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| 2. |
- Brantberg, K., et al.
(författare)
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Tilt suppression, OKAN, and head-shaking nystagmus at long-term follow-up after unilateral vestibular neurectomy
- 1996
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Ingår i: Journal of Vestibular Research-Equilibrium & Orientation. - 0957-4271 .- 1878-6464. ; 6:4, s. 235-241
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Tidskriftsartikel (refereegranskat)abstract
- The functional status of the velocity storage mechanism was studied in patients at long-term follow-up (2 to 4 years) after unilateral vestibular neurectomy. The time constant of the vestibulo-ocular reflex (VORtc), the effect of head tilt on postrotatory nystagmus, optokinetic after-nystagmus (OKAN), and nystagmus after rapid head shaking were studied in 10 patients. In agreement with previous findings, VORtc was found to be short and most patients manifested OKAN, suggesting that unilateral peripheral vestibular loss is associated with a complete loss of storage within the the VOR but only a partial loss of velocity storage for visual input. However, at postrotatory head tilt the VOR time constant was further shortened, supposedly due to discharge of functioning velocity storage. Moreover, most patients manifested nystagmus after head shaking. These findings on tilt suppression and head-shaking nystagmus suggest that velocity storage within the VOR may function even in patients with complete unilateral vestibular lesions.
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| 3. |
- Brantberg, Krister, et al.
(författare)
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Vestibular evoked myogenic potentials in response to laterally directed skull taps
- 2002
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Ingår i: Journal of Vestibular Research-Equilibrium & Orientation. - 0957-4271 .- 1878-6464. ; 12:1, s. 35-45
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Tidskriftsartikel (refereegranskat)abstract
- In recent years it has been demonstrated that loud clicks generate short latency vestibular evoked myogenic potentials (VEMP). It has also been demonstrated that midline forehead skull tap stimulation evokes similar VEMP. In the present study, the influence of skull tap direction on VEMP was studied in 13 normal subjects and in five patients with unilateral vestibular loss. Gentle skull taps were delivered manually above each ear on the side of the skull. The muscular responses were recorded over both sternocleidomastoid muscles using skin electrodes. Among the normals, laterally directed skull taps evoked "coordinated contraction-relaxation responses", i.e. skull taps on one side evoked a negative-positive "inverted" VEMP on that side and a positive-negative "normal" VEMP on the other side. Among patients with unilateral vestibular function loss, skull taps above the lesioned ear evoked similar coordinated contraction-relaxation responses. However, skull taps above the healthy ear did not evoke that type of response. These findings suggest that laterally directed skull taps activate mainly the contralateral labyrinth.
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| 4. |
- Brantberg, Krister, et al.
(författare)
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Vestibular evoked myogenic potentials in response to skull taps for patients with vestibular neuritis
- 2003
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Ingår i: Journal of Vestibular Research-Equilibrium & Orientation. - 0957-4271 .- 1878-6464. ; 13:2-3, s. 121-130
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Tidskriftsartikel (refereegranskat)abstract
- In recent years it has been demonstrated that loud clicks generate short latency vestibular evoked myogenic potentials (VEMP). It has also been demonstrated that skull tap stimulation evokes similar VEMP. In the present study, the differences between the click-induced and the skull-tap induced VEMP were studied in 18 patients at onset of vestibular neuritis. Gentle skull taps were delivered manually above each ear on the side of the skull and on the forehead midline. The muscular responses were recorded over both sternocleidomastoid muscles using skin electrodes. Abnormal skull tap VEMP were found in the majority of the patients (10/18, 56%). However, only 4/18 (22%) showed asymmetry in the click-induced VEMP. The high percentage of abnormal skull tap VEMP might suggest that this response is not only dependent on the inferior division of the vestibular nerve, because the inferior division of this nerve is usually spared in vestibular neuritis. Moreover, the patients with abnormal skull tap VEMP differed from those with normal VEMP in their settings of the subjective visual horizontal with static head tilt in the roll plane. This might suggest that skull tap VEMP are (also) related to utricular function.
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| 5. |
- Ledin, T., et al.
