Vestibular Function Test

Step by step explanation of tests done to assess Vestibular Function. Illustrated using appropriate diagrams and clinical pics.

1. Assessment of Vestibular Functions Venkatesh Karthikeyan III MBBS Velammal Medical College Email: [email protected]

2. Tests done Clinical Test s Laboratory test Vestibular Function Test

3. Clinical tests Spontaneous nystagmus Fistula test Romberg’s test Gait Past pointing and falling Dix - Hallpike manoeuver (positional test) Test of cerebellar dysfunction Vestibular Function Test

4. Laboratory tests Caloric test Electronystagmography Optokinetic test Rotation test Galvanic test Posturography Vestibular Function Test

5. Clinical tests Spontaneous nystagmus Fistula test Romberg test Gait Post pointing and falling Hallpike manoeuver (positional test) Test of cerebellar dysfunction Vestibular Function Test

6. Spontaneous Nystagmus Nystagmus: R hythmical I nvoluntary O scillatory movement of eyes

7. Types of nystagmus Horizontal nystagmus Vertical nystagmus Rotatory nystagmus

8. Horizontal nystagmus Direction of fast component Direction of slow component Direction of Nystagmus

9. Vertical Nystagmus

10. Rotatory Nystagmus

11. Eliciting Nystagmus Patient is seated in front of examiner or lies supine on the bed. Finger at 30 cm from patient’s eye in central position. Move the finger. Avoid Gaze nystagmus. SPONTANEOUS NYSTAGMUS ALWAYS INDICATES AN ORGANIC LESION.

12. VESTIBULAR NYSTAGMUS Peripheral – due to lesion in labyrinth or CN VIII Central – due to lesion in vestibular nuclei or brainstem or cerebellum

13. Peripheral Nystagmus Irritative lesions of the labyrinth (serous labyrinthitis ) – nystagmus to the side of lesion. Paretic lesions – nystagmus to healthy side (purulent labyrinthitis , trauma to labyrinth and section of VIIIth nerve) Suppressed by optic fixation by looking at fixed point Enhanced in darkness or by using Frenzel glasses (+20 D)

14. Central Nystagmus Cannot be suppressed by Optic fixation. Types of Central Nystagmus: Torsional Nystagmus Vertical downbeat Nystagmus Vertical Upbeat Nystagmus Pendular Nystagmus

15. Type of Nystagmus Level of Lesion Conditions in which it is seen Torsional nystagmus Brainstem or Vestibular nuclei Syringomyelia Vertical downbeat nystagmus Craniocervical region Arnold Chiari malformation or degenerative lesions of cerebellum Vertical upbeat nystagmus Junction of Pons and medulla or pons and midbrain - Pendular nystagmus - Congenital or Multiple Sclerosis Maybe disconjugate

16. Clinical tests Spontaneous nystagmus Fistula test Romberg test Gait Past pointing and falling Hallpike manoeuver (positional test) Test of cerebellar dysfunction Vestibular Function Test

17. Fistula Test Basis of the test : Inducing nystagmus by producing pressure changes in external ear which are then transmitted to labyrinth True Negative – Normal

18. Fistula test - True Positive Erosion of horizontal semicircular canal as in cholesteatoma Surgically created window in horizontal canal (Fenestration) Abnormal opening in oval window (post stapedectomy fistula) Abnormal opening in round window (Rupture of round window)

19. Fistula Test – False Negative Dead labyrinth Cholesteatoma covering the site of fistula and not allowing the pressure changes to be transmitted to labyrinth.

20. Fistula test – False positive Congenital syphilis – due to hypermobile stapes footplate Meniere’s disease – due to fibrous bands connecting utricular macula to stapes footplate. In both these conditions, movement of stapes results in stimulation of Utricular macula.

21. Clinical tests Spontaneous nystagmus Fistula test Romberg test Gait Past pointing and falling Hallpike manoeuver (positional test) Test of cerebellar dysfunction Vestibular Function Test

22. Romberg Test Peripheral Vestibular Lesion – patients sways to side of lesion. Central Vestibular Lesion – patient shows instability.

23. Sharpened Romberg Test Inability indicates Vestibular impairment

24. Clinical tests Spontaneous nystagmus Fistula test Romberg test Gait Post pointing and falling Hallpike manoeuver (positional test) Test of cerebellar dysfunction Vestibular Function Test

25. Gait In case of uncompensated lesions of peripheral vestibular system, with eyes closed, the patient deviates to affected side

26. Clinical tests Spontaneous nystagmus Fistula test Romberg test Gait Past pointing and falling Hallpike manoeuver (positional test) Test of cerebellar dysfunction Vestibular Function Test

27. Clinical tests Spontaneous nystagmus Fistula test Romberg test Gait Past pointing and falling Hallpike manoeuver (positional test) Test of cerebellar dysfunction Vestibular Function Test

28. Hallpike manoeuvre Useful when patient complains of vertigo in certain head positions Helps differentiate a peripheral from a central lesion

29. Positional Nystagmus elicited by Hallpike maneuver Peripheral lesion Central lesion Latency 2-20 seconds No latency Duration <1 minute >1 minute Direction of nystagmus Direction fixed Direction changing Fatigability Fatigable (disappears on subsequent repetitions) Non fatigable Accompanying symptoms Severe vertigo None or slight

