Diagnostics in our ENT office
Diagnostics of vertigo
The diagnosis of patients with vertigo, disturbances of the equilibrium or attacks of fall requires a considerable amount of time, and both personnel and instrument-based effort. The difficulty is intensified by the fact that the number of persons affected by such a disease is noticeably increasing. Vertigo is not a disease, but a symptom with many possible causes. Overworked people may suffer from attacks of vertigo as well as people with nerve inflammation, heart disease or stroke. The correct diagnosis is accordingly difficult to make. Depending on the specialist the person seeking help ends up, he or she is arbitrarily dealt with or sent to the next specialist.
Our balance functional laboratory is amongst other things equipped with a modern revolving chair installation which identifies all vestibulo-spinal, vestibular and optically-vestibular? dysfunctions by electro- and/or video-nystagmography.
After detailed anamnesis and ENT basis examination with orienting examination of the peripheral and the central vestibulocochlear organ, specifying technically detailed examinations of the complex vestibulocochlear organ are performed, commencing with an examination on a posturographical platform.
Here staggering around the central axis as well as the distribution of the centre of gravity are scaled by means of the soles of the feet. There dysfunctions of balance control can be scaled, whereby the system does not only provide the opportunity to identify vestibular dysfunctions, but determines influences of the cervical spine as well as neurologically caused functional damages such as ataxia or the like. After that more examinations can be performed, aiming for the peripheral or the central system.
Here it is examined whether the vertigo can be caused by a certain position of the body. In the course of positional testing the eyes are first watched by video recording while sitting, and then in supine and sideways position, whether they move saccadically (nystagmus). Since the vestibular organs are linked with the eyes via complex nerval switching, dysfunctions linked with vertigo are to be recognized by eye twitching. In the course of the Dix-Hallpike test it can be detected whether the vertigo is caused by movement. This is tested by overflexion of the head, to be followed by turning it aside and positioning in place. Possible reasons for vertigo are the benign paroxysmal positional vertigo (sensitive balance system), vertigo caused by the blood flow (e. g. by clamping the cervical blood vessels), vertigo caused by heavy tensions in the region of the cervical spine
Subjective Visual Horizontal/Vertical
The subjective visual vertical (SVV), horizontal (SVH) is the most sensible test on an acute unilateral peripheral or central vestibular lesion: In more than 90% of all acute single-sided peripheral or central vestibular lesions there is a pathological deflection of the SVV/SVH. The subjective vertical serves the examination of the otolith function of the horizontal or the vertical semicircular canal.
Vestibular Evoked Myogenic Potentials (VEMP)
These potentials serve the utriculus-, sacculus diagnostics (otolith organs) (in case of e. g. M. Meni´re). Ocular and cervical vestibular evoked potentials are a reflex of the balance system to acoustic stimuli. The VEMP-test allows the diagnosis of most different diseases of the sacculus (Morbus Meni´re), of the otolith function and the function of the vestibular nerve (N. Saccularis) c-VEMP as well as the Utriculus o-VEMP. With the help of the cVEMP and oVEMP results it can be determined whether the upper and/or the lower part of the vestibular nerve is damaged in a peripheral vestibular way.
Revolving and Pendulum Chair
These rotation tests are more sensitive than caloric tests, though in most cases both tests are used to make a complete assessment of the vestibular nerve. Reactions of the vestibulocochlear system (semicircular ducts) to rotations with different speeds and movement patterns are performed and recorded by video nystagmography (VNG). Rotation tests produce less false-negative results than caloric tests and are solely suitable for compensated unilateral lesions and bilateral vestibular lesions.
Caloric Examination of the Vestibular System
While being examined the patient lies on the back, his head slightly raised. To make orientation in the room impossible the eyes are covered by VNG goggles. By rinsing the auditory canal with cold or warm air (86 F, 11,2 F) a movement of the endolymph in the vestibular organ is triggered, which is related with vertigo. In case of an intact vestibular organ a nystagmus, i. e. a typically sidewise twitch of the eye, can be observed and analysed. In most cases the eye moves to the direction of the irritated ear, when the ear is rinsed with warm air, and to the opposite direction when the ear is rinsed with cold air. By this technique patients with defects of the eardrum can be examined, too.
Head Impulse Test (HIT)
The Head Impulse Test (HIT) checks the function of all three semicircular canals and by this the ability of view stabilization in case of quick accelerations of the head in the optimal stimulation levels.
- Fixation suppression test
- Slow eye movement
- Optokinetic test
Disturbances of the eye movement or a nystagmus may originate from regions of the brainstem. Symptoms are amongst other things rotary or staggering vertigo caused by e. g. an acute loss of the acoustic labyrinth, an infarct of the brainstem or cerebellar diseases.
Before considering unhealthy eye movements an enumeration of the six physiological forms is given:
- eye movement, the eye follows a moving eye target
- saccades, which are sudden eye dashes from one fixation spot to another
- vergences, which are movements, in which the eyes do not move parallel, but relatively to each other
- vestibulo-ocular reflex (VOR, the signal triggering the eye movement originates from the acoustic labyrinths) and
- optokinetic reflex (consisting of slow eye movements and saccades).
All these eye movements serve to keep the eye target on the macula stable in order to avoid oscillopsias and blurred vision.
Instrument-Based Vertigo Training
By means of a posturographical platform patterns can be trained on a separate video system.