approach to ataxia

1. APPROACH TO ATAXIA
DR Y RAGHU NANDHINI
UNIT 4

2. INTRODUCTION
Important concepts in Ataxia
ATAXIA MIMICKERS
Tests of Cerebellar dysfunction
Step-wise approach to Cerebellar Ataxias
Summary
ALGORITHM for cerebellar ataxias

3. ‘In Simple Terms…”
• ATAXIA- “Absence of ORDER” (Greek Word)
• In Neurological Terms-
“Incoordination of movement”
• A major feature of a disease or just one of the
various clinical features of a disease

4. Definition
• Ataxia is the inability to make smooth,
accurate and coordinated movements
• Arises from disorders of:
––Cerebellum
––Sensory pathways (Sensory Ataxia)
––Posterior columns, dorsal root ganglia,
peripheral nerves
––Frontal lobe lesions
––Extra pyramidal system
––Vestibular system

5. Tests to differentiate Various systems
in Ataxia- “The Ataxia Mimickers”

6. Cerebellar Ataxia
Cortical Ataxia
Myopathy
Labrynthine Ataxia
Sensory Ataxia
(Posterior Column)
Thalamic Ataxia
Sensory Ataxia
(Peripheral
Neuropahy))

7. SENSORY ATAXIA
“Disturbances in the sensory input to the cerebellum”
•Tests of proprioception- Joint sense, passive
movement
“The corrective effects of the Visual system”
•Classical Sensory Ataxic Gait
•Romberg’s sign
•Loss of tendon reflexes
•Features of Peripheral neuropathy

9. Labrynthine Disorders
• Input to cerebellum
• Dizziness, light headedness, perception of
“movement”, rotatory nystagmus
• Infections, neoplasms, vascular causes

10. Cortical Ataxias
 FRONTAL LOBE ATAXIA refers to disturbed coordination due to
dysfunction of the contralateral frontal lobe;
-Results from disease involving the frontopontocerebellar fibers
en route to synapse in the pontine nuclei.
• hyperreflexia, increased tone and Release reflexes

12. Thalamic Ataxias
- transient ataxia affecting contralateral limbs
after lesion of anterior thalamus
- may see associated motor (pyramidal tract)
signs from involvement of internal capsule
- also can result in asterixis in contralateral
limbs (hemiasterixis)

13. CEREBELLAR
ATAXIAS
“ATAXIA IS THE MOST IMPORTANT FEATURE
AMIDST OTHER CLINICAL SIGNS OF CEREBELLAR
DYSFUNCTION”

14. NEO CEREBELLUM
FLOCCULONODULAR
LOBE
SPINO CEREBELLUM

15. Cerebellar Dysfunction: Anatomy
Cerebellar parts Functions Signs
Posterior
(Flocculo-nodular lobe)
Archicerebellum
Body equilibrium
Eye movements
Eye movement disorders:
Nystagmus;
Vestibulo-ocular reflex
(VOR)
Postural and gait dysfunction
Midline
(Vermis; vermis of ant. lobe
pyramid , uvula and
paraflocculus)
Paleocerebellum
Input from spinal cord
Muscle tone
Axial stance and gait
Truncal & gait ataxia
Hemisphere
(middle portion of vermis,
cerebellar hemisphere)
Neocerebellum
Connected with Pons
and cortex through
thalalmus
Planning and initiation
of movements
Regulation of fine limb
movements
Limb ataxia:
Dysmetria,
Dysdiadochokinesis,
"intention" tremor
Dysarthria
Hypotonia

16. TESTS OF CEREBELLAR DYSFUNCTION

17. ATAXIA
“errors in the RATE, RANGE, FORCE & DIRECTION
of movement”
•GAIT ATAXIA
•TRUNCAL ATAXIA
•LIMB ATAXIA

18. CLASSIC FEATURES AND TESTS
Dyssynergia: results in jerky decomposed
movements (heel-knee-shin test)
Dysmetria: due to delayed activation of
antagonists
•- often correction to target by series of jerky
corrections (finger nose test)
•- may lead to intention tremor in limbs with
finger-to-nose or foot-to-target testing as
rhythmic oscillation emerges close to target
Dysdiadochokinesis: irregularities of force,
speed, and rhythm

