Neuroanatomical Localisation

Question 1

What is the focal pattern of weakness?

Answer 1

In distribution of peripheral nerve or spinal root, hemi-distribution, pyramidal distribution

Question 2

What is the non-focal pattern of weakness?

Answer 2

Generalised = predominantly proximal or distal

Includes bulbar motor function if truly generalised (otherwise quadri/tetraparesis)

Question 3

What is the distribution of UMN weakness?

Answer 3

Corticospinal, hemiparesis, quadriparesis, paraparesis, monoparesis, faciobrachial

Question 4

What are some features of UMN pattern?

Answer 4

Central pattern sensory loss
Increased deep tendon reflexes (flaccid if very acute)
decreased superficial reflexes
Increased pathological reflexes
Sometimes impaired sphincter function
Increased muscle tone and muscle hypertrophy

Question 5

What are some features of LMN pattern?

Answer 5

Normal/decreased deep tendon reflexes
Normal superficial and pathological reflexes
Usually normal sphincter function -except cauda equina
Normal/decreased muscle tone with muscle wasting

Question 6

What is the UMN patter of weakness?

Answer 6

Increased tone with brisk reflexes

Pyramidal or corticospinal pattern = weakness in arm extensors and leg flexors

Question 7

What is the LMN pattern of weakness?

Answer 7

Wasting, fasciculation, decreased tone and absent/decreased reflexes, flexor plantars

Question 8

What is the muscle disease pattern of weakness?

Answer 8

Wasting = usually proximal
Decreased tone
Absent/decreased tendon reflexes

Question 9

What is the NMJ pattern of weakness?

Answer 9

Fatiguable weakness
Normal or decreased tone
Normal tendon reflexes and no sensory symptoms

Question 10

What is the pattern of functional weakness?

Answer 10

No wasting, normal tone and reflexes, erratic power, non-anatomical loss

Question 11

What can cause UMN lesions in the CNS?

Answer 11

Acute stroke, space occupying lesions and spinal cord problems

Question 12

What are some patterns of UMN lesions?

Answer 12

Hemispheric = contralateral pyramidal weakness in face, arms or legs
Spinal cord = pyramidal weakness below level of lesion (cervical = arms and legs, thoracolumbar = legs)
Parasagittal frontal lobe lesion = paraparesis

Question 13

What causes LMN lesions in anterior horn cells?

Answer 13

Motor neuron disease and spinal muscular atrophy

Question 14

What are some causes of LMN lesions in peripheral nerves?

Answer 14

Diabetes, alcohol or metabolic insults

Question 15

How may LMN lesions in peripheral nerves present?

Answer 15

Symmetrical polyneuropathy with weakness and sensory symptoms
Mononeuropathy due to nerve compression
Mononeuritis multiplex due to diabetes or vasculitis

Question 16

What are the nerves and muscles involved in shoulder abduction and elbow extension?

Answer 16

Shoulder abduction = deltoid muscle, axillary nerve, C5 nerve root
Elbow extension = triceps muscle, radial nerve, C7 nerve root

Question 17

What are the nerves and muscles involved in finger extension and index finger abduction?

Answer 17

Finger extension = extensor digitorum, posterior interosseous nerve, C7 nerve root
Index finger abduction = first dorsal interosseous, ulnar nerve, T1 nerve root

Question 18

What muscles and nerves are involved in hip and knee flexion?

Answer 18

Hip flexion = iliopsoas muscle, femoral nerve, L1-2 nerve roots
Knee flexion = hamstring muscle, sciatic nerve, S1 nerve root

Question 19

What muscles and nerves are involved in ankle dorsiflexion?

Answer 19

Peroneal muscle = innervated by common peroneal and sciatic nerves, L4-5 nerve roots

Question 20

What are the roots of the deep tendon reflexes?

Answer 20

Ankle = S1-2
Knee = L3-4
Biceps = C5-6
Triceps = C7-8

Question 21

What are some patterns of sensory loss?

Answer 21

Stocking = implies length dependent neuropathy
Dermatomal = mononeuropathy, radicular/plexus lesion
Sensory level = implies spinal cord lesion

Question 22

What does hemianaesthesia suggest?

Answer 22

Contralateral cerebral lesion or a non-organic disorder if there is an absence of other signs

Question 23

What symptoms are suggestive of hemicord damage?

Answer 23

Dissociated sensory loss with lost spinothalamic but preserved dorsal column

Question 24

What are the signs of cerebellar dysfunction?

Answer 24

Broad based and unsteady gait
Intention tremor, ataxia, nystagmus, dysarthria
Dysdiadochokinesis = clumsy fast alternating movements

Question 25

How is an intention tremor or ataxia assessed?

Answer 25

Arms = finger-nose test Legs = knee-heel test Tremor gets worse nearer to target

Question 26

What are the characteristic features of extrapyramidal symptoms (Parkinsonism)?

