The video head impulse test during post-rotatory nystagmus: physiology and clinical implications.


Autoria(s): Mantokoudis, Georgios; Tehrani, Ali S Saber; Xie, Li; Eibenberger, Karin; Eibenberger, Bernhard; Roberts, Dale; Newman-Toker, David E; Zee, David S
Data(s)

01/01/2016

Resumo

The aim of this study was to test the effects of a sustained nystagmus on the head impulse response of the vestibulo-ocular reflex (VOR) in healthy subjects. VOR gain (slow-phase eye velocity/head velocity) was measured using video head impulse test goggles. Acting as a surrogate for a spontaneous nystagmus (SN), a post-rotatory nystagmus (PRN) was elicited after a sustained, constant-velocity rotation, and then head impulses were applied. 'Raw' VOR gain, uncorrected for PRN, in healthy subjects in response to head impulses with peak velocities in the range of 150°/s-250°/s was significantly increased (as reflected in an increase in the slope of the gain versus head velocity relationship) after inducing PRN with slow phases of nystagmus of high intensity (>30°/s) in the same but not in the opposite direction as the slow-phase response induced by the head impulses. The values of VOR gain themselves, however, remained in the normal range with slow-phase velocities of PRN < 30°/s. Finally, quick phases of PRN were suppressed during the first 20-160 ms of a head impulse; the time frame of suppression depended on the direction of PRN but not on the duration of the head impulse. Our results in normal subjects suggest that VOR gains measured using head impulses may have to be corrected for any superimposed SN when the slow-phase velocity of nystagmus is relatively high and the peak velocity of the head movements is relatively low. The suppression of quick phases during head impulses may help to improve steady fixation during rapid head movements.

Formato

application/pdf

Identificador

http://boris.unibe.ch/76306/1/art%253A10.1007%252Fs00221-015-4458-7.pdf

Mantokoudis, Georgios; Tehrani, Ali S Saber; Xie, Li; Eibenberger, Karin; Eibenberger, Bernhard; Roberts, Dale; Newman-Toker, David E; Zee, David S (2016). The video head impulse test during post-rotatory nystagmus: physiology and clinical implications. Experimental brain research, 234(1), pp. 277-286. Springer 10.1007/s00221-015-4458-7 <http://dx.doi.org/10.1007/s00221-015-4458-7>

doi:10.7892/boris.76306

info:doi:10.1007/s00221-015-4458-7

info:pmid:26449967

urn:issn:0014-4819

Idioma(s)

eng

Publicador

Springer

Relação

http://boris.unibe.ch/76306/

Direitos

info:eu-repo/semantics/restrictedAccess

Fonte

Mantokoudis, Georgios; Tehrani, Ali S Saber; Xie, Li; Eibenberger, Karin; Eibenberger, Bernhard; Roberts, Dale; Newman-Toker, David E; Zee, David S (2016). The video head impulse test during post-rotatory nystagmus: physiology and clinical implications. Experimental brain research, 234(1), pp. 277-286. Springer 10.1007/s00221-015-4458-7 <http://dx.doi.org/10.1007/s00221-015-4458-7>

Palavras-Chave #610 Medicine & health
Tipo

info:eu-repo/semantics/article

info:eu-repo/semantics/publishedVersion

PeerReviewed