19. Other features
Hypotonia: decrease in resistance to passive movement of
muscles related to depression of gamma motor neuron
activity (usually seen transiently in acute phase of
cerebellar lesions), pendullar knee jerk
Rebound phenomenon: related to poor tone and weak
check response, so when tap or displace limb, wider range
of movement in return to static position, incl. Holmes
phenomenon when suddenly release flexed arm held
against resistance - unable to stop flexion and arm strike
self (delay in activation of antagonist triceps muscle)
Dysarthria: often scanning type with irregularities in tone,
with words broken into syllables; often slow with
occasional rapid portions ("explosive speech")

20. Other features
Ocular Motor Abnormalities:
- usually if vestibular connections or flocculonodular lobe
affected
- pursuit movements no longer smooth, but saccadic
- may over- or under-shoot target with attempts at fixation
(ocular dysmetria)
- in primary position may see saccadic intrusions (such
as macro square-wave jerks) or primary nystagmus (incl.
vertical, esp up-beat nystagmus) or periodic alternating
nystagmus
-rebound nystagmus can occur with contralateral-beating
nystagmus on return of eyes to primary position after
eccentric gaze evoked nystagmus to one side
Writing abnormalities
Positional projectile vomiting (posterior fossa lesions)

21. APPROACH TO CEREBELLAR ATAXIA
IN ADULTS

22. THE “FOUR” QUESTIONS????
• Mode of ONSET ?
• PROGRESSION ?
• Focal /Symmetric involvement ?
• Localisation of the cerebellar lesion ?
HISTORY
EXAMINATION

23. MODE OF ONSET
• ACUTE- hours to days
• SUB ACUTE- days to weeks
• CHRONIC- months to years

24. ACUTE ONSET ATAXIA
• INTOXICATION: alcohol , lithium , phenytoin ,
barbiturates
• POST INFECTIOUS: Acute Viral Cerebellitis,
VZV
• VASCULAR: Infarction (AICA, PICA syndromes),
Haemorrhage, Subdural hematoma

25. SUB ACUTE ATAXIA
• INTOXICATION: Mercury, Solvents, Glue
• NUTRITIONAL: B1 and B12 deficiency
• INFECTION: HIV
• DEMYELINATING: Multiple Sclerosis
• NEOPLASTIC: Glioma, Metastases

26. CHRONIC ATAXIA
• AUTOIMMUNE CAUSES : Paraneoplastic
syndromes, Gluten hypersensitivity, Anti GAD
abs.
• HYPOTHYROIDISM
• INFECTIONS: Syphilis (Tabes Dorasalis)
• CONGENITAL LESIONS: Arnold-Chiari and Dandy
Walker Syndromes
• INHERITED ATAXIAS: AD,AR,XR,XD,Mitochondrial

27. PROGRESSION
• Progressive
• Static
• Intermittent symptoms
• Reversible Ataxias

28. STATIC ATAXIAS
• Vascular causes
REVERSIBLE ATAXIAS
• Infectious causes – post viral
• Thyroid
• Drugs
• Toxins
INTERMITTENT SYMPTOMS
• Episodic Ataxias (Inherited etiology)

29. FOCAL / SYMMETRIC ATAXIAS
• Cerebellar symptoms on same side of lesion, or
• Bilateral symptoms
FOCAL ATAXIAS
Vascular causes, Multiple Sclerosis, Cerebellar
abscess, cerebellar glioma, PML (HIV), Congenital
causes
SYMMETRIC ATAXIAS
Intoxication, Nutritional, Post inhectious,
Hypothyroid, Autoimmune causes

32. THE NEXT STEP …RULE OUT
ACQUIRED ATAXIAS
INHERITED ATAXIAS
SPORADIC or
IDIOPATHIC
ATAXIAS

33. ACQUIRED ATAXIAS
• First rule out the Structural causes (MRI Brain/
CT head)
-CVJ anomalies
-Posterior fossa tumors
-Demyelinating diseases
-Hypoxic encephalopathies
-Vascular causes- infarct, haemorrhage

34. Acquired Causes
• HYPOTHYROIDISM- Mild gait ataxia PLUS
Systems of hypothyroidism

35. ALCOHOLISM
• Vermian Atrophy

36. TOXINS
• Cancer chemotherapeutics 5 FU, Cytarabine
• Metals Bismuth, Mercury (parasthesiass,
restricted visual defects), Lead
• SolventsPaint thinners , toluene (Cognitive
defects PLUS pyramidal tract signs)
• AnticonvulsantsPhenytoin (purkinje cell
loss)avoid in epileptics with ataxia

