Journal of Vestibular Research - Volume 19, issue 1-2

Authors: Bisdorff, Alexandre | Von Brevern, Michael | Lempert, Thomas | Newman-Toker, David E.

Article Type: Research Article

DOI: 10.3233/VES-2009-0343

Citation: Journal of Vestibular Research, vol. 19, no. 1-2, pp. 1-13, 2009

Authors: Cohen, Helen S. | Gottshall, Kim R. | Graziano, Mariella | Malmstrom, Eva-Maj | Sharpe, Margaret H.

Article Type: Research Article

Abstract: The goal of this study was to determine how occupational and physical therapists learn about vestibular rehabilitation therapy, their educational backgrounds, referral patterns, and their ideas about entry-level and advanced continuing education in vestibular rehabilitation therapy. The Barany Society Ad Hoc Committee for Vestibular Rehabilitation Therapy invited therapists around the world to complete an E-mail survey. Participants were either known to committee members or other Barany Society members, known to other participants, identified from their self-listings on the Internet, or volunteered after reading notices published in publications read by therapists. Responses were received from 133 therapists in 19 countries. They …had a range of educational backgrounds, practice settings, and referral patterns. Few respondents had had any training about vestibular rehabilitation during their professional entry-level education. Most respondents learned about vestibular rehabilitation from continuing education courses, interactions with their colleagues, and reading. All of them endorsed the concept of developing standards and educating therapists about vestibular anatomy and physiology, vestibular diagnostic testing, vestibular disorders and current intervention strategies. Therefore, the Committee recommends the development of international standards for education and practice in vestibular rehabilitation therapy. Show more

Keywords: Vestibular disorders, physical therapy, occupational therapy, standards of care

DOI: 10.3233/VES-2009-0339

Citation: Journal of Vestibular Research, vol. 19, no. 1-2, pp. 15-20, 2009

Authors: Hofman, R. | Segenhout, J.M. | Wit, H.P.

Article Type: Research Article

Abstract: Three-dimensional reconstructions of the inner ear of the pigeon (Columba livia domestica), from two-dimensional images, obtained with (conventional) light microscopy or orthogonal-plane fluorescence optical sectioning (OPFOS), are presented. The results are compared with available information on the dimensions and orientation of the semicircular canals.

Keywords: Pigeon, vestibular system, OPFOS, light microscopy, semicircular canals

DOI: 10.3233/VES-2009-0346

Citation: Journal of Vestibular Research, vol. 19, no. 1-2, pp. 21-26, 2009

Authors: Kingma, C.M. | Wit, H.P.

Article Type: Research Article

Abstract: To investigate the effect of an acute endolymphatic hydrops on the functioning of the vestibular system a hydrops was created by microinjection of artificial endolymph through the basilar membrane into scala media in 10 guinea pigs. To control for the effect of perforation of the basilar membrane, the same procedure was performed in 9 other guinea pigs, but without injection of endolymph. Contralateral ears served as control ears. Vestibular evoked potentials, evoked by vertical acceleration pulses applied to the guinea pig's head, were measured in all ears before, immediately after, and 2, 4, and 5 hours after perforation/injection. Acute endolymphatic …hydrops did not affect the amplitude of the VsEP immediately after injection. After 4 to 5 hours VsEP was significantly reduced in both hydrops and perforated-only ears, compared to control ears. However, no significant difference was found between VsEP of the hydrops ears and perforated-only ears. Reduction of VsEP is not caused by a direct hydromechanical effect on the vestibular system, but possibly by leakage of perilymph through the perforation hole, supporting the membrane rupture theory for Menière-attacks. Show more

Keywords: VsEP, vestibular evoked potential, endolymphatic hydrops, vestibular function, endolymph, peforation, basilar membrane, guinea pig

DOI: 10.3233/VES-2009-0341

Citation: Journal of Vestibular Research, vol. 19, no. 1-2, pp. 27-32, 2009

Authors: Rosengren, Sally M. | Govender, Sendhil | Colebatch, James G.

Article Type: Research Article

Abstract: We compared the effectiveness of a series of different sound stimulus waveforms in evoking VEMPs in normal volunteers. The waveforms were clicks (0.1âĂŞ0.8 ms), biphasic clicks (0.8 ms) and sine waves (1250 Hz, 0.8 ms and 500 Hz, 2 ms) with different peak intensity and duration but similar root mean square area. VEMP amplitudes varied widely (corrected values 0.35 to 1.06), but when the amplitudes were plotted against the physical energy content and A-weighted intensity (L A e q : a measure of acoustic energy) of the waveforms, the relationship was found to be highly linear. …However, when the stimuli were matched for their A-weighted energy, a 500 Hz 2 ms sine wave was the most effective waveform, suggesting that frequency tuning in the vestibular system is also an important factor. VEMP amplitude is thus determined by three stimulus-related factors: physical energy, transmission through the middle ear and vestibular frequency tuning. Use of a 500 Hz stimulus will maximise the prevalence and amplitude of the VEMP for a given sound exposure level. Show more

Keywords: Vestibular, VEMP, acoustic, sound, frequency

DOI: 10.3233/VES-2009-0345

Citation: Journal of Vestibular Research, vol. 19, no. 1-2, pp. 33-40, 2009

Authors: Cornell, Elaine D. | Burgess, Ann M. | MacDougall, Hamish G. | Curthoys, Ian S.

