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The electroencephalogram (EEG) is an important test for neurologists. However, many neurological trainees only have limited exposure to EEG and most will not have directly reported EEGs. When you report EEGs rather than look at illustrative examples you concentrate much harder recognising the importance that your interpretation will have; you look for what information you can from the request form; you try and get as much out of the technician’s report – and as a result you learn much more.
To attempt to recreate this level of concentration we have devised this simple game. Below there are seven fragments of EEGs, eight sets of clinical information, eight technician reports, and eight EEG conclusions. Your job is to match them up—to make the sets of happy families— and a table has been provided to make this easier. You will appreciate that you have one “spare” request form, technician report, and conclusion to make it a little harder. For the sake of the game the technician reports and conclusions have been edited to separate the description from the conclusion.
All the EEGs are on the same montage for the sake of consistency. The montage is colour coordinated and is given in fig 1. Some of the abnormalities would be better seen on different montages and with digital recordings these would normally be switched, but that would disrupt the game.
The correct answers are given in a table on page ii46.
The game aims to help you identify common EEG abnormalities but also to help you appreciate the importance of filling in an EEG request form to provide the neurophysiologist with useful information that will make their report more useful to you.
A: 65 year old man. Memory loss over last six weeks. Confused.
B: 19 year old man. Single generalised seizure without warning. History of brief jumps in am for 2–3 years.
C: 44 year old woman. Two episodes of unwitnessed loss of consciousness—vision bit blurred before hand.
D: 56 year old man. Three generalised seizures in last three weeks.
E: 24 year old man. Admitted with sudden onset seizures, fever, confusion, and memory loss.
F: 26 year old woman; episodes of déjà vu and dizziness over the last six months. No loss of consciousness (LOC).
G: 12 year old girl. Always been a daydreamer. Blanking out for periods? epilepsy?
H: 44 year old man: frequent episodes of flashing in the right visual field—last about 30 seconds—noted to be dazed afterwards.
i) There is pronounced slowing over the left hemisphere. The right hemisphere is normal.
ii) There is nearly continuous biphasic/triphasic sharp wave discharges of varying interburst interval over the left hemisphere. Intermittently there is spread to involve the right hemisphere. There is no clear evolution in frequency or amplitude. Between the discharges the background is disorganised and slow.
iii) There are frequent focal sharp waves arising in the left temporal region. The background EEG is normal.
iv) Two episodes were observed during the video–EEG recording of sudden jerking of the head. This was associated with a spike/polyspike and wave discharges (associated with some occipital muscle artefact).
v) There is 10–12 Hz α waves. No response to photic stimulation or hyperventilation.
vi) There is pronounced slowing over the right hemisphere. The left hemisphere is normal.
vii) A grossly abnormal record with fairly frequent bursts of high amplitude irregular delta over both hemispheres with anterior preponderance R>L. The background is disorganised with excessive slowing.
viii) The resting record was normal. During hyperventilation there were frequent runs of 3 Hz spike/wave discharges associated with brief cessation of hyperventilation and momentary unresponsiveness.
a) Normal record. A normal record does not rule out epilepsy.
b) A normal sleep record.
c) This is likely to be prion disease, though non-convulsive status should be considered. A repeat EEG may help.
d) This EEG indicates an increased liability to focal onset seizures arising from the left temporal lobe. A structural trigger needs to considered.
e) This is childhood absence epilepsy.
f) This record indicates this is a primary generalised epilepsy, most likely juvenile myoclonic epilepsy.
g) A structural lesion in the left hemisphere needs to be considered.
h) This is likely to represent a viral encephalitis.
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