Posttraumatic Peripheral Vertigo / 대한평형의학회지

Posttraumatic vertigo can be defined as the vertiginous disorder occurred after head and neck trauma without other pre-existing vestibular disorder. Central, peripheral, and combined deficits might cause this condition. Especially, various peripheral vestibulopathies are possible causes of posttraumatic vertigo; benign paroxysmal positional vertigo, temporal bone fracture, perilymphatic fistula, labyrinthine concussion, posttraumatic hydrops, and cervical vertigo. Since the differential diagnosis of the posttraumatic vertigo is often difficult, it is essential to acquire knowledge of their pathophysiology and clinical features. In this review, peripheral vestibulopathy as the possible causes of posttraumatic vertigo were described according to the current literature.

Vestibulo-ocular reflex and the head impulse test / Reflexo vestíbulo-ocular e o teste do impulso da cabeça

The authors highlights the importance of the vestibulo-ocular reflex examination through the head impulse test as a diagnostic method for vestibular dysfunction as well as, and primarily, a bedside semiotic resource capable of differentiating between acute peripheral vestibulopathy and a cerebellar or brainstem infarction in emergency rooms.

Os autores ressaltam a importância do exame do reflexo vestíbulo-ocular por meio do teste do impulso da cabeça como método diagnóstico de hipofunção vestibular. Este método é também - e principalmente - um instrumento semiótico de beira do leito capaz de auxiliar no diagnóstico diferencial entre a vestibulopatia periférica aguda e o infarto cerebelar ou do tronco cerebral na sala de emergência.

Pseudo-Vestibular Neuritis Caused by a Vascular Tumor Involving the Anterior Inferior Cerebellum / 대한평형의학회지

Acute vestibular syndrome (AVS) is characterized by the rapid onset of dizziness/vertigo accompanied by nausea/vomiting, gait unsteadiness, and nystagmus lasting a day or more. Some patients with AVS have potentially dangerous central etiologies. AVS caused by central etiologies without significant other neurologic deficit, so called pseudo-vestibular neuritis (pseudo-VN), could be difficult to be differentiated from acute vestibular neuritis. In addition to imaging studies, bedside oculomotor examination-head impulse test, nystagmus and test of skew)-is essential to identify patients with pseudo-VN. Among several central causes of AVS, brain tumor is extremely rare. We report a case of vascular tumor involving the anterior inferior cerebellum with AVS presentations.

Isolated Flocculus Infarction Mimicking Acute Labyrinthitis

Acute vestibular syndrome characterized by vertigo, spontaneous nystagmus, and postural instability is caused by a unilateral injury to either peripheral or central vestibular structures. However, central vestibular syndromes, such as labyrinthine ischemia due to occlusion of anterior inferior cerebellar artery (AICA), may cause abrupt unilateral labyrinthine dysfunction that mimics peripheral vestibulopathy. Here we report an AICA infarction with isolated flocculus lesion on magnetic resonance imaging mimicking acute labyrinthitis with vertigo, unidirectional horizontal-torsional nystagmus, ipsilesional sensorineural hearing impairment, and positive head-thrust test without any typical findings of floccular lesion.

Vestibular Evoked Myogenic Potential: Recording Methods and Clinical Application

Only a few tests can evaluate the function of the saccule and inferior vestibular nerve. Vestibular-evoked myogenic potentials (VEMP) are inhibitory potentials recorded in the contracting muscles, usually in the sternocleidomastoids (SCM), when sound stimuli are applied. A disynaptic pathway originating in the saccule is known to mediate VEMP. The main pathway of saccule-induced inhibitory postsynaptic potentials to ipsilateral SCM motoneurons seems to be the medial vestibulospinal tract which descends within the medial longitudinal fasciculus. VEMP have been applied to determine saccular function in many disorders involving the peripheral vestibular apparatus. However, the characteristics and the diagnostic values of VEMP require further exploration in central vestibulopathies. In this review, the basic principles and recording methods of VEMP are overviewed. We will also review VEMP responses found in central as well as peripheral vestibular disorders. Despite several issues that need further elucidation, such as the exact neural pathway mediating VEMP, aging effects on VEMP, and normalization of the muscle contraction during the recording, VEMP allows us exclusive information on the function of saccule and its neural pathway, which cannot be provided by other vestibular function tests.

