Vestibular system
Vestibular disorders
Stereocilia are mechanoreceptors within the ear that sense head position, head movement, and when the body is in motion. Head position is sensed by the utricle and macula. Head movement is sensed via the semicircular canals. The movement of fluid within the semicircular canals generates nerve impulses that travel to cranial nerve VIII (vestibulocochlear nerve) and then to the brainstem and cerebellum.
Vestibular dysfunction can develop at any age. Factors precipitating vestibular disorders can be external or internal. External factors could be whiplash, a fall, an airplane ride, or pollutants. Internal factors may be infections, use of medications, stroke, brain injury, or migraine. Vestibular dysfunctions can further be divided into central and peripheral disorders — management of symptoms will be based on the classification of the vestibular disorder.
Generalized symptoms of vestibular disorders
- Dizziness
- Balance deficits
- Vertigo
- Blurred vision
- Recurrent falls
- Nausea and vomiting
The examination for vestibular dysfunction is critical in determining the type of disorder and the appropriate treatment options.
Determining the type of disorder
- Symptom history and duration
- Vestibular ocular reflex testing — assessing nystagmus, clarity of vision with head movements, and body movements
- Vertebral artery testing
- Sensory testing
- Clinical test of sensory interaction on balance (CTSIB)
- Functional testing — transfers, gait, dynamic sitting, and dynamic balance
- Vestibulospinal reflex testing — examining posture and balance in all positions
- Positional changes and their impact on symptoms
- Cervical range of motion
- Outcome measures as appropriate, such as the dynamic gait index
The CTSIB is conducted with the patient standing with their hands at their sides and feet together, performing the following six sensory conditions:
- Stand on a firm surface with eyes open — testing the vestibular system
- Stand on a firm surface with eyes closed — testing the vestibular system
- Stand on a firm surface with a visual conflict dome — testing the visual system
- Stand on a foam surface with a visual conflict dome — testing the visual system
- Stand on a foam surface with eyes open — testing the somatosensory system
- Stand on a foam surface with eyes closed — testing the somatosensory system
Central vestibular disorders
Central vestibular dysfunction symptoms
- Nystagmus in vertical, horizontal, or rotational planes
- Non-fatigable nystagmus
- No hearing loss or tinnitus
- Vertigo is sometimes present
- Disequilibrium is severe
- Can be associated with other cranial nerve or cerebellar signs
- Visual fixation and head position have no impact
Treatment for central vestibular dysfunction
- Identify triggers, if any, that are noted to be external
- Gaze stabilization exercises to assist with improving the vestibular ocular reflex
- Coordination activities to address cerebellar symptoms
- Adaptation exercises to decrease dizziness to allow for retraining of the brain
- Substitution of visual and somatosensory systems in the presence of vestibular dysfunction
Peripheral vestibular dysfunction
Most peripheral vestibular dysfunction is unilateral. The following are common causes:
Symptoms of peripheral vestibular dysfunction
- Nystagmus is horizontal and torsional
- Nystagmus decreases with visual fixation
- Nystagmus is fatiguable and lasts less than one minute
- Vertigo is always present
- Loss of hearing
- Ringing in the ears
- Disequilibrium
- Feeling of fullness in the ear
Differential diagnosis of peripheral vestibular dysfunction with intervention strategies
Benign paroxysmal positional vertigo (BPPV)
An endolymph disorder causing brief, intense vertigo due to a change in head position — the otoconia within the semicircular canals become dislodged.
Confirmation of BPPV
- Confirmed by performing the Dix-Hallpike test — before completing the test, the therapist must perform a vertebral artery test and ensure appropriate cervical range of motion is present
- Patient positioned in long sitting, with the head turned 45 degrees toward the affected side
- Patient is quickly lowered to supine with the head remaining at 45 degrees and hanging over the edge of the mat, while the therapist observes for nystagmus
- Nystagmus will resolve within 30-60 seconds
- A positive test occurs when the patient experiences nystagmus and vertigo with a head position change
- Repeat the test on the contralateral side
Understanding what nystagmus means in relation to BPPV
- Ageotropic
- Fast beating phase of the nystagmus is moving away from the ground (towards the upper ear) — this indicates lateral canal BPPV
- Geotropic
- Fast beating phase of nystagmus is moving towards the ground (towards the lower ear) — this indicates posterior canal BPPV
Differentiation of BPPV and canals impacted
Lateral canal BPPV
- Can manifest as ageotropic or geotropic horizontal nystagmus
- Treatment is with the log roll maneuver or barbeque roll maneuver to move the otoconia into position (performed as a home exercise program)
Log roll maneuver
- Lie on your back with your head centered and neck flexed about 30 degrees.
