Journal of Vestibular Research - Volume 24, issue 1

Authors: Clément, Gilles | Delière, Quentin | Migeotte, Pierre-François

Article Type: Research Article

Abstract: Background: Artificial gravity using short-radius centrifugation has been proposed as an integrative countermeasure during spaceflight. Objective: To determine the rotation parameters of a short-radius centrifuge so that subjects rotating in the dark would feel as if they were standing upright. Methods: Twelve subjects were lying supine in a nacelle on a 2.8 m-radius centrifuge with their head closer to the axis of rotation and their feet pointing radially outwards. Subjects verbally reported body orientation for 26 combinations of centrifuge rotation rate and nacelle pitch tilt. ECG and respiratory responses were also recorded. …Results: Five subjects felt like they were vertical when centrifugation elicited 1 g at their center of mass along their body longitudinal axis, whereas seven subjects felt they were vertical when they experienced about 1 g at ear level, regardless of the nacelle tilt angle. Heart rate variability varied with the subjects' perception of verticality. Conclusions: These results suggest that one group of subject was relying principally on the otolith organs for the perception of verticality, whereas the other group was also relying on extravestibular somatosensory receptors. The crewmember's perception of verticality might be a factor to take into account for the prescription for artificial gravity during spaceflight. Show more

Keywords: Subjective vertical, otoliths, vestibular-autonomic reflex, artificial gravity

DOI: 10.3233/VES-130504

Citation: Journal of Vestibular Research, vol. 24, no. 1, pp. 1-8, 2014

Authors: Winters, Stephanie M. | Bos, Jelte E. | Klis, Sjaak F.L.

Article Type: Research Article

Abstract: Background: To test for otolith asymmetries, several studies described horizontal translation of the body and head en bloc during fast vertical axis rotation. This stimulus causes one otolithic organ to rotate on-axis, and the other to experience centripetal acceleration. Objective: To test a new, more simple method of unilateral stimulation with head tilt and the body remaining on axis. Methods: During stationary and during 360 deg/s rotation, 12 healthy blindfolded subjects had their heads tilted 30 degrees sideways, positioning one otolithic organ on the axis of rotation after the other. The haptic subjective vertical (SV) …was recorded several times by means of a manually adjustable rod. Results: It was found that during stationary the SV tilted about 4 degrees on average in the direction of the head. During rotation, the SV tilted about 9 degrees on average. We therefore estimate the effect of eccentric otolith rotation to be 5 degrees on average. Conclusions: Tilt of the subjective vertical induced by head tilt during on-axis body rotation can provide a relatively uncomplicated alternative to test unilateral otolithic function as compared to body and head translation during rotation. Moreover, unlike eccentric rotation of the entire body, somatosensory cues are minimized by keeping the body fixed on axis and by subtracting the effect of head tilt per se. Show more

Keywords: Unilateral centrifugation, otolith function test, subjective vertical

DOI: 10.3233/VES-130508

Citation: Journal of Vestibular Research, vol. 24, no. 1, pp. 9-15, 2014

Authors: Tal, Dror | Wiener, Guy | Shupak, Avi

Article Type: Research Article

Abstract: Background: Exposure to unfamiliar motion patterns commonly results in motion sickness and a false perception of motion, termed mal de debarquement, on the return to stable conditions. Objective: To investigate whether motion sickness severity is correlated with the duration and severity of mal de debarquement; to study the possible preventive effect of projecting earth-referenced scenes (an artificial horizon) during exposure to motion on the development of mal de debarquement. Methods: Thirty subjects were exposed to the recorded motion profile of a boat in a 3-degrees-of-freedom ship motion simulator. During the simulated voyage, the study …participants were repeatedly put through a performance test battery and completed a motion sickness susceptibility questionnaire, while self-referenced and earth-referenced scenes were projected inside the simulator cabin. Six hours post disembarkation, subjects completed a questionnaire on mal de debarquement duration and severity. Results: Mal de debarquement, mostly of mild severity, was reported following 59% of the exposures to the provocative motion profile, and in 79% of cases lasted less than 6 hours. The incidence of mal de debarquement, its duration, and the severity of symptoms did not differ between the various artificial horizon projection modes. Significant correlations were found between motion sickness severity and the duration and severity of the mal de debarquement that followed. Conclusions: The significant correlations found between motion sickness severity and mal de debarquement duration and severity imply that both syndromes might stem from a failure to adapt to new motion conditions. There is a disparity between the previously reported reduction in motion sickness symptoms by an artificial horizon, and its failure to influence the duration and symptoms of mal de debarquement. This might be explained by the different response in the two syndromes, physical versus cognitive. Show more

