My Patient is Dizzy

Dr Raj Nandi Clinical Lead and Consultant in Audiovestibular Medicine 2 Outline

▪ Anatomical and Physiological overview

▪ Balance Assessment

▪ - History

▪ - The central role of eye movement examination

▪ -

▪ - Positional tests

▪ - Tests of stance and gait

▪ Common causes of dizziness

▪ Take aways

3 Balance organs

3 semi-circular canals (anterior, posterior and lateral, in 3 planes approximately right angles to each other) and 2 otolith organs (utricle and saccule).

Neural elements of the semi-circular canals are called the ‘cristae ampullaris’ and those of the otolith organs are known as the ‘maculae’

Semi-circular canals detect angular motion in 3 planes – ‘yaw’, ‘ptich’ and ‘roll’ Otolith organs (utricle and saccule) detect linear motion Anterior semicircular canal

Crista ampullaris

Otolith organs, Posterior semicircular U= utricle canal S= saccule

Figure – Balance organs 5 6 7 Physiology of balance

▪ Vestibular stimulation results in reflex responses

▪ Vestibulo-ocular reflex (VOR) – maintains gaze on an object while head or body is in motion

▪ Vestibulo-spinal reflex – maintains and modulates posture through myotatic (deep tendon) reflexes

▪ Vestibulo-collic reflex – thought to act on neck muscles to stabilize head. Balance – neural connections ▪ Majority of afferent vestibular nerves terminate in the vestibular nuclei

▪ Convergence of vestibular, visual and somatosensory inputs at vestibular nuclei with cerebellar, spinal and cortical inputs

▪ Underpins posture, locomotion, spatial orientation and gaze stabilization

▪ Also contributions to autonomic, endocrine, emotion and executive function

Balance assessment

History ▪ Onset ▪ Duration ▪ Description of symptoms and associated features (such as loss or headache) Examination ▪ Clinical vestibular assessment is broadly divided into – 1) Neuro-otological examination of eye movements, and 2) Assessment of postural control

Investigations ▪ Investigations (such as the caloric test, rotational chair tests, posturography etc) help gather quantitative information regarding balance function Peripheral vs Central

Peripheral Central ▪ Normal CNS exam ▪ Abnormal CNS exam ▪ Auditory symptoms +++ ▪ Auditory symptoms +/- ▪ Unsteadiness +++ ▪ Unsteadiness +++ (acute); +/- (chronic) (acute); +++(chronic) ▪ +++ (acute); +/- (chronic) ▪ Vertigo ++ (acute); +/- (chronic) ▪ Eye Movements = Normal ▪ Eye Movements = ▪ Nystagmus = Horizontal / Abnormal torsional; reduces with ▪ Nystagmus = in any fixation plane; enhances with fixation History

▪ Presentation = Rotational / Positional / Unsteadiness / Non specific

▪ Duration = Seconds (paroxysmia or BPPV) - Minutes ( Migraine or Panic or TIA) - Hours (Migraine or Meniere’s) - Days & weeks (Vest neuritis or brainstem or cerebellar pathology; migraine) ▪ Triggers

▪ Associated Symptoms Examination

▪ Aural Examination ▪ Head Thrust Auricle / External auditory meatus / ▪ Head shake Tympanic membrane . Fistula sign. Tuning fork tests ▪ Positional Tests

▪ Eye Movements ▪ Stance and Gait Examination ▪ Postural response to ▪ - Cover Test perturbation force ▪ - Range of eye movements ▪ - Saccades ▪ Blood Pressure (x3) ▪ - Smooth Pursuit ▪ General neurological ▪ - Nystagmus – Spontaneous / examination – cranial nerves, Gaze evoked / Positional / co-ordination, vibration and Congenital etc joint position Aural examination

▪ Evidence for possible peripheral lesions ▪ Middle ear disease – tubo-tympanic / serous / cholesteatoma / chronic otitis media ▪ ▪ Glomus tumours ▪ Fistula sign - horizontal (horizontal canal) - torsional (anterior canal) - vertical ( posterior canal) Eye movements

▪ “The vestibulo-ocular reflex (VOR) is a reflex that acts at short latency to generate eye movements that compensate for head rotations in order to preserve clear vision during locomotion. The VOR is the most accessible gauge of vestibular function. Evaluating the VOR requires application of a vestibular stimulus and measurement of the resulting eye movements.” ▪ Fife, Tusa, Furman et al Neurology 2000;55;1431 (reviewed January 2011) VOR