- Turn your head 90 degrees toward the affected ear.
- Hold for 30 seconds, or until vertigo and nystagmus stop.
- Turn your head back to center.
- Turn your head 90 degrees away from the affected ear.
- Lie on your stomach with your elbows bent.
- Roll back onto your back toward the affected ear.
Barbeque roll maneuver
- Lie on the affected side and wait for 30 seconds.
- Roll onto your back and wait for 30 seconds.
- Roll onto your opposite side and wait for 30 seconds.
- Tuck your chin down slightly, roll onto your stomach, and prop yourself up on your elbows. Wait for 30 seconds.
- Roll onto your left-hand side and wait for 30 seconds.
- Slowly return to a sitting position, keeping your chin level.
- Sit for five minutes, then repeat the previous step.
- Sit for 15 minutes to finish.
Posterior canal BPPV (most common BPPV)
- Typically presents with rotary, geotropic nystagmus
- The Epley maneuver is performed to reposition the otoconia
Epley maneuver
- Sit in a long sitting position.
- Turn your head toward the side that causes vertigo.
- Quickly lie down on your back with your head in the same position, just off the edge of the table. You will likely feel more intense vertigo symptoms at this point.
- Slowly move your head to the opposite side.
- Turn your body so that it is in line with your head. You will be lying on your side with your head and body facing to the side.
- Sit upright.
Anterior canal BPPV (least common BPPV)
- Typically presents with vertical downbeat nystagmus
- The Yacovino maneuver is performed to reposition the otoconia
Yacovino maneuver
- Sit on the edge of a bed with your head in a neutral position.
- Quickly lie back onto your back, allowing your head to hang slightly below horizontal, ensuring your neck is supported by the bed.
- Stay in this head-hanging position until dizziness subsides, usually for 30 seconds or more.
- While still lying down, slowly move your head into a chin-to-chest position, keeping your body relaxed.
- Slowly return to a sitting position while maintaining the chin-to-chest position.
Meniere’s disease
Episodes of vertigo can last from minutes to days. Due to the chronicity of the disease, management focuses on reducing the frequency of attacks and managing symptoms.
Management of symptoms
- Low sodium diet — reduces fluid levels
- Regular exercise — improves balance and reduces stress
- Management of stress — stress can exacerbate an episode of vertigo
- Diuretics — reduce fluid within the ear
- Surgery — drains excess fluid or removes the damaged portion of the inner ear
Physical therapy management of individuals with Meniere’s disease is symptom-based, and episodes of care are short. The focus will primarily be to assist with any balance deficits or muscle weakness, provide an individualized home exercise program, and reinforce patient education.
Vestibular neuritis
Symptoms include sudden onset of severe vertigo (spinning sensation), nausea and vomiting, dizziness and lightheadedness, difficulty walking, and nystagmus. Symptoms are typically sudden and improve with medical intervention over a few days.
Treatment options
- Antibiotics for the management of infection
- Corticosteroid medication for the management of inflammation
- Anti-nausea medication for persistent nausea and vomiting
Physical therapy interventions to treat vestibular neuritis are rare, as the symptoms resolve quickly. If any balance or coordination deficits continue, then physical therapy interventions will be prescribed at that time.
Labyrinthitis
Symptoms include vertigo, nausea and vomiting, balance problems, hearing loss, tinnitus (ringing in the ears), and ear pain. Most symptoms resolve within a few weeks, but some permanent hearing loss may be present.
Treatment interventions
- Antihistamines — for treatment of vertigo symptoms
- Anti-nausea drugs — for treatment of nausea and vomiting
- Corticosteroids — for treatment of inflammation
- Antibiotics — for treatment of infection