37. INFECTIONS
• VZV in children
• EBV in children
• Bickerstaff’s encephalitis (brain
stemophthalmoplegia,ataxia,lower c.n
palsies)
• HIV ( Lymphomas, PML, Infections,
Toxoplasmosis)
• CJD (17% classic CJD, Ataxic variant of CJD)
• Syphilis (Tabes Dorsalis)
• Whipple’s disease

38. AUTOIMMUNE CAUSES
PARANEOPLASTIC SYNDROMES
•ANTI Hu abs. Small Cell Cancer Lung
(extrapyramidal signs)
•ANTI Yo abs. Ovarian cancer
•ANTI Ri abs. Breast cancer (opsoclonus –
saccadomania, Trunk ataxia)
•ANTI Tr abs. Hodgkin’s lymphoma (hearing
loss)

39. • GLUTEN SENSITIVITY - Anti Gliadin abs.
(ataxia, brisk reflexes, peripheral neuropathies)
• ANTI GAD abs. – Diabetes, hypothyroidism,
peripheral neuropathySTIFF PERSON
syndrome
AUTOIMMUNE CAUSES

40. NUTRITIONAL CAUSES
• FAT MALABSORPTION- Vit. E deficiency
• Vit. B12 , B1 deficiencies

41. INHERITED ATAXIAS
• AD
• AR
• MITOCHONDRIAL DISTURBANCES
• X LINKED RECESSIVE
• X LINKED DOMINANT

42. INHERITED ATAXIAS

43. AUTOSOMAL DOMINANT

44. • SPINO CEREBELLAR ATAXIAS (Types131)-
previously olivopontocerebellar atrophies
• DentatoRubroPallidoLuysian Atrophy
• EPISODIC ATAXIAS (Types 17)
AUTOSOMAL DOMINANT

45. SCA SALIENT FEATURES
• 3-5th decade of life ONSET, loss of ambulation
over 10-15 yrs. from onset
• Phenomena called ANTICIPATION and
PENETRANCE differs from each
SCAresponsible for various ages of
presentation and variable phenotypic
expression
• CAG repeat expansion in most of them

46. Spinocerebellar Ataxia (SCA)
Dominant SCA syndromes have many overlapping signs: Difficult to
distinguish on clinical grounds
Common features to all: Gait ataxia; Dysarthria
Features in some ataxias: Ocular D; Extrapyramidal; Peripheral nerve;
Intellectual D; Seizures
Features with some predictive value for specific gene defects

47. SCA: Clinical Syndromes
•SCA 1: Hypermetric saccades; ++Tendon reflexes; Evoked motor
potentials Long conduction times
•SCA 2 Slowing saccads; Myoclonus or action tremor
•SCA 3/Machado-Joseph: Gaze-evoked nystagmus; Prominent
spasticity or neuropathy
•SCA 4: Cerebellar syndrome; Sensory neuropathy
•SCA 5: Pure cerebellar syndrome
•SCA 6: Pure cerebellar syndrome; -ve family history; Late onset > 50
•SCA 7: Retinal degeneration; Hearing loss; Onset in 1st decade
•SCA 8: Pure cerebellar syndrome
•SCA 10: Pure cerebellar syndrome ± Seizures
•SCA 11: Pure cerebellar syndrome
•SCA 12: Early arm tremor; Late dementia
•SCA 13: Early childhood onset; Mental retardation
•SCA 14: Ataxia; Myoclonus (with early onset)

48. Relationship between ADCAs and SCAs
ADCA type SCA type
I -Cerebellar plus
(Pyramidal, Extra-pyramidal,
Ophthalmoplegia, & Dementia) 1,2,3,4,12,16,17, DRPLA
II Cerebellar + pigmentary
maculopathy 7
III pure cerebellar ± Mild
pyramidal signs 5,6,8,11,14,15,22
Ataxia and epilepsy 10
Early onset with mental retardation 13

49. SCA 5
SCA 2MJD
SCA 7

50. SPINOCEREBELLAR ATAXIA 1 ;SCA 1
SPINOCEREBELLAR ATORHY I
OLIVOPONTOCREBELLAR ATORPHY I; OPCA 1
OPCA I
MENZEL TYPE OPCA
 CLINICAL SYNOPSIS
 Neurological:
 Miscellaneous:
 Labs:
 Gene Map Locus:6p 22-p23 CAG 40-83 ( N 6-40)
 cerebellar ataxia
 chorea
 upper motor neuron signs
 extensor planter, hyperreflexia
 lower bulbar palsies
 gaze paresis 50% , slow saccades 100 %
 scanning and explosive speech
 inco-ordination
 onset third/fourth decade
 earlier onset when inherited from father , anticipation
 axonal neuropathy
 atrophy of cerebellum, pons, olive,lower CN nuclei,
dorsal columns and spinocerebellar tracts
 Reduced aspartic acid in brain
 mutant protein Ataxin- 1, Intranuclear inclusions