Figure – Neural connections underlying vestibulo-ocular reflex 18 19 Cover test

▪ To examine for strabismus – changing optic fixation can result in abnormal eye movement examination ▪ Manifest strabismus – exotropion (outwards) - esotropion (inwards) ▪ Latent strabismus – exophorion (covered eye goes inwards) - esophorion (covered eye goes outwards) ▪ Latent nystagmus - nystagmus seen in both eyes only when one eye is occluded, with nystagmus fast phase towards uncovered eye. Congenital Range of eye movements

▪ Horizontal and Vertical planes, 300 from midline

▪ Conjugate but not full range of movements = Gaze paresis –> cortical lesions / ponto medullary / mesencephalic (supranuclear gaze palsy)

▪ Dysconjugate eye movements => Ocular paresis – IIIrd / IVth / VIth nerve lesions Saccades

▪ Fast, 350-6000 /second, maintain foveal fixation ▪ Latency / velocity / accuracy of saccades - hypermetria usually in cerebellar lesions ▪ Internuclear ophthalmoplegia ------▪ One and a half syndrome – Smooth Pursuit

▪ Maintain gaze on a moving target

▪ Gain of 1 up to 300 / second or 0.1 kHz sinusoidal rotation

▪ Test at 0.2 to 0.4Hz

▪ ‘Broken smooth pursuit’ – lesions of the fovea / calcerine cortex / parieto-occipital & parieto- temporal cortex / pontine nucleus / cerebellar flocculus.

▪ Note effects of age / alcohol and drugs (including vestibular sedatives) 24 25 Optokinetic nystagmus ▪ To foveate on moving objects with head held steady (example – looking out from a moving train)

▪ Low frequency

▪ Peripheral retina – accessory optic tract – vestibular nuclei – reticular formation

▪ Directional preponderance in peripheral lesions

▪ Reversal of OKN in congenital nystagmus

▪ Central lesions – OKN impaired ipsilateral to damaged brainstem or cerebellum Nystagmus

▪ Spontaneous nystagmus – peripheral vestibular (Alexander’s Law) ▪ Gaze evoked nystagmus – asymmetrical in structural brain lesions; symmetrical after use of anticonvulsants, psychotropic drugs and alcohol ▪ Positional nystagmus – Benign paroxysmal BPPV positional vertigo / CentralCentral Positional positional Latent periodnystagmus to onset of (MS, ArnoldNo latent Chiari, period cerebellar nystagmus vascular disease) Adapts, fatigues on repetition Persists Torsional and geotropic Any direction Localizing central nystagmus

▪ Downbeat nystagmus => Cervicomedullary junction

▪ Upbeat nystagmus => Vermis

▪ Convergence – retraction nystagmus => Dorsal midbrain

▪ See – saw nystagmus => Third ventricular, parasellar

▪ Rebound nystagmus => cerebellar

▪ PAN => cerebellar

▪ Brun’s nystagmus => CP angle lesion, most common acoustic neuroma 28 ▪ Congenital nystagmus – usually horizontal, binocular, no oscillopsia, ‘null point’, reversal of OKN, abolished with sleep.

▪ Torsional (or rotary) nystagmus – around visual axis – lesion to vestibular nuclei / ‘see saw’ nystagmus in thalamic lesion

▪ Periodic alternating nystagmus – changes direction – congenital (albinism) or acquired (caudal cerebellum or brainstem lesion).

▪ Pendular nystagmus – brainstem disease or in long standing visual defects. ▪ Rebound nystagmus – gaze evoked nystagmus that on adopting primary gaze beats in the opposite direction transiently = cerebellar disease

▪ Up beat nystagmus = brainstem lesions / meningitis / Wernicke’s encephalopathy / organophosphorous poisoning

▪ Down beat nystagmus = cranio-cervical joint lesions (ex Arnold Chiari) / spinocerebellar degeneration

▪ Bruns nystagmus = coarse large amp nystagmus towards side of lesion (in CP angle tumours) and fine small amp nystagmus towards the opposite side. Clinical tests of vestibular loss ▪ Head thrust sign - catch-up saccade with quick head turns toward the side of unilateral vestibular loss

▪ Head-shaking nystagmus - Observe for nystagmus away from the side of unilateral vestibular loss after head shaking

▪ Vibration-induced nystagmus - Observe for nystagmus away from the side of unilateral vestibular loss when mastoid vibration is applied

