Vestibular Disorders: Pearls and Pitfalls

Woo Young Choi, MD, PhD, FRCPC; Daniel R. Gold, DO

Semin Neurol. 2019;39(6):761-774.

Abstract and Introduction

Abstract

Dizziness and vertigo are symptoms that commonly lead patients to seek neurologic or emergency care. Because symptoms are often vague and imprecise, a systematic approach is essential. By categorizing vestibular disorders based on the timing, triggers, and duration of symptoms, as well as emphasizing focused ocular motor and vestibular examinations, the majority of vestibular diagnoses can be made at the bedside. This paper will discuss the pearls and pitfalls in the history and examination of the most common acute, episodic, and chronic vestibular disorders.

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Table 1. The most common vestibular conditions categorized by timing and triggers, with specific ocular motor and vestibular features that should be sought for each
	Vestibular conditions to consider	Targeted ocular motor and vestibular examinations
Acute vestibular syndrome (>24 h)	1. Vestibular neuritis 2. Stroke (demyelination and other central etiologies less common) 3. Wernicke's	1. HINTS + : HIT abnormal (see example—https://collections.lib.utah.edu/ark:/87278/sx398q2) AND unidirectional nystagmus that obeys Alexander's law (see example—https://collections.lib.utah.edu/ark:/87278/s64205qx) AND skew deviation absent (see alternate cover testing at 1 and 3 minutes—https://collections.lib.utah.edu/ark:/87278/s6tn1htv) AND no acute hearing loss; peripheral pattern of HSN 2. HINTS + : HIT normal (see demonstration in a normal patient—https://collections.lib.utah.edu/ark:/87278/s63b97tz) OR gaze-evoked nystagmus (see example—https://collections.lib.utah.edu/ark:/87278/s6kh4n5k) OR skew deviation present (see example—https://collections.lib.utah.edu/ark:/87278/s6c0045t) OR acute hearing loss; look for central patterns of HSN (see example—https://collections.lib.utah.edu/ark:/87278/s61c5vkg) 3. Bilaterally abnormal HIT, spontaneous vertical (see example—https://collections.lib.utah.edu/ark:/87278/s6h74j6d) and gaze-evoked nystagmus are common, also 6th NP, ataxia
Episodic spontaneous vestibular syndrome^a	1. TIA 2. Vestibular migraine 3. Meniere's 4. Vestibular paroxysmia	1. Usually symptoms have resolved and eye movement exam is normal; otherwise, may use HINTS^b 2. Can see peripheral or central patterns of nystagmus (spontaneous, gaze-evoked, head shaking-induced, positional) during the attack, often normal interictally; often spontaneous, but typical migraine triggers are common too 3. Nystagmus can be in excitatory or inhibitory patterns during the attack, often normal interictally 4. Hyperventilation-induced nystagmus (see demonstration in a normal patient—https://collections.lib.utah.edu/ark:/87278/s6pz98ht)
Episodic triggered vestibular syndrome	1. BPPV 2. Central positional vertigo or nystagmus 3. SCDS	1. Dix-Hallpike in posterior canal variant (see example—https://collections.lib.utah.edu/ark:/87278/s6s79d1w) and supine roll test in horizontal canal variant (with bow and lean to localize, see example—https://collections.lib.utah.edu/ark:/87278/s68h2wk9) 2. Consider this diagnosis when history/exam features are atypical for BPPV, including an unexpected nystagmus vector; downbeat (see video example https://collections.lib.utah.edu/ark:/87278/s66t3w9k) and apogeotropic nystagmus patterns are most common 3. Valsalva and pinched-nose Valsalva (see example—https://collections.lib.utah.edu/details?id=1213443), tragal compression, loud sounds
Chronic vestibular syndrome	1. BVL 2. PPPD 3. Cerebellar disease 4. Acoustic neuroma 5. Oculopalatal tremor	1. Bilaterally abnormal HIT (see example—https://collections.lib.utah.edu/ark:/87278/s62z4z8g), additional cerebellar signs can narrow differential and loss of four or more lines with dynamic visual acuity (see example of how to perform this maneuver—https://collections.lib.utah.edu/ark:/87278/s6tn19w8) 2. No typical ocular motor/vestibular findings 3. Flocculus/paraflocculus: gaze-evoked nystagmus, spontaneous downbeat nystagmus, saccadic pursuit and VORS (when VOR is present), saccadic dysmetria (see example—https://collections.lib.utah.edu/ark:/87278/s6dj8q9h), alternating skew deviation (see example—https://collections.lib.utah.edu/ark:/87278/s6d83n91) while additional vestibular loss can narrow differential (e.g., CANVAS, see example—https://collections.lib.utah.edu/ark:/87278/s6s50fth) Nodulus/uvula: periodic alternating nystagmus (see example— https://collections.lib.utah.edu/ark:/87278/s62k013r) 4. Hyperventilation-induced nystagmus (see example—https://collections.lib.utah.edu/ark:/87278/s63f8cgs), and Brun's nystagmus (see example—https://collections.lib.utah.edu/ark:/87278/s60p4p3j) 5. Vertical or vertical–torsional pendular nystagmus with palatal tremor (see example—https://collections.lib.utah.edu/ark:/87278/s6mh1mnm)

