2.1 Neurophysiology Diagnostics

Question 1

Electrodes in EEG are connected from the head to the recording system, which are attached to the scalp according to a standardized system of electrode placement

Answer 1

Ten Twenty Placement

Question 2

Where does the electrical signals come from?

Answer 2

Pyramidal cells of cerebral cortex

Question 3

What type of EEG has standard 30 minute recording of awake and sleep EEG activity that can extend to 24 hrs recording video?

Answer 3

Surface/ scalp EEG

Question 4

An EEG can determine changes in brain activity that may be useful in diagnosing brain disorders like:

Answer 4

Epilepsy or other seizure disorder
Brain tumor
Head injury
Brain dysfunction
Brain death in a persistent coma

Question 5

Procedure: Pt will be ask not to sleep at night before the procedure or to stay up late or wake up early

Answer 5

Sleep deprivation test

Question 6

Occurs often during sleep and are seizures originating in front of the brain that produces unusual symptoms that appear to be related to psychiatric problem or sleep disorder

Answer 6

Frontal lobe seizure

Question 7

3Ps of frontal lobe seizure:

Answer 7

Pedaling motion
Pelvic thrusting
Profanity screams

Question 8

How do you distinguished the left brain from right brain in an EEG?

Answer 8

RELO
Right side Even numbers
Left side Odd numbers

Question 9

A test that detects electrical activity in the brain using small discs attached to the scalp.

Answer 9

Electroencephalography (EEG)

Question 10

Different EEG activation procedures

Answer 10

S- leep deprivation
H- yperventilation
E- ye opening/ E-ye closure
P- hotic stimulation
S- ensory stimuli

Question 11

Characteristics of normal sleep EEG

Answer 11

P- POST
S- Spindle
V- Vertex wave

Question 12

Commonly seen on EEG and have been said to be more common during daytime naps than nocturnal sleep. Commonly seen in adolescents and middle aged adults

Answer 12

Positive Occipital Sharp Transient of Sleep

Question 13

Powerful strobe of light is placed about 15 in from pt’s eyes and fleshed at frequencies of 1 to 20 per sec with the pt’s eyes open and close

Answer 13

Photic stimulation

Question 14

Common procedure used in the EEG lab in children and adults using strobe of flashing lights at different frequencies to detect abnormal epileptogenic sensitivity to flickering light

Answer 14

Intermittent photic stimulation (IPS)

Question 15

Patient is asked to breathe in and out deeply and rapidly 20x for 3 to 5 minutes

Answer 15

Hyperventilation

Question 16

Considered most specific and sensitive test confirming a diagnosis of absence seizures

Answer 16

Generalized spike and wave pattern

Question 17

Hyperventilation brings out seizures called

Answer 17

Staring spells or abscence

Question 18

The pt is instructed to open and close his eyes. Then determine whether there are certain responses during closure or opening of the eye

Answer 18

Eye opening/ eye closure

Question 19

Closing of the eyes indicate:

Opening of the eyes indicate:

Answer 19

Closed: negative wave deflection
Open: positive wave deflection

Question 20

During EEG, the pt is instructed to raise his hands during the procedure or the pt is instructed to close and open his fists

Answer 20

Sensory stimuli

Question 21

Abnormal EEG pattern seen in sensory stimuli

Answer 21

Spike and polyspike wave pattern or sharp transient of waves

Question 22

Is used to evaluate the function esp. the ability of electrical conduction of the motor and sensory nerve. It also determine nerve damage and destruction

Answer 22

Nerve conduction studies (NCS)

Question 23

How many electrodes are placed on the skin over the nerve in NCS

Answer 23

2; 1 electrode stimulates the nerve with a very mild electrical impulse and the second electrode records it

Question 24

Is calculated by measuring the distance between electrodes and the time it takes for electrical impulses to travel between electrodes in NCS

Answer 24

Nerve conduction velocity

Question 25

Usual nerves tested in NCS all have motor and sensory function except

Answer 25

Sural nerve (only sensory)

Question 26

Develops after injury to axon and myelin, as in transection of the nerve. Muscle atrophy is seen

