IMPAIRED BALANCE AND INCOORDINATION

Question 1

What embryological structure does the cerebellum develop from?

Answer 1

The metencephalon (a division of the hindbrain)

Question 2

How is the cerebellum separated from the occipital and temporal lobes?

Answer 2

By the tentorium cerebelli (a tough layer of dura mater)

Question 3

Anatomical structure of the cerebellum?

Answer 3

Consists of 2 hemispheres connected by the vermis
Grey matter is on the surface, and is tightly folded forming the cerebellar cortex
White matter is located underneath the cerebellar cortex

Question 4

4 cerebellar nuclei?

Answer 4

Dentate
Emboliform
Globose
Fastigi

Question 5

3 functional areas of the cerebellum?

Answer 5

Cerebro/pontocerebellum (cerebellar hemispheres)
Spinocerebellum (paravermis)
Vestibulocerebellum (vermis)

Question 6

Function of the cerebrocerebellum?

Answer 6

Planning movements and motor learning; receives inputs from the cerebral cortex and pontine nuclei, and sends outputs to the thalamus and red nucleus
Also regulates coordination of muscle activation and is important in visually guided movements

Mostly: fine coordinatiom

Question 7

Function of the spinocerebellum?

Answer 7

Postural tone
Regulating body movements by allowing for error correction
Receives Proprioceptive information also

Mostly postural tone

Question 8

Function of the vestibulocerebellum?

Answer 8

Controls balance and ocular reflexes, mainly fixation on a target; receives inputs from the vestibular system and sends outputs back to vestibular nuclei

Mostyl equilibrium and balance

Question 9

Blood supply to the cerebellum?

Answer 9

Superior cerebellar artery - branch of basilar artery
Anterior inferior cerebellar artery - branch of basically artery
Posterior inferior cerebellar artery - branch of vertebral artery

Question 10

Venous drainage of cerebellum?

Answer 10

Superior and inferior cerebellar veins - drain into superior petrosal, transverse and straight dural venous sinuses

Question 11

What is “faintness” and what can cause it?

Answer 11

The sensation experienced with decreased cerebral perfusion
E.g. getting out of a very hot bath, heavy bout of coughing, before fainting, meds causing postural hypotension

Question 12

What influences balance?

Answer 12

Vision - provide information about surroundings to help understand body’s position relative to its environment
Motor praxis - planning and execution of coordinated movements
Sensory awareness - vision, proprioception, tactile sensations
Cerebellum
Vestibular apparatus - detects changes in head position and movement

Question 13

What area of the brain is responsible for motor praxis?

Answer 13

Frontal lobe

Question 14

What is motor apraxia?

Answer 14

The inability to perform complex motor tasks despite normal power, coordination, sensation and comprehension
Motor disorder caused by damage to the brain - specifically frontal and parietal lobes

Question 15

Presentations of motor apraxia

Answer 15

Magnetic gait - feel as if feet are pulled down to ground by magnet
Unable to make voluntary movements even though you have the physical ability and understanding to do so
Difficulty copying hand gestures
Difficulty miming tasks e.g. mimicking using scissors

Question 16

Criteria for idiopathic normal pressure hydrocephalus diagnosis?

Answer 16

Progressive gait apraxia and balance disturbance
Variable and mild cognitive impairment - dementia and bradyphrenia
Bladder dysfunction / urinary incontinence

Question 17

Brain scans of idiopathic normal pressure hydrocephalus?

Answer 17

Ventriculomegaly - with no sulcal enlargement (not atrophy but sulci are pushed together due to increased pressure)

Question 18

What causes normal pressure hydrocephalus?

Answer 18

Reduced CSF absorption at the arachnoid villi
May be secondary to head injury, subarachnoid haemorrhage or meningitis

Question 19

Why can peripheral neuropathy cause diffiuclty with balance and gait?

Answer 19

Damage to large sensory fibres harms the ability to feel vibration and touch and damage to small sensory fibres harms the ability to feel pain or changes in temperature
All of these factors contribute to balance

Question 20

Most obvious symptom when there is a lesion in the vermis/flocculonodular lobe of the cerebellum (vestibulocerebellum)?

