Benign paroxysmal vertigo - Diagnosis

In benign paroxysmal positional vertigo, the anamnesis does not provide comprehensive information for establishing a diagnosis. It is more important to conduct an examination of the patient by a neurologist or otoneurologist according to a standard protocol. Specific tests for establishing benign paroxysmal positional vertigo are the Dix-Hallpike, Brandt-Daroff, and other positional tests.

The Dix-Hollgayk positional test is performed as follows: the patient sits on a couch and turns his head 45 degrees to the right or left. Then the doctor, fixing the patient's head with his hands, quickly moves him to a supine position, while the patient's head hangs over the edge of the couch and is in a relaxed state, held by the doctor's hands. The doctor observes the patient's eye movements and asks him about the occurrence of dizziness. It is necessary to warn the patient in advance about the possibility of the occurrence of dizziness typical for him and convince him of the reversibility and safety of this condition. The nystagmus that occurs in this case, typical for benign paroxysmal positional vertigo, necessarily has a latent period, which is associated with some delay in the movement of the clot in the plane of the canal or the deviation of the cupula when the head is tilted. Since the particles have a certain mass and move under the action of gravity in a liquid with a certain viscosity, there is a short period of sedimentation velocity gain.

Typical positional nystagmus for benign paroxysmal positional vertigo is rotational and directed toward the ground (geotropic). This is characteristic only of pathology of the posterior semicircular canal. The rotational direction of nystagmus is due to the organization of the weight of the tibulo-ocular reflex from the posterior semicircular canal, in which the end link is the eye muscles, including the oblique ones, the contraction of which causes rotational movement of the eyes. When the eyes are diverted in the opposite direction from the ground, vertical movements can be observed. Nystagmus, characteristic of pathology of the horizontal canal has a horizontal direction, for the anterior - torsional, but directed away from the ground (ageotropic).

The latent period (the time from the execution of the nucleon to the appearance of nystagmus) for pathology of the posterior and anterior semicircular canals does not exceed 3-4 sec., for horizontal - 1-2 sec. The duration of positional nystagmus for canalolithiasis of the posterior and anterior canals does not exceed 30-40 sec., horizontal 1-2 min. Cupulolithiasis is characterized by a longer positional nystagmus. The typical positional nystagmus of benign paroxysmal positional vertigo is always accompanied by dizziness, which occurs together with nystagmus, decreases and disappears also harmoniously. When a patient with benign paroxysmal positional vertigo returns to the original sitting position, one can often observe reverse nystagmus and dizziness, directed in the opposite direction and, as a rule, less pronounced than when bending. When the test is repeated, nystagmus and dizziness are repeated with harmoniously reduced characteristics.

When examining the horizontal semicircular canal to determine benign paroxysmal positional vertigo, it is necessary to turn the patient's head and body, lying on his back, to the right and left, respectively, with the head fixed in certain positions. For benign paroxysmal positional vertigo of the horizontal canal, positional nystagmus is also specific and is accompanied by positional vertigo.

Patients with benign paroxysmal positional vertigo experience the greatest imbalance in a standing position with their head thrown back or turned in the plane of the affected canal, which was shown in studies using statokinetic tests and objective electronic systems for recording deviations in the center of gravity.

Laboratory research

Laboratory tests have no specific manifestations in benign paroxysmal positional vertigo, but in a small group of patients with macroglobulinemia they can help identify the etiology of the disease.

Instrumental research

It should be taken into account that benign paroxysmal positional vertigo is accompanied by peripheral vestibular nystagmus, which is suppressed by gaze fixation, so it is not always possible to register it during visual examination of the patient. It is recommended to use devices that enhance visual observation of nystagmus and eliminate gaze fixation. The simplest devices are Blessing or Frenzel glasses with astigmatic or dioptric (+20) lenses. Electrooculography in its traditional design does not allow registering torsional (rotational) eye movements, but makes it possible to obtain information on the horizontal and vertical components of the nystagmus cycle. Modern diagnostic video oculography systems, consisting of opaque glasses with built-in infrared tracking cameras and mathematical processing of eye movements, allow for objective and highly accurate registration of nystagmus. As a rule, such diagnostic systems record not only nystagmus, but also the patient’s position at the time of the examination and comments on his sensations.

Differential diagnosis of benign paroxysmal vertigo

Benign paroxysmal positional vertigo is accompanied by positional vertigo caused by pathology of the inner ear. However, positional vertigo can also have central causes. First of all, these are diseases of the posterior cranial fossa, including tumors, which are characterized by the presence of neurological symptoms, severe balance disorder and central positional nystagmus.

Central positional nystagmus is characterized, first of all, by a special direction (vertical or diagonal); fixation of the gaze does not affect it or even intensifies it, it is not always accompanied by dizziness and does not wear off (it lasts for the entire time the patient is in the position in which it appeared).

Positional nystagmus and dizziness may accompany the development of multiple sclerosis and vertebrobasilar insufficiency, but in this case, neurological symptoms characteristic of both diseases will be recorded.

Indications for consultation with other specialists

The most important specialists for the diagnosis of benign paroxysmal positional vertigo are a neurologist and an otolaryngologist (otoneurologist or audiologist). Since this disease has specific manifestations (positional nystagmus and positional vertigo), consultations with other specialists and additional research methods, except for vestibulometric ones, are not required to establish a diagnosis.

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