Journal of Vestibular Research - Volume 20, issue 6

Authors: Khalmuratova, Roza | Hah, Young-Sool | Ahn, Seong-Ki | Jeon, Sea-Yuong | Kim, Jin-Pyeong | Balaban, Carey D.

Article Type: Research Article

Abstract: The association between migraine and balance disorder morbidities has been a topic of interest for many years, and serotonin (5-HT) receptor is known to be closely related with migraine and also to be associated with vestibular symptoms. However, the mechanism underlying the pathogenesis of migrainous vertigo and its association with 5-HT has not been elucidated. Of the many 5-HT receptors, 5-HT 7 receptor has recently attracted attention in the context of migraine treatment. The purpose of this study was to investigate the localization and expression of 5-HT 7 receptor in …the rat vestibular nuclei by immunohistochemical staining and reverse transcriptase-polymerase chain reaction (RT-PCR). The present study might provide additional insight into the role of 5-HT 7 receptor in the pathogenesis of migraine-related vestibular symptoms. Show more

Keywords: Migraine, vertigo, 5-HT7 receptor, vestibular nuclei

DOI: 10.3233/VES-2010-0390

Citation: Journal of Vestibular Research, vol. 20, no. 6, pp. 401-406, 2010

Authors: Tjernström, Fredrik | Bagher, Ali | Fransson, Per-Anders | Magnusson, Måns

Article Type: Research Article

Abstract: We investigated changes of postural responses to repeated bipolar galvanic vestibular stimulation on 5 consecutive days and once again after 3 months. Subjects consisted of 21 healthy volunteers. Except for the first day did the induced torque variance in response to galvanic vestibular stimulation not decrease {within} each test session, but there was a major reduction {from day to day} (p< 0.001) reflecting a continued processing of the postural experience gained during the stimulation. The decreased end level magnitude of postural responses after 5 days was retained after 3 months. The galvanic stimulation failed to induce larger torque variance compared …to quiet stance toward the end of the 5 days as well as after 3 months, indicating a down-regulation of a repeated erroneous vestibular stimulation by the postural control system – i.e. sensory reweighting. This argues that a major adaptation effect to galvanic vestibular perturbation takes place after the exposure to the stimulation – similar to the concept of the consolidation process involved in motor learning. This should be considered when repeatedly assessing vestibular function both clinically and in studies. It implies that sensory training involved in rehabilitation from vestibular diseases/deficiencies should be executed with spaced intervals in order to procure more efficient learning processes and in the end, a better function. Show more

Keywords: Posture, adaptation, galvanic stimulation, memory

DOI: 10.3233/VES-2010-0391

Citation: Journal of Vestibular Research, vol. 20, no. 6, pp. 407-417, 2010

Authors: Mallinson, A.I. | Longridge, N.S. | Pace-Asciak, P. | Ngo, R.

Article Type: Research Article

Abstract: Introduction: Electronystagmography (ENG) testing has been supplanted by newer techniques of measuring eye movement with infrared cameras (VNG). Most techniques of quantifying caloric induced nystagmus measure the slow phase velocity in some manner. Although our analysis is carried out by very experienced assessors, some systems have computer algorithms that have been “taught” to locate and quantify maximum responses. We wondered what differences in measurement might show up when measuring calorics using different techniques and systems, the relevance of this being that if there was a change in slow phase velocity between ENG and VNG testing when measuring caloric response, then …normative data would have to be changed. There are also some subjective but important aspects of ENG interpretation which comment on the nature of the response (e.g. responses which might be “sporadic” or “scant”). Methods: Our experiment compared caloric responses in 100 patients analyzed four different ways. Each caloric was analyzed by our old ENG system, our new VNG system, an inexperienced assessor and the computer algorithm, and data was compared. Conclusions: All four systems made similar measurements but our inexperienced assessor failed to recognize responses as sporadic or scant, and we feel this is a limitation to be kept in mind in the rural setting, as it is an important aspect of assessment in complex patients. Assessment of complex VNGs should be left to an experienced assessor. Show more

Keywords: Calorics, electronystagmography, vestibular

DOI: 10.3233/VES-2010-0386

Citation: Journal of Vestibular Research, vol. 20, no. 6, pp. 419-426, 2010

Authors: Park, HongJu | Lee, YeoJin | Park, MunSu | Kim, JaeMyung | Shin, JungEun

