11.4 Vestibular Rehabilitation: BPPV, Hypofunction & Balance Retraining

11.4 Vestibular Rehabilitation: BPPV, Hypofunction & Balance Retraining

[!NOTE] DHA Licensing Competency Focus: Dizziness and imbalance are among the most common referrals an allied-health physiotherapist receives in Dubai outpatient and geriatric practice, and vestibular disorders sit inside DHA's published Neurorehabilitation coverage topic. Candidates must be able to separate peripheral from central vertigo before treating, name the correct positional test for each semicircular canal, select the matching repositioning maneuver, and prescribe adaptation versus habituation exercises for the correct diagnosis. Items in this area are usually written as a short vignette that hides one distinguishing feature — the direction of the nystagmus, whether it fatigues, or whether the head impulse test is normal.

Vertigo is a symptom, not a diagnosis. The physiotherapist's first obligation is triage: distinguish a benign, mechanically treatable inner-ear problem from a posterior-circulation stroke that needs emergency medical management. Only after that screening is complete does the clinician choose between repositioning maneuvers (for otoconial disorders) and exercise-based retraining (for hypofunction). Treating the wrong category wastes the episode of care; missing a central cause is a patient-safety failure of exactly the type DHA's professional-conduct expectations are written to prevent.

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1. Peripheral Vestibular Anatomy & the Vestibulo-Ocular Reflex

Each inner ear contains five vestibular end organs: three semicircular canals (posterior, horizontal/lateral, anterior/superior) that sense angular acceleration, and two otolith organs — the utricle and saccule — that sense linear acceleration and head tilt. The otolith organs carry calcium carbonate crystals (otoconia) embedded in a gelatinous macula. When otoconia detach and migrate into a semicircular canal, they convert that canal into a gravity-sensitive organ, which is the mechanical basis of BPPV.

The vestibulo-ocular reflex (VOR) is a three-neuron arc that generates an eye movement equal in magnitude and opposite in direction to head movement, holding an image stable on the fovea. Its performance is expressed as VOR gain (eye velocity ÷ head velocity); normal gain is approximately 1.0. When gain falls, images slip across the retina during head motion, producing the classic complaints of blurred vision while walking, difficulty reading road signs, and visual discomfort in supermarkets or shopping malls.

      Head turns RIGHT                    Eyes rotate LEFT
   ----------------------->            <-----------------------
   Right horizontal canal   -->  Vestibular nuclei  -->  CN VI / CN III
   excited (Ewald's 1st law)     (brainstem)             (extraocular muscles)
   Left horizontal canal
   inhibited

Ewald's laws explain why nystagmus points where it does: eye movement occurs in the plane of the canal being stimulated, and for the horizontal canal, ampullopetal (toward the ampulla) endolymph flow is the stronger stimulus. A sudden loss of input from one labyrinth therefore produces a tonic imbalance and a nystagmus whose fast phase beats away from the damaged ear.

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2. Screening Decision: Peripheral vs. Central Vertigo

Before any maneuver is performed, classify the presentation. The single highest-yield exam discriminator is that peripheral nystagmus is suppressed by visual fixation and never changes direction, while central nystagmus is not suppressed and may be vertical, purely torsional, or direction-changing.

The HINTS Examination

For a patient in acute vestibular syndrome (continuous vertigo of hours-to-days duration with nystagmus, nausea, and gait unsteadiness), the three-step HINTS battery is more sensitive for posterior-circulation stroke than early MRI:

• Head Impulse: an abnormal test (a corrective catch-up saccade when the head is rapidly rotated toward the affected side) indicates a peripheral lesion. A normal head impulse in a vertiginous patient is worrying — it suggests a central cause.
• Nystagmus: direction-changing gaze-evoked nystagmus is central. Unidirectional nystagmus is peripheral.
• Test of Skew: a vertical corrective movement on alternate cover testing (skew deviation) is central.

The mnemonic INFARCT captures the dangerous combination: Impulse Normal, Fast-phase Alternating, Refixation on Cover Test. Any one of these findings mandates immediate referral, not vestibular rehabilitation.

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3. BPPV: Canal Involvement, Positional Testing & Nystagmus Patterns

Benign paroxysmal positional vertigo is brief (seconds), position-provoked vertigo caused by otoconia inside a semicircular canal. Two mechanisms are described: canalithiasis (free-floating debris in the canal lumen — latency present, short duration, fatigable) and cupulolithiasis (debris adherent to the cupula — minimal latency, longer duration, less fatigable).

Dix-Hallpike technique. From long sitting, rotate the head 45 degrees toward the test side, then move the patient rapidly into supine with the head extended roughly 20 degrees below horizontal. Hold the position and observe the eyes for at least 30-45 seconds. A positive posterior-canal response shows:

1. Latency of about 2-5 seconds before nystagmus begins (rarely up to 30-40 seconds).
2. Duration under 60 seconds — a paroxysm that builds then decays (crescendo-decrescendo).
3. Fatigability — the response weakens with immediate repeat testing.
4. Reversal of nystagmus direction on returning to sitting.