51. SPINOCEREBELLAR ATAXIA 2; SCA 2
SPINOCEREBELLAR ATROPHY II
OLIVOPONTOCEREBELLAR ATROPHY, HOLGUIN TYPE
OLIVOPONTOCEREBELLAR ATROPHY 2
SPINOCEREBELLAR ATAXIA, CUBAN TYPE
 CLINICAL SYNOPSIS
 Neurological
 Limbs
 Miscellaneous
 Labs
 Gene Map Locus :12q23-24.1 CAG 34-59 ( N 14-31)
 adult onset progressive cerebellar ataxia
 palatal myoclonus , myokimia
 slow saccadic eye movements 100%
 dysarthria
 ophthalmoparesis 40%, optic atrophy
 pyramidal signs 20%
 peripheral sensory loss, abolished tendon reflexes
 dementia
 extrapyramidal signs in Tunisian kindred
 bladder dysfunction
 no parkinsonian features
 flexion contracture of legs
 onset 2 - 65 yrs, 40% < 25 yrs, anticipation, may be
sporadic
 involvement of cerebellum & inferior. olivary
nuc.,pons,spinal cord Ataxin - 2 , nuclear aggregates

52. SPINOCEREBELLAR ATAXIA 3 ; SCA 3
MACHODO-JOSEPH DIEASE,MJD
AZOREAN NEUROLOGIC DISEASE
NIGROSPINODENTATAL DEGENERATION, SPINOPONTINE AROPHY
 CLINICAL SYNOPSIS
 Neurological:
 Eyes
 Muscle
 Endocrinal
 Miscellaneous
 Labs
 Gene Map Locus : 14q32..1 CAG 56-86 (N -12-38)
 ataxia
 parkinsonian features
 facial and lingual fasciculations
 muscle fasciculations
 loss of leg reflexes
 cerebellar tremors
 extensor planter
 bulging eyes, limited eye movements, nystagmus
 muscle atrophy
 diabetes mellitus
 onset after 40 yr, paternal> maternal anticipation
 I- earlier onset(5-30), II- intermediate(~36 yr),
 III- cerebellar,PN,Optho(>40yr), IV- parkinsonian,
fasciculations, sensory(38-47yr levodopa responsive)
 neuronal loss and gliosis in SN, STN,GP,Dedtate nuclei,
nuclei pontis, vestibular & cranial nerve
nuclei,,post.columns and ant. Horns
 abnormal EOG
 ATAXIN- 3, nuclear/cytoplasmic inclusions

53. SCA 3
• ALSO KNOWN AS MACHEDO JOSEPH DISEASE
• 3 TYPES
• TYPE 1 –ALS PARKINSONS DYSTONIA TYPE
• WEAKNESS ND SPASTICITY OF LIMBS
• DYSTONIA OF FACE, NECK,TRUNK
• PHARYNGEAL WEAKNESS,HORIZANTAL ND
VERTICAL NYSTAGMUS
• OPYHALMOPARESIS,FACIAL FASICULATIONS
ND MYOKINESIA

54. TYPE 2-ATAXIC
CEREBELLAR DEFECTS
PYRAMIDAL ND EXTAPYRAMYDAL SYMOTOMS
OPTHALMOPARESIS
FACIAL ND LINGUAL FASICULATIONS

55. • TYPE 3-ATAXIC AMYYOTROPHIC
• CEREBELLAR SYMPTOMS
• DISITAL SENSORY LOSS
• DISITAL ATROPY
• DEPRESSED OR ABSENT DTR
• NO PYRAMIDAL OR EXTRA PYRAMIDAL
SYMPTOMS

56. DENTATORUBRAL-PALLIDOLUYSIAN ATROPHY; DRPLA
MYOCLONIC EPILEPSY WITH CHOREOATHETOSIS
NAITO-OYANAGI DISEASE; NOD
ATROPHIN 1, INCLUDED
 CLINICAL SYNOPSIS
 Neurological:
 Miscellaneous:
 Labs:
 Gene Map Locus: 12p13.31 CAG 49-75
(N<24)
 Myoclonus
 epilepsy ( longer repeats)
 Dementia
 Ataxia
 Choreoathetosis
 Onset usually in the 20s and death in the
40s
 commaon in Japan
 Combined degeneration of dentatorubral
and pallidoluysian systems
 DRPLA protein , neuronal cytoplasm