Vestibular Neuritis and Bilateral Vestibulopathy

Vestibular neuritis is the second most common cause of peripheral vestibular vertigo. The key signs and symptoms are the acute onset of sustained rotatory vertigo without hearing loss, postural imbalance with Romberg's sign, and peripheral type nystagmus. Head thrust and caloric tests show ipsilateral hyporesponsiveness, but hearing test shows normal. Either an inflammation of the vestibular nerve or labyrinthine ischemia was proposed as a cause of vestibular neuritis. Recovery after vestibular neuritis is usually incomplete. Despite the assumed viral cause, the effects of corticosteroids, antiviral agents, or the two in combination are uncertain. Bilateral vestibulopathy is a rare disorder of the peripheral labyrinth or the eighth nerve. The most frequent etiologies include ototoxicity, autoimmune disorders, meningitis, neuropathies, sequential vestibular neuritis, cerebellar degeneration, tumors, and miscellaneous otological diseases. The two key symptoms are unsteadiness of gait and oscillopsia associated with head movements or when walking. The diagnosis is made with the simple bedside tests for defective vestibulo-ocular reflex (head thrust and dynamic visual acuity tests). Bilateral vestibulopathy is confirmed by the absence of nystagmus reaction to both caloric and rotatory chair tests. The spontaneous recovery is relatively rare and incomplete. Vestibular rehabilitation is supportive of the improvement, but the efficacy of physical therapy is limited.

Unilateral Peripheral Vestibulopathy associated with Cerebral Venous Infarction

Cerebral venous infarction is associated with a wide variety of clinical symptoms and signs, which may often delay appropriate diagnosis. Unilateral vestibular deficit as a presenting sign of cerebral venous infarction has rarely been reported. We report a patient with cerebral venous infarction who had severe prolonged vertigo, vomiting, occipital headache, positive head thrust testing, and unilateral caloric weakness as main clinical features. Although the patient had occipital headache, overall symptoms and signs closely mimicked those of acute peripheral vestibulopathy.

Significance of Vestibular Evoked Myogenic Potentials in Peripheral Vestibulopathy

BACKGROUND: Loud monaural clicks evoke myogenic potentials in the tonically contracting ipsilateral sternocleido-mastoid muscle. Clinical studies have suggested that these myogenic potentials are of vestibular origin, especially inferior vestibular nerve. Neurophysiological experimental studies also suggest that they are most likely to be of saccular origin. These potentials are called vestibular evoked myogenic potentials (VEMPs). Vestibular neuritis (VN) affects only part of the vestibular nerve trunk, usually the superior division (horizontal canal paresis) which may be detected by caloric test. But inferior vestibular nerve involvement in VN may not be detected by caloric test. So we compared the results of caloric test and VEMPs in patients with VN, in order to evaluate inferior vestibular nerve function. METHODS: Twenty-one normal controls were selected to determine the normal data of VEMPs. Patients group was consisted of clinically suspected peripheral vertigo [vestibular neuritis 10, benign paroxysmal positional vertigo of the posterior semicircular canal (PSC-BPPV) 7, Meniere's disease 3]. Caloric test and VEMPs were performed in all subjects according to our protocol. RESULTS: Normal VEMPs responses were found in all control groups. In all VN patients, caloric test was unilaterally abnormal and abnormal VEMPs was found in 4 of 10 VN patients. In patients with PSC-BPPV, abnormal caloric response was found in 2 of 7 patients but p13/n23 in VEMPs was present normally in all patients. CONCLUSIONS: These results suggest that VEMPs could provide different information from the caloric test and could be helpful in evaluating inferior vestibular nerve involvement in patients with peripheral vestibulopathy. (J Korean Neurol Assoc 19(5):498~502, 2001)

