Eeg Chapter 14 Abnormalities

Front 1

Periodic slow complexes

Back 1

Usually slow complexes or transients (may not always be of high voltage) occuring at approximately regular intervals

Front 2

Burst surpression activity

Back 2

Characterized by bursts of slow activity (theta or delta) and/or spikes or sharp waves, with relatively long intervening periods of very low voltage activity

Front 3

Abnormal Sleep

Back 3

atypical morphology for a given level of sleep e.g no sleep spindles, or atypical sleep onset such as REM-stage sleep

Front 4

Alpha Coma

Back 4

Defined by morphology, location, state of consciousness, and reactivity. Typically the alpha is seen as 9-10 Hz in central-frontal location rather than occipital. It is usually non-reactive.

Front 5

Spindle Coma

Back 5

Defined by frequency, morphology, and state of consciousness. Usually 12-14 Hz bursts distributed similarly to sleep spindles and seen in coma, sometimes posttraumatic.

Front 6

Excessively slow activity (theta and/or delta)

Back 6

can be intermittent, continuous, focal, or nonfocal

Front 7

FIRDA

Back 7

Frontal intermitent rythmical delta activity

Front 8

OIRDA

Back 8

Occipital intermittent rythmical delta activity

Front 9

Electrocerebral inactivity

Back 9

Profound attenuation (suppression) with no activity greater than 2 uV attributable to cerebral function

Front 10

RMTD

Back 10

rhythmical mid-temporal discharges usually found during drowsiness in temporal theta. It is rare and is uncertain in significance in adults.

Front 11

SSS or also BETS

Back 11

Small sharp spikes/Benign epileptiform transients are surface negative fast transients that usually have a voltage between 30-50 uV although it may reach 100 uV. They occur in drowsiness and sleep in the frontal and temporal

Front 12

Six per second spike and wave activity

Back 12

small spikes usually no larger than 50 uV followed by a low votage slow wave ranging in the 4-7 Hz with a burst less than a second. Located in either the anterior or posterior regions.

Front 13

Fourteen and/or 6 Hz Positive Spikes

Back 13

surface positive spike-like bursts and are in the occipital and posterior temporal regions and found during drowsiness and early sleep. They occur in runs of 14 or 6 Hz or both frequencies mixed.

Front 14

Rythmic hypersynchronous activity

Back 14

Rythmic activity emerging from the background and appearing to be nonreactive. May be focal or generalized.

Front 15

Periodic lateralized epileptiform discharges (PLEDS)

Back 15

Sharp and slow discharges occuring at an approximately periodic rate usually less than 1 sec