Answer 26

Bradykinesia, rigidity, resting tremor and impaired gait/posture

Question 27

What are some additional extrapyramidal symptoms?

Answer 27

Hypomimia and hypophonia | Reduced arm swing, stooped posture, small steps, festination, turning en bloc and impaired postural reflexes

Question 28

How can symptom distribution be used to differentiate between different causes of Parkinsonism?

Answer 28

``` Asymmetry = Parkinson's disease Symmetry = drug induced or atypical Parkinson's ```

Question 29

What is the function of the frontal lobe?

Answer 29

Generates novel strategies and executive functions

Question 30

What are some features of the orbitofrontal cortex?

Answer 30

Responds to primitive stimuli | Damage causes disinhibition

Question 31

What is the function of the dorsolateral prefrontal cortex?

Answer 31

Responds to external stimuli

Question 32

What are the cingulate gyrus and dorsomedial frontal lobe responsible for?

Answer 32

Motivation = damage causes lack of will or even akinetic mutism

Question 33

What are some signs of frontal lobe dysfunction?

Answer 33

Personality dysfunction, paraparesis, paratonia, magnetic gait, cortical hand, seizures, incontinence, visual field defects, expressive dysphasia, anosmia

Question 34

What are some signs of temporal lobe dysfunction?

Answer 34

Memory dysfunction = especially episodic memory Agnosia and temporal lobe epilepsy Congruous upper homonymous quadrantanopia Auditory and limbic dysfunction Receptive aphasia

Question 35

What are some signs of parietal lobe dysfunction?

Answer 35

Congruous lower homonymous quadrantanopia Sensory dysfunction, dyspraxia, inattention and denial Gerstmann's syndrome

Question 36

What is Gerstmann's syndrome?

Answer 36

Disease of the dominant angular gyrus = dysgraphia, left-right disorientation, finger agnosia, acalculia

Question 37

What is the treatment of Parkinson's disease?

Answer 37

Levodopa or dopamine agonists MAO-B inhibitors may be used as add on or alone Anticholinergics have severe side effects Amantadine may help resting tremor

Question 38

What are the symptoms of Parkinson's disease?

Answer 38

Asymmetrical = resting tremor, rigidity, bradykinesia, postural instability

Question 39

What does postural instability lead to in Parkinson's disease?

Answer 39

Falls = usually late in disease course

Question 40

What would be a strong indicator that a patient doesn't have idiopathic Parkinson's disease?

Answer 40

Failure to respond to large doses of levodopa

Question 41

What is a common side effect of levodopa?

Answer 41

Dyskinesia

Question 42

What are some features of multiple sclerosis?

Answer 42

Symptoms = visual compromise, stiffness, weakness Symptoms may worsen after fever or high temperature May have lesions on MRI without clinical compromise directly related to those lesions

Question 43

What are some features that would indicate a patient has had an ischaemic stroke?

Answer 43

Sudden onset, focal signs and symptoms usually in keeping with a vascular territory, usually negative symptoms (ie loss of function)

Question 44

How common is intracerebral haemorrhage as a cause of stroke?

Answer 44

Account for 10% of all strokes

Question 45

What imaging can be used to identify strokes?

Answer 45

MRI T1/2 and FLAIR = old lesions, non-vascular lesions T2 = bleeds and microbleeds Time of flight sequences and diffusion weighted image CT

Question 46

What are diffusion weighted images used to identify?

Answer 46

New ischaemic lesions (hyperintensities) and a decrease in signal on apparent diffusion coefficient of water

Question 47

What do time of flight sequences identify?

Answer 47

Occlusions of extra and intracranial arteries

Question 48

What may a CT show in a patient with an ischaemic stroke?

Answer 48

Hyperintensities = bleeds Subtle ischaemic signs in acute phase of stroke = loss of lentiform nucleus limit, poor white matter differentiation, loss of insular ribbon

Question 49

What are some features of lacunar strokes?

Answer 49

No visual field defect or higher cortical/brainstem issue Pure motor hemiparesis, pure sensory unilateral deficit, sensorimotor/ataxic hemiparesis At least two of face, arm or leg involved

Question 50

What is needed to diagnose a posterior circulation stroke?

Answer 50

Any 1 of = cranial nerve palsy, cerebellar dysfunction, unilateral or bilateral motor/sensory deficit, disorder of conjugate eye movements, homonymous hemianopia or cortical blindness

Question 51

What are the symptoms of a total anterior circulation stroke?

Answer 51

Hemiplegia and homonymous hemianopia contralateral to lesion Either aphasia or visuospatial disturbances May also have sensory deficit contralateral to lesion

Question 52

What is needed to diagnose a partial anterior circulation stroke?

Answer 52

One or more of = unilateral motor or sensory deficit, aphasia, visuospatial neglect (with or without homonymous hemianopia)

Question 53

How can you differentiate between a partial anterior circulation stroke and a lacunar stroke?

Answer 53

Motor or sensory deficits may be more extreme in a lacunar stroke