Electroencephalography Flashcards

1
Q

Delta

A

Frequency1-4Hz
Normally foundFrontally in adults and posteriorly in children
Normally seen inSlow 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

A

Frequency4-8Hz
Normally foundGeneralised
Normally seen inYoung 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

A

Frequency8-12Hz
Normally foundPosteriorly
Normally seen inWhen relaxed and when the eyes are closed (whilst awake)

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4
Q

Beta

A

Frequency12-30Hz
Normally foundFrontally
Normally seen inWhen busy or concentrating

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5
Q

Sigma

A

Frequency12-14Hz
Normally foundFrontal and central regions
Normally seen in(aka 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 😴 Sigma waves mark the beginning of stage 2 sleep and are seen normally in sleep. They generally occur immediately following muscle twitching and are thought to enable the sleeper to remain in a tranquil state.

They are generated in the reticular nucleus of the thalamus and result from interaction between the thalamus and the cortex.

Loss of sigma waves is a feature of familial fatal insomnia (prion disease).

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6
Q

Gamma

A

Frequency30-100Hz
Normally foundNo specific areas
Normally seen inMeditation

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7
Q

CJD (sporadic only, does not apply to variant)

A

EEG findingsEarly 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

Huntington’s

A

EEG findingsLow voltage EEG, in particular no alpha (flattening)

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9
Q

Delirium

A

EEG findingsDiffuse slowing, decreased alpha, increased theta and delta

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10
Q

Delirium tremens

A

EEG findingsHyperactive trace, fast

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11
Q

Alzheimer’s

A

EEG findingsReduced alpha and beta, increased delta and theta

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12
Q

Petit mal epilepsy (absence seizure)

A

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

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13
Q

Generalised eilepsy

A

EEG findingsSharp spikes, 25-30Hz

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14
Q

Partial epilepsy

A

EEG findingsFocal spikes

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15
Q

Myoclonic epilepsy

A

Generalised spike and wave activity

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16
Q

Encephalopathy

A

Diffuse slowing

17
Q

Normal aging

A

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

18
Q

Antipsychotics (typical)

A

Decreased beta with Increased alpha, and delta, haloperidol least effect

19
Q

Antipsychotics (atypical)

A

Varied effect, clozapine most significant effect

20
Q

Antidepressants

A

Reduce beta, increase all others

21
Q

Anticonvulsants

A

No effect

22
Q

Lithium

A

Slowing

23
Q

Benzodiazepines

A

Increase beta, decrease alpha

24
Q

Barbiturates

A

Increase beta

25
Q

Drug of abuseStimulants (cocaine, nicotine)

A

Increase alpha

26
Q

Drug of abuseDepressants (alcohol, opioids)

A

Decrease alpha

27
Q

Cannabis

A

Increase alpha