Nervous System: Electroencephalography Lab Flashcards
Electroencephalography
Noninvasive method to record electrical
activity of the brain
The movement of ions within the ________ generate electrical activity that is recorded as ______ ______ on an _____________.
neurons, brain rhythms, electroencephalogram
What is electroencephalography used for?
Used to diagnose conditions such as, epilepsy, sleep disorders, coma, and encephalopathies
The absence of brain rhythms is taken as?
clinical evidence of death
Certain characteristics of brain rhythms can have a
frequency that varies between?
1 to 30 Hz,
Certain characteristics of cycles per sec and an
amplitude that varies between?
5 to 200 microvolts (μV)
what are the 4 simple periodic rhythms that are recorded in an electroencephalogram?
alpha, beta,
delta, and theta.
Alpha rhythms have a wave frequency range of what?
8 to 13 Hz
alpha rhythms are prominent when?
The individual is in a relaxed state with the eyes closed.
Alpha rhythms of the
greatest amplitude is recorded over the?
occipital and parietal regions of the cerebral
cortex.
T/F: In general, females have a higher alpha wave frequency and wave amplitudes are likely to be higher in extroverted subjects.
True
When does alpha block occur?
Occurs if the eyes open or if the individual begins to concentrate on some mental problem or visual stimulus.
During alpha block the waves _______ in amplitude but _________ in frequency producing ______ ________.
decrease, increase, beta rhythms
T/F: Beta rhythms are closely related to alpha rhythms
True
T/F: Beta rhythms have a higher wave frequency (14 to 30 Hz) and have lower wave amplitude compared to alpha rhythms.
True
when are Beta rhythms prominent?
They are prominent in an
attentive or alert state
T/F: In beta rhythms, During episodes of fright or excitement, the wave frequency increases even more
True
Delta rhythms are high-amplitude waves with a frequency of?
4 Hz or less
When are delta rhythms observed?
during deep sleep
As the subject moves from lighter to deeper stages of
sleep what happens?
alpha rhythms are gradually replaced by delta rhythms.
Theta rhythms are large abnormally contoured waves with a frequency of?
4 to 7 Hz.
Theta rhythms are normal in ________, they are abnormal in awake ________.
children, adults
In times of emotional stress, what types of rhythms are observed?
theta rhythms
typical amplitude of alpha rhythms?
20-200 uV
typical amplitude of beta rhythms?
5-10 uV
typical amplitude of delta rhythms?
20-200uV
typical amplitudes of theta rythms
10