57. EPISODIC ATAXIA, TYPE 1; EA1
PAROXYSMAL ATAXIA WITH NEUROMYOTONIA, HEREDITARY
EPISODIC ATAXIA WITH MYOKYMIA; EAM
ATAXIA, EPISODIC, WITH MYOKYMIA; AEM; AEMK
MYOKYMIA WITH PERIODIC ATAXIA
 CLINICAL SYNOPSIS
 Neurological
 Miscellaneous
 Labs
 Treatment
 Gene Map Locus: 12p13
 Myokymia
 Continuous muscle movement
 Periodic ataxia
 Continuous muscle movement
 Periodic ataxia
 Ataxic attacks provoked by abrupt postural
change, emotional stimulus, and caloric-vestibular
stimulation, startle
 Onset in second decade
 Hand posture resembling carpopedal spasm
 Potassium voltage-gated channel gene mutation
 Continuous spontaneous activity on EMG at rest
 Muscle biopsy consistent with denervation, with
enlargement of muscle fiber
 Phenytoin, not Acetazolamide

58. EPISODIC ATAXIA, TYPE 2; EA2
PERIODIC VESTIBULOCEREBELLAR CEREBELLOPATHY,
HEREDITARY PAROXYSMAL ATAXIA,
FAMILIAL PAROXYSMAL ATAXIA
ACETAZOLAMIDE-RESPONSIVE PAROXYSMAL CEREBELLARATAXIA; APCA
EPISODIC ATAXIA, NYSTAGMUS-ASSOCIATED CEREBELLAR ATAXIA
 CLINICAL SYNOPSIS
 Neurological
 Miscellaneous
 Labs
 Treatment
 Gene Map Locus: 19p13
 Episodic ataxia
 Cerebellar ataxia
 Vertigo
 Diplopia
 Downbeat nystagmus
 Ataxia precipitated by stress or
excitement, not by startle
 attacks last 1/2 to 6 hrs.
 point mutation alpha 1A calcium
voltage dependant channel
 allelic with SCA6 & familial
hemiplegic migraine
 Response to oral acetazolamide

59. AUTOSOMAL RECESSIVE ATAXIAS

60. • FRIEDERICK’S ATAXIA
• ATAXIA TELANGIECTASIA
• ATAXIA WITH ISOLATED VIT.E DEFICIENCY
• ABETALIPOPROTEINEMIA
• ENZYME DEFICIENCIES (Maple Syrup urine
disease, Urea cycle defects, Sialidosis,
Adrenoleucodystrophy,Organic aciduria,
Pyruvate dehydogenase def.)
AUTOSOMAL RECESSIVE ATAXIAS

61. Friederick’s ataxia
• Unstable expansion of GAA repeatsFRATAXIN
proteiniron accumulation in mitochondriamito
injuryneuronal injury
• DORSAL GANGLION CELLS- absent reflexes
• DORSAL COLUMN DEGENERATION-
dec.post.column senses
• SPINOCEREBELLAR TRACT-gait atxia, dysarthria
• CORTICOSPINAL TRACT- Babinski Positive
• OTHER SIGNS- dysphagia,optic atrophy, spinal and
foot deformities, diabetes (10%), cardiac defects
(50%)

62. Friederick’s ataxia

63. • NATURAL HISTORY:
-onset <25 yrs. At ADOLESCENCE
-loss of ambulation 15 yrs. Since onset
-Death usualyy due to cardiac complications
• VARIANTS:
-FA with Retained reflexes
-Late onset FA
Friederick’s ataxia

64. ATAXIA TELANGIECTASIA
• OCULOMOTOR APRAXIA , TELANGIECATSIAS
IN EYES, SKIN
• Hematological malignancies (defective DNA
repairs)
• Infections (Ig deficiencies)
• Other features-peripheral neuropathy,
choreoathetosis

65. ATAXIA TELANGIECTASIA

66. Mitochondrial Inheritance
• MERRF
• MELAS
• NARP
• RP degeneration
• Short stature, Endocrine deficiencies,

67. X linked ATAXIAS
• X linked Dominant- Fragile X syndrome
• CGG repeats’ expansion

68. • X linked Recessive Ataxias- Sideroblastic
anemia with ataxia
X linked ATAXIAS