Keywords: Mal de debarquement, motion sickness, motion perception, prevention, questionnaires, vestibular organs

DOI: 10.3233/VES-130505

Citation: Journal of Vestibular Research, vol. 24, no. 1, pp. 17-23, 2014

Authors: Singh, Niraj Kumar | Apeksha, Kumari

Article Type: Research Article

Abstract: Background: Cervical vestibular evoked myogenic potential (cVEMP) is a biphasic potential recorded from the Sternocleidomastoid muscle in response to loud acoustic stimulation and assesses the intactness of the Sacculocolic pathway. The literature on clinical utility of cVEMP has been growing rapidly, though not without inconsistencies despite involving alike population. A close scrutiny of the methods across such studies revealed an inconsistent use of stimulus parameters; especially rise/fall times (RFTs). However the effect of RFTs on cVEMP has been largely unexplored. Objective: The study aimed at exploring the effect of varying RFTs on cVEMP and obtaining optimum RFT …to enable reliable recording of cVEMPs. Methods: The cVEMPs were recorded from both ears of 30 healthy individuals with normal audio-vestibular system using 500 Hz short tone-bursts (STBs) at 95 dB nHL and varying the RFTs from 1 to 8 ms at all integer values. Results: There was significant prolongation of latencies with increasing RFTs (p< 0.05). The largest amplitudes were obtained for 2 to 3 ms RFTs, though significantly smaller amplitude was obtained only for 8 ms RFT (p< 0.05), thereby rendering 8 ms RFT unfit for cVEMP recording. The 1 ms RFT produced smallest variability across individuals and would also result in lesser duration of exposure to loud sound. Conclusions: The RFT of 1 ms of 500 Hz STBs are optimum for recording cVEMPs. This is owing to large amplitudes and least variability demonstrated for this RFT. Show more

Keywords: Sternocleidomastoid muscle, cervical vestibular evoked myogenic potential, rise/fall time

DOI: 10.3233/VES-130503

Citation: Journal of Vestibular Research, vol. 24, no. 1, pp. 25-31, 2014

Authors: Cohen, Helen S.

Article Type: Research Article

Abstract: The Vestibular Disorders Activities of Daily Living Scale (VADL) is one of several self-rated scales in the literature that may be useful for determining level of functional limitation or disability in people with vestibular disorders. The VADL was designed by an occupational therapist for use in treatment planning during vestibular rehabilitation. Unlike many other scales the VADL is specifically focused on essential functional skills and important mobility and instrumental skills. This paper reviews the findings about the VADL, including the original research about its development and more recent papers using it. The scale is most useful for assessing the patient's …perception about independence in personal, self care and basic mobility skills. It provides an outline for discussing instrumental activities of daily living. Show more

Keywords: Quality of life, self care, limitation of activity, vertigo, dizziness, occupational therapy, physical therapy

DOI: 10.3233/VES-130475

Citation: Journal of Vestibular Research, vol. 24, no. 1, pp. 33-38, 2014

Authors: Amini, Afshin | Heidari, Kamran | Asadollahi, Shadi | Habibi, Tahereh | Shahrami, Ali | Mansouri, Behnam | Kariman, Hamidreza

Article Type: Research Article

Abstract: Background: Vertigo imposes considerable health restrictions with significant impact on the patient's quality of life. The most effective antivertigo agent is undetermined thus far. Objective: This study was performed to assess whether promethazine has superior vertigo reduction compared with lorazepam in ED patients. Methods: In this randomized, double-blind, parallel group trial 184 patients were assigned (1:1 ratio) to receive either promethazine, 25 mg intravenously, or lorazepam, 2 mg intravenously. Primary endpoint was mean change in vertigo intensity at 2 hours measured using visual analog scale (VAS). Secondary endpoints were mean change in nausea score, …need for second dose of study medications, and adverse events (AEs). Results: Promethazine was associated with significantly more reduction (46.5 mm) in vertigo than lorazepam (25.7 mm, p< 0.001). Mean change in nausea score 2 hours after drug injection on the VAS was 28.7 mm for promethazine and 22.8 for lorazepam (p=0.002). The most frequently reported AEs were lethargy (14.1% in lorazepam group, 4.3% in promethazine group, p=0.013) and drowsiness (10.8% for promethazine, 2.1% for lorazepam, p=0.017). Conclusion: Our study demonstrated the evidence that promethazine is superior to lorazepam in management of peripheral vertigo and vertigo-related nausea in ED adults. Show more

Keywords: Vertigo, nausea, promethazine, lorazepam, clinical trial

DOI: 10.3233/VES-130506

Citation: Journal of Vestibular Research, vol. 24, no. 1, pp. 39-47, 2014