Abbreviations: BPPV, benign paroxysmal positional vertigo; BVL, bilateral vestibular loss; CANVAS, cerebellar ataxia, neuropathy, vestibular areflexia syndrome; HIT, head impulse test; HINTS +, head impulse, nystagmus, test of skew, "Plus" bedside assessment of auditory function; NP, nerve palsy; PPPD, persistent postural perceptual dizziness; SCDS, superior canal dehiscence syndrome.
^aIf first attack of TIA, vestibular migraine or Meniere's, may be better described as the acute transient vestibular syndrome (<24 hours).
^bHINTS has been studied in the acute vestibular syndrome, and should not be relied upon in the episodic or acute transient vestibular syndrome.
Source: Neuro-Ophthalmology Virtual Education Library: NOVEL. (online) Available from: https://collections.lib.utah.edu/ark:/87278/s68d47vr.

Table 2. Most commonly performed audiovestibular laboratory tests, and the specific conditions in which they may assist in making or supporting the diagnosis
Test	TIA/stroke	VN	VM	Meniere's	SCDS	BPPV	VP	BVL	PPPD	Cerebellar syndrome	Acoustic neuroma
Audiogram	+	+	+	++	++	−	+	++	−	−	++
vHIT	+	++	−	−	−	−	−	++	−	+	++
VNG, ENG or VOG	+^a	+^a	−	−	+^b	+^b	+^b	−	−	−	+^b
Rotary chair	−	+^c	+^c	−	−	−	−	++	−	−	+
Calorics	+^d	++	−	+	−	−	−	++	−	−	++
VEMPs	−	+^e	−	+	++	−	−	+	−	−	−
Imaging^f	++	−	+	+	++	−	++	+(+)	−	++	++

Abbreviations: BPPV, benign paroxysmal positional vertigo; BVL, bilateral vestibular loss; ENG, electronystagmography; PPPD, persistent postural perceptual dizziness (no specific test is helpful to make this diagnosis, but patients often develop PPPD as the result of another poorly treated or anxiety-provoking vestibular disorder, e.g., vestibular migraine, BPPV or vestibular neuritis); VEMPs, vestibular evoked myogenic potentials; vHIT, video head impulse test; VM, vestibular migraine; VN, vestibular neuritis; VNG, video-nystagmography; VOG, videooculography; VP, vestibular paroxysmia; SCDS, superior canal dehiscence syndrome.
Source: Neuro-Ophthalmology Virtual Education Library: NOVEL. [online] Available from: https://collections.lib.utah.edu/ark:/87278/s6zh14pc.
Note: (−) Not usually helpful; (+) may be helpful; (++) very helpful.
^aIn the acute setting when spontaneous nystagmus is present.
^bDuring provocative maneuvers (including Valsalva, pinched-nose Valsalva, tragal compression, loud sounds, Dix-Hallpike/supine roll test, hyperventilation).
^cRotary chair may show slightly low time constants and gains with unilateral vestibular loss, and may show prolonged time constants in migraine.
^dDepending on the posterior fossa localization, there may be caloric weakness with some strokes.
^eVEMPs may assist in the localization of inferior versus superior division vestibular neuritis.
^fNeuroimaging is needed (MRI internal auditory canal [IAC]) protocol w/wo) in migraine and Meniere's cases where there is diagnostic uncertainty or atypical features. In SCDS, CT temporal bones is the test of choice. For vestibular paroxysmia, heavily T2-weighted CISS or FIESTA imaging. In BVL, if the cause is clearly ototoxicity from gentamicin for instance, neuroimaging will not be helpful. Otherwise, neuroimaging is essential.
For additional reading on audiometry: https://collections.lib.utah.edu/details?id=1306738.
For additional reading on vHIT: https://collections.lib.utah.edu/ark:/87278/s62n91vq.
For additional reading on VNG, ENG, and VOG: https://collections.lib.utah.edu/ark:/87278/s6fz193n.
For additional reading on rotary chair: https://collections.lib.utah.edu/ark:/87278/s6b60jbs.
For additional reading on calorics: https://collections.lib.utah.edu/ark:/87278/s6kq21sh.
For additional reading on VEMPs: https://collections.lib.utah.edu/ark:/87278/s66d9smh.

