Material and Methods
Patients were included prospectively and consecutively in the study. The
study was conducted in the Otorhinolaryngology and Audiology Clinic of
the tertiary university hospital between October 2017 and September
2018. Demographic characteristics of the patients and pathological SCC
detected by examination and diagnostic maneuver for BPPV patients were
recorded. VOR gain was calculated in all patients and all six SCCs. Two
sub-study groups were formed according to age (<50 or
>50). The study was prepared with the reporting guideline
of the STROBE checklist.
Inclusion: Only patients with complaints of acute onset vertigo
(<5 days) were included in the study. The diagnosis of BPPV
was made by examination, clinical history, clinical head impulse test
(cHIT), and Dix Hallpike maneuver for vertical SCCs and examination,
clinical history, clinical head impulse test (cHIT), and roll test for
the lateral SCC. Vestibular Neuritis was diagnosed by medical history,
physical examination, and caloric tests. The final diagnosis in VN
patients was made by caloric test (irrigation of each ear with water at
a temperature of 30 and 44 °C) A 20% difference calculated by Jongkees
formula between the ears was accepted a pathological response. Meniere’s
disease (MD) diagnosis was made in accordance with the diagnostic
criteria of AAO-HNS Committee on Hearing and Equilibrium Meniere’s
Disease [8].
Exclusion: The patients with immunocompromised conditions,
autoimmune system diseases, malignancy, history of ear surgery, history
of migraine, and history of antivertigo drugs in the last two weeks
excluded from the study. Patients who did not receive the three
diagnoses included in this study during or after the study protocol and
the findings of these patients were not included in the final analysis.
vHIT protocol : Initially, the physiological lower limit of VOR
gain was determined in 20 healthy participants and recorded by the
instrument (Fig. 1) . The accepted lower value of VOR gain
determined as 0.9 for the lateral SCCs and 0.7 for vertical SCCs. vHIT
protocol of Micromedical Technologies Company’s VisualEyes™
Four-Canal-Videonystagmography (VNG) instrument was used for the test.
This test consists of 3 parts. The first part is Lateral (Left Lateral:
LL - Right Lateral: RL) test which is used for examination of lateral
SCCs (LSCC). The second and third parts are RALP (Right Anterior : RA -
Left Posterior: LP) and LARP (Left Anterior: LA - Right Posterior: RP)
tests which are used for examination of vertical canals. During the
test, fast pushing force is applied to patient’s head with approximately
20°-30° angle by audiologist/physician according to SCCs canal axis.
Patients were asked to unloose her/his head, not to contract trapezius
muscle and not to turn her/his eyes away from the point adjusted on the
wall in 1.5-meter-distance from the patient. For each canal, at least
10-15 head push movements were applied. Lateral, RALP, LARP parameters
of all patients were evaluated and VOR gains for six SCCs were
determined separately. As a result of VHIT implemented on 20 normal
patients, standard VOR values were priorly recorded by the instrument.
Normal standard lower value of VOR was accepted as 0.92 for lateral
canal and 0.74 for vertical canals. Based on these values VOR gain
values of patients were examined.
Statistical Analysis: Data for the study were deposited with an
electronic file. The findings analyzed by the SPSS 22.0 (SPSS Inc.,
Armonk, NY) software system. The normality assumption was measured by
the Kolmogorov Smirnov test. Categorical variables were compared with
the chi-square test, and scale variables were compared with the
Kruskal-Wallis test. Sensitivity and specificity were calculated for all
and each SCCs causing BPPV. Results with a significance coefficient of
p>0.05 will be considered statistically significant.
Ethics Committee Approval: Verbal and written consent was
obtained after all participants were informed. All procedures performed
in studies involving human participants were following the 1964 Helsinki
Declaration and its later amendments or comparable ethical standards.