Vol.:(0123456789)
1 3
European Archives of Oto-Rhino-Laryngology
https://doi.org/10.1007/s00405-018-5020-6
OTOLOGY
Parameters of skull vibration-induced nystagmus in normal subjects
Enrique García Zamora
1
· Pedro Espírito‑Santo Araújo
2
· Vanesa Pérez Guillén
1
· María Fernanda Vargas Gamarra
1
·
Victoria Fornés Ferrer
3
· Magdalena Courel Rauch
1
· Herminio Pérez Garrigues
1
Received: 22 January 2018 / Accepted: 26 May 2018
© Springer-Verlag GmbH Germany, part of Springer Nature 2018
Abstract
Hypothesis The knowledge of vibration-induced nystagmus test (SVINT) values in the normal population is highly relevant
to provide a rapid orientation on the diagnosis attitude in a patient with vertigo.
Background Although mastoid bone vibration should only induce nystagmus in the presence of vestibular asymmetry, it
has also been reported in normal individuals raising doubts as to how to interpret the SVINT. To date, no population studies
involving the use of the SVINT and that establish normative values have been published.
Methods This study was carried out at two tertiary healthcare centres on a total of 122 subjects. We stimulated at three fre-
quencies (30, 60 and 100 Hz), in increasing order, first stimulating the right mastoid and then the left mastoid, and waiting for
30 s between each stimulus. The response was recorded with a videonystagmography system. The following variables were
evaluated in each subject: the mean and maximum speed of the slow phase of nystagmus, the frequency of the nystagmatic
response (NR) and the component and direction of the rapid phase of nystagmus.
Results Only 26 subjects (20.5%) of the subjects studied here (122 subjects) developed any kind of nystagmatic response and
96 subjects (79.5%) did not display any response. Stimulation at 100 Hz provoked the largest number of responses (p = 0.04),
while there was no difference in the number of responses induced by 30 and 60 Hz stimulations (p = 0.85). The frequency of
nystagmus was ≤ 0.7 n/s in 80.8% of the positive responses. The mean velocity of the horizontal component of the NR was
2.2°/s (SD 1.6) and that of the vertical component was 1.3°/s (SD 1.2).
Conclusions Healthy subjects do not generally develop to NR upon vibratory stimulation and only 20% of the subjects studied
here developed any kind of NR, this being a slow and inconsistent response of low frequency. The establishment of normal
values contributes to improve the orientation in clinical practice in the pathological population and this opens possibilities
for tackling more reliable studies in this population.
Keywords Skull vibration-induced nystagmus · Normal subjects
Introduction
Vibration-induced nystagmus was first reported in1973 by
Lücke [1], describing the effects of 100 Hz mastoid bone
vibration in a patient with unilateral vestibular loss. In
1993, Hamann demonstrated that mastoid vibratory test
elicited nystagmus in 75% of patients with unilateral ves-
tibular deficit and 10% of patients with central vestibular
disorders [2]. Despite these and more recent reports, bone
vibration-induced nystagmus did not receive much attention
from clinicians and it was not a commonly used test. How-
ever, and like vestibular stimulus, interest has resurged in
assessing the myogenic vestibular potentials associated with
bone vibration and in the skull vibration-induced nystagmus
test (SVINT) [3]. The SVINT involves applying vibration
to a point of the skull that propagates the stimulus simul-
taneously to both labyrinths. If both respond identically,
a nystagmatic response (NR) is not obtained. However, if
one labyrinth responds more strongly to the stimulus than
the other, nystagmus develops. Thus, the SVINT enables
unilateral vestibular hypofunction to be readily detected
* Enrique García Zamora
enrique.ga.zam@gmail.com
1
Otoneurology Unit, ENT Department, Hospital “La Fe”,
Valencia, Spain
2
Otoneurology Unit, ENT Department, Hospital “da Luz”,
Lisbon, Portugal
3
Unidad de Bioestadística, Instituto of Investigation Sanitaria
“La Fe”, Valencia, Spain
@Phil_Robichaud
@deepthiw
@JoseServera