Neurology

Question 1

Cranial Nerve examination

Answer 1

•	General inspection
o	Craniotomy scars
o	Neurofibromas
o	Cushing’s syndrome, acromegaly 
o	Paget’s disease
o	Facial asymmetry or ptosis 
o	Characteristic facies of myotonic dystrophy or myasthenia 

• CN I – smell
o Ask the examiners whether they want you to test smell

• CN II – optic nerve
o Visual acuity (corrected)
o Visual fields with red hatpin
o Fundoscopy

• CN III, IV, VI – oculomotor, trochlear, abducens
o Ptosis (CN 3, sympathetic lesion)
o Light reflex, RAPD (CN 2 – optic tract – lateral geniculate ganglion – Edinger-Westphal nucleus of CN 3 – fibres to ciliary muscle)
o Accommodation
o Eye movements: quickly from left to right and then follow hatpin
 Ask for diplopia
 Nystagmus, failure of movement
o Saccades: hold finger and pen up about 6cm apart and look between (allow blink to rest eye)
 Undershoot or overshoot seen in cerebellar dysfunction (“past pointing”)

• CN V – trigeminal nerve
o Corneal reflex (CN 5 sensory, CN 7 motor)
o Facial sensation (neurotip & light touch)
o Motor: masseters (clench teeth) and pterygoid (open mouth)
o Jaw jerk (pseudobulbar palsy)

• CN VII – facial nerve
o Power
o Taste anterior 2/3 tongue usually not required

• CN VIII – vestibulocochlear nerve
o Whisper test
o Rinne’s & Weber’s test with a 256Hz tuning fork
 Rinne’s test: tuning fork on mastoid then at external meatus
a. Normal/positive = audible at meatus (air > bone conduction)
o Sensorineural hearing loss also (air > bone)
b. Negative/Non-audible = Conductive hearing loss (bone > air)
 Weber’s test: tuning fork in the middle of forehead
a. Normal = heard in centre of forehead
b. Sensorineural hearing loss = sound transmitted to normal ear
c. Conductive hearing loss = sound louder in abnormal ear
o Auriscope

• CN IX, CN X – glossopharyngeal & vagus nerve
o Palate and uvular displacement (uvula drawn to unaffected side)
o Gag reflex optional (ask first)
o Cough/hoarseness (bovine cough for recurrent laryngeal nerve lesion)

• CN XI – accessory nerve
o Trapezius and sternocleidomastoid power/bulk

• CN XII – hypoglossal nerve
o Tongue wasting or fasciculations
o Deviation towards the weaker side

Question 2

Visual field defects:

1. Tunnel vision
2. Enlarged blind spot
3. Central scotoma
4. unilateral field loss
5. bitemporal hemianopia
6. Homonymous hemianopia
7. Upper quadrant homonymous hemianopia
8. Lower quadrant homonymous hemianopia

Answer 2

1. Tunnel vision: glaucoma, papilloedema
2. Enlarged blind spot: optic nerve enlargement
3. Central scotoma: optic nerve to chiasmal lesion e.g. demyelination, toxic, vascular, nutritional
4. Unilateral field loss: optic nerve lesion e.g. vascular, tumour
5. Bitemporal hemianopia: optic chiasma lesion e.g. pituitary lesion, sella meningioma
6. Homonymous hemianopia: optic tract to occipital cortex, lesion at any point e.g. vascular or tumour. Incomplete lesion results in macula sparing
7. Upper quadrant homonymous hemianopia: temporal lobe lesion
8. Lower quadrant homonymous hemianopia: parietal lobe lesion

Question 3

Eye examination

Answer 3

•	Inspect: cornea (arcus, kayser-fleischer rings), sclera (jaundice, pallor, injection), ptosis, exophthalmos, xanthelasma
•	Cranial nerve examination 
•	Visual acuity/Snellen’s – each eye 
•	Visual fields
o	Red hatpin confrontation
o	Central vision