(författare)
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Dynamic posturography in assessment of polyneuropathic disease
- 1991
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Ingår i: Journal of Vestibular Research-Equilibrium & Orientation. - 0957-4271 .- 1878-6464. ; 1:2, s. 123-128
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Tidskriftsartikel (refereegranskat)abstract
- Twenty-eight patients with polyneuropathy aged 49-82 years (mean 67 years) were assessed by dynamic posturography. The patient group was compared to a control group comprising 29 healthy controls aged 70 through 75 years (mean 73 years). The dynamic posturography method comprises a sensory organization part in which the platform and visual surround are either stable or referenced to the patient's sway; furthermore, the eyes are open or closed. In a movement coordination part the platform makes active movements. In the sensory organization part of the dynamic posturography the patient group showed significantly lower equilibrium performance compared to the control group in the test conditions with absent vision, sway-referenced surrounding, and, finally, sway referenced platform and surrounding. In these conditions the influx of somatosensory information is of paramount importance for stable posture. In the movement coordination test, the patient group showed prolonged muscular response latencies in both forward and backward platform perturbations compared to the control group. It is concluded that dynamic posturography is a valuable diagnostic tool in assessment of the dynamic equilibrium performance in patients with polyneuropathy.
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| 6. |
- Ledin, T., et al.
(författare)
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Effects of balance training in elderly evaluated by clinical tests and dynamic posturography
- 1991
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Ingår i: Journal of Vestibular Research-Equilibrium & Orientation. - 0957-4271 .- 1878-6464. ; 1:2, s. 129-138
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Tidskriftsartikel (refereegranskat)abstract
- All persons aged 70 through 75 years (N = 457) in a Swedish community were invited to participate in a 9 week balance training study. Out of 55 interested subjects, 15 were chosen at random for a study group; 15 matched controls were also selected. Before and after the investigation period the balance function was assessed by clinical balance tests and dynamic posturography. In the clinical balance tests, the training group significantly improved their balance standing on one leg with eyes closed as well as standing on one leg while shaking the head; they also walked 15 m back and forth faster. In the dynamic posturography the training group significantly improved their equilibrium scores in the 3 most difficult test conditions. The results of the control group were unchanged except for one test condition in the dynamic posturography. The differences in one-leg standing with head shaking, walking 2 x 15 m, and the equilibrium score using sway-referenced platform in dynamic posturography were proved to be attributable to the training. The first investigation in all 29 subjects formed normative dynamic posturography data for the age group 70 through 75 years. The normative posturographic data of this age group differed from previously obtained data in the age groups 20 through 59 and 60 through 69 years. It is concluded that elderly may improve their balance by regular balance training exercises for as short a period as 9 weeks. This might prove to be of great value in improving balance and thereby preventing accidental falls and subsequent fractures in elderly.
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| 7. |
- Lindell, Ellen, 1979, et al.
(författare)
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Asking about dizziness when turning in bed predicts examination findings for benign paroxysmal positional vertigo
- 2018
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Ingår i: Journal of Vestibular Research: Equilibrium and Orientation. - 0957-4271 .- 1878-6464. ; 28:3-4, s. 339-347
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Benign paroxysmal positional vertigo (BPPV) is the single most common cause of vestibular vertigo and is characterised by short episodes of rotational vertigo precipitated by changes in head positions like lying down or turning in bed. OBJECTIVE: This study aims to assess useful questions when suspecting benign paroxysmal positional vertigo (BPPV) caused dizziness as well as identifying if a single question can be useful in identify or distinguish patients with BPPV from other dizziness aetiology. METHOD: A total of 149 patients admitted due to dizziness were included. Patients answered a questionnaire and were investigated for BPPV with diagnostic manoeuvres. RESULT: Two of the 15 questions were of diagnostic importance. Dizziness when laying down or turning in bed, increased likelihood of BPPV by an odds ratio (95% confidence interval) of 60 (7.47-481.70). Continuous dizziness duration as opposed to lasting seconds decreased likelihood of BPPV with an odds ratio of 0.06 (0.01-0.27). CONCLUSION: Vertiginous attacks by turning or laying down in bed together with dizziness <1 minute, are important questions and strongly related to BPPV. Such questions are important when taking a medical history and may help to early identify BPPV, also for non-medical staff, as well as reduce the need of further investigations.
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| 8. |
- Mendel, Barbro, et al.
