Review of Vestibular System PDF

Review of vestibular system Vestibular Assessments and Rehabilitation AAUD 4203 Nurul Syarida binti Mohd Sakeri [email protected] Audiologist The balance team  Hearing & balance physiology Audiologist Hearing &...

Review of vestibular system Vestibular Assessments and Rehabilitation AAUD 4203 Nurul Syarida binti Mohd Sakeri [email protected] Audiologist The balance team  Hearing & balance physiology Audiologist Hearing & vestibular test instruments Hearing rehabilitation..and a bit of vestibular rehabilitation Role of an audiologist in VA Screening, assessment, diagnosis, and management of persons with balance system disorders, often as part of an interdisciplinary team. Professional roles and activities in audiology include clinical/educational services (diagnosis, assessment, planning, and management); prevention and advocacy; and education, administration, and research. Vestibular assessment tools Pure tone audiometry (PTA) Acoustic Brainstem Response (ABR) Electrocochleagraphy (ECochG) Video Nystagmography (VNG) Caloric test Vestibular Evoked Myogenic Potentials (VEMP) Video Head Impulse Test  Caloric test Video - Head Impulse ECochG Test Ocular - VEMP Cervical - VEMP Auditory Brainstem Pure Tone Audiometry Response + Acoustic reflexes  Caloric test Video - Head Impulse ECochG Test Ocular - VEMP Ocular - VEMP Auditory Brainstem Pure Tone Response Audiometry + Acoustic reflexes Key learning issues in vestibular physiology in relation to its assessment Vestibular hair cells have relatively high tonic firing rate (resting potentials of about 70-100 spikes/sec) Vestibular organs work in pairs How vestibular ocular reflex work? >> Same applies to vestibular spinal reflex Repair / compensation Adaptive plasticity for peripheral vestibular lesions Happens when one sensory context may not work within another Vestibular compensation Adaptation Habituation Substitution Limited with central lesions Effects can be profound and permanent Critical Periods in VOR adaptation Studies on Monkey after UL Rate of recovery decreases with reduced sensory input Patients should be encouraged to move about in well lit areas to engage their VOR and VSR, this should be done as soon as possible after intervention. CNS takes over Bilateral vestibular loss Unable to recalibrate VOR Test using rotational chair Use compensatory mechanisms – using other sensory Eg: Dependence on other sensory systems, namely proprioceptive and visual, Differentiating vestibular disorders  Dizziness is a nonspecific term Need to have patients describe what is actually happening to them / their problems What differentiate one vestibular pathology from another? Time course Associated symptoms Triggers  The important of a proper History Taking A good history can give you a sense of: What the pathology might be Any problems you might have arise during testing What are the most important tests to be performed What further testing may be necessary What management recommendations you might give  description of the the dizziness Disequilibrium ? Lightheadedness Vertigo? ? What does the dizziness Why? feel like? Different pathologies will create different sensations Vertigo is likely of a vestibular origin Lightheadedness could be anxiety or cardiac related Disequilibrium could be due to proprioceptive loss and/or vestibular origin  time course How long does it last for? Seconds? Minutes? Hours? Days? Constant? Constant but fluctuating? Why? Different pathologies will have different time courses Meniere’s attacks >> do not last for seconds BPPV >> does not last for hours Any other associated symptoms? Is it associated with anything? Hearing loss? Tinnitus? Nausea/Vomiting? Sweating? Migrainous Headaches? Numbness on the face? Why? Different pathologies will have different associated symptoms BPPV is not associated with fluctuating hearing loss Meniere’s does not involve facial palsy SCD does not involve migraines What are the triggers? Does anything trigger it? Getting into bed? High salt or coffee? Stress? Certain situations? Quick head movement? Why? Triggers can be pathology specific BPPV by head/position changes SCD by loud noise, intense pressure Migraines can be triggered by smell, bright light, food, hormonal changes ….etc Co-morbidities, or exacerbating triggers Stress/anxiety – high association with vestibular disorders Quick head movement – usually indicates vestibular vs non vestibular origin What happened? Did anything happen around the time it started? Trauma Head Cold? Why? Different Pathologies can have different causes BPPV can be induced by head trauma Vestibular Neuronitis/labyrinthitis  What about in the dark? Is your balance worse in the dark? Why? Different Environment remove visual cues Individuals with vestibular dysfunction will have greater difficulty with their balance Common vestibular disorders  Labyrinthitis Labyrinthitis Vestibular neuronitis/neuritis Common Vestibular Vestibular neuronitis/neuritis peripheral neuronitis/neuritis vestibular Ménière's disease disease disorders BPPV BPPV  Sudden onset vertigo Hearing loss + tinnitus Usually cause by viral infection Herpes zoster oticus Labyrinthitis Influenzal otitis (inflammation Recovery will appear in 3 stages of the inner An acute period, which may include severe vertigo and vomiting lasting 1-2 ear) days two weeks of sub-acute symptoms and rapid recovery chronic compensation which may last for months or years.  Vestibular neuronitis/neuritis Sudden onset vertigo Usually no association with hearing loss Cause –infection usually a member of the herpes family, the same group that causes cold sores in the mouth as well as a variety of other disorders (Arbusow et al, 2000). The patient has severe rotational vertigo + nausea + vomiting Tinnitus The balance problems recover over a few days or may recur with less severe episodic vertigo  Treatment for labyrinthitis and vestibular neuritis Acutely, vestibular neuritis is usually treated symptomatically meaning that medications are given for nausea (anti-emetics) to reduce dizziness (vestibular suppressants) Vestibular retraining therapy Meniere's Disease Paroxysmal attacks of vertigo with hearing loss and tinnitus. Vertigo or hearing loss alone is not necessarily true Meniere’s disease. The attacks last for a few hours and occur in clusters  Meniere's Disease Definite Meniere’s Disease Probable Meniere’s Disease 2 or more spontaneous episodes 2 or more spontaneous of vertigo lasting 20 minutes – 12 episodes of vertigo lasting 20 hours minutes – 12 hours Documented low-medium freq Fluctuating aural symptoms SNHL (hearing, tinnitus, fullness) in Fluctuating aural symptoms the affected ear (hearing, tinnitus, fullness) in the Not better explained by affected ear another vestibular diagnosis Not better explained by another vestibular diagnosis Cause of Meniere's Disease Endolymphatic hydrops a build-up of fluid in the inner ear Treatment : avoid overtiredness stress coffee, tea, red wine and cheese Benign paroxysmal positional vertigo (BPPV) benign = not a very serious or progressive condition paroxysmal = sudden and unpredictable in onset positional = comes about with a change in head position vertigo = a sense of dizziness. the most common cause of vertigo due to a peripheral vestibular disorders >20% of all dizziness complains is due to BPPV Age distribution of BPPV Age Complaint of BPPV(%) BPPV(n) dizziness (N) 0- 9 9 0.0% 0 10-19 32 3.1% 1 20-29 64 3.1% 2 30-39 191 17.8% 34 40-49 261 16.5% 43 50-59 207 22.2% 46 60-69 298 26.2% 78 70-79 376 23.7% 89 80-89 176 33.1% 58 90-99 14 50.0% 7 What is commonly found in BPPV There is no hearing loss or severe ringing associated with these attacks , which help to distinguish BPPV from other inner ear conditions. What causes BPPV head injury (