• Fundi:
o Cornea
o Lens
o Colour of disc and state of cup (papilloedema, optic atrophy)
o Retina – vessels, exudates, haemorrhages, pigmentation

• Pupils: shape, size, symmetry
o Light reflex
o RAPD
o Accommodation

• Eye movements
o CN 3, 4, 6
o Gaze palsies (e.g. supranuclear lesions)
o Fatiguability (myasthenia)

• Corneal reflex
• Orbits – palpate for tenderness, brow (loss of sweating in Horner’s)

•	Additional features depending on findings but may include: 
o	Other cranial nerves 
o	Long tract signs 
o	Urinalysis (diabetes) 
o	Cerebellar signs
o	Hemiparesis

Question 4

Provide differentials for the following visual lesions:

A. Absent light reflex but intact accommodation reflex

B. Constricted pupil

C. Dilated pupil

D. Papilloedema

Answer 4

Optic nerve lesions
Absent light reflex but intact accommodation reflex:
1. Midbrain lesion e.g. Argyll Robertson pupil
2. Ciliary ganglion lesion e.g. Adie’s pupil
3. Parinaud’s syndrome
4. Bilateral afferent pupil defects

Pupil abnormalities - Constricted pupil:

1. Horner’s syndrome
2. Argyll Robertson pupil
3. Pontine lesion (often bilateral)
4. Narcotics
5. Pilocarpine drops
6. Old age

Pupil abnormalities - Dilated pupil:

1. Mydriatics, atropine poisoning
2. Third nerve lesion
3. Adie’s pupil (efferent sympathetic pathway lesion; dilated pupil with decreased or absent light reflex and slow or incomplete accommodation) – usually young women
4. Iridectomy, lens implant
5. Post trauma, deep coma or death
6. Congenital

Papilloedema

1. Space occupying lesion or retroorbital mass
2. Hydrocephalus
3. Idiopathic intracranial hypertension
4. Hypertension (grade IV)
5. Central retinal or venous sinus thrombosis
6. High CSF protein e.g. GBS

Question 5

Eye movements & palsies

Describe normal nerve and muscle control of eye movements

Answer 5

o	SO4 (superior oblique trochlear nerve), LR6 (abducens nerve), all the rest are controlled by 3
o	Superior oblique intorts the eye 
o	Lateral rectus abducts the eye 

       Right eye                                      Left eye SR (III)                    IO (III)          IO (III)                        SR (III)

LR (VI) MR (III) MR (III) LR (VI)

IR (III) SO (IV) SO (IV) IR (III)

Question 6

3rd nerve palsies

• Aetiology
• Clinical features (3)

6th Nerve palsy

• Aetiology
• Clinical features (3)

Answer 6

Third (oculomotor) nerve palsy
- Aetiology:
Central: vascular (e.g. brain stem infarct), tumour, demyelination (rare), trauma
Peripheral:
• Compressive lesions (aneurysm on the PCA), tumour, nasopharyngeal carcinoma, meningitis
o Orbital lesions – Tolosa-Hunt syndrome (superior orbital fissure syndrome – painful lesion of 3, 4, 6 and V1)
• Infarction: diabetes mellitus, arteritis
• Trauma
• Cavernous sinus lesions

o Features:
1. Complete ptosis (partial may occur with incomplete lesion)
2. Divergent strabismus (eye ‘down and out’)
3. Dilated pupil unreactive to direct or consensual light and accommodation
Exclude a 4th nerve lesion by asking the patient to tilt their head to the side of the lesion and the affected eye will intort if CN4 is intact

Sixth (abducens) nerve palsy

• Features:
  1. Failure of lateral eye movement
  2. Affected eye is deviated inwards in severe lesions
  3. Diplopia – maximal on looking to affected side; images horizontal

o Aetiology:
 Bilateral: Trauma, Wernicke’s, Raised ICP, Mononeuritis multiplex
 Unilateral:
• Central: stroke, tumour, Wernicke’s, MS (rare)
• Peripheral: diabetes and other vascular lesions, trauma, idiopathic, raised ICP