▪ Subjective visual vertical - Patient directs bar or line to what he or she perceives to be straight vertical; in acute otolith dysfunction, the bar or line deviates to the side of unilateral vestibular (otolith) loss

▪ Dynamic visual acuity - three-line decrease in visual acuity during rapid head turning indicative of bilateral peripheral vestibular loss

▪ Hyperventilation induced nystagmus – cerebellar pathology; nystagmus towards site of vestibular schwannomma Halmagyi Head Thrust manoeuvre 33 Video Head Impulse Test Dynamic visual acuity Dix Hallpike manoeuvre Side lying (posterior canal BPPV)

37 38 Supine head roll test (Horizontal canal BPPV)

39 40 Central lesions, especially those involving the nodulus and uvula, enhance responses of secondary vestibular neurons > resultant increase in postrotatory signals > generate the paroxysmal form of positional nystagmus 41 Algorithm for evaluating positional vertigo – from Fife, Continuum Lifelong learning in Neurology 18(5):1060-1085, October 2012

42 Semont

43 Lempert 3600 manoeuvre

44 Gufoni (A= geotropic; B=apogeotropic)

45 Central positional nystagmus

46 TRV Chair

Tests Supine position Dix-Hallpike Roll Test Inverted Position

Treatments Epley Maneovre Semont BBQ Roll Dynamic BBQ Roll Anterior Canal Subjective visual vertical

▪ Line deviates towards side of lesion (in otolith dysfunction) 49 Stance and position

Romberg’s test Unterberger’s test ▪ Dorsal column of spinal ▪ ‘March on the spot’ with cord lesions (ex – tabes eyes closed, arms dorsalis) extended for about 50 steps ▪ ‘Positive’ = ↑body sway ▪ Angle of rotation and with eyes closed forward / backward ▪ Acute vestibular deficits movement recorded ▪ Cerebellar disease ▪ Deviates towards side of lesion ▪ However, variable test results, use with caution ! Tests of Stance and Posture 52 Tests of Gait Tandem gait test

▪ For assessing vestibulospinal function ▪ With eyes open, tandem walking tests cerebellar function ▪ With eyes closed tests vestibular function (if cerebellar and proprioception is normal) ▪ Feet in tandem position, arms folded on chest, 10 steps Single episode of prolonged vertigo

▪ Vestibular neuritis ▪ Index episode of migrainous vertigo ▪ First episode of Meniere’s ▪ Acute brainstem or cerebellar lesion ▪ Perilymph fistula ▪ Bacterial ▪ Labyrinthine infarction ▪ Drug / Alcohol toxicity Recurrent vertigo / dizziness

▪ BPPV ▪ Incompletely compensated vestibular deficit ▪ Migrainous vertigo / Benign recurrent vertigo ▪ Meniere’s disease ▪ Paroxysmal recurrent vertigo ▪ Perilymph fistula ▪ Autoimmune inner ear disease ▪ Vestibular schwannoma ▪ Vertebro-basilar TIA ▪ Vestibular epilepsy ▪ Episodic ataxia type 2 ▪ Otosclerosis Investigations

▪ PTA ▪ ABR ▪ Bithermal Calorics ▪ Video Head Impulse Test ▪ Rotational Tests ▪ Oculomotor recording ▪ Vestibular Evoked Myogenic Potentials ▪ Posturography ▪ Imaging Conclusion

▪ History is vitally important – when, how (triggers), how long, what happened, what else happened (associated symptoms)…. ▪ Examination – the eyes are the window to the ! Eye movement examination needs to be carefully done ▪ General neurological examination and systemic examination - ? Multifactorial dizziness. ▪ Investigations only help confirm or refute what history and examination suggest. Thank you

Email : [email protected] 59 References

▪ R Davies. Bedside neuro-otological examination and interpretation of commonly used investigations. J Neurol Neurosurg Psyciatry 2004 75:iv32-iv44 ▪ Luxon and Davies, Editors – Handbook of vestibular rehabilitation, Wiley, London 1997 ▪ Adolfo Bronstein and Thomas Lempert – Dizziness, a practical approach to diagnosis and management. Cambridge University Press 2007. ▪ Baloh and Honrubia: Clinical Neurophysiology of the Vestibular system (3rd Edition) Oxford University Press, 2001. ▪ Images courtesy of Baloh and Honrubia and Google Images