Answer 20

Gaze instability and nystagmus

Question 21

Most obvious symptom when there is a lesion in the posterior lobe of the cerebellum (cerebrocerbellum)?

Answer 21

Dysmetria

Question 22

Most obvious symptom when there is a lesion in the anterior lobe of the cerebellum (spinocerbellum)?

Answer 22

Gait and truncal ataxia

Question 23

Features of cerebellar dysfunction?

Answer 23

Vanish’d

Vertigo
Ataxia
Nystagmus
Intention tremor
Slurred, staccato or scanning speech
Hypotonia
Dysmetria, dysdiadochokinesia

Question 24

Cerebellar lesions ipsilateral or contralateral?

Answer 24

Ipsilateral

Question 25

What is vertigo?

Answer 25

The false sensation that the body or environment is moving E.g. might feel as if drifting to one side when walking, feeling as if fall is swaying after getting off a boat

Question 26

Pathophysiology of vertigo?

Answer 26

Within the inner ear is the vestibular apparatus. It consists of 3 semicircular canals filled with endolumena and these are all orientated in different directions to detect various movements of the head As the head turns, the fluid shifts inside the canals and this shift is detected by stereocilia in the ampulla. The sensory input of shifting fluid is transmitted to the brain by the vestibular nerve and lets the brainstem and cerebellum know that the head is moving in a particular direction. The vestibular nucleus then sends signals to the oculomotor, trochlear, abudecens nuclei, thalamus, spinal cord and cerebellum The cerebellum is then responsible for coordinating movement through the body and the vestibular signals also help the CNS coordinate eye movement Vertigo can be caused by damage to the vestibular system, brainstem or cerebellum which interfere with the physiology above

Question 27

Central and peripheral causes of vertigo?

Answer 27

Central: Posterior circulation stroke Vertebrobasilar ischaemia Brainstem - MS, mass, stroke (e.g. Wallenberg syndrome) Cerebellopontine angle - acoustic neuroma Cerebellum - stroke or mass Low CSF Peripheral: Viral labrynthitis Benign paroxysmal positional vertigo Menierres disease Vestibular neuronitis Ototoxicity

Question 28

What is benign paroxysmal positional vertigo?

Answer 28

Cystsals of calcium carbonate (otoconia) become displaced into the semicircular canals e.g. my head trauma, age, viral infection, etc The crystals disrupt the normal flow through the canals = positional vertigo Acute onset, paroxysmal (<1 min) repeated attacks brought out on by changes in head position e.g. on lying down, turning head Lasts days-weeks-months Prone to relapse Will complain of headaches and stiff neck as they try to stop themselves turning their head

Question 29

What is Ménière’s disease?

Answer 29

An excessive buildup of endolumena in the semicircular canals causing higher pressure than normal and disrupting sensory signals Causes ~hour long attacks of hearing loss, tinnitus, vertigo and sensation of fullness in the ear Symptoms are not positional Spontaneous nystagmus during attacks Overtime hearing gradually deteriorates

Question 30

What is acute vestibular neuronitis?

Answer 30

Inflammation of the vestibular nerve Usually attributed to a viral infection Acute onset vertigo that improves within a few weeks

Question 31

What is labryinthitis?

Answer 31

Inflammation of the labyrinth Also causes hearing loss (distinguishes it from vestibular neuronitis) Usually attributed to a viral infection Acute onset of persistent vertigo that improves within a few weeks - may not be able to get out of bed, associated nausea No other focal neurological signs

Question 32

Symptoms of central vs peripheral vertigo?

Answer 32

Peripheral is sudden onset, lasts seconds-minutes, often hearing loss is present, coordination is intact and severe nausea Central is gradual onset (other than stroke), is persistent, no hearing loss, impaired coordination and mild nausea

Question 33

What is the HINTS examination?

