Vestibular Examination Methods

Vestibular Examination Methods consist of a) a detailed interview of the patient regarding their complaints and subjective sensations related to the static apparatus, and b) the objective examination of the vestibular apparatus. This examination is divided into 1) the study of Romberg's sign, 2) the examination of rapid head movements, 3) the examination of gait, 4) the pointer test and the test of arm tone, 5) the determination of the reaction to counter-rotation of the eyes, 6) the determination of the presence or absence of spontaneous nystagmus, 7) the examination of pressor nystagmus, 8) the examination of rotary reaction, 9) calorific reaction, and 10) galvanic reaction. During the interview, the patient is asked whether they experience dizziness, nausea, or vomiting. If dizziness is present, its nature is established (constant dizziness or periodic, nausea and vomiting in a certain position of the patient, rotation of objects before the patient to one side or the other, etc.). The objective examination begins with the examination of 1) Romberg's sign: the patient is made to stand with their feet together with their eyes closed. Normally, a slight swaying in the sagittal plane can be noted. This physiological swaying is more pronounced in neurasthenics. In the presence of Romberg's sign (a "positive Romberg"), it is usually most frequently necessary to differentiate between neurasthenia, hysteria, tabes, cerebellar disease, and labyrinthine disease. Falling in hysterics is usually backward; unlike falling in labyrinthine and cerebellar disease, hysterics fall back carefully and make no attempt to maintain balance. Falling in tabes differs from falling in labyrinthine disease in the acute stage: in a tabetic, swaying decreases if the patient is allowed to feel a wall with their finger, which cannot be noted in labyrinthine disease; furthermore, in a tabetic, closing the eyes increases the intensity of swaying, which does not occur in labyrinthine or cerebellar diseases. In cases of labyrinthectomy and in chronic cerebellar diseases, falling differs from cases of acute labyrinthitis and acute disease of the central vestibular system: in the latter cases, there is a strong tendency to fall in one specific direction. 2. The study of nystagmus (see below) during rapid head movements is performed in cases of suspicion of cysticercosis of the fourth ventricle, cerebellar tumor, multiple sclerosis, traumatic neurosis, limited labyrinthitis, disease of the bony capsule of the labyrinth; this nystagmus can also be expressed in some complicated cases of adhesive catarrh of the middle ear. During a rapid turn of the head to the affected side, a sharply expressed rotatory nystagmus in the same direction can sometimes be noted in the aforementioned diseases, accompanied by dizziness. In this, unlike diseases of the fourth ventricle, in labyrinthine disease it should be noted that the aforementioned nystagmus is rapidly exhausted. 3. The examination of gait so far gives few points of support for differential diagnosis. Nevertheless, it has been established that in the acute stage of labyrinthitis, a distinct deviation of gait to the affected side can be noted. The examination of gait can have some diagnostic value in the presence of simultaneous deviation (see below) to the same side in cases of otolith damage. 4. The examination of the pointer test is performed as follows: the doctor sits in front of the patient with an arm extended forward and the index finger; the patient with closed eyes tries to hit the doctor's finger with their own extended index finger, as the doctor's hand moves from their knee upward, then lowers the hand again and hits again. In cases of cerebellar disease, as well as with experimental irritation of the labyrinth by rotation or calorization, normal hitting does not occur, and in such cases one speaks of deviation. Based on a whole series of considerations and experiments by Barany (Vágvölgyi), he attempts to find paths for the typical diagnosis of cerebellar lesions. However, it turns out that deviation can depend on a whole series of causes and, first of all, on the semicircular canals, on the position of the head, on the position of the eyes, and on the otoliths. Incidentally, in cases of deviation and deviation of gait in the same direction, otolith apparatus damage is diagnosed, according to Quix, but in this case both gait and the pointer test are examined in the following positions of the head: head straight, head on the right shoulder, on the left shoulder, head forward and head backward. The absence of deviation after experimental irritation of the labyrinth speaks with great probability for cerebellar damage. Closely related to the question of the examination of the pointer test is the examination of arm tone (Arm tone reaction Wodak-Fischer's), since both these tests belong to so-called tonic reactions. If the patient is made to sit with their hands extended horizontally forward in the supination position and cold water is poured into the auditory canal, the same hand drops, while the opposite hand rises. In some lesions (especially of cerebellar pathways), such deviations can occur spontaneously. For differential diagnosis, this test, like the pointer test, requires further study. 