Presentation is loading. Please wait.

Presentation is loading. Please wait.

Vestibular Examination

Similar presentations

Presentation on theme: "Vestibular Examination"— Presentation transcript:

1 Vestibular Examination
ANATOMY & FUNCTION Carmen Casanova Abbott PT, PhD

2 Lecture Objectives Discuss vestibular structure as it relates to vestibular function when examining a dizzy patient. Discuss signs and symptoms associated with vestibular disorders Differentiate between peripheral and central vestibular pathology Discuss components of a physical therapy vestibular examination.

3 Vestibular System Function
Provides information concerning gravity, rotation and acceleration Serves as a reference for the somatosensory & visual systems Contributes to integration of arousal, conscious awareness of the body via connections with vestibular cortex, thalamus and reticular formation Allows for: gaze & postural stability sense of orientation detection of linear & angular acceleration

4 Vestibular Anatomy Peripheral sensory apparatus
detects & relays information about head angular & linear velocity to central processing system orients the head with respect to gravity Central processing system processes information in conjunction with other sensory inputs for position and movement of head in space Motor output system generates compensatory eye movements and compensatory body movements during head & postural adjustments

5 Peripheral Apparatus Membranous Labyrinth Semicircular canals (SSC)
Otolith organs

6 Netter ‘97

7 Semicircular Canals Angular acceleration
Ampulla contains sensory epithelium

8 SSC Coplanar Pairing Spatial arrangement of the 6 SSC cause 3 coplanar pairings R & L lateral, L anterior and R posterior; l posterior & R anterior; R & L horizontal Allows for a Push-Pull arrangement of the two sides (e.g., as head turns right, right SSC will increase firing rate & the left SSC will decrease firing rate) Advantages sensory redundancy common mode rejection/noise assist in compensation for sensor overload

9 Inhibitory Cutoff Depolarization of the ipsilateral hair cells occurs during angular head movements Hyperpolarization of contralateral hair cells occurs at the same time Hair cells are only able to hyperpolarize to what they were at rest = cut off of inhibitory influences from the movement going in the opposite direction even if the ipsilateral hair cells continue to spike higher firing rates

10 Purves 2001

11 Otoliths Utricle and saccule Otolith sensory structures
Maculae Otolithic membrane Otoconia Movement of gel membrane & otoconia cause a shearing action to occur over the hair cells → sensitivity of otoliths

12 Otolith Function Respond to: Linear head motion on acceleration
Static tilt Two organs respond to respective accelerations or tilts in their respective planes Saccule has vertical orientation of maculae Utricle has horizontal orientation of maculae

13 Bear 1996

14 Purves 2001.

15 Hair Cells 2 types: kinocilium & stereocilia
Sensory structures for the peripheral end organs (maculae and ampula) Hyperpolarized or depolarized depending upon the direction of deflection of the stereocilia (movement of stereocilia towards the kinocilium causes depolarization of the hair cell) Affect the firing rate of the primary vestibular afferents to the brainstem

16 Bear 1996

17 Striola of the Macula Striola serves as a structural landmark
Contains otoconia arranged in narrow trenches, dividing each otolith Orientation of the hair cells change over the course of the macula Allows otoliths to have multidirectional sensitivity

18 Purves 2001.

19 Principles of the Vestibular System
Tonic firing rate Vestibular Ocular Reflex Push-pull mechanism Inhibitory cutoff Velocity storage system

20 Ascending Pathways Vestibular nerve Vestibular nuclei Cerebellum
Oculomotor complex CN 3, 4, and 6 Along with vestibulospinal reflexes coordinate head and eye movements

21 Relay Centers Thalamus Vestibular Cortex
Connection with vestibular cortex and reticular formation → arousal and conscious awareness of body; discrimination between self movement vs. that of the environment Vestibular Cortex Junction of parietal and insular lobe Target for afferents along with the cerebellum Both process vestibular information with somatosensory and visual input

22 Netter 1997

23 Tonic Firing Rate Vestibular nerve and vestibular nuclei have a normal resting firing rate ( cycles/sec) Baseline firing rate present without head movement Tonic firing is equal in both sides; if not, a sense of motion is felt e.g., vertigo, tilt, impulsion, spinning Excitation and inhibition of the vestibular system can then occur from stimulation of the hair cells Spontaneous recovery with light

24 Vestibular-Ocular Reflex (VOR)
Causes eyes to move in the opposite direction to head movement Speed of the eye movement equals that of the head movement Allows objects to remain in focus during head movements

25 Compensatory Eye Movements
VOR Optokinetic reflex Smooth pursuit reflex, saccades, vergence Neck reflexes combine to stabilize object on the same area of the retina=visual stability

26 Purves 2001.

27 Vestibular Processing Gain
Keeps eye still in space while head is moving Ratio of eye movement to head movement (equals 1)

28 Vestibular Processing Velocity Storage Mechanism
Perseveration of neural firing in the vestibular nerve by the brainstem after stimulation of SSC to increase time constant (10sec.) SSC respond by producing an exponentially decaying change in neural firing to sustained head movement Otolith & somatosensory input also drive mechanism

