<s>
The	O
10	B-Algorithm
–	I-Algorithm
20	I-Algorithm
system	I-Algorithm
or	O
International	O
10	B-Algorithm
–	I-Algorithm
20	I-Algorithm
system	I-Algorithm
is	O
an	O
internationally	O
recognized	O
method	O
to	O
describe	O
and	O
apply	O
the	O
location	O
of	O
scalp	O
electrodes	O
in	O
the	O
context	O
of	O
an	O
EEG	B-Application
exam	O
,	O
polysomnograph	O
sleep	O
study	O
,	O
or	O
voluntary	O
lab	O
research	O
.	O
</s>
<s>
Note	O
that	O
there	O
is	O
no	O
"	O
central	O
lobe	O
"	O
;	O
due	O
to	O
their	O
placement	O
,	O
and	O
depending	O
on	O
the	O
individual	O
,	O
the	O
"	O
C	O
"	O
electrodes	O
can	O
exhibit/represent	O
EEG	B-Application
activity	O
more	O
typical	O
of	O
frontal	O
,	O
temporal	O
,	O
and	O
some	O
parietal-occipital	O
activity	O
,	O
and	O
are	O
always	O
utilized	O
in	O
polysomnography	O
sleep	O
studies	O
for	O
the	O
purpose	O
of	O
determining	O
stages	O
of	O
sleep	O
.	O
</s>
<s>
"	O
Z	O
"	O
electrodes	O
are	O
often	O
utilized	O
as	O
'	O
grounds	O
 '	O
or	O
'	O
references	O
,	O
'	O
especially	O
in	O
polysomnography	O
sleep	O
studies	O
,	O
and	O
diagnostic/clinical	O
EEG	B-Application
montages	O
meant	O
to	O
represent/diagnose	O
epileptiform	O
seizure	O
activity	O
,	O
or	O
possible	O
clinical	O
brain	O
death	O
.	O
</s>
<s>
Note	O
that	O
the	O
required	O
number	O
of	O
EEG	B-Application
electrodes	O
,	O
and	O
their	O
careful	O
,	O
measured	O
placement	O
,	O
increases	O
with	O
each	O
clinical	O
requirement	O
and	O
modality	O
.	O
</s>
<s>
Even-numbered	O
electrodes	O
(	O
2	O
,	O
4	O
,	O
6	O
,	O
8	O
)	O
refer	O
to	O
electrode	O
placement	O
on	O
the	O
right	O
side	O
of	O
the	O
head	O
,	O
whereas	O
odd	O
numbers	O
(	O
1	O
,	O
3	O
,	O
5	O
,	O
7	O
)	O
refer	O
to	O
those	O
on	O
the	O
left	O
;	O
this	O
applies	O
to	O
both	O
EEG	B-Application
and	O
EOG	O
(	O
electrooculogram	O
measurements	O
of	O
eyes	O
)	O
electrodes	O
,	O
as	O
well	O
as	O
ECG	B-Application
(	O
electrocardiography	B-Application
measurements	O
of	O
the	O
heart	O
)	O
electrode	O
placement	O
.	O
</s>
<s>
Chin	O
,	O
or	O
EMG	O
(	O
electromyogram	O
)	O
electrodes	O
are	O
more	O
commonly	O
just	O
referred	O
to	O
with	O
"	O
right	O
,	O
"	O
"	O
left	O
,	O
"	O
and	O
"	O
reference	O
,	O
"	O
or	O
"	O
common	O
,	O
"	O
as	O
there	O
are	O
usually	O
only	O
three	O
placed	O
,	O
and	O
they	O
can	O
be	O
differentially	O
referenced	O
from	O
the	O
EEG	B-Application
and	O
EOG	O
reference	O
sites	O
.	O
</s>
<s>
Cz	O
and	O
Fz	O
are	O
'	O
ground	O
 '	O
or	O
'	O
common	O
 '	O
reference	O
points	O
for	O
all	O
EEG	B-Application
and	O
EOG	O
electrodes	O
,	O
and	O
A1-A2	O
are	O
used	O
for	O
contralateral	O
referencing	O
of	O
all	O
EEG	B-Application
electrodes	O
.	O
</s>
<s>
This	O
EEG	B-Application
montage	O
may	O
be	O
extended	O
to	O
utilize	O
T3-T4	O
,	O
P3-P4	O
,	O
as	O
well	O
as	O
others	O
,	O
if	O
an	O
extended	O
or	O
"	O
seizure	O
montage	O
"	O
is	O
called	O
for	O
.	O
</s>
<s>
Specific	O
anatomical	O
landmarks	O
are	O
used	O
for	O
the	O
essential	O
measuring	O
and	O
positioning	O
of	O
the	O
EEG	B-Application
electrodes	O
.	O
</s>
<s>
When	O
placing	O
the	O
A	O
(	O
or	O
M	O
)	O
electrodes	O
,	O
palpation	O
is	O
often	O
necessary	O
to	O
determine	O
the	O
most	O
pronounced	O
point	O
of	O
the	O
mastoid	O
process	O
behind	O
either	O
ear	O
;	O
failure	O
to	O
do	O
so	O
,	O
and	O
to	O
place	O
the	O
reference	O
electrodes	O
too	O
low	O
(	O
posterior	O
to	O
the	O
ear	O
pinna	O
,	O
proximal	O
to	O
the	O
throat	O
)	O
may	O
result	O
in	O
"	O
EKG	B-Application
artifact	O
"	O
in	O
the	O
EEGs	B-Application
and	O
EOGs	O
,	O
due	O
to	O
artifact	O
from	O
the	O
carotid	O
arteries	O
.	O
</s>
<s>
EKG	B-Application
artifact	O
can	O
be	O
reduced	O
with	O
post-filtering	O
of	O
signals	O
,	O
or	O
by	O
"	O
jumping	O
"	O
(	O
co-referencing	O
)	O
of	O
A/M	O
reference	O
electrodes	O
,	O
if	O
replacement	O
of	O
reference	O
electrodes	O
is	O
not	O
possible	O
,	O
ameliorative	O
,	O
or	O
if	O
other	O
clinical	O
considerations	O
prevent	O
otherwise	O
good	O
placement	O
(	O
such	O
as	O
congenital	O
malformation	O
,	O
or	O
post-surgical	O
considerations	O
such	O
as	O
Cochlear	O
Implants	O
)	O
.	O
</s>
<s>
When	O
recording	O
a	O
more	O
detailed	O
EEG	B-Application
with	O
more	O
electrodes	O
,	O
extra	O
electrodes	O
are	O
added	O
using	O
the	O
10%	O
division	O
,	O
which	O
fills	O
in	O
intermediate	O
sites	O
halfway	O
between	O
those	O
of	O
the	O
existing	O
10	B-Algorithm
–	I-Algorithm
20	I-Algorithm
system	I-Algorithm
.	O
</s>
<s>
Also	O
,	O
the	O
MCN	O
system	O
renames	O
four	O
electrodes	O
of	O
the	O
10	B-Algorithm
–	I-Algorithm
20	I-Algorithm
system	I-Algorithm
:	O
</s>
