CVT Assessment & Diagnosis of Vestibular Disorders 1 — Questions and Answers

Question 1: Which test evaluates the function of the semicircular canals?

Head impulse test (Correct answer)
Weber test
Rinne test
Romberg test

Correct answer: Head impulse test

The Head Impulse Test (HIT), also known as the Head Thrust Test, is a quick bedside test specifically designed to assess the function of the semicircular canals, particularly the horizontal canals. It involves rapidly turning the patient's head while they fixate on a target. A corrective saccade (a 'catch-up' eye movement) indicates a deficit in the vestibulo-ocular reflex (VOR) on the side of the head turn, suggesting hypofunction of that semicircular canal.

Question 2: What does the Dix-Hallpike maneuver assess?

Central vestibular function
Benign paroxysmal positional vertigo (BPPV) (Correct answer)
Hearing thresholds
Sinus infections

Correct answer: Benign paroxysmal positional vertigo (BPPV)

The Dix-Hallpike maneuver is a diagnostic test used to identify Benign Paroxysmal Positional Vertigo (BPPV). It involves specific head and body movements designed to provoke vertigo and nystagmus if otoconia (calcium carbonate crystals) have dislodged into one of the semicircular canals, most commonly the posterior canal. The characteristic nystagmus and vertigo confirm the diagnosis and help identify the affected canal.

Question 3: Which imaging technique is commonly used to rule out central causes of dizziness?

X-ray
MRI (Correct answer)
Ultrasound
CT of the abdomen

Correct answer: MRI

Magnetic Resonance Imaging (MRI) is the preferred imaging technique for evaluating central causes of dizziness and vestibular symptoms. It provides detailed images of the brainstem, cerebellum, and other central nervous system structures, allowing clinicians to identify conditions such as tumors, strokes, multiple sclerosis, or other lesions that could be affecting vestibular pathways. This helps differentiate central from peripheral vestibular disorders.

Question 4: What symptom often distinguishes peripheral from central vestibular disorders?

Gradual onset
Auditory symptoms such as hearing loss (Correct answer)
Visual hallucinations
Seizure history

Correct answer: Auditory symptoms such as hearing loss

Peripheral vestibular disorders originate in the inner ear or the vestibular nerve, which are anatomically close to the cochlea (the hearing organ). Therefore, symptoms like hearing loss, tinnitus (ringing in the ears), or aural fullness often accompany peripheral vestibular issues, such as Ménière's disease or labyrinthitis. Central vestibular disorders, affecting the brain, typically do not present with these auditory symptoms.

Question 5: Which condition is characterized by episodes of vertigo, tinnitus, and hearing loss?

Vestibular neuritis
Labyrinthitis
Ménière’s disease (Correct answer)
Acoustic neuroma

Correct answer: Ménière’s disease

Ménière’s disease is a chronic inner ear disorder characterized by a classic triad of symptoms: episodic rotational vertigo, fluctuating sensorineural hearing loss, and tinnitus, often accompanied by aural fullness. These symptoms are believed to be caused by an abnormal buildup of endolymphatic fluid within the inner ear, known as endolymphatic hydrops, which disrupts the normal function of the vestibular and auditory systems.

Question 6: What does spontaneous nystagmus suggest during examination?

Normal function
Bilateral symmetry
Acute vestibular dysfunction (Correct answer)
Improved recovery

Correct answer: Acute vestibular dysfunction

Spontaneous nystagmus, which is nystagmus that occurs without any specific head movement or visual stimulus, is a key indicator of acute vestibular dysfunction. It suggests an imbalance in the tonic firing rate between the two vestibular systems, often seen in conditions like vestibular neuritis or acute labyrinthitis. The direction and characteristics of the nystagmus can help localize the lesion to a peripheral or central origin.

Question 7: Why is patient history critical in diagnosing vestibular disorders?

To evaluate muscle tone
To determine range of motion
To identify patterns in vertigo and dizziness (Correct answer)
To rule out diabetes

Correct answer: To identify patterns in vertigo and dizziness

A thorough patient history is paramount in diagnosing vestibular disorders because symptoms like vertigo and dizziness can be vague and have numerous causes. Eliciting details about the onset, duration, triggers, associated symptoms (e.g., hearing loss, nausea), and the specific quality of dizziness helps clinicians identify characteristic patterns. This information guides the differential diagnosis and subsequent physical examination, significantly narrowing down potential conditions.

Question 8: What is the purpose of the Romberg test in vestibular assessment?

To test eye movement
To assess gait
To detect balance deficits (Correct answer)
To evaluate hearing thresholds

Correct answer: To detect balance deficits

The Romberg test is a common clinical assessment used to evaluate static balance and proprioception. The patient stands with feet together, first with eyes open and then with eyes closed. Increased sway or loss of balance when eyes are closed suggests a proprioceptive or vestibular deficit, as the patient is unable to compensate for the lack of visual input, highlighting a reliance on vision for stability.

Question 9: What does caloric testing assess?

Middle ear pressure
Tympanic membrane mobility
Horizontal canal function (Correct answer)
Cochlear function

Correct answer: Horizontal canal function

Caloric testing, a component of videonystagmography (VNG), assesses the function of the horizontal semicircular canals. It involves irrigating the ear canal with warm or cool air/water, which creates a temperature gradient that induces endolymphatic flow within the horizontal canal. This stimulates the vestibular system, provoking nystagmus, and the characteristics of this nystagmus provide information about the integrity and symmetry of the horizontal canal's function.

CVT Assessment & Diagnosis of Vestibular Disorders 1

Which test evaluates the function of the semicircular canals?