| 31. |
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| 32. |
- Johansson, Rolf, et al.
(författare)
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Discrimination between Patients with Acoustic Neuroma and with Peripheral Vestibular Lesion by Human Posture Dynamics
- 1994
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Ingår i: Acta Oto-Laryngologica. - : Informa UK Limited. - 1651-2251 .- 0001-6489. ; 114:3, s. 479-483
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Tidskriftsartikel (refereegranskat)abstract
- A group of normal subjects (n = 17) was compared with two groups of patients, either with vestibular neuritis (n = 18) or with acoustic neuroma (n = 35) by means of posturography when stance was perturbed with vibrators attached to the calf muscles. Dynamic control of human posture was quantified by means of system identification, and the characteristic parameters of swiftness, stiffness, and damping of a transfer function from vibration to force platform response were used for further comparison. Fisher linear discriminant analysis was used to distinguish sets of parameters characteristic of each disease. Hence it was possible to distinguish the vestibular neuritis group both from the normal group (p < 0.01), and from the patients with acoustic neuroma (p < 0.001). The normal group was characterized by a different postural performance, with higher swiftness and stability parameters (stiffness, damping) than those of the patient groups. These findings indicate that there are differences in the dynamic control of posture between the two patient categories, which may require the development of differentiated rehabilitation programs.
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| 33. |
- Johansson, Rolf, et al.
(författare)
-
Discrimination of Patients with Acoustic Neuroma and Peripheral Vestibular Lesions with Human Posture Dynamics
- 1995
-
Ingår i: Acta Oto-Laryngologica. - : Informa UK Limited. - 1651-2251 .- 0001-6489. ; 115:S520, s. 27-28
-
Tidskriftsartikel (refereegranskat)abstract
- A group of normal subjects (n = 17) was compared with groups of patients with a diagnosis of vestibular neuritis (n = 18), and acoustic neuromas (n = 35). Fisher linear discriminant analysis was applied to distinguish clusters of parameters characteristic for each disease. Hence it was possible to distinguish the vestibular neuritis patients from the normal group with statistical significance (p < 0.01). Also the patients with an acoustic neuroma could be distinguished from the normal subjects with statistical significance (p < 0.05).
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| 34. |
- Johansson, Rolf, et al.
(författare)
-
Multi-Stimulus Multi-Response Posturography
- 2001
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Ingår i: Mathematical Biosciences. - 0025-5564. ; 174:1, s. 41-59
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Tidskriftsartikel (refereegranskat)abstract
- In this study a method for the analysis of simultaneous multiple measurements of kinematics and stabilizing forces related to human postural dynamics is proposed. Each subject in a group of normal subjects (n=10) was tested with eyes-open and eyes-closed with simultaneous but uncorrelated vestibular and proprioceptive stimuli in order to investigate the contributions of individual sensory feedback loops. Statistical analysis was made by means of multi-input multi-output identification of a transfer function from stimuli to stabilizing forces of the feet and the resulting body position, the transfer function being compatible with a biomechanical model formulated as a stabilized segmented inverted pendulum subject to feedback of body sway and position. Each individual model estimated is effective in predicting a subject's response to new stimuli and in describing the interacting effects of stimuli on body kinetics. The proposed methodology responds to the current needs of data analysis of multi-stimulus multi-response experiments.
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| 35. |
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| 36. |
- Karlberg, Mikael, et al.
(författare)
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Acute vestibular neuritis visualized by 3-T magnetic resonance imaging with high-dose gadolinium.
- 2004
-
Ingår i: Archives of Otolaryngology - Head and Neck Surgery. - 1538-361X. ; 130:2, s. 229-232
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Tidskriftsartikel (refereegranskat)abstract
- Sudden idiopathic unilateral loss of vestibular function without other signs or symptoms is called acute vestibular neuritis. It has been suggested that reactivation of human herpes simplex virus 1 could cause vestibular neuritis, Bell palsy, and sudden unilateral hearing loss. Enhancement of the facial nerve on gadolinium-enhanced magnetic resonance imaging (MRI) is a common finding in Bell palsy, but enhancement of the vestibular nerve has never been reported in acute vestibular neuritis. We present 2 consecutive cases of acute vestibular neuritis where high-field-strength MRI (3.0 T) with high-dose (0.3 mmol/kg of body weight) gadolinium–pentetic acid showed isolated enhancement of the vestibular nerve on the affected side only. These findings support the hypothesis of a viral and inflammatory cause of acute vestibular neuritis and might have implications for its treatment.
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| 37. |
- Karlberg, Mikael
(författare)
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Akut yra patienter.
- 2009
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Ingår i: Läkartidningen. - 0023-7205. ; 106:35, s. 2134-2138
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Forskningsöversikt (refereegranskat)
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| 38. |
- 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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| 39. |
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| 40. |
- 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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