Answer 33

The examination used to distinguish between central and peripheral causes of vertigo Head Impulse, Nystagmus, Test of Skew

Question 34

What is the head impulse test?

Answer 34

patient sitting upright and fixing their gaze on the examiner’s nose. The examiner holds the patient’s head and rapidly jerks it 10-20 degrees in one direction while the patient continues looking at the examiner’s nose. The head is moved slowly back to the centre before repeating in the opposite direction. A patient with a normally functioning vestibular system will keep their eyes fixed on the examiner’s nose. In a patient with an abnormally functioning vestibular system, the eyes will saccade (rapidly move back and forth) as they eventually fix back on the examiner. The head impulse test is positive in peripheral cause of vertigo

Question 35

What is the test of skew?

Answer 35

The test of skew (also called the alternate cover test) involves the patient sitting upright and fixing their gaze on the examiner’s nose. The examiner covers one eye at a time, alternating between covering either eye. The eyes should remain fixed on the examiner’s nose with no deviation. If there is a vertical correction when an eye is uncovered (the eye has drifted up or down and needs to move vertically to fix on the nose when uncovered), this indicates a central cause of vertigo.

Question 36

Questions to ask in a vertigo history?

Answer 36

Check what they mean by vertigo Is it rotational or non-rotational? Are symptoms constant and persistant? Duration of each attack? Are attacks brought on by postural change? Do they veer to one side with walking? Are symptoms worse with eyes closed or in the dark? Are attacks periodic with compete resolution in between attacks? Any associated migraine symptoms, headaches, hearing loss, neurological Sx Previous history of travel sickness or dislike of rotational fairground rides?

Question 37

What is rombergs test?

Answer 37

Standing still with eyes closed Increased loss of balance is a positive test The exam is based on the premise that a person requires at least 2 of the following 3 senses to maintain balance whilst standing: proprioception, vestibular function and vision.

Question 38

What is Unterberger’s test?

Answer 38

ask the patient to undertake stationary stepping for one minute with their eyes closed. A positive test is indicated by rotational movement of the patient towards the side of the lesion. Positive in dysfunction of one labrynth e.g. benign paroxysmal positional vertigo (Imagine there are 2 engines i..e labrynth, if we lose 1 then it will rotate to the side of the dead engine - this is why with eyes closed or pt not concentrating they will veer to 1 side when walking)

Question 39

What is a vestibular migraine?

Answer 39

Vertigo can be part of migrainous aura Can last hours Is associated with other migrainous features

Question 40

What is an acoustic neuroma?

Answer 40

A vestibular schwannoma A benign brain tumour that grows on the vestibular nerve

Question 41

History for acoustic neuroma?

Answer 41

Features can be predicted by the affected cranial nerves: cranial nerve VIII: vertigo, unilateral sensorineural hearing loss, unilateral tinnitus cranial nerve V: absent corneal reflex cranial nerve VII: facial palsy

Question 42

Investigation for acoustic neuroma?

Answer 42

MRI of cerebellopontine angle Audiometry

Question 43

Practical points to advise patients with vertigo?

Answer 43

Change positions slowly Dont walk in darkness Focus on a point Have a chair in the shower

Question 44

Management of vertigo?

Answer 44

Short courses of vestibular sedatives Best Tx: Vestibular exercises Treat associated headaches and neck aches Practical points e.g. change position slowly, don’t walk in the dark

Question 45

Vestibular exercises?

Answer 45

Epley manoeuvre Brandt Daroff Semont and Cawthorne Cooksey exercises

Question 46

What is the Epley manoeuvre?

Answer 46

A series of head movements to relieve symptms of benign positional vertigo - it dislodges the crusts from the semicircular canals Sit on bed with head turned 45 degrees to the left, lie down on back at sickly as possible with head hanging over the edge and wait until dizziness resolves. Then turn head 45 degrees to the right wait until dizziness resolves. Turn to lie on your right hand side then turn head slightly to the right so you are facing the floor and wait wait until dizziness resolves. Slowly sit up tilting head down and sit for 15 mins Repeat

Question 47

What is the Brandt-Daroff exercise?