29 VOR Dysfunction Direction of gaze will shift with the head movement
Cause degradation of the visual image In severe cases, visual world will move with each head movement

30 Oscillopsia Visual illusion of oscillating movement of stationary objects Can arise with lesions of peripheral or central vestibular systems Indicative of diminished VOR gain motion of images on fovea diminished visual acuity

31 Cerebellum Monitors vestibular performance
Readjusts central vestibular processing of static & dynamic postural activity Modulates VOR Provides inhibitory drive of VOR (allows for VORc)

32 Descending Pathways Provide motor output from the vestibular system to: Extraocular muscles (part of VOR) Spinal cord & skeletal muscles (generate antigravity postural activity to cervical, trunk & lower extremity muscles) Response to changing head position with respect to gravity (righting, equilibrium responses)

33 Vestibulospinal Reflex (VSR)
Generates compensatory body movement to maintain head and postural stability, thereby preventing falls

34 Netter 1997

35 Vestibular Dysfunction

36 Demographics Vestibular disorders manifested by vertigo are a significant health problem, secondary only to low back pain NIH study estimates that 40% of the population over the age of 40 will experience a dizziness disorder during their lifetime

37 Fall Demographics Falls will be experienced in community dwelling individuals: 28-35 % over age 65 42-49% over age 75 Greater than 60% will have bilateral vestibular lesion (BVL) in the <65 or >75 years of age

38 Fall Risk Factors ≥ 4 risk factors, 78% chance of falling in an older adult
Sedatives Cognitive impairment Palmomental reflex LE disability Foot problems Balance abnormalities Dizziness ↑ dependence on visual cues Fear of falling Orthostatic hypotension (Tideiksaar R 1998)

39 Other Fall Risk Factors?

40 Aging Changes Progressive changes begin at age 40
Decreased number of hair cells Decreased vestibular nerve fibers Lead to dizziness and vertigo Harder to deal with competing visual and somatosensory input

41 Fear of Falling (FOF) FOF affects willingness to participate in physical activity & exercise FOF occurs in an average of 30% of older adults who have not fallen FOF increases to an average of 60% of older adults who have fallen FOF is higher among women Prevalence of FOF is underestimated Greater FOF associated with lower quality of life in mental health, social & leisure pursuits (Legters, 2002)

42 Falls Related Self-efficacy
Falls Efficacy Scales (FES) better for frail indoor activities Activities-Specific Balance Confidence Scale (ABC) higher functioning indoor & outdoor activities > discrimination between fearful & nonfearful (Legters, 2002)

43 Vestibular Pathophysiology
Disorders of tone & or gain (vertigo / movement- induced vertigo) Vestibular nerve / nuclei give abnormal sensory information Tone automatically recovers in a few days; does not need visual input Compensation for reduced gain depends on visual images; takes month to years to complete; high speeds & accelerations may never be complete Nystagmus usually transient sign of vestibular lesion; movement-induced symptoms can be chronic

44 Dizzy Patient Presentation: unexplained or new onset of symptoms
Medical referral is indicated constant vertigo lateralpulsion facial asymmetry speech & or swallowing difficulties oculomotor dysfunction vertical nystagmus severe headaches recurrent falls unilateral hearing loss, tinnitus, fullness, ear pain

45 Vertigo An asymmetrical firing of the two vestibular systems
Gives an illusion of spinning, movement Indicative of any one or combination of causes (acute UVH, BPPV, brainstem lesion, vascular hypotension…)

46 Differentiation Between Peripheral & Central Causes of Vertigo
Nausea severe moderate Imbalance mild severe Hearing Loss common rare Oscillopsia mild severe Neurologic Symptoms rare common Compensation rapid slow (Furman JM, Whitney SL. 2000)

47 Peripheral Vestibular Disorders
Vestibular Neuronitis Labyrinthitis Meniere’s Acoustic Neuroma Fistula Benign Paroxysmal Positional Vertigo (BPPV)

48 Central Vestibular Disorders
Vascular Wallenberg’s Syndrome Head Injury Cerebellar Infarct Postconcussive Syndrome Demyelinating Disease Congenital

49 Degenerative Cerebellar Disease
Signs & symptoms abnormal ocular pursuit gradual decline irregular saccades gaze end point nystagmus ataxia

50 Objective of Clinical Exam
Establish location & severity of lesion (central or peripheral) Typical examination - history (hearing status) - cranial nerves - vestibular spontaneous nystagmus (imbalance in tone) postural instability (abnormal tone & gain; proprioceptive loss) VOR gain (maintained fixation, dynamic visual acuity) head shaking (compensated UVL; not necessarily PVL) calorics pressure sensitivity (fistula) positional nystagmus (Hallpike-Dix test) hyperventilation (anxiety; acoustic neuroma)

51 Nystagmus Rapid alternating movement of eyes in response to continued rotation of the body Primary diagnostic indicator in identifying vestibular lesions Physiologic nystagmus vestibular, visual, extreme lateral gaze Pathologic nystagmus spontaneous, positional, gaze evoked Labeled by the direction of the fast component Central vs. peripheral cause differentiated by duration