Platelet Aggregability in the Patients with Peripheral Vestibulopathy / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Circulatory disturbance to vestibular organ has been regarded as one of the causes that bring about vertigo, and alteration of the platelet function is known to be an important factor inducing circulatory deficit. This study was designed to evaluate platelet aggregability in the patients with peripheral vestibulopathy, and to evaluate difference according to duration of illness. MATERIALS AND METHODS: Platelet aggregation tests to adenosine diphosphate (ADP), ristocetin, epinephrine and collagen were performed in 10 normal subjects and 15 patients with peripheral vestibulopathy. Maximum aggregation rates from aggregation curves were compared between the two groups, and also between the two groups of patients who had different duration of illness. RESULTS: In the patient group, platelet aggregations to ADP, ristocetin and collagen were increased compared to normal subjects and significant differences were found in aggregations to ADP and ristocetin. However, there was no significant difference according to different duration of illness in the patient group. CONCLUSION: These results suggest that platelet aggregability is increased in the patients with peripheral vestibulopathy, and duration of illness does not affect platelet aggregability.

Diagnostic Value of Velocity Step Rotational Test on Unilateral Peripheral Vestibulopathy / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Rotational chair tests are divided into two categories according to the types of stimuli, namely, the velocity step test and the sinusoidal harmonic acceleration (SHA) test. In particular, the velocity step test evaluates the pattern of nystagmic responses to the step rotational stimuli. However, its diagnostic value has not been well documented. This study attempts to answer the following three questions: 1) what is the most useful parameter of the velocity step rotational test in the diagnosis of the unilateral peripheral vestibulopathy, 2) what is the normal range of parameters in the velocity step test, 3) what is the clinical usefulness of the velocity step rotational test in the diagnosis of compensation status and the localization of the peripheral vestibulopathy. MATERIALS AND METHODS: Velocity step rotational tests were performed in twenty patients diagnosed with unilateral peripheral vestibulopathy at Dankook University Hospital. The five parameters of the test, namely, gain, initial velocity, duration, slow cumulative eye position (SCEP) and a time constant, were compared with those of the controls (n=32). We divided the patients into the compensated and the uncompensated groups, and evaluated the differences among the patient groups and the control group. RESULTS: SCEP was apparently the most useful parameter, as shown by the Receiver Operating Characteristics (ROC) analysis. SCEP (m+/-sd) of the compensated and the uncompensated groups were 341.1+/-92.9degrees, 170.9+/-134.0degrees, respectively. These values were significantly different from those of the control group (537.7+/-157.5degrees). The values between the uncompensated group and the compensated group were also significantly different. CONCLUSION: Directional preponderance as well as the raw value of the parameters proved to be useful in confirming the degree of compensation in unilateral peripheral vestibulopathy.

Active Head Rotation Test in Unilateral and Bilateral Peripheral Vestibulopathy / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Active head rotation test measures vestibulo-ocular reflex at frequencies of 1 Hz to 8 Hz which correspond to the frequencies of head movements in daily living. However, the normative data of several authors are not in unity, and the usefulness of the test in the evaluation of the peripheral vestibulopathy is yet to be determined. The purpose of this study is to make our own normative data using our own testing condition and facilities and to evaluate the usefulness of the test in the evaluation of the peripheral vestibulopathy. MATERIALS AND METHODS: Active head rotation test was performed in 22 controls and 34 peripheral vestibulopathy patients (24 unilateral, 10 bilateral) using the VORTEQ system in darkness with eyes open (VOR-EO). Gain, phase and symmetry were compared between the control group and the patient groups. RESULTS: The control group showed the gain of 1.0 to 1.1 at frequencies of 1 Hz to 4 Hz. Phase was between 4 to 7 degrees, and symmetry was close to zero. Unilateral vestibulopathy group did not show a significant difference in gain, phase and symmetry from the normal group at the majority of frequencies. Bilateral vestibulopathy group showed a significant gain reduction compared to the normal group and unilateral group (p<0.05). But phase and symmetry were not significantly different. CONCLUSION: The active head rotation test was not useful in evaluating unilateral peripheral vestibulopathy although it was useful in assessing funcitonal deficit of VOR in bilateral vestibulopathy.