5. Counter-rotation of the eyes occurs when the position of the head changes. Therefore, each position of the head corresponds to a certain position of the eyes. To study these counter-rotations, Barany constructed a special instrument. According to Barany, when the head is deviated to the shoulder by 60°, counter-rotation in the normal state varies from 4 to 16°. At present, the described reaction is used primarily, but not exclusively, to study the function of the otolith apparatus. 6. By labyrinthine, or vestibular, nystagmus is meant the reflex of the labyrinth on the eyes, expressed in visible rhythmic jerks of the eyeball. In this jerk, two components can be clearly distinguished: a slow and a fast one, continuously replacing each other with a certain regularity. Depending on the plane in which the nystagmus is directed, one speaks of horizontal, vertical, or rotatory nystagmus. The nystagmus is considered to be directed to the side to which its fast component is directed. Spontaneous nystagmus and reaction nystagmus are distinguished. In spontaneous nystagmus, there are spontaneous rhythmic jerks of the eyeball, which intensify if the patient is made to fix the doctor's finger at a distance of ¹/₂ m from the examined eye, deviated to the side of the fast component. Experimentally induced nystagmus is divided into pressor nystagmus, rotary nystagmus, calorific nystagmus, and galvanic nystagmus. 7. By concentrating or rarefying air in the auditory canal using a Politzer balloon, for example, in the presence of a fistula in the labyrinth, one can sometimes obtain nystagmus to the ear being examined upon concentration and to the opposite side upon rarefaction of air ("fistula symptom"). However, even in the absence of a labyrinth fistula in some diseases (hereditary syphilis, hyperemia of the labyrinth, acute otitis media, etc.), it is sometimes possible to induce such nystagmus (fistula symptom without a fistula). 8. To determine rotary nystagmus, resp. rotary reaction, the examined patient is rotated on a special chair for rotation 10 times over 20 seconds (1 revolution in 2 seconds) and the nystagmus is observed after the rotation has stopped (post-reactionary nystagmus, or post-nystagmus). Rotation is to the right, and then to the left. Normally, the duration of post-nystagmus to the right and to the left should be approximately the same and, on average, equal to 25 seconds. In the case of damage to the function of one of the labyrinths, the duration of post-nystagmus shortens both to the right and to the left, but significantly more to the affected side. In recent times, some authors propose rotation by the method of weak stimuli (finding the threshold of excitability or reducing the number of rotations to 4-5). Precise generally accepted figures for this method are not yet available in the literature. 9. Calorific reaction according to Barany, resp. nystagmus, is obtained by pouring water below or above the body temperature into the auditory canal. In the first case, nystagmus is obtained to the opposite ear, in the second-to the ear into which water is poured. In the case of labyrinth paralysis, calorific nystagmus is usually not possible to induce. Kobrak proposed the method of weak stimuli, by which he determines the focus of calorific excitability (he caloricizes 5 cc of water, starting from 36°, gradually lowering to 1°). The significance of the calorific reaction is that, in contrast to the rotary reaction, it makes it possible to irritate each labyrinth in isolation. 10. Galvanic nystagmus can be obtained by attaching an electrode to the right and left concha. With a current strength from 2 to 5 mA, a horizontal-rotatory nystagmus is obtained in the normal state, the fast component of which is directed toward the cathode. The galvanic reaction is often possible to obtain where rotary and calorific reactions are absent. In such cases, at least, one can speak of the integrity of the retro-labyrinthine part of the nerve.