Assessment of Vestibular system UG MBBS.pptx

prepared this presentation for undergraduate MBBS students. Please go through this and provide your valueable suggestions to improve . Thank You Dr Diwash Sunar MBBS, MS - ENT (AIIMS, New Delhi) Lecturer - Birat Medical College Teaching Hospital [email protected]

1. Assessment of Vestibular System Dr. Diwash Sunar MBBS (Manipal, KU) MS – ENT Head & Neck Surgery ( AIIMS, New Delhi ) Lecturer – BMCTH, KU

2. Learning Objectives Understand the Anatomy of the Vestibular System Perform a Clinical Examination of the Vestibular System Interpret the Results of Vestibular Function Tests Develop a Differential Diagnosis for Vertigo and Dizziness Understand the Management of Common Vestibular Disorders Apply Knowledge in Clinical Scenarios

3. Pre-Test

4. 1 . Which of the following is not a test for the evaluation of peripheral vertigo? a. Romberg test b . Dix-Hallpike test c. Fukuda stepping test d. Chimani -Moos test 2. True for Peripheral Nystagmus is- Lasts >1min b. Direction fixed c. No latency d. Vertigo absent 3. In case of BPPV, which SCC is affected Lateral SCC b. Posterior SCC Anterior SCC d. Superior SCC 4. All of the following will have positive fistula test, except – Dead ear b. Labyrinthine fistula Hypermobile stapes footplate d. following fenestration surgery 5. In Fitzgerald hallpike caloric test, left ear is irrigated with 30 degree celcius in normal person. Response will be – a. Nystagmus to right ear b. Nystagmus to left ear c. Direction changing nystagmus d. positional nystagmus

5. The vestibular system is present within the bony labyrinth. peripheral vestibular organ consists of three Semicircular canals (SCCs), utricle and saccule, cochlear duct and endolymphatic sac, and its duct utricle and saccule are together called otolith organs (macula) The macula of the utricle is present in the horizontal plane, and the macula of the saccule is situated in the vertical plane.

6. The semicircular canals of both temporal bones are synergistic. Horizontal canals are synergistic, but the superior canal on one side is synergic with the posterior canal on the opposite side. Crus commune is the junction of posterior and superior SCC . All canals opened into the utricle of the vestibule SCCs have smaller non-ampullated (1 mm) and larger ampullated ends (2 mm). Ampullated ends contain crista ampullaris (contain sensory hair cells) and a cupula that receives input from the head position (angular acceleration).

7. Utricle and saccule are responsible for the assessment of linear acceleration of the head. Otoconia is the gelatinous matrix around vestibular hair cells. Perilymph surrounds the membranous labyrinth, and endolymph is present within th e membranous labyrinth.

8. Sensory hair cells are of two types  T ype I and type II. Type I cells are a flask-shaped single layer of cells. Type II cells are cylindrical and multilayer cells. Kinocilium is the thicker projection presented at the sensory cells end, and stereocilia is the thinner projection. Sensory cells are fenced by supporting cells

9. Potassium channels open up by ciliary bundle movement toward the kinocilium, generating depolarization potential in the active ear ( ampullopetal flow ). The movement of endolymph in the opposite direction suppresses the generation of potential ( ampullofugal flow ).

10. Utricle, superior SCC and horizontal SCC received afferent fibres from a superior vestibular nerve. Saccule and posterior SCC received afferent fibres from an inferior vestibular nerve. The vestibular nerve (25,000 nerve fibres) transmits information to the central vestibular system. The four vestibular nuclei (lateral, medial, superior, and inferior) receive input from a peripheral organ. Vestibular nuclei with various central connections ( vestibulo -ocular, vestibulospinal, vestibulothalamic , vestibulocerebellar , and vestibulocortical pathway) comes under the central vestibular system.

11. What is Vertigo ???

12. VERTIGO It is the false perception of motion It is defined as an illusion of movement It is defined as a hallucination of movement The disagreeable sensation of instability or disordered orientation in space is Vertigo. Vertigo is defined as a perception of movement when there is none. Vertigo is defined as an illusion of either oneself or the environment rotating .

13. Assessment of vestibular functions can be divided into two groups:  Clinical tests Laboratory tests

14. Clinical Tests It includes - D etailed clinical history C omplete N euro- otological evaluation C erebellar function tests Test of nystagmus C ranial nerve examination

15. D etailed clinical history The guided questions are very helpful in reaching the diagnosis Ask if It is vertigo, imbalance, and light-headedness Approximate duration of each episode (seconds, minutes, or hours) with a detailed description of the first episode Continue or episodic Aggravating (head movement, specific head position, loud noise, pressure, etc.) and relieving factors Associated symptoms (hearing loss, tinnitus, ear fullness, ear discharge, otalgia, diplopia, blurring of vision, dysphagia, dyspnea , palpitation, etc.) Family history, history of trauma Chronic medical illness (diabetes, anemia , hypothyroidism, central nervous system disorders, cardiac diseases, postural hypotension, etc.) and history of surgery. History of psychological disorders (anxiety, depression, etc.) History of drug abuse and chronic medication

