Vestibular Dz & Differential Dx

What are the 3 types of peripheral vestibular disorders?

• Reduced

• Fluctuating

• Distorted

Describe reduced vestibular function.

• Reduced sensitivity of peripheral vestibular system to stimuli

• May be partial or complete

• Unilateral vs Bilateral hypofunction

What are some causes of reduced vestibular function?

• Direct damage to CN VIII, labyrinth, or hair cells

• Vestibular neuritis

• Age-related degeneration

• Drug induced ototoxicity

• Trauma

• Vascular occlusions

• Acoustic neuroma

What symptoms are commonly seen with a unilateral hypofunction?

• Rapid onset

• Severe rotational vertigo exacerbated by head movement

• Spontaneous nystagmus

• Postural instability

• Nausea

Which symptom is NOT present with a unilateral hypofunction?

Hearing loss

Which tests may have (+) results if a pt has a unilateral hypofunction?

• Observation → spontaneous nystagmus

• Gaze evoked nystagmus → follows Alexander’s law

• HIT → one side only

• HSN → nystagmus follows Alexander’s law

• DVA

What are causes of a bilateral vestibular hypofunction?

• Ototoxic drugs

• Meningitis (infection)

• Polyneuropathy

• Congenital malformations

• AGE

What are the primary clinical symptoms of a bilateral hypofunction?

• Oscillopsia

• Ataxic gait

• Imbalance

Which symptom is NOT present with a bilateral hypofunction?

Vertigo

Which tests may have (+) results if a pt has a bilateral hypofunction?

• HIT → both sides

• DVA

Describe fluctuating vestibular function.

• Conditions produce occasional disruption in vestibular input followed by periods of normal function

• Meniere’s Dz vs Perilymph fistula

What are some causes of fluctuating vestibular function?

• Idiopathic

• Autoimmune

• Trauma

• Infection

What are possible symptoms of fluctuating vestibular function?

• Episodic vertigo

• Possible hearing loss

• Tinnitus

• Disequilibrium

What is Meniere’s Disease?

• Increase in endolymph causes distention of membranous tissues

• Endolymph flows at rest causing vertigo

What are the main symptoms of Meniere’s Disease?

• Low frequency hearing loss

• Episodic vertigo

• Sense of fullness in the ear

• Tinnitus (roaring)

What can chronic Meniere’s Disease result in?

Unilateral hypofunction

Describe a typical Meniere’s Disease attack.

1. Sensation of fullness of ear, reduction in hearing, tinnitus (roaring)

2. Rotational vertigo, postural imbalance, nystagmus & N/V after few min

3. Severe disequilibrium lasting 30 min - 24 hours

4. Gradually, severe sx will decrease, generally ambulatory within 72 hrs

5. Postural unsteadiness could last for days or weeks after episode

For patients with Meniere’s Disease, when are vestibular exercises NOT recommended?

DURING an episode (attack)

Describe a perilymphatic fistula.

• Rupture of membranes that separate the middle & inner ear

• Perilymph leaks into middle ear causing vertigo and hearing loss

What are causes of a perilymphatic fistula?

• Head Trauma

• Deep water diving

For patients with a perilymphatic fistula, when is PT contraindicated?

• Acutely

• Membrane needs to heal or surgery happens

When is surgery performed for patients with a perilymphatic fistula?

ONLY if sx last >4 weeks

Describe distorted vestibular function.

• Due to mechanical disruption in typically functioning vestibular system

• BPPV

What are symptoms of distorted vestibular function?

• Nystagmus

• Temporary vertigo with change in head position

• Nausea w/ or w/out vomiting

• Disequilibrium

What are symptoms of BPPV?

• Brief episodes of vertigo

• Precipitated by rapid changes of head posture

Which sx are NOT present in BPPV?

• Hearing loss

• Aural fullness

• Tinnitus

Which tests will be (+) if a pt has BPPV?

ONLY positional testing

What damaged structures/pathologies can cause central vestibular dysfunction?

• Cerebellum

• Pons

• Medulla

• Central pathway

• CVA/TIA

• TBI (concussion)

• Tumors

• Demyelinating diseases (MS)

What are sx of a central dysfunction?

• Vertigo

• Nausea

• Nystagmus

• Ataxia

• Disequilibrium

• Visual field deficits

• Diplopia

• Headaches

• Sensory loss

• Hemiparesis

Which tests will be (+) if a pt has a central dysfunction?

• Observation → skew & nystagmus

• H-test

• Gaze evoked nystagmus → change direction

• Smooth Pursuit → jerky, jumpy, saccadic intrusion

• Saccades → hypermetria or hypometria

• Convergence

• DVA

What screen is used to differentiate between an acute peripheral vestibular dysfunction (vestibular neuritis) and a central disorder in the ER?

HINTS

What does HINTS stand for?

• HIT

• Nystagmus

• Test for Skew

What results on the HINTS would indicate an EMERGENCY central dysfunction?

• Normal HIT

• Direction changing nystagmus

• Vertical skew

Which condition is the HINTS NOT sufficient to detect?

AICA strokes

When would you use HINTS+ ?

When there are central signs but you get a (+) HIT

How is the HINTS+ different from the HINTS and what do the results mean?

• Adds bedside hearing test → finger rub next to ear

• Peripheral = normal hearing

• Central = hearing loss on side of (+) HIT

What 2 tests measure nystagmus and VOR and can help diagnose BPPV & a hypofunction?

• Electronystagmography (ENG)

• Vidionystagmography (VNG)

What test is performed during VNG that evaluates each labyrinth independently with water or air in the external auditory canal (EAC)?

Calorics

What does COWS stand for in calorics?

• Cold opposite → nystagmus toward contralateral ear

• Warm same → nystagmus toward ipsilateral ear