Neuro investigations

Question 1

What is an EEG

Answer 1

Electroencephalogram- Tests for epilepsy

• 21 Electrodes on scalp
• Impulse from reticular formation>thalamus> pyramidal cells then picked up
• Left odd numbers, even right, letter is F Central T O
• Looks at beta, alpha, theta and delta frequencies
• May have one lead ECG at bottom
• Uses activation techniques during the 20 minutes

Question 2

What is an EP test?

Answer 2

Evoked potential- Assess silent regions in nerve patients. For MS

Question 3

What is NCS and EMG

Answer 3

Nerve conduction studies and electromyography

Electromyography
- Recording needle into muscle and looks at the trace

Question 4

What is IOM

Answer 4

Intraoptive monitoring

Question 5

What is an MSLT

Answer 5

Multiple sleep latency test- Diagnoses narcolepsy - looks how quick fall into rem sleep, If rem 3 out of 5 then narcolepsy

Question 6

In EEG what is Beta frequency?

Answer 6

Fastest. Increased in anxiety and drugs

Question 7

In EEG what is Alpha frequency?

Answer 7

• Prevelent when eyes closed, then goes when eyes open

Question 8

In EEG what is Theta Frequency?

Answer 8

• Increased in drowsiness, more common in children

Question 9

In EEG what is Delta Frequency?

Answer 9

Slowest- seen in sleep in young or in adults encephalopathies or vascular issues e.g. dementia, space occupying regions

Question 10

Which activation techques are used in an EEG?

Answer 10

1. Hyperventilation- Used if looking for absent seizures as this triggers then, space occ lesions and temp lobe abnormal
2. Photic- Flash light- for juvenile myoclonic epilepsy
3. Tactile and auditory- Sees if unconscious patients have cortisol response to stimuli

Question 11

Treatment for absent seizures

Answer 11

Ethosuxamide or SV

Question 12

MOA of Ethosuxamide

Answer 12

inhibits NADPH-linked aldehyde reductase necessary for the formation of gamma-hydroxybutyrate, which has been associated with the induction of absence seizures

Question 13

MOA of Sodium Valproate

Answer 13

inhibit succinic semialdehyde dehydrogenase. This inhibition results in an increase in succinic semialdehyde which acts as an inhibitor of GABA transaminase ultimately reducing GABA metabolism and increasing GABAergic neurotransmission.

Question 14

What is Landua-Kleffner Syndrome

Answer 14

• Sudden regression in speech then no speech
• Can be mistaken for deafness
• May have seizures with this
• Children 4-8

Question 15

What would Landua-Kleffner Syndrome EEG look?

Answer 15

Sharp and slow waves

Question 16

Which nerves do nerve conduction studies look at

Answer 16

1. Sensory and motor

If got numbness tingling, weakness e.g PN, carpal tunnel, GB

Question 17

What does the nerve conduction study look at?

Answer 17

Lactency-Time taken for stimulus to travel (Myelination) Trapping?
Amplitude- Size of the response. the amount of fibres stimulated

Question 18

What is carpal tunnel syndrome

Answer 18

• Compression of median nerve
• Get pain numbness tingling
• If slowing of nerve (Latency) then its trapped

Question 19

What does the ulnar nerve supply?

Answer 19

Little finger and half of ring finger

Question 20

What is cubital tunnel syndrome

Answer 20

• Ulnar nerve trapped at the elbow

Question 21

What is preipheral neuropathy?

Answer 21

• Longer nerves affected first so feet

Question 22

What is an EMG

Answer 22

Electromyography

- Recording needle into muscle and looks at the trace

Question 23

What are the 3 types of evoked potentials

Answer 23

1. Visual EP- for MS- Put electrode on scalp, stimulate optic nerve and check time for brain response. Look at latency and amplitude which shows silent regions. P100 should be 100
2. Auditory- Headphones on and use clicks- Can be used for MS
3. Sensory- Stimulate nerve in arm or leg

All look for silent lesions in MS