EEGs Flashcards

1
Q

Delta waves

A

1-4Hz, Frontally in adults and posteriorly in children

Slow wave sleep and in babies. Should not be present when awake, when present if awake this strongly suggests pathology

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2
Q

Theta waves

A

4-8Hz, generalised.

Young children, drowsy and sleeping adults, with certain medications, meditation. Small amount seen in awake adults, excessive amount when awake may indicate pathology

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3
Q

Alpha waves

A

8-12Hz, posteriorly.

When relaxed and when the eyes are closed (whilst awake)

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4
Q

Beta waves

A

12-30Hz, frontally.

When busy or concentrating

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5
Q

Sigma waves

A

12-14Hz, frontal and central regions

Sleep spindles. Bursts of oscillatory activity that occur in stage 2 sleep. Along with k-complexes they are the defining characteristic of stage 2 sleep

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6
Q

Gamma waves

A

30-100Hz. Meditation

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7
Q

Sporadic CJD - eeg

A

Early on there is non specific slowing, later periodic biphasic and triphasic synchronous sharp wave complexes superimposed on a slow background rhythm

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8
Q

Hungtingdon’s - eeg

A

Low voltage EEG, in particular no alpha (flattening)

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9
Q

Delirium - eeg

A

Diffuse slowing, decreased alpha, increased theta and delta

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10
Q

Delirium Tremens - eeg

A

Hyperactive trace, fast

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11
Q

Alzheimer’s - eeg

A

Reduced alpha and beta, increased delta and theta

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12
Q

Absence seizure

A

Generalised, bilateral, synchronous, 3Hz (3 waves per second) spike and wave pattern

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13
Q

Generalized epilepsy

A

Sharp spikes, 25-30Hz

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14
Q

Partial epilepsy

A

Focal spikes

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15
Q

Myoclonic epilepsy

A

Generalised spike and wave activity

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16
Q

Encephalopathy - eeg

A

Diffuse slowing

17
Q

Normal ageing - eeg

A

Diffuse slowing, which can be focal or diffuse, if focal most commonly seen in the left temporal region

18
Q

Typical antipsychotics - eeg

A

Diffuse slowing, which can be focal or diffuse, if focal most commonly seen in the left temporal region

19
Q

Antidepressants - eeg

A

Reduce beta, increase all others

20
Q

Atypical antipsychotics - eeg

A

Varied effect, clozapine most significant effect, quetiapine least significant. Clozapine > Olanzapine > Risperidone > Typicals > Quetiapine

21
Q

Lithium - eeg

A

Slowing

22
Q

Benzodiazepines - eeg

A

Increase beta, decrease alpha

23
Q

Barbituates - eeg

A

Increase beta

24
Q

Stimulants - eeg

A

Increase alpha

25
Q

Depressants - eeg

A

Decrease alpha

26
Q

Cannabis - eeg

A

Increase alpha

27
Q

Stage I sleep

A

Alpha disappears

Desynchronised theta and delta appear

28
Q

Stage II sleep

A

Low voltages and delta waves with sleep spindles and K complexes

29
Q

Stage III sleep

A

High voltage slow waves
Delta <50%
Sleep spindles and K complexes diminish

30
Q

Stage IV sleep

A

Delta waves >50%

Sleep spindles and K complexes absent