52 Vestibular Function Tests
Caloric test Rotary Chair test Posturography

53 Results of Vestibular Function Tests
Presence of complete vs. incomplete loss Presence of peripheral vs. central dysfunction Direct patient management Help in outcome prediction

54 Dizziness Handicap Inventory
Three subscales function emotion physical aspects Scoring Yes 4 pts. Sometimes 2 pts. No pts. Excellent test-retest reliability

55 Hallpike-Dix Maneuver
Gold standard used to check for the presence of benign paroxysmal positional vertigo (BPPV) Nystagmus induced by this test is an objective measurement from which we can determine SSC dysfunction and assess a response to treatment

56 Benign Paroxysmal Positional Vertigo (BPPV)
Signs & symptoms sudden, severe attacks of vertigo precipitated by certain head positions & movements e.g., rolling over, neck extension, bending forward lightheadedness; nausea anxiety avoids movement direction & duration of nystagmus differentiates between BPPV & a central vestibular lesion (CVL)

57 Benign Paroxysmal Positional Vertigo (BPPV)
5 criteria crucial in diagnosis (Hallpike-Dix Test): torsional/linear-rotary nystagmus; reproduced by provocative positioning with affected ear down nystagmus of 1-5 sec. latency nystagmus of brief duration (5-30 sec.) reversal of nystagmus direction on returning to upright position response diminishes with repetition of maneuver (fatigability) (Massoud ’96)

58 BPPV Cupulolithiasis Debris, probably fragments of otoconia from the utricle, adhere to the cupula Treatment Brandt-Daroff habituation exercises Semont, liberatory maneuver

59 BPPV Canalithiasis Debris floating freely in the endolymph in the long arm of the posterior SSC Treatment Canalith repositioning maneuver (Epley) 84-90% remission rate Sleep upright one night only (more severe cases)

60 Problems Experienced with Vestibular Loss
Balance & gait deficits Head movement-induced dizziness Head movement-induced visual blurring (oscillopsia) LE dressing difficulty Driving deficits Disability related to work, social & leisure activities

61 Systems Approach to Examination
Examination of balance & mobility using a variety of tests & measurements to document functional abilities, determine underlying sensory, motor, & cognitive impairments contributing to functional disabilities

62 Balance Can be viewed as a motor skill that emerges from the interaction of multiple systems These systems are organized to meet functional task goals & are constrained by the type of environment Balance, like any skill, can improve with practice

63 Balance Components Steadiness Symmetry Dynamic stability

64 Balance Training: Postural Biofeedback
Postural symmetry & dynamic stability have been consistently improved by training using force platform systems

65 Clinical Test of Sensory Interaction In Balance (CTSIB)
Assesses pattern of sensory dependence for balance from timed stance tests during distortion of sensory environment

66 Berg Balance Scale Performance -orientated balance assessment
Interpretation: > 45/56 score highly specific (96%) for nonfallers subjects who fell most frequently were those closer to cut off Correlates with other balance tests

67 Functional Gait Assessment (FGA)
Assesses postural stability during walking Modified version of the Dynamic Gait Index Added 3 new tasks to increase challenge and sensitivity of the test to minor changes in gait Stronger vestibular components (head turns, narrow BOS, ambulating backwards and with eyes closed)

68 General Therapeutic Intervention Objectives
Changing impairments Improving functional performance Improving capacity to adapt performance to changing task & environmental demands

69 Mechanism of Recovery: Compensation
Results from changes in CNS rebalancing of tonic activity within vestibular nuclei (spontaneous recovery) recovery of VOR (vestibular adaptation) habituation (progressive decline in response to same stimulus) alternative strategies/substitution; in complete loss of vestibular function Enhanced by active movements & processing of visual, vestibular, & somatosensory stimuli

70 Result of Early Intervention
Gain returns quicker Increased function Decreased gait ataxia Decreased perception of disequilibrium (Herdman 2000)

71 Vestibular Exercise Program Objectives
Complement CNS natural compensation diminish dizziness & vertigo enhance gaze stabilization enhance postural stability in static & dynamic situations Increase overall functional activities Patient education nature of pathology episodic nature, prognosis control of exacerbations

72 Vestibular Program Components
Gaze stabilization exercises to retrain VOR function Balance retraining to retrain VSR function Conditioning exercises to increase fitness level Habituation or canal repositioning maneuvers as indicated

73 e.g., Unilateral Vestibular Lesion: Exercise Guidelines
Adaptation is best stimulated by producing an error signal; work at limit of abilities Incorporation of head movements & visual input Provide context specific stimulation to promote adaptation Adaptation is positively affected by voluntary muscle control (Herdman 2000)

74 Vestibular Function Recovery Rates
UVL: 6-8 weeks BPPV: remission in 1/few treatments BVL: 6 months - 2 years CNS Lesion: 6 months - 2 years

75 Physical Therapy Intervention: Prescription
Individualized vestibular rehabilitation program: Outpatient, 1-2 times / week (4-6 weeks) HEP, 5 minutes, 3x / day Walking program (health & fitness prescription) Compliance to daily program essential to success Exercise graduated for possible increase of symptoms during the first week

Download ppt "Vestibular Examination"

Similar presentations

Ads by Google