Article Type: Research Article

Abstract: The purpose of this study was to analyze test-retest reliability of vibration-induced nystagmus (VIN) in dizzy patients. Fifty-two consecutive patients with positive eye movements induced by vibration at all four different stimulation sites were enrolled. Evaluation of VIN was repeated in 2 separate sessions, 30 minutes apart. Maximum slow-phase eye velocities at different sites from the first and second sessions were assessed via the intraclass correlation coefficient (ICC) and the Pearson correlation coefficient. The incidence of directional changing of evoked nystagmus and the abnormal rates were also evaluated. Excellent reliability with ICC values ranging from 0.89–0.98 and substantial-to-excellent correlation was …obtained for the maximum slow-phase eye velocities at different sites. The incidence of directional changes of evoked nystagmus was 0%–4% at each stimulation site. Forty-three patients (83%) had abnormal results in the first session and 41 patients (79%) had abnormal results in the second session. Overall, the direction and maximum slow-phase eye velocities of VIN for different stimulation sites had excellent test-retest reliability. The VIN test is a reliable test for detecting vestibular imbalance in evaluating a dizzy patient. Show more

Keywords: Test-retest reliability, vibration, nystagmus, vestibular function test

DOI: 10.3233/VES-2010-0389

Citation: Journal of Vestibular Research, vol. 20, no. 6, pp. 427-431, 2010

Authors: Vannucchi, Paolo | Pecci, Rudi

Article Type: Research Article

Abstract: Objective: To study the pathophysiology of lateral semicircular canal (LSC) paroxysmal positional vertigo (PPV). Study design: Retrospective study. Methods: Between June 2004 and June 2005 we observed 471 patients with PPV. In the apogeotropic forms of LSC-PPV, we tried to transform the nystagmus into the geotropic form, either by diagnostic or therapeutic menoeuvres. If we failed, we advised barbecue rotations toward the healthy side and sleeping on the affected side. Patients were evaluated once a week until resolution. Results: 91 patients suffered LSC involvement, in 61 cases in the geotropic form …and in 30 cases in the apogeotropic form. Out of these, five transformed into the geotropic form during the first examination; in 5 patients we observed geotropic nystagmus at the follow-up visit; the last 20 never showed geotropic nystagmus before resolution. Conclusion: We hypothesize that in the geotropic form the debris is free floating in the posterior arm of the LSC (canalolithiasis). In the apogeotropic form the debris can be free floating in the anterior arm or attached to the cupula of the ampulla; if we observe transformation from the apogeotropic into the geotropic form this suggested a canalolithiasis, otherwise we have assumed a cupulolithiasis. Show more

Keywords: Positional vertigo, apogeotropic nystagmus, nystagmus transformation

DOI: 10.3233/VES-2010-0387

Citation: Journal of Vestibular Research, vol. 20, no. 6, pp. 433-438, 2010

Authors: Wilhelmsen, Kjersti | Glad Nordahl, Stein Helge | Moe-Nilssen, Rolf

Article Type: Research Article

Abstract: Objective: Head stability, central for balance control during locomotion, is associated with attenuation of trunk oscillations. The study aimed at exploring trunk attenuation in patients with unilateral vestibular disorder (UVD) assuming it was compromised, and to see if attenuation could be influenced by vestibular rehabilitation therapy. Methods: Patients with UVD (N=21), mean age (SD): 50.7 (11.5) years, women: 57%, were tested before and after intervention. Patients walked at different velocities with triaxial accelerometers over the lower and upper trunk. Normalization of data allowed comparison across patients over time. Self-reported symptoms and perception of handicap were registered. …Results: Acceleration was significantly higher at the lower compared to the upper trunk on both occasions. Increased accelerations at the lower and decreased accelerations at the upper trunk following intervention caused attenuation to increase along the antero-posterior (p=0.05) and medio-lateral axes (p< 0.01). Cadence was reduced (p=0.01), step-length increased (p= 0.01), and self-reported balance (p=0.05) and handicap (p<0.01) improved. Conclusion: More effective attenuation of trunk oscillations was found during walking following intervention. The observed increased stability of the upper trunk is compatible with improved head control, and this was associated with increased mobility of the lower trunk facilitating balance control during ambulation. Trunk accelerations may be useful for identification of balance control in UVD patients. Show more

Keywords: Vestibular disorders, dynamic balance, gait, accelerometry, vestibular rehabilitation

DOI: 10.3233/VES-2010-0388

Citation: Journal of Vestibular Research, vol. 20, no. 6, pp. 439-446, 2010