16. Aggravating factors for Vertigo Head and neck movements BPPV Cervical vertigo Pressure and Loud sounds/Noise Superior SCC dehiscence syndrome Pressure Perilymph fistula Labyrinthine fistula Meniere’s disease Otosyphilis Superior SCC Dehiscence syndrome Stress Psychological illnesses Standing up from sitting position Orthostatic Hypotension

17. Nystagmus involuntary, rhythmical, oscillatory movement of eyes. It can be spontaneous or induced (generated by a test). Nystagmus of peripheral vs central disease ?? It may be H orizontal / V ertical / R otatory. Vestibular nystagmus has a slow and a fast component, direction of nystagmus is indicated by the direction of the fast component. The slow component is toward the disease side.

18. To elicit nystagmus, patient is seated in front of the examiner or lies supine on the bed. The examiner keeps his finger about 30 cm from the patient's eye in the central position and moves it to the right or left, up or down, but not moving at any time more than 30° from the central position to avoid gaze nystagmus. INDUCED NYSTAGMUS

19. Presence of spontaneous nystagmus always indicates an organic lesion. Nystagmus of peripheral origin suppressed by optic fixation by looking at a fixed point enhanced in darkness or by the use of Frenzel glasses (+20 dioptre glasses) both of which abolish optic fixation. Nystagmus of central origin cannot be suppressed by optic fixation.

20. In irritative nystagmus, the fast component is toward the disease side, due to the labyrinth's hyperfunctioning in paralytic nystagmus, a fast component is toward the healthy side, due to the hypofunction of a diseased labyrinth.

21. Fistula Test P rinciple - to induce nystagmus by producing pressure changes in the external canal which are then transmitted to the labyrinth via an abnormal communicating connection. Pressure is i nduced by Siegel's speculum (pneumatic otoscopy) or pushing the tragus against the external auditory canal (EAC) The parts of the fistula test are nystagmus, vertigo, and head movement.

22. Normally, Fistula test is negative because the pressure changes in the external auditory canal cannot be transmitted to the labyrinth. P ositive Fistula test - when there is erosion of H orizontal SCC as in cholesteatoma or a surgically created window in the horizontal canal (fenestration operation), abnormal opening in the oval window (post-stapedectomy fistula) or the round window (rupture of round window membrane). A positive fistula test also implies that the labyrinth is still functioning . Negative fistula test : Normal ear and dead labyrinth A false negative fistula test is also seen when cholesteatoma covers the site of fistula and does not allow pressure changes to be transmitted to the labyrinth. A false positive fistula test (i.e. positive fistula test without the presence of a fistula) is seen in congenital syphilis and in about 25% cases of Ménière's disease ( Hennebert's sign). In congenital syphilis, stapes footplate is hyper-mobile while in Ménière's disease it is due to the fibrous bands connecting utricular macula to the stapes footplate. In both these conditions, movements of stapes result in stimulation of the utricular macula.

23. Head Impulse/Head Thrust Test P atient is instructed to look at a central point (examiner's nose and central part of forehead). The test is performed by sudden head thrush by 10-15° (rapidly turning the head to one side ) done on both sides The test enhances the effect of the vestibulo -ocular reflex

24. Head Shake Test Unequal input of the disease side generates nystagmus when the head is shacked 20 times (20-30 cycles) and is stopped suddenly. Nystagmus is induced in both central and peripheral vestibular dysfunction.

25. Positional Tests/ Maneuvers

26. most commonly used maneuver in ENT practice patient is asked to fix their gaze on the examiner's nose. patient's face is turned 45° toward the diseased side in an upright position. Then the patient is quickly brought to the supine head-hanging position. (head hangs 30° below the horizontal ) Vertigo and nystagmus are checked Presence of Nystagmus and/or Vertigo is Test positive. The latency for induced nystagmus is approximately 10-20 seconds, and the duration of nystagmus is <1 minute. patient is brought back to a sitting position. similar procedure is done on another side. presence of nystagmus and vertigo is documented as a positive test for posterior canal benign paroxysmal positional vertigo (BPPV). Dix-Hallpike Test

27. This test is particularly useful when patient complains of vertigo in certain head positions.

28. For Horizontal SCC BPPV  S upine roll test The patient is made supine with head 30° elevated in central position first. Then the head is turned to 90° on one side and the position is maintained for 30 seconds and then head is turned to opposite side again keeping the position for 30 seconds. A positive test is the appearance of nystagmus and Vertigo

29. Romberg Test P atient is asked to stand with feet together and arms by the side with eyes first open and then closed. when the patient is asked to stand straight with closed eyes with feet together for a minute In peripheral vestibular lesions, the patient sways to the side of lesion. In central vestibular disorder, patient shows instability. If patient can perform this test without sway, " sharpened Romberg test " is performed.