Question 7

Describe one-and-a-half syndrome

Localise the lesion

Answer 7

• One and a half syndrome = defect in conjugate gaze (i.e. connections between bilateral CN3 & 6 which coordinate eyes in unison)

o Failure of adduction of ipsilateral eye
o Associated horizontal nystagmus in contralateral eye
o Lesion in the medial longitudinal fasciculus (ipsilateral to eye which fails to adduct)

Question 8

Detail higher centres examination

Answer 8

• General inspection

• Shake hand (? Weakness)
• Observe for obvious cranial nerve or limb lesions
• Enquire as to handedness
• Speech
• Parietal lobe function:
• Dominant parietal lobe (Gertsmann’s syndrome) – AALF
• • Acalculia; test mental arithemetic
• • Agraphia; test inability to write
• • Left-right disorientation; ask patient to put right palm on left ear and vice versa
• • Finger agnosia; inability to name individual fingers (left angular gyrus lesion in right handed and about ½ left handed patients)

o General parietal functions:
- Sensory and visual inattention

o Non-dominant parietal function
1. Dressing apraxia; turn their shirt inside out and ask them to put it on correctly
2. Cortical sensory loss:
• Agraphaesthesia; inability to appreciate numbers written on palm
• Astereognosis; inability to name objects placed in hand
• Joint position sense & 2-point discrimination
3. Constructional apraxia; inability to draw clock face and fill in numbers

• Temporal lobe (both medial temporal lobe functions)

• Short-term recall; 3 words
• Long-term recall; when did WWII finish

•	Frontal lobes
o	Primitive reflexes
- Grasp reflex
- Pout reflex
- Palmar-mental reflex 
o	Proverb interpretation (e.g. ‘a rolling stone gathers no moss’) 
o	Anosmia
o	Gait apraxia: frontal abnormality with marked unsteadiness and feet typically behave glued to floor with hesitant shuffling gait 

• Other
o Visual fields
o Blood pressure

Question 9

Detail Speech examination

Answer 9

Start simple and increase complexity….

• Comprehension (i.e. reception, Wernicke’s area)

• Single command “close your eyes”
• • “Poke out your tongue” – watch for perseveration
• 2-stage command; “touch your left hand to your right ear”
• • Helps left-right disorientation also
• 3-stage command; “touch your nose then your chin then your forehead”

• Repetition (i.e. conductive aphasia, arcuate fasciculus – temporal lobe)

• “Blue sky” or “Baby hippopotamus”
• “No ifs ands or buts”

• Naming function (nominal aphasia, parietal/temporal lobe – angular gyrus)

• Name parts of the hand, name fingers and knuckles
• Parts of a shirt
• Test orientation
• Describe a picture (check for fluency and errors)

• Dysphasia
- If reception is severely impaired then further assessment is very challenging; can trial written information
- Fluency of speech
– Paraphasic errors in receptive or nominal aphasia
• Substitutions for similar sound = phonemic error
• Substitution for similar meaning = semantic error
- Non-fluent, slow (hesitant) speech is likely an expressive dysphasia

• Dysarthria (disorder of articulation)
o Consider cerebellar disease and lower cranial nerve lesions
- Cerebellar speech is slurred or “scanning” (i.e. irregular and staccato)
- Pseudobulbar palsy causes slow, hesitant, hollow-sounding speech with a harsh, strained voice
- Bulbar palsy causes nasal speech with imprecise articulation

• “Baby hippopotamus”, “British Constitution”
• “pa pa pa”, “ta ta ta”, “ka ka ka”
• Depending on findings move to cerebellar examination or cranial nerves
• Jaw jerk should not be forgotten

• Other
o If vascular territory lesion check for aetiology
 HR/atrial fibrillation
 Blood pressure
 Carotid bruits
 Ask for relevant investigations such as an ECG, HbA1c