)
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Impulse noise and continuous noise of equivalent frequency spectrum and total sound energy
- 1987
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In: Acta Oto-Laryngologica. Supplement. - : Informa UK Limited. - 0365-5237 .- 0001-6489 .- 1651-2251. ; 104:S 441, s. 45-58
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Journal article (peer-reviewed)abstract
- It has been proposed that impulse noise and continuous noise affect the inner ear differently and investigations have found impulse noise to be harmful to both the inner hair cells and the outer hair cells. Scanning electron microscopy and non-standard methods for statistical analysis have facilitated the evaluation of different types of morphological changes after exposure to various kinds of noise. Morphological differences were compared in groups of guinea pigs exposed to either impulse noise or continuous noise of equivalent duration, spectral content and energy. Functionally, the groups also showed similar threshold elevations. In order to separate the two groups, subtle hair cell changes were recorded and evaluated either alone, in combination with each other or with hair cell loss. It was found that both the inner hair cells and the outer hair cells were affected differently by impulse noise than by continuous noise even though the auditory thresholds were similar.
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| 8. |
- 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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| 9. |
- Rydmarker, S, et al.
(author)
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Impulse noise of different durations
- 1987
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In: Acta Oto-Laryngologica. Supplement. - : Informa UK Limited. - 0365-5237 .- 0001-6489 .- 1651-2251. ; 104:S 441, s. 3-23
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Journal article (peer-reviewed)abstract
- This paper describes a comparison between auditory threshold elevations and morphological cochlear changes evaluated with scanning electron microscopy in order to identify cochlear defects in guinea pigs exposed to impulse noise of varying durations. There was a significant difference in the auditory threshold shifts between animals exposed for 3 and 12 hours. Hair cell loss is generally used as a morphological correlate to noise-induced hearing loss. Minor stereocilia changes, quantified with non-standard statistical methods have been used as a complement. Morphologically, it was not possible to separate cochleas exposed to impulse noise for 3 and 12 hours when only lost hair cells were evaluated. Quantitative evaluation of subtle morphological changes are valuable in the correlation of noise-induced hearing loss with morphologic changes.
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| 10. |
- Schalén, L, et al.
(author)
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Clinical aspects of eye tracking test
- 1988
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In: Acta Oto-Laryngologica, Supplement. - : Informa UK Limited. - 0365-5237 .- 0001-6489 .- 1651-2251. ; 105:Suppl 455, s. 28-32
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Journal article (other academic/artistic)abstract
- The eye tracking test is today a well established part of clinical otoneurological examination. In the present paper some applications of the test in evaluating of the level of lesion within the vestibular system are reviewed.
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