Ataxia and Gait Disorders

Question 1

In very general terms, what are the two types of ataxia?

Answer 1

cerebellar ataxia
sensory ataxia (loss of position sense)

Question 2

How can you tell where in the cerebellum a lesion has occurred?

Answer 2

vermal lesion = truncal and gait ataxia

hemispheric - ipsilateral limb ataxia

Question 3

How does an acute cerebellar hemorrhage or infarct typically present?

Answer 3

abrupt onset of vertigo, vomiting and inability to walk

the level of arousal may be depressed if there is compression of the fourth ventricle with hydrocephalus or if there is pressure on the brainstem

Question 4

What is the most common cause of acquired cerebellar degeneration?

Answer 4

long-standing alcohol abuse

Question 5

What part of the cerebellum bears the brunt of the damage in alcoholic cerebellar degeneration?

Answer 5

the vermis, so you typically get progressive gait and truncal ataxia evolving over weeks to months

Question 6

Postinfectious cerebellitis after varicella or other viral infection typically presents in kids ages 2-7. What is the prognosis?

Answer 6

good - the illness lasts a few weeks and recovery is usually complete

Question 7

Paraneoplastic cerebellar degeneration typically causes a pancerebellar syndrome. What are the typical cancers for this process?

Answer 7

gynecological or small cell lung cancer

Question 8

What are the two most common antibodies seen in paraneoplastic cerebellar degeneration?

Answer 8

anti-yo and anti-hu (but not specific)

Question 9

How does Friedreich Ataxia usually present?

Answer 9

progressive ataxia affecting the arms more than legs with severe dysarthria - onset usually in childhood with loss of reflexes, spasticity, extensor plantar responses and impaired vibration and positional sense

Question 10

The episodic ataxia syndromes are characterized by brief episodes of ataxia, vertigo, nausea, and vomiting. What is EA-1 a mutation of and what additional feature is associated in the interim between ataxia attacks?

Answer 10

mutations in a voltage gated potassium channel

interattack skeletal muscle myokymia

Question 11

What is EA-2 a mutation of what and how does it differ clinically from EA-1?

Answer 11

mutation in the pore-forming alpha1 subunit of the PQ-type voltage gated calcium channel

ataxia attacks are longer, lasting several minutes, with interictal nystagmus

a progressive irreversible ataxia may develop late in the disease

Question 12

When do the autosomal dominant spinocerebellar degenerations present?

Answer 12

typically in early adulthood with an insidious onset of progressive impairment of gait and dysarthria, often with cognitive decline as a late feature

Question 13

Most of the defects identified in the SCAs are what?

Answer 13

CAG trinucleotide expansions

Question 14

Which SCA is allelic to EA-2?

Answer 14

SCA6

Question 15

What disorder is characterized by the triad of ataxia, areflexia and ophthalmoplegia?

Answer 15

Miller Fisher Syndrome

Question 16

What is the ataxia due to in Miller Fisher Syndrome?

Answer 16

proprioceptive loss, not cerebellar dysfunction

Question 17

What is the likely pathogenesis of Miller Fisher Syndrome?

Answer 17

It’s probably a variant of Guillain Barre - most likely mediated by a postinfectious immune process because IgG anti-GQ1b antibodies are detectable in the serum of over 90% of people with this syndrome

Question 18

Describe a hemiparetic gait.

Answer 18

affected leg is stiff and does not flex at the hip, knee or ankle

the leg is circumducted, with a tendency to scrape the floor with the toes

arm is held in flexion and adduction and doe snot swing freely

Question 19

Describe a spastic (paraparetic gait.

Answer 19

It’s basically a bilateral hemiparetic gait, so both legs have increased adductor tone with the legs tending to cross during walking (a scissoring gait)

Question 20

Describe an akinetic-rigid gait.

Answer 20

posture is stooped with flexion of the shoulders, neck and trunk

gait is narrow-based, slow and shuffling with small steps and reduced arm swing. arms are carried flexed slightly ahead of the body. Often difficulty with gait initiation

Question 21

Why do you see festination, propulsion (small steps forward) and retropulsion (small steps backward) in an akinetic-rigid gait?

Answer 21

the postural reflexes are impaired, so these movements are used in an effort to preserve equilibrium

Question 22

What is the usual diagnosis for an akinetic-rigid gait?

Answer 22

idiopathic Parkinson disease, but can also be seen in other extrapyramidal disorders

Question 23

How does the gait of progressive supranuclear palsy differ form that of PD?

Answer 23

the posture tends toward extension rather than flexion

Question 24

Describe a frontal gait

Answer 24

posture if flexed with feet slightly apart.

gait initiation is impaired and the word “magnetic” is used to describe the patient’s difficulty in lifting the feet off the ground.

the patient advances with small, shuffling steps

with increasing severity, the patient may make abortive stepping movements in one place without being able to move forward

Question 25

What is a waddling gait characteristic of?

Answer 25

hip girdle weakness

Question 26

Describe a waddling gait

Answer 26

weakness of the abductors and consequent failure to stabilize the weight-bearing hip causes the pelvis and trunk to tilt toward the opposite side during walking

Question 27

Where is the location of the lesion for a hemiparetic gait?

Answer 27

brainstem or cerebral hemisphere

Question 28

Where is the lesion in a paraparetic gait?

Answer 28

spinal cord with demyelination, transverse myelitis or compressive myelopathy

or it could be bihemispheral in the cerebellum, but this is less likely

Question 29

Describe the gait that occurs with sensory ataxia.

Answer 29

the patient can’t determin his/her position in space, so the gait becomes cautious

it is wide-based and steps are slow

contact with the ground is made with the hell and the forefoot strokes the floor with a slapping sound (slapping gait)

Question 30

What’s the fancy term for a psychogenic gait?

Answer 30

astasia-abasia

yes, that’s seriously a term

Question 31

What is the inheritance pattern for Freiderich’s ataxia/

Answer 31

autosomal recessive

Question 32

Where does the FXN gene reside and what is the mutation?

Answer 32

chromosome 9
it’s an expanded GAA trinucleotide repeat (expanded to at least 66 units)

this severely reduces the amount of frataxin protein produced in cells

Question 33

What are some associated symptoms of Freiderich’s Ataxia besides the neurological symptoms?

Answer 33

sensorineural hearing loss, diabetes mellitus and impaired glucose tolerance, hypertrophic cardiomyopathy and arrhythmias