Box 1. Vestibular History
Pitfall • Overreliance on qualitative description of symptoms is an ineffective approach to most vestibular disorders and often leads to the wrong diagnosis. Pearls • Once medical and obvious nonvestibular conditions are excluded, the history should focus on symptom timing and the presence or absence of triggers. The diagnosis is usually made at this point (or the differential diagnosis is narrowed substantially), and the targeted exam either confirms the suspected etiology (e.g., DH in BPPV) or allows the clinician to select the appropriate diagnostic test (e.g., MRI and MR angiography in the setting of a HINTS exam suggesting a central cause).

Box 2. Vestibular Examination
Pitfalls • A normal general neurologic examination does not imply that the etiology of vertigo is peripheral; the ocular motor and vestibular bedside examination should be emphasized instead. • The DH maneuver should be performed and interpreted in the correct setting. It may aggravate symptoms in patients with any vestibular condition, but this should not be falsely interpreted as a positive DH. Pearls • The DH maneuver should be performed in patients with positionally-triggered symptoms. • Once an appropriate differential diagnosis is established based on the timing and triggers of vestibular symptoms, a targeted ocular motor and vestibular examination will commonly lead to the correct diagnosis (Table 1).

Box 3. Acute Vestibular Syndrome
Pitfalls • HINTS cannot be relied upon in patients with episodic vestibular disorders or in patients with continuous symptoms but without spontaneous nystagmus (e.g., a patient whose symptoms are due to a medical condition). • In the acute vestibular syndrome, the HINTS examination is more sensitive than neuroimaging, as CT misses approximately 90% of vestibular strokes, while MRI misses approximately 20% of vestibular strokes in the first 24 to 48 hours. Beware of patients with AICA territory ischemia, who may have peripheral and central vestibular signs, and assess auditory function to evaluate for labyrinthine (cochlear) ischemia. Pearls • HINTS and HINTS "Plus" are superior to MR-DWI in AVS in the first several days.

Box 4. Episodic Vestibular Syndrome, Triggered
Pitfalls • Not all forms of positional vertigo and nystagmus is benign; therefore, when atypical features (for BPPV) are present (especially when nystagmus is downbeat or apogeotropic), a posterior fossa disorder should be considered. Pearls • Repositioning maneuvers are highly effective in the treatment of BPPV, particularly for posterior and horizontal canal variants. • If triggers include sound or pressure, consider SCDS.

Box 5. Episodic Vestibular Syndrome, Spontaneous
Pitfalls • Before diagnosing a patient presenting with one or two vertigo attacks with vestibular migraine or Meniere's, first consider dangerous conditions, including dissection causing head/neck pain or hearing loss due to AICA ischemia. • If the head/neck pain associated with vertigo or dizziness is abrupt in onset, continuous, or severe, do not assume vestibular migraine is the cause; neuroimaging is indicated. Pearls • Mild aural symptoms (without low-mid frequency sensorineural hearing loss typical of Meniere's) are common in vestibular migraine. • Vascular loops that appear to contact the eighth cranial nerve are common incidental findings with CISS and FIESTA imaging. The diagnosis of vestibular paroxysmia is made based on history, examination, and often following an empirical trial of an antiseizure medication.

Box 6. Chronic Vestibular Syndrome
Pearls • Consider the diagnosis of PPPD in a patient who suffered an event that caused dizziness, vertigo or imbalance (especially in someone with pre-existing anxiety or who had a particularly anxiety-provoking response to the inciting event) that is followed by constant daily nonspinning dizziness with a postural component. • In patients with BVL, a comprehensive neurological examination is helpful in narrowing the differential in the absence of a clear trigger such as gentamicin. For example, if the patient also has cerebellar ocular motor signs (GEN, saccadic pursuit) and severe neuropathy, think about cerebellar ataxia, neuropathy, and vestibular areflexia syndrome (CANVAS). • A patient with chronic dizziness or imbalance and unilateral auditory dysfunction should undergo a contrast-enhanced MRI with IAC protocol to evaluate for an acoustic neuroma. Rarely, acoustic neuromas present with acute onset of vestibular or auditory symptoms or signs. • Visualization of the palate (looking for palatal tremor) is important in patients with chronic imbalance/ataxia. OPT can be diagnosed in a patient with pendular nystagmus months to years after a traumatic, hemorrhagic, or ischemic (less common) event. PAPT can be diagnosed in an ataxic patient without nystagmus.