30. Sharpened Romberg test: Patient stands with feet one behind the other and arms folded in an "X" to let the hands touch the opposite shoulder.  Presence of sway is checked, which indicates an ipsilateral vestibular or cerebellar lesion

31. Fukuda Stepping Test/ Unterberger Test

32. Caloric Test B asis of this test - to induce nystagmus by thermal stimulation of the vestibular system Advantage -each labyrinth can be tested separately. Patient is also asked whether vertigo induced by the caloric test is qualitatively similar to the type experienced by him during the episode of vertigo. If yes, it proves labyrinthine origin of vertigo.

33. 1. MODIFIED KOBRAK TEST. 2. FITZGERALD-HALLPIKE TEST (BITHERMAL CALORIC TEST). 3. COLD-AIR CALORIC TEsT. Caloric Test

34. 1. MODIFIED KOBRAK TEST. It is a quick office procedure. Patient is seated with head tilted 30° forward / 60° backwards to place horizontal canal in vertical position. Ear is irrigated with ice water for 60 s first with 5 mL and if there is no response, 10, 20 and 40 mL. Normally, nystagmus beating towards the opposite ear will be seen with 5 mL of ice water. If response is seen with increased quantities of water between 5 and 40 mL, labyrinth is considered hypoactive. No response to 40mL of water indicates dead labyrinth

35. 2. FITZGERALD-HALLPIKE TEST ( Bithermal Caloric Test) In this test, patient lies supine with head tilted 30° forward so that horizontal canal is vertical The diseased ear followed by a healthy ear is irrigated first with warm water (44°C) and then cold water (30°C) i.e. 7° below and above normal body temperature 250 cc is rinsed in 40 seconds. The sequence is right 44°C, left 44°C, right 30°C, and left 30°C. The nystagmus appears in a 30-second interval. It reaches its peak in 30-45 seconds. eyes observed for appearance of nystagmus till its end point. Time taken from the start of irrigation to the end point of nystagmus is recorded and charted on a calorigram If no nystagmus is elicited from any ear, test is repeated with water at 20 °C for 4 min before labelling the labyrinth dead. A gap of 5 min should be allowed between two ears

36. Cold water induces nystagmus to opposite side and warm water to the same side (@ COWS: cold-opposite, warm-same ). Depending on response to the caloric test, we can find – C anal paresis or dead labyrinth, D irectional preponderance, i.e. nystagmus is more in one particular direction than in the other, or B oth canal paresis.

37. CANAL PARESIS It indicates that response (measured as duration of nystagmus) elicited from a particular canal (labyrinth), right or left, after stimulation with cold and warm water is less than that from the opposite side. It can also be expressed as percentage of the total response from both ears. Where L30 is the response from left side with water at 30 °C and L44 is response from left ear after stimulation with warm water at 44 °C. Less or no response from a particular side is indicative of depressed function of the ipsilateral labyrinth, vestibular nerve or vestibular nuclei and is seen in Ménière's disease, acoustic neuroma, postlabyrinthectomy or vestibular nerve section.

38. DIRECTIONAL PREPONDERANCE It takes into consideration the duration of nystagmus to the right or left irrespective of whether it is elicited from the right or left labyrinth. We know that right beating nystagmus is caused by L30 and R44 and left beating nystagmus is caused by Ro and L44. If the nystagmus is 25-30% or more on one side than the other, it is called directional preponderance to that side. D irectional preponderance occurs towards the side of a central lesion, away from the side in a peripheral lesion ; however, it does not help to localize the lesion in central vestibular pathways. Canal paresis and directional preponderance can also be seen together. Canal paresis on one side with directional preponderance to the opposite side is seen in unilateral Ménière's disease canal paresis with directional preponderance to ipsilateral side is seen in acoustic neuroma.

39. 3. COLD-AIR CALORIC TEST This test is done when there is perforation of tympanic membrane because irrigation with water in such a case with perforation is contraindicated. The test employs Dundas Grant tube , which is a coiled copper tube wrapped in cloth. The air in the tube is cooled by pouring ethyl chloride and then blown into the ear.

40. It is a method of detecting and recording of nystagmus, which is spontaneous or induced by caloric, positional, rotational or optokinetic stimulus. The test depends on the presence of corneoretinal potentials which are recorded by placing electrodes at suitable places round the eyes. The test is also useful to detect nystagmus, which is not seen with the naked eye. It also permits to keep a permanent record of nystagmus. Videographic recording of responses is known as Videonystagmography (VNG) Posturography : It records the effect of balance disturbance generated by moving platforms with movable visual input. Electronystagmography