Zastosowanie testu VHIT (Videonystagmography Head Impulse Test) w diagnostyce uszkodzeń kanałów półkolistych

Evaluation of VHIT values compared to other diagnostic tests that can be performed in a patient with dizziness and balance disorders

Introduction. The aim of the study was to assess the value of the VHIT test against the background of other diagnostic tests, including videonystagmographic (VNG) examination, Dix-Hallpike maneuver, VHIT test, posturographic examination, which are possible to perform in a patient with dizziness. Material and methods. The study was performed in 200 patients aged 18-78 years, who were divided into two groups: I study – 100 patients with mixed dizziness, aged 18-78 years, II (reference group) – 100 healthy patients (students of the Faculty of Military and Medical University of Lodz and patients of the Clinic, without anamnesis of body imbalances (preventive examination), aged 20-60 years. After performing an otorynolaryngological subjective and physical examination, each patient was subjected to a caloric test according to Fitzgerald-Hallpike in the VNG test using a water calorimeter. Then the Dix-Hallpike maneuver was performed, while the activity of semicircular canals in the VHIT test was determined on the basis of the GAIN value. In randomly selected patients, posturographic examinations were additionally carried out. Results. Based on the positive Dix-Hallpike maneuver, damage in the posterior semicircular canal in group I was found in 9 women (9.0%) and 4 men (4.0%), while a negative maneuver was noted in all people in group II. In group I in the VHIT study, damage to the semicircular canals most often concerned: anterior in 29 women (44.60%) and in 15 men (42.85%); posterior, in 19 (29.23%) and 8 (22.85%), respectively; lateral, in 3 (4.61%) and 3 (8.57%), respectively. Conclusions. The VHIT study in detail assesses the labyrinth canal deficit in all cases of peripheral and mixed dizziness, including otolithic origin, but does not allow for evident differentiation of ŁNPZG with mixed dizziness of other origin. The VHIT test is a recommended diagnostic tool in ŁNPZG in combination with other positional tests that allow to determine otolithiasis, such as: Hallpike test for the posterior semicircular canal. The VHIT test should be analyzed against the background of other diagnostic tests that can be performed in a patient with dizziness and balance disorders.

Quantitative analysis of gains and catch-up saccades of video-head-impulse testing by age in normal subjects

OBJECTIVES

To evaluate video-head-impulse test (vHIT) results in normal subjects, to determine the normative values of vHIT for the vestibulo-ocular reflex (VOR) and to characterise the catch-up saccades (CSs).

DESIGN

Prospective cohort study.

SETTING

Tertiary care academic referral centre.

PARTICIPANTS

Fifty healthy subjects with no history of vestibular impairment, ten each in their 20's, 30's, 40's, 50's and 60's, underwent vHITs in the lateral semicircular canal plane.

MAIN OUTCOME MEASURES

vHIT gains and the incidence and amplitudes of covert and overt CSs.

RESULTS

The mean vHIT gain was 1.02 ± 0.07, and the mean gain asymmetry was 2.39 ± 1.96%, with no significant differences among age groups. CSs were observed during 22.6% of the trials and in 49% of the ears. The incidence of CSs was not associated with age. The mean velocity of CSs was 55.5 ± 16.9°/s, and its mean interaural difference was 11.8 ± 10.7°/s.

CONCLUSIONS

vHIT gains were consistently equal to 1.0 in all age groups (20's to 60's), suggesting that abnormal criteria for vHIT gain (e.g. 0.8) and gain asymmetry (e.g. 8%) can be used, regardless of age. CSs were observed in about half of normal ears, suggesting that VOR is a hypometric system. The amplitudes and interaural difference of CSs were also similar in all age groups, suggesting that abnormal criteria for CS amplitude (e.g. 100°/s) and interaural difference (e.g. 40°/s) can be used, regardless of age.

The video head impulse test

CONCLUSION

Additional research is needed to validate the importance of the video head impulse tests (vHIT), but it provides an important contribution to the evaluation of anterior and posterior semicircular canal disorders.

OBJECTIVES

To share observations of the vHIT test in clinical neurotology and to discuss the significance of the study findings.

METHODS

This study comprised 200 patients with a clinical history of vestibular disturbances who were submitted to a vHIT including all six semicircular canals.

RESULTS

Abnormal responses of the anterior and posterior canals were found in several patients, either alone or combined with altered responses in the lateral canals. A unilateral hypoactive response of a posterior canal was found in a patient with a small vestibular schwannoma.

