Presentation on theme: "Clinical Tests for Vestibular Function Dr. Vishal Sharma."— Presentation transcript:
Clinical Tests for Vestibular Function Dr. Vishal Sharma
Nystagmus Involuntary rhythmical oscillatory movement of eye ball Vestibular disorders cause jerk nystagmus with slow & fast phases Direction is given by fast phase
Nystagmus Intensity grading (Alexander’s law): 1° only present when looking towards fast phase 2° also seen when looking straight 3° also seen when looking towards slow phase
Nystagmus Vestibular lesion nystagmus gets suppressed by optic fixation & enhanced with its removal with Frenzel glasses Irritative vestibular labyrinthine lesion: Ipsilateral nystagmus Paralytic vestibular labyrinthine lesion: Contralateral nystagmus
Test for gaze evoked nystagmus
Examiner’s finger kept 30 cm from pt's eyes in centre. Moved in horizontal & vertical planes. Pt is asked to follow it with his eyes. Keep displacement from midline to maximum of 30° (to avoid physiological end-point nystagmus).
Fistula test Transmission of increased air pressure in E.A.C., via middle ear, into inner ear through a labyrinthine fistula causes vertigo + nystagmus towards affected ear. E.A.C. pressure is by intermittent tragal pressure or Siegelization.
Mechanism Convection current formation in endo-lymph due to temperature gradient → ampullo-petal flow or ampullo-fugal flow due to warm or cold water activation of Vestibulo-Ocular Reflex → vertigo + horizontal nystagmus
Fitzgerald-Hallpike Bithermal Caloric Test
Procedure Pt supine + 30° head elevation. Each ear irrigated in turn for 40 sec with warm water at 44°C & then cold water at 30°C. Duration of nystagmus is from start of irrigation to end point of nystagmus. Normal = 90–140 sec Direction of fast component: Cold → Opposite ear; Warm → Same ear
Canal Paresis Duration of nystagmus with both 44°C & 30°C irrigations in one ear is 30 % less than opposite ear. Seen in same sided peripheral vestibular lesion. C. P. (%) = (R30 + R44) – (L30 + L44) X 100 R30 + R44 + L30 + L44
Directional Preponderance Duration of nystagmus in one direction is 30 % more than opposite direction. Seen in same sided central vestibular lesion & opposite peripheral vestibular lesion. D.P. (%) = (L30 + R44) – (R30 + L44) X 100 R30 + R44 + L30 + L44
Special cases Same sided canal paresis + same sided directional preponderance: Acoustic Neuroma Same sided canal paresis + opposite sided directional preponderance: Meniere’s disease
Modified Kobrak's Test E.A.C. irrigated for 60 sec with ice cold water in increasing quantity (5, 10, 20 & 40 ml) till nystagmus is noticed. Nystagmus noticed with: 5 ml = Normal vestibular labyrinth. 10 / 20 / 40 ml = Hypoactive labyrinth. No nystagmus (40 ml) = Dead labyrinth
Dundas Grant Cold Air Caloric Test Done in T.M. perforation as water syringing is contraindicated Air in coiled copper tube is cooled by pouring ethyl chloride in it Effluent cool air is blown into E.A.C. to produce vertigo + nystagmus
Dix-Hallpike Manoeuvre 1. Pt in sitting position on a couch. 2. Pt’s head turned 45° towards diseased ear. 3. Pt moved rapidly into supine position with head hanging 30° below couch. Pt’s eyes observed for nystagmus for 1 minute. 4. Pt moved rapidly back into sitting position. 5. Manoeuvre repeated for opposite ear.
Nystagmus in B.P.P.V. Latent period (2–20 sec) before nystagmus Rotatory Fixed direction, towards ground (geotropic) Duration < 1 minute due to adaptation Direction reversal on return to sit position Fatiguing on repeating Hallpike maneuver Associated vertigo & autonomic symptoms
Epley’s particle repositioning manoeuvre
Step 1 3
Step 5 to 6
Epley’s Manoeuvre 1. Pt in sitting position on a couch 2. Pt’s head turned 45° towards diseased ear 3. Pt moved rapidly into supine position with head hanging 30° below couch 4. Pt’s head rotated by 90° to opposite side 5. Further 90° head + trunk rotation 6. Pt moved rapidly back into sitting position
Epley’s Manoeuvre 7. Pt’s head brought in midline 8. Slight flexion of pt’s head Cervical collar given to pt for 48 hours Pt to sleep in 30 o head end elevation & avoid violent head jerks Pt must have nystagmus at every step of Epley’s manoeuvre if it is done properly