Article Type: Research Article

Abstract: Bone-conducted vibration (BCV) delivered to the skull causes linear acceleration of the mastoids and results in small potentials (oVEMPs) from the extraocular muscles in humans. Very small eye movements to both air- and bone-conducted sound with latencies of around 9 ms and amplitudes up to 16.5 mdeg have also been reported (where mdeg = millidegrees =0.001 degree). To clarify the otolith-ocular responses we investigated the effect of unilateral and bilateral BCV (500 Hz of the mastoid) on eye movements in human subjects, and the effect of gaze position on these movements using a video-based eye-movement recording system. We found very …small, short-latency eye-movement responses similar to those previously reported, but these were followed by larger (up to 0.57°) prolonged responses peaking at around 120 ms post-stimulus. For unilateral stimulation the eyes moved downwards when directed away from the stimulated mastoid and upwards when directed towards stimulation. Horizontal movements were towards the stimulated mastoid with little effect of gaze position. Bilateral stimulation enhanced the downward responses, suggesting that the depressor muscles are preferentially activated by BCV. Bilateral stimulation either eliminated the horizontal response or produced convergence of the eyes: the convergence suggests that the eye-movement response is probably primarily driven by the contralateral mastoid. Show more

Keywords: Bone conducted vibration, otolith, eye movements

DOI: 10.3233/VES-2009-0338

Citation: Journal of Vestibular Research, vol. 19, no. 1-2, pp. 41-47, 2009

Authors: Wei-Lynn So, Christina | Bent, Leah R.

Article Type: Research Article

Abstract: Objective: Numerous studies have identified an association between headache disorders and vestibular symptoms, such as dizziness, vertigo, and motion sensitivity. Using bipolar, binaural galvanic vestibular stimulation (GVS), our objectives were to (1) determine the degree of vestibular sensitivity in borderline headache sufferers, and (2) characterize the postural response to vestibular perturbation in these individuals. Methods: Fourteen volunteers participated in this study: 8 individuals with chronic headache (6 with migraine and 2 with tension type headache (TTH)), and 6 healthy control subjects. Thirty trials of 15-second duration were conducted across 6 conditions (GVS left (L) or right (R), …or no stimulation (No GVS) with either eyes open (EO) or eyes closed (EC)). Peak medial-lateral (M-L) centre of pressure (CoP) was calculated during quiet stance. Results: Headache subjects demonstrated significantly higher peak displacement of the M-L CoP than control subjects (p=0.0461). Although peak M-L CoP in both the EO (p = 0.0753) and EC (p=0.09623) visual conditions were not significantly different between headache sufferers compared to healthy controls, there is some suggestion that people with chronic headache may use vestibular information to a greater extent and that the presence of vision may not sufficiently compensate for vestibular induced instability. The initial push M-L CoP was not significantly different between groups, suggesting different sensory contributions for the initial and latter response to GVS. Conclusions: People with chronic headache exhibit increased postural sway, which may reflect the re-weighting of sensory information with an increased vestibular and a reduced visual contribution to postural control. Significance: These results support existing research on vestibular abnormalities in chronic headache sufferers that may provide a basis for future treatment therapies. Show more

Keywords: Headache, galvanic vestibular stimulation, vestibular system, posture, stance, vision

DOI: 10.3233/VES-2009-0340

Citation: Journal of Vestibular Research, vol. 19, no. 1-2, pp. 49-58, 2009

Authors: Eleftheriadou, A. | Deftereos, S.N. | Zarikas, V. | Panagopoulos, G. | Sfetsos, S. | Karageorgiou, C.L. | Ferekidou, E. | Kandiloros, D. | Korres, S.

Article Type: Research Article

Abstract: Aim of the study: To evaluate the ability of VEMP to disclose spatial dissemination of Multiple Sclerosis. Materials and methods: Forty-six MS patients with auditory and /or vestibular symptoms were studied. Patients were divided in two groups. Group 1 included 24 patients with brainstem MRI findings, and Group 2 included 22 patients without MRI findings. VEMP and BAEP have been recorded and assessed. Results: Abnormal p13n23 wave was observed in 50%, while unilateral absence or bilateral delay of the n34p44 in 43% of the patients. The overall diagnostic value considering abnormal cases suggested by both first …and second VEMP waves was increased to 71%. Statistically significant differences revealed between patients and controls for p13 latency (p=0.018). The p13n23 was abnormal in 7 patients, although MRI scanning did not reveal brainstem lesions. In 9 out of 18 MS patients suffering from unilateral hearing loss, n34p44 was present in the unaffected ears and absent in the affected side, although p13n23 was normal. Conclusion: Abnormal VEMP imply the presence of lesions undetected by MRI neuroimaging, which verifies the diagnostic value of the method. Unilateral absence of n34p44 complex was related with sensorineural hearing loss, supporting the hypothesis that n34p44 is of cochlear origin. Show more

Keywords: VEMP, BAEP, MS, n34-p44

DOI: 10.3233/VES-2009-0342

Citation: Journal of Vestibular Research, vol. 19, no. 1-2, pp. 59-66, 2009