69. SPORADIC or IDIOPATHIC ATAXIAS
• Unknown genetic defects after ruling out
acquired causes
• Old age of onset
• Presents with Dysautonomia –Orthostatic
hypotension, erectile dysfunction, Urinary
incontinence

70. Investigations
• MRI Brain and Upper cervical cord
• CT Head
• Vit. E, B12 levels
• Total cholesterol levels, Thyroid hormones
• NCV and EMG studies (to rule out other systems’
involvement)
• Toxicology screen (includes phenytoin levels)
• Serology screen (for autoantibodies)
• CSF analysis
• Genetic Analyses (GAA, CGG, CAG repeat
analyses)

71. TREATMENT
• Reversible causes to be identified and treated
• Structural lesions to be considered for surgery
• Dietary modifications
• IDEBENONE- in Friederick’s Ataxia
• RILUZOLE- in Friederick’s Ataxia
• ACETAZOLAMIDE- in Episodc Ataxia
• GENETIC COUNSELLING

72. HISTORY SUMMARY
1. Duration: acute, subacute vs chronic
2. Rate of Progression: static vs progressive
3. Constant vs Paroxysmal
4. Associated features:
- headache & vomiting suggesting mass lesion with raised ICP
- previous neurological events (similar with ataxia - as in
episodic ataxias, or other as in multiple sclerosis or
vertebrobasilar TIAs)
5. Medical History:
- recent infection, Hx of malignancy or weight loss, breast
mass / tenderness, cough / hemoptysis
- drug use / intoxication, medications, alcohol, smoking,
environmental exposures
6. Family History positive or negative (in siblings or cousins
but not parents suggesting autosomal recessive or parents
and/or sibs suggesting autosomal dominant inheritance

73. EXAMINATION SUMMARY
General examination:
- signs of primary neoplasm (with paraneoplastic or metastatic
ataxia), vascular disease (stroke), cardiac abnormality
(Friedreick's) or Kayser-Fleischer rings (Wilson's)
-short stature and cataracts with mitochondrial disease
Higher Mental Functions:
- confusion associated with ataxia in Wernicke's, drug or
environmental toxicity, prion diseases or any condition
obstructing 4th ventricle leading to hydrocephalus with raised
ICP

74. Cranial Nerves:
- ophthalmoplegia seen in Wernicke's, brainstem infarcts,
demyelinating lesions, and Miller-Fisher syndrome (MFS)
- nystagmus common in most vestibulocerebellar (or
pancerebellar) disorders but prominent if drug toxicity (eg.
phenytoin), Wernicke's and multiple sclerosis (also episodic
ataxia-2)
- associated brainstem (cranial nerve) dysfunction if
concomitant involvement of brainstem or compression of it
by mass effect from cerebellum
- hearing loss or tinnitus with lesions of the cerebellopontine
angle (eg. vestibular schwannoma or meningioma)
EXAMINATION SUMMARY

75. EXAMINATION SUMMARY
Motor:
- weakness associated with ataxia is uncommon but can be
seen ipsilaterally with infarcts (or other lesions) of the basis
pontis or internal capsule (ataxic hemiparesis syndrome)
- also seen in MFS (with concomitant demyelinating
polyneuropathy), cord dysfunction (in paraneoplastic
syndromes or demyelinating multifocal disease)
- tremor associated either as intention tremor of cerebellar
origin or postural tremor in FXTAS (Fragile X), multiple
sclerosis, Wilson's disease
- myoclonus in prion disorders with cerebellar involvement
- parkinsonism with ataxia in multiple systems atrophy (also
dystonia and chorea if DRPLA)

76. SUMMARY
• RULE OUT “ATAXIA MIMICKERS”
• CONFIRM PREDOMINANT CEREBELLAR
INVOLVEMENT WITH RESPECTIVE TESTS
• ANSWER THE “FOUR” QUESTIONS
(Onset, progression, Symmetry, Localisation of
lesion)
• RULE OUT ACQUIRED CAUSES
• LARGE PEDIGREE CHART
• GENETIC ANALYSES

77. ALGORITHM
PEDIGREE CHART
ACQUIRED
CAUSES
AD
IMAGING
(MRI,CT)
SCA1,2
MJD
SCA6,7
SCA10,12
DRPLA
SCA17
FA
AT
AVED
ABETALIPOPROTEINEMIA