30. Clinical tests Spontaneous nystagmus Fistula test Romberg test Gait Post pointing and falling Hallpike manoeuver (positional test) Test of cerebellar dysfunction Vestibular Function Test

31. Test for Cerebellar function All cases of giddiness should be tested for cerebellar diseases. Diseases of cerebellar hemisphere causes: Asynergia (abnormal finger nose test) Dysmetria (inability to control range of motion) Adiadochokinesia (inability to perform rapid alternative movements) Rebound phenomenon (inability to control movements of extremity when opposing forceful restraint is suddenly released)

32. Midline diseases of cerebellum causes: Wide based gait Falling in any direction Inability to make sudden turns while walking Truncal ataxia

33. Laboratory tests Caloric test Electronystagmography Optokinetic test Rotation test Galvanic test Posturography Vestibular Function Test

34. Caloric Test Basis : Induce nystagmus by thermal stimulation of vestibular system. Advantage : Each labyrinth can be tested separately. Helps proving labyrinthine origin of vertigo.

35. Caloric Tests Modified Kobrak test Fitzgerald- Hallpike test Cold-air caloric test

36. Modified Kobrak test Patient seated with head tilted 60 degrees backwards (Horizontal canal  Vertical in position) Ear is irrigated with cold water for 60 seconds. 5mL 10mL 20mL 40mL

37. Normal – Nystagmus beating towards opposite ear with 5mL of ice water Hypoactive labyrinth – response with increased quantities of water (5 to 40 mL) Dead labyrinth – no response to 40 mL of water

38. Fitzgerald – Hallpike test

39. Irrigate the ears for 40 seconds alternately with water at 30 C and at 44 C Eyes are observed for appearance of nystagmus till its end point Chart the time taken from the start of irrigation to the end point of nystagmus on a calorigram If no nystagmus is elicited from any eye, test is repeated with the water at 20 C for 4 minutes before labelling the labyrinth dead. Allow a gap of 5 minutes between two ears

40. C old water - Nystagmus to o pposite side W arm water – Nystagmus to s ame side

41. Caloric test helps in assessing: Canal paresis – response elicited from a particular canal after stimulation is less than that from opposite side Directional preponderance – Duration of nystagmus to left or right, irrespective of whether it is elicited from the right or left labyrinth

42. Canal paresis It can be expressed as percentage of total response from both ears. Response from left ear = L 30 + L 44 L 30 + L 44 + R 30 + R 44 Response from right ear = R 30 + R 44 L 30 + L 44 + R 30 + R 44 X 100 X 100

43. Less or no response from particular side is indicative of depressed function of ipsilateral labyrinth or vestibular nerve or vestibular nuclei. Depressed functions are seen with: Meniere’s disease Acoustic neuroma Post labyrinthectomy Vestibular nerve section

44. Directional preponderance Right beating nystagmus is caused by L 30 and R 44 (COWS) Left beating nystagmus is caused by L 44 and R 30 Right beating nystagmus = L 30 + R 44 L 30 + L 44 + R 30 + R 44 Left beating nystagmus = L 44 and R 30 L 30 + L 44 + R 30 + R 44 X 100 X 100

45. If nystagmus is 25 – 30% or more on one side than the other side, it is called directional preponderance to that side. Directional preponderance occurs towards the side of central lesion, away from side of peripheral lesion. Unilateral Meniere’s disease – Canal paresis on one side and directional preponderance to opposite side Acoustic neuroma – Both to ipsilateral side

46. Laboratory tests Caloric test Electronystagmography Optokinetic test Rotation test Galvanic test Posturography Vestibular Function Test

47. Electro- nystagmo - graphy Depends on presence of corneo -retinal potentials which are recorded by placing electrodes at suitable places around the eye. Used for: Detecting nystagmus (even which is not seen by naked eye) Recording nystagmus (permits to keep a permanent record)

48. Laboratory tests Caloric test Electronystagmography Optokinetic test Rotation test Galvanic test Posturography Vestibular Function Test

49. Optokinetic test Used to diagnose central lesions (brainstem and cerebral hemisphere lesions) Normally, it produces nystagmus with slow component in the direction of moving stripes and fast component in opposite direction R  L L  R

50. Laboratory tests Caloric test Electronystagmography Optokinetic test Rotation test Galvanic test Posturography Vestibular Function Test

51. Rotational test Patient seated with head tilted 30 forward Rotated 10 turns in 20 seconds Stop the chair abruptly and observe the nystagmus (Normal : 25-40 seconds) Performed in case of congenital abnormalities where ear canal has failed to develop (unable to perform caloric test) Disadvantage : Labyrinths cannot be tested individually

52. Laboratory tests Caloric test Electronystagmography Optokinetic test Rotation test Galvanic test Posturography Vestibular Function Test

53. Galvanic test Helps differentiating end organ lesion from vestibular nerve lesion. Feet together, eyes closed, arms out-stretched. Current of 1 mA passed to one ear – normally, patient sways towards side of anodal current.

54. Laboratory tests Caloric test Electronystagmography Optokinetic test Rotation test Galvanic test Posturography Vestibular Function Test

55. Helps in evaluating vestibular function by measuring postural stability

56. Firing Round

57. Thank you  Adam Politzer – Father of modern Otology