(författare)
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Dizziness : a common, troublesome symptom but often treatable
- 2010
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Ingår i: Journal of Vestibular Research-Equilibrium & Orientation. - : IOS Press. - 0957-4271 .- 1878-6464. ; 20:5, s. 391-398
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To investigate the prevalence of self-rated dizziness/unsteadiness and health as well as to estimate the proportion of participants with peripheral vestibular disorders. Methods: Altogether, 2547 participants (66%) participated in an epidemiological cross-sectional study, including self-rated questions about dizziness/unsteadiness, concomitant auditory symptoms and self-rated general, psychosocial and mental health. Results: The overall prevalence of dizziness was 21% and higher among women (27%) than men (14%) (p < 0.001). Dizziness, provoked by the movement of lying-down (benign paroxysmal positional vertigo), was noted in 5% of the participants with the symptom occurring more often in women than in men (p < 0.001). Twenty-four percent of the men and 21% of the women with dizziness simultaneously experienced a sense of rotation and loss of hearing and tinnitus. Fifteen percent reported falls because of dizziness. Both men and women suffering from dizziness symptoms perceived worse self-rated health generally, psychosocially and mentally than those without symptoms of dizziness (p < 0.001). Conclusion: Dizziness-related symptoms are common in all age groups and may manifest worse self-rated health. About 50% of the participants had symptoms indicating origin of peripheral vestibular disorders. Self-rated questions seem capable of identifying patients for referral to clinical examinations and subsequently those who can be successfully treated.
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| 9. |
- Niklasson, Magnus, et al.
(författare)
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The influence of visual and somatosensory input on the vestibulo-oculomotor reflex of pigmented rats
- 1991
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Ingår i: Journal of Vestibular Research-Equilibrium & Orientation. - 0957-4271 .- 1878-6464. ; 1:3, s. 251-262
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Tidskriftsartikel (refereegranskat)abstract
- Eye movements were recorded in the pigmented rat during vestibular, optokinetic and combined visual-vestibular stimulation. The dominant time constant in pigmented rats, tested during angular vestibular stimulation in darkness, is about two times longer than the cupular time constant. The gain and the duration of nystagmus, achieved by angular vestibular stimulation, can be enhanced by visual impulses. This is most evident during an optokinetic temporonasal stimulation, but is also seen with a nasotemporal stimulation. A mere optokinetic monocular stimulation without a synchronous vestibular excitation causes nystagmus only when the stimuli has a temporonasal direction. The duration of nystagmus, achieved by angular vestibular stimulation, is prolonged by disturbances of the neck proprioceptive system. This is more evident during a simultaneous visual input than in darkness. The ability to cancel nystagmus during conflicting vestibular and optokinetic impulses is well developed in the pigmented rat.
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| 10. |
- Tribukait, Arne, et al.
(författare)
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Changes in the perceived head transversal plane and the subjective visual horizontal induced by Coriolis stimulation during gondola centrifugation
- 2006
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Ingår i: Journal of Vestibular Research-Equilibrium & Orientation. - 0957-4271 .- 1878-6464. ; 16:3, s. 105-116
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Tidskriftsartikel (refereegranskat)abstract
- For studying the influence of the vertical semicircular canals on spatial orientation in roll, the subjective visual horizontal (SVH) and the subjective transversal plane of the head (STP) were measured in a situation where the vertical canals sense a roll-velocity stimulus while the otolith organs persistently signal that the head is upright in roll. During gondola centrifugation (resultant gravitoinertial force vector 2.5 G, gondola inclination 66 degrees) subjects were exposed to controlled rotational head movements (angular speed 27 degrees/s, magnitude 40 degrees) about the yaw (body z-) axis, produced by means of a motor-driven helmet. This causes a roll-plane Coriolis stimulus to the canals, while the otoliths persistently sense upright head position in roll. The subjects reported intense sensations of rotation and tilt in the roll plane. This was reflected in tilts of both the SVH and STP. The initial tilt of the SVH was 13.0 +/- 9.7 degrees (mean +/- S.D., n=10). The STP was changed in the opposite direction. The initial tilt was 23.8 +/- 12.2 degrees (mean +/- S.D., n=5). The changes in the SVH and STP were not of equal magnitude. A few subjects who had almost no deviations in the SVH showed pronounced tilts of the STP. The time constant for exponential decay of the tilts of the SVH and STP was on average approximately 1 minute. These findings indicate that a difference in activity of the vertical canals in the right versus left ear may cause substantial tilts of the SVH even if there is no asymmetry in the activity of the otolith system. Further, the canal stimulus may induce a tilt of the fundamental egocentric frame of reference.
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