Answer 47

Treatment for benign paroxysmal positional vertigo Sit up and turn head 45 degrees to the left Lie down on left side keeping head turned 45 degrees. Stay for 30 seconds Sit up for 30 seconds Repeat on right side Do this a total of 5 times on each side Sit up and wait till you don’t feel dizzy before standing up

Question 48

What is the Semont exercise?

Answer 48

Treatment for benign paroxysmal positional vertigo art by sitting upright on the edge of a bed. Turn your head 45 degrees to the left (or as far as is comfortable). 2. Quickly lie down on your right-hand side. Remain in this position for 30 seconds (or until you no longer feel dizzy). 3. Quickly move to lie down on your left-hand side, keeping your head in the same position (your head should be facing down on the bed). 4. Return slowly to a sitting position and wait a few minutes.

Question 49

Cerebellar hemisphere lesions cause “insert answer” Ataxia?

Answer 49

Peripheral - often described as “finger-nose ataxia” This is because the lesion affects the cerebrocerebellum which is responsible for cooordinating voluntary movements and motor planning

Question 50

Cerebellar vermis lesions cause “insert answer” Ataxia?

Answer 50

Truncal ataxia i.e. Gait This is because it affects the spinocerebellum which is involves in regulating posture and coordination of body movements associated with proximal limbs

Question 51

Causes of ataxia/cerebella dysfunction?

Answer 51

Head injury Brain infections e.g. encephalitis or meningitis Strokes, TIA CP MS Chronic Alcohol misuse Vitamin B12 deficinecy Brain tumours Toxic chemicals e.g. mercury Hypothyroidism Hereditary causes Meds e.g. phenytoin Can be paraneoplastic (anti-Hu antibodies) Idiopathic late-onset cerebellar ataxia

Question 52

Types of hereditary ataxia?

Answer 52

Friedreichs ataxia (most common)- age 5-20 Ataxia-telangiectasia <5 years Spinocerebellar ataxia Episodic ataxia

Question 53

Why does an alcoholic cerebellar degeneration cause prominent gait ataxia in the absence of major upper limb, speech or oculomotor problems?

Answer 53

As it mainly results in vermian cerebellar degeneration

Question 54

What is ataxia?

Answer 54

Clumsy and uncoordinated movements of the limbs, trunk and cranial muscles resulting from pathology in the cerebellum and its connections

Question 55

Cerebellar ataxia symptoms and signs?

Answer 55

Unsteady gait with tendency to falls Impaired hand coordination Dysarthria or dysphagia Ocular symptoms e.g. nystagmus, inaccurate saccades, jerkiness on attempted smooth pursuit

Question 56

Investigations for ataxia?

Answer 56

Imaging of brain e.,g for stroke If nothing on imaging… CSF examination e.g. for infections Genetic testing may be done

Question 57

Typical age for Friedreich’s ataxia?

Answer 57

10-15 years old

Question 58

Presentation of Friedreich’s ataxia?

Answer 58

Gait ataxia Kyphoscoliosis Absent ankle jerks or extensor plantars Cerebellar ataxia Optic atrophy Spinocerebellar tract degeneration High-arched palate HOCM Diabetes mellitus

Question 59

Most common cause of death in pt with Friedreich’s ataxia?

Answer 59

HOCM - 90 % of pt have it

Question 60

What is the diagnostic test for benign paroxysmal positional vertigo?

Answer 60

A positive Dix-Hallpike manoeuvre - rapidly lower the pt to the supine position with an extended neck A positive test recreates the symptoms of BPPV and you will see rotatory nystagmus

Question 61

What is Friedreichs ataxia?

Answer 61

An autosomal recessive disorder causing loss of function of FXN gene (a mitochondrial gene that normally codes for frataxin) Causes neurological dysfunction, cardiomyopathy and diabetes mellitus Many people live until at least 30s and some can live into their 60s or beyond

Question 62

How many clonus beats are normal?

Answer 62

<5