Supine roll test. With the patient supine and the head flexed 20-30 degrees, rotate the head rapidly 90 degrees to one side, observe, return to midline, then repeat to the other side. In geotropic horizontal-canal BPPV, the more intense response identifies the affected ear; in apogeotropic BPPV, the less intense side is affected.

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4. Canalith Repositioning: Matching the Maneuver to the Canal

The Epley sequence for a right posterior canal: (1) Dix-Hallpike right, hold 30-60 seconds past the end of nystagmus; (2) rotate the head 90 degrees to the left (still extended), hold; (3) roll the patient onto the left shoulder while turning the head a further 90 degrees so the nose points toward the floor, hold; (4) bring the patient up to sitting with the chin slightly tucked.

Two points are examined repeatedly:

• Post-procedural postural restrictions (sleeping upright, avoiding the affected side, cervical collars) are not recommended by the 2017 AAO-HNSF guideline update — they do not improve outcomes.
• Vestibular suppressants (meclizine, betahistine, benzodiazepines) are not indicated for BPPV and should not be used as a substitute for repositioning.

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5. Vestibular Hypofunction: Adaptation, Substitution & Habituation

Where BPPV is a mechanical problem solved by a maneuver, unilateral vestibular hypofunction (UVH) — typically after vestibular neuritis, labyrinthitis, or acoustic neuroma resection — is a sensory loss solved by driving central compensation with exercise.

Adaptation (gaze stabilization). Retinal slip is the error signal that recalibrates VOR gain. Prescribe:

• VOR x1: the patient fixates a stationary target held at arm's length and rotates the head horizontally (then vertically) at a speed that keeps the target in focus, typically 1-2 Hz.
• VOR x2: the target moves opposite to the head, doubling the required gain — a progression, not a starting point.
• Dose: begin at 1-2 minutes per direction, 3-5 times per day, progressing to 20-40 minutes total daily; symptoms of mild dizziness during the exercise are expected and are part of the stimulus.

Substitution. Where vestibular input cannot be restored (e.g., bilateral vestibular loss), train alternative strategies: pre-programmed saccades and smooth pursuit to replace VOR function, and increased reliance on somatosensory and visual cues.

Habituation. Repeated, graded exposure to the specific movements that provoke symptoms (motion sensitivity), classically delivered as Cawthorne-Cooksey exercises. Habituation targets symptom provocation; adaptation targets gaze stability. Confusing the two is a common item distractor.

Balance and gait retraining. Progress by systematically removing sensory cues — firm to foam surface, eyes open to eyes closed, static to dynamic, head still to head turning — and add dual-task and community ambulation for higher-functioning patients.

[!IMPORTANT] Prolonged vestibular suppressant use (beyond roughly 24-72 hours in the acute phase) delays central compensation. Early mobilization plus gaze-stabilization exercise produces better long-term outcomes than bed rest and medication.

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6. Outcome Measures & Fall-Risk Cutoffs

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7. Clinical Scenarios & DHA Exam Traps

Clinical Scenario: Choosing the Test Before the Treatment

A 58-year-old Dubai office worker reports 20-30 seconds of violent spinning each time she rolls to her right in bed and when she looks up to a high shelf. There is no hearing loss, no headache, and a normal neurological screen. Dix-Hallpike to the right reproduces vertigo after a 3-second latency with upbeating-torsional nystagmus lasting about 25 seconds, which fatigues on repetition.

Interpretation: right posterior canal canalithiasis. Action: perform an Epley maneuver to the right; no medication, no postural restrictions, and re-test at follow-up. Had the nystagmus been purely horizontal, the diagnosis would shift to the horizontal canal and the treatment to a BBQ roll — the maneuver must follow the canal, not the diagnosis label.

DHA Exam Traps to Master

1. "Normal head impulse test" is a central sign, not a reassuring one. In an acutely vertiginous patient, a normal HIT points away from the labyrinth and toward the brainstem or cerebellum.
2. Downbeating positional nystagmus is not standard BPPV. Screen for a central cause before repositioning.
3. Epley treats the posterior canal only. A stem describing purely horizontal, geotropic nystagmus on the supine roll test requires the Lempert 360-degree roll or Gufoni maneuver.
4. Brandt-Daroff is habituation, not repositioning, and is not the first-line answer for a freshly diagnosed posterior canal BPPV.
5. VOR x1 before VOR x2. An item that offers VOR x2 for a patient in the first week after vestibular neuritis is offering a progression the patient cannot yet perform.
6. Do not prescribe long-term meclizine or betahistine for a patient who needs central compensation; suppressants blunt the very error signal that drives recovery.
7. Fatigability distinguishes canalithiasis from cupulolithiasis. A response with no latency that persists beyond a minute suggests cupulolithiasis and a longer treatment course.