Neurophysiological measurements Flashcards
1
Q
EEG
A
- records electrical activity of the brain
- uses 21 electrodes on scalp
- 10/20 International system of Electrode Placement
- strenuous hyperventilation used to bring up abnormal discharges
- sometimes strobes of light used
- 24 hour sleep deprivation can lead to activation of paroxysmal EEG discharges in some casees
- EEG recording during sleep can be used when wake tracing is normal
2
Q
Beta waves
A
> 13hz
-seen on normal waking EEG
3
Q
Alpha waves
A
8-13hz
- dominant wave frequency when eyes are closed and relaxing
- disappears with anxiety, arousal, eye opening or focused attention
- dominance reduces in old age
4
Q
Theta waves
A
- 4-8hz
- small amount of sporadic theta seen in waking at frontotemporal area
- prominant in drowsy or sleep EEG
- excessive theta in awake EEG is a sign of pathology
5
Q
Delta waves
A
- <4 hz
- not seen in waking EEG
- common in deep sleep
- presence of focal/generalised delta in awake EEG is a sign of pathology
6
Q
Mu waves
A
- 7-11 hz
- occurs over motor cortex and is associated with motor activity and limb movement
7
Q
Lambda
A
- Single waves
- single occipital triangular, symmetrical sharp wave produced by visual scanning whilst awake or in light sleeo
8
Q
Fast waves
A
-alpha (8-12) and beta (13)
9
Q
Slow waves
A
-theta (4-8) and delta (<4hz)
10
Q
Newborns
A
-dominant delta and theta waves
11
Q
Infants
A
-irregular medium to high voltage delta activity
12
Q
Early childhood
A
-alpha range develops in posterior areas
13
Q
Mid adolescence
A
-EEG essentially has the appearance of an adult tracing by 12-14 years
14
Q
Adult EEG
A
-normal dominant alpha rhythm
15
Q
Diffuse slowing
A
- most common EEG abnormality
- non-specific
- signifies the presence of encephalopathy
