End 1350

Front 1

Frequency

Back 1

number of times a repetitive wave recurs in onw second (measured in hertz)

Front 2

Rhythmic

Back 2

have similar intercals between individual waves; waveforms are usually regular

Front 3

semirhythmic

Back 3

contain some recurring similar morphology waveforms as well as some intermixed irregular waveforms

Front 4

Arrhythmic

Back 4

EEG activity in which no stable rhythms are present

Front 5

Spindles

Back 5

groups of rhythmical repetitive waves that fradually increase and then decrease in amplitude

Front 6

Amplitude

Back 6

heigth of wave

Front 7

Attenuation

Back 7

reduction of amplitude of EEG activity resulting from decreased voltage

Front 8

Hypersynchrony

Back 8

seen as an increase in voltage and regularity of rhythmic activity

Front 9

Paroxysmal

Back 9

activity that emerges from background with a rapid onset, reaching quite high voltage, and ending with an abrupt return to lower voltage activity (term does not imply abnormality)

Front 10

Monomorphic/regular

Back 10

rhythmic run of waceforms of similar shape

Front 11

Sinusoidal

Back 11

when regular waves are similar to sine waves

Front 12

Irregular

Back 12

waveforms that do not have a sinusoidal or simple geometric shape

Front 13

Transient

Back 13

an event that clearly stands out against the background

Front 14

Comp;ex

Back 14

a sequence of two or more waves that have a characteristic form or recur with a fairly consistent shape

Front 15

Monophasic

Back 15

has a single deflection either up or down from the baseline

Front 16

Diphasic (biphasic)

Back 16

has two components on opposite sides of the baseline

Front 17

Triphasic

Back 17

has three components alternating about the base line

Front 18

polyphasic/multiphasic

Back 18

two or more components of different direction

Front 19

Topography

Back 19

location

Front 20

Generalized

Back 20

not limited to a specific area

Front 21

Lateral

Back 21

coming from one side

Front 22

Bilateral

Back 22

coming from both sides

Front 23

Focal

Back 23

coming from a local region

Front 24

Symmetry

Back 24

equal distribution of EEG activity over homologous head areas

Front 25

Bilaterally synchronous

Back 25

waves which occur at the same time on both sides of the head

Front 26

Duration

Back 26

the interval from beginning to end of an individual wave or complex

Front 27

Alpha

Back 27

Frequency- 8-13hz
Amplitude/voltage-15-45microvolts (often higher on right side)
Topography-bilaterally synchronous and posterior dominant
Attenuates with eyes opening and concentration

Front 28

Posterior Slow Waves of Youth

Back 28

Composed of delta activity intermixed with activity of alpha
Most often seen in ages 8-14 years
Attenuates with alpha on eye opening
Disappear with stage 1 sleep
Increase with hyperventilation

Front 29

Beta

Back 29

Frequency-14hz and higher
Amp-rarely exceeds 20 microvolts
Topography- fronto-central
Non-reactive to eye opening and concentration
Accenuated by medications

Front 30

Theta

Back 30

Frequency-4-7hz
Amp-variable, typically lower than the alpha
Topography- variable, depending on the patients age and level of consciousness
Non-reactive to eye opening and concentration
Considered normal in the waking records of young children and the elderly, and is normal component of drowsiness and sleep

Front 31

Delta

Back 31

Frequency-less than 4hz (typically falls between 1-3hz)
Amp- variable
Topography- variable
Non-reactive to eye opening and concentration
Normal component of deep sleep
Considered abnormal in the adult waking record or when focal in sleep

Front 32

Vertex (sharp wave transient)

Back 32

Maximal over the central vertex
Seen on the end of stage one sleep and throughout stage two sleep
Bilaterally Synchronous and symmetrical (waves which occur at the same time on both sides of the head)
May appear in response to sensory stimulus, such as tapping on the foot or hands of patients

Front 33

Sleep Spindles

Back 33

Maximal in the central vertex areas
Occur in spindle fashion; progressively increasing, then gradually decreasing amplitude
Frequencey range of 11-15hz
Seen in the stage 2&3 of sleep
Voltage may range up to 150 microvolts

Front 34

K-Complexes

Back 34

Maximal over the central vertex
Consist of vertex wave followed immediately by sleep spindles
Elicited by auditory stimulation, but they also appear withour stimulation
Repeated stimulation of the same tone quality will no longer cause reaction (becomes habitual)
Seen in stage 2&3 of sleep

Front 35

Positive Occipital Sharp Transients (POSTS)

Back 35

Series of surface positive transients
Seen in stage one of sleep and can persist to stage two of sleep
Normal in all patients

Front 36

Stage one of sleep

Back 36

Alpha drop out or waxing and waning
Diffusely scattered theta activity
POSTS
possible appearance of Vertex waves
Slow eye movements

Front 37

Stage two of sleep

Back 37

Sleep Spindles (11-15hz)
Vertex waves defined clearly
K-complexes
Theta activity is greater

Front 38

Stage three of sleep

Back 38

20-50% of the recording will consist of 2hz or less over 75 microvolts
K-complexes and sleep spindles may persist

Front 39

Stage four of sleep

Back 39

More than 50% of the record will consist of high voltage delta (75microvolts) with occasional superimposed faster activity
Older we get, less time in slow wave sleep (SWS)

Front 40

Stage five of sleep
(REM sleep)

Back 40

EEG similar to stage one of sleep, with sharp theta waves called sawtooth waves appearing int he central region
Rapid eye movements
Major decrease in muscle tone
Occur at the intervals of 90 minutes
First REM shorter than later REMs
Men have penile erection
Dreams are recalled when aroused from REM

Front 41

Normal Variants

Back 41

a waveform or complex that contains features that closely resemble abnormal patterns but has little or no clinical significance

Front 42

Squek Phenomena

Back 42

Seen in posterior head regions
Voltage variable
Brief increase in frequency and amplitude after eye closure followed by rapid deceleration to individuals normal baseline

Front 43

Mu Rhythm

Back 43

Negative arch shaped rhythm of about 8-10Hz
Prominent at C3 and C4
Seen during wakefulness
Typically unilateral of asymmetrical
Key to identification is by movement of the contralateral arm

Front 44

Lambda

Back 44

Positive waves present when viewing a scene or complex image
Seen occipital during wakefulness
Blocked by eye closure

Front 45

14&6 positive spikes

Back 45

Sharply contoured, variable frequency
Mainly seen in the temporal regions
At times it is 14 and other times 6hz
6hz is prominent in young children, while older children exhibit the 14hz rhythm.

Front 46

Alpha variant (fast, slow)

Back 46

Posterior rhythm is either harmonic or sub harmonic (half or double the normal rhythm)
Seen in wakefulness with eyes closed
Attentuates with eyes open