[The video head impulse test: first clinical experiences]

BACKGROUND

Side-specific test procedures are mandatory in order to assess the function of peripheral vestibular receptors. Semicircular canals (SCC) and vestibulo-ocular reflex (VOR) can be tested by the Halmagyi and Curthoy head impulse test (HIT) and recently by means of the video head impulse test (vHIT). The vHIT procedure is a new method to measure eye and head velocity during brief and rapid head impulses. This method provides objective information of VOR and detects both overt and covert catch-up saccades.

MATERIALS AND METHODS

As clinical experiences with vHIT are limited, in this study the horizontal VOR (hVOR) was examined by means of the vHIT in 142 consecutive patients with acute or chronic vestibular syndrome.

RESULTS

A total of 20 healthy volunteers served as a control group and exhibited a normal average VOR gain of 0.97 ± 0.09 without re-fixation saccades. In patients, 47.6% showed a pathological vHIT whereas 52.4% revealed a normal test result. Covert catch-up saccades could be revealed in 13.7% by means of vHIT whereas in 86.3% overt catch-up saccades alone or in combination with covert catch-up saccades were found in the majority of catch-up saccades in peripheral vestibular disorders.

CONCLUSIONS

By means of the vHIT it is possible to obtain a side-specific and quantitative assessment of hVOR. Video-head impulse test is a reliable tool for vestibular testing even in bedside examinations of patients suffering from dizziness.

[The evaluation of the efficiency of kinesitherapy in the patients with mixed-type vertigo]

INTRODUCTION

The aim of this work was to evaluate the efficiency of kinesitherapy in the patients with mixed-type vertigo.

MATERIAL AND METHODS

The study was conducted on a randomized group of 35 patients, 21 women and 14 men aged 24-75 years (mean age 42.5 years), who were treated at the Department of Otolaryngology and Laryngological Oncology Medical University Teaching Hospital in Lodz for mixed-type vertigo. The inclusion criteria were an interview, physical and otorhinolaryngological examinations, laboratory investigations, complete audiological and otoneurological examinations, including BERA and VNG, USG examination of the blood vessels to the cranium, and CT of the cervical spine. Each patient underwent an individually selected set of habituation exercises, corrective exercises for posture and its orientation in space through 2 months. The efficiency of the implemented therapy was evaluated after two weeks, one month and two months with the use of the complete videonystagmographic test and Silvoniemi's criteria.

RESULTS

The mean excitability of the labyrinths was 25.38 degrees/s before rehabilitation and 22.26 degrees/s after rehabilitation, absolute directional preponderance was 7.62 degrees/s and 1.92 degrees/s respectively, relative directional preponderance was 31.36 degrees/s and 12.57 degrees/s, and unilateral deficit 32.12 degrees/s and 14.34 degrees/s. The subjective evaluation of the vertigo intensification based on the 5 stages of Silvoniemi's scale indicates that the mean point-based evaluation reported by the patients at the beginning of the therapy was 3.85 points, whereas after the therapy was 2.91 points after two weeks, 2.35 points after one month, and 1.2 points after two months.

CONCLUSIONS

Kinesitherapy is an alternative and very effective method for treating mixed-type vertigo.

Electronystagmography versus videonystagmography in diagnosis of vertigo

OBJECTIVES

Vertigo is a very common symptom mainly caused by the lesion of vestibular system (peripheral or central) and often accompanied by some work-related diseases and occupational intoxications. The aim of this study was to assess the value of electronystagmography (ENG) and videonystagmography (VNG) for diagnosing vertigo of various origin.

MATERIALS AND METHODS

The study included four groups, 25 subjects each, of patients suffering from vestibular disorders of peripheral, central and mixed origin versus healthy controls. All were examined by means of ENG and VNG, using the bithermal caloric test with 30°C and 44°C air irrigations of the ears. The findings (frequency of induced nystagmus FRQ, its slow phase velocity SPV, canal paresis CP, directional preponderance DP, vestibular excitability VE) were analysed and compared.

RESULTS

In all patients with vertigo due to vestibular neuritis, barotrauma and kinetosis, significant CP, the important sign of peripheral site of vestibular lesion was identified both in ENG and VNG. None of the patients with central origin disorders showed CP in VNG; in the majority of cases DP was observed. However, in ENG we found CP in 5 patients with central origin disorders. There were no essential differences between ENG and VNG in measurements of FRQ and SPV except for higher values in VNG in controls and patients with mixed vertigo.

CONCLUSIONS

The results suggest that the VNG should be recommended in preference as the valuable method to assess vertigo and to discriminate between the peripheral and the central vestibular lesions.