Answer 26

Wallerian degeneration

Question 27

Develops after damage to the myelin sheath or schwann cell. Muscle is not denervated therefore no atrophy develops, with poor nerve conduction velocity

Answer 27

Segmental demyelination

Question 28

Develops when damage to cell body of the neuron results in distal dying of the axon and subsequent loss of myelin. Muscle is denervated, muscle atrophy develops

Answer 28

Neuronal (axonal) degeneration

Question 29

Follow segmental demyelination

Answer 29

Segmental remyelination

Question 30

Associated with formation of clusters of small and thin myelinated fibers

Answer 30

Axonal regeneration

Question 31

Decrease amplitude of CMAP/ SNAP and normal conduction velocity

Answer 31

Axonal nerve damage

Question 32

Normal amplitude and slower conduction velocity

Answer 32

Demyelinating nerve damage

Question 33

Result of damage to a single nerve or nerve group by trauma, injury, local compression, prolonged pressure or inflammation

Answer 33

Mononeuropathy

Question 34

Damage to multiple nerves in roughly the same areas on both sides of the body. E.g is GBS

Answer 34

Poly neuropathy

Question 35

Used in the presence of unexplained weakness based on the defect of neuromuscular transmission (sarcolemmal membrane or nerve terminal abnormality). CMAPs are recorded during repetitive stimulation of motor nerve.

Answer 35

Repetitive nerve stimulation

Question 36

10% decremental response confirms:

Answer 36

Myasthenia gravis

Question 37

10% incremental response after exercise confirms:

Answer 37

Lambert Eaton Syndrome

Question 38

Usually performed in pts with bell's palsy

Answer 38

Facial nerve or blink reflex

Question 39

Assess the health of muscles and nerve cells that control them. Motor neurons transmit electrical signals that cause muscles to contract. Contraction can be recorded by needle electrodes

Answer 39

Electromyography

Question 40

Four things to remember about EMG:

Answer 40

``` ISMR I: insertional activity S: spontaneous activity M: motor unit action potentials R:recruitment ```

Question 41

_________ insertional activity is seen in denervated muscle or muscle that is being reinnervated

Answer 41

Increased

Question 42

_______ of insertion activity found after prolonged denervation when muscle fibers have been replaced by connective tissue with fibrosis

Answer 42

Reduced

Question 43

To view waveforms and to listen to muscular activity use an:

Answer 43

Ocsilloscope

Question 44

``` EMG: ISMR I: increased S: fibrillation positive wave M: large unit limited recruitment R: reduced fast firing rate ```

Answer 44

Lower motor neurogenic lesion

Question 45

Measure the electrophysiologic responses of the nervous system to a variety of stimuli. Study the more proximal segments of sensory pathway

Answer 45

Evoked potential

Question 46

Electrophysiologic assessment of large fiber sensory pathways of peripheral nerves, spinal cord and brain (AL system and dorsal column). Used to judge conduction velocity and demyelination in the posterior funiculus or to predict outcome for coma pt

Answer 46

Somatosensory evoked potentials

Question 47

Used in the assessment of the clinical state of the cochlea, auditory nerve and the middle portion of the brainstem. Has 8 peaks generated on click stimulation

Answer 47

Brainstem auditory evoked potentials

Question 48

Peaks I-V are clinically useful such as:

Answer 48

``` I auditory nerve II cochlear nucleus III superior olivary nucleus IV lateral lemniscus V inferior colliculus Others: VI medial geniculate VII thalamocortical connection ```

Question 49

Lesions in the upper to middle pons tend to lead to _______ BAEP abnormalities

Answer 49

Ipsilateral

Question 50

Measures cognitive factors such as attention, memory, language and others. Use in the diagnosis of dementia.

Answer 50

Cognitive event related potentials

Question 51

Event related potential component elicited in the process of decision making.

Answer 51

P300 wave

Question 52

____________ = cognitive slowing

Answer 52

Prolonged P300 latency

Question 53

Test the function of the visual pathway from the retina to the occipital cortex. Most useful for testing optic nerve function

Answer 53

Visual evoked potentials

Question 54

VEP usually measure the amplitude and latency of:

Answer 54

P100 wave