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- Karlberg, Mikael, et al.
(författare)
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Asymmetric optokinetic after-nystagmus induced by active or passive sustained head rotations
- 1996
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Ingår i: Acta Oto-Laryngologica. - 1651-2251. ; 116:5, s. 647-651
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Tidskriftsartikel (refereegranskat)abstract
- Asymmetric vestibular function affects optokinetic after-nystagmus (OKAN) in man, but little is known about the involvement of cervical proprioception in the visual-vestibular interaction reflected as OKAN. We studied the effect of asymmetric cervical proprioception induced by active maximal, or passive 70 degrees sustained horizontal head rotations on OKAN in 16 healthy subjects. We evoked optokinetic nystagmus (OKN) by means of a whole-field optokinetic drum rotated at a velocity of 90 degrees/s for 60 s. Following left- and right-beating OKN, we recorded OKAN in complete darkness for 60 s by DC electro-oculography. Both passively and actively sustained head rotations significantly reduced the intensity of OKAN beating in the direction opposite to the head rotation, while OKAN beating in the direction of the head rotation remained unchanged. This resulted in significant asymmetry between OKAN beating in the direction of the head rotation vs. that in the opposite direction. The findings show that in normal subjects neck proprioception converges with visual and vestibular signals and affects subcortical OKN. Asymmetric neck proprioception from neck disorders may be hypothesized to induce dizziness or vertigo in situations where OKN is evoked.
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| 4. |
- Karlberg, Mikael, et al.
(författare)
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Dizziness of Suspected Cervical Origin Distinguished by Posturographic Assessment of Human Postural Dynamics
- 1996
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Ingår i: Journal of Vestibular Research. - 1878-6464. ; 6:1, s. 37-47
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Tidskriftsartikel (refereegranskat)abstract
- Useful clinical tests are lacking for the controversial entity "cervical vertigo". In earlier studies patients assumed to suffer from cervical vertigo or dizziness manifested disturbed postural control as compared to healthy subjects, but were hard to distinguish from patients with other balance disorders. Using posturography in which stance was perturbed by a vibratory stimulus applied towards the calf muscles, we studied 16 consecutive patients with recent onset of neck pain and concomitant complaints of vertigo or dizziness, but normal findings at otoneurological examination and electronystagmography; 18 patients with recent vestibular neuritis; and 17 healthy subjects. We performed system identification of a model of the control of upright human stance, using the vibratory stimulus as input and the recorded body sway as output. According to values for the three normalized parameters of the transfer function of the model (i.e., swiftness, stiffness, and damping), cervical vertigo patients were distinguished both from healthy subjects (P < 0.001), and from vestibular neuritis patients (P < 0.001). It was also possible to distinguish the vestibular neuritis group from the group of healthy subjects (P < 0.01). The results show disturbed postural control in patients with cervical vertigo to differ from that in patients with recent vestibular neuritis, and indicate posturographic assessment of human posture dynamics to be a possible future tool for use in diagnosing cervical vertigo.
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- Persson, Liselott, et al.
(författare)
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Effects of different treatments on postural performance in patients with cervical root compression. A randomized prospective study assessing the importance of the neck in postural control
- 1996
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Ingår i: Journal of Vestibular Research. - 1878-6464. ; 6:6, s. 439-453
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Tidskriftsartikel (refereegranskat)abstract
- Patients with cervical root compression were used as a "model" to investigate the possible importance of neck disorders and cervical sensory information in postural control. We assessed postural performance with posturography before and after treatment in 71 consecutive patients with MRI-verified cervical root compression without medullary compression. The patients were randomized to surgery (n = 22), physiotherapy (n = 24) or treatment with cervical collars (n = 25). There were no differences in postural performance or pain intensity between the groups before treatment. After treatment, the surgery group manifested significant improved postural performance and reduced neck pain scores, as compared to the two conservative treatment groups, and their postural performance had improved to the same level manifested by healthy controls. The conservative treatment groups manifested no consistent significant changes in postural performance or pain scores. Decreased muscular tension due to reduction of cervical pain after surgery and normalization of cervical proprioception are suggested as possible explanations of the improved postural control.
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