<s>
Clinical	O
Electrophysiological	B-Application
Testing	O
is	O
based	O
on	O
techniques	O
derived	O
from	O
electrophysiology	B-Application
used	O
for	O
the	O
clinical	O
diagnosis	O
of	O
patients	O
.	O
</s>
<s>
Electrophysiology	B-Application
has	O
a	O
very	O
important	O
role	O
in	O
ensuring	O
accurate	O
clinical	O
diagnoses	O
.	O
</s>
<s>
While	O
electrophysiological	B-Application
tests	O
generally	O
passively	O
collect	O
electrical	O
data	O
,	O
it	O
is	O
sometimes	O
necessary	O
to	O
apply	O
an	O
external	O
stimulus	O
to	O
the	O
desired	O
target	O
in	O
order	O
to	O
produce	O
transient	O
evoked	B-Algorithm
potentials	I-Algorithm
that	O
can	O
provide	O
further	O
insight	O
not	O
obtained	O
from	O
solely	O
passive	O
recording	O
methods	O
.	O
</s>
<s>
Electroencephalography	O
data	O
can	O
be	O
viewed	O
as	O
a	O
qualitative	O
wave	O
form	O
,	O
or	O
it	O
can	O
be	O
further	O
processed	O
through	O
analytical	O
procedures	O
to	O
produce	O
quantitative	B-Algorithm
electroencephalography	I-Algorithm
(	O
qEEG	B-Algorithm
)	O
.	O
</s>
<s>
If	O
qEEG	B-Algorithm
data	O
is	O
mapped	O
from	O
multiple	O
parts	O
of	O
the	O
brain	O
then	O
it	O
is	O
a	O
topographic	O
qEEG	B-Algorithm
(	O
also	O
known	O
as	O
brain	B-Algorithm
electrical	I-Algorithm
activity	I-Algorithm
mapping	I-Algorithm
or	O
BEAM	O
)	O
.	O
</s>
<s>
If	O
EEGs	O
are	O
recorded	O
after	O
intentionally	O
stimulating	O
the	O
brain	O
,	O
then	O
the	O
resulting	O
data	O
is	O
called	O
a	O
event	B-Algorithm
related	I-Algorithm
potential	I-Algorithm
.	I-Algorithm
</s>
<s>
With	O
proper	O
equipment	O
it	O
is	O
possible	O
to	O
locate	O
where	O
in	O
the	O
brain	O
neurons	O
have	O
been	O
activated	O
and	O
measure	O
their	O
event	B-Algorithm
related	I-Algorithm
potentials	I-Algorithm
.	O
</s>
<s>
Event-related	B-Algorithm
potentials	I-Algorithm
can	O
be	O
classified	O
as	O
either	O
:	O
sensory	O
,	O
motor	O
or	O
cognitive	O
.	O
</s>
<s>
Although	O
the	O
development	O
of	O
MRI	B-Algorithm
has	O
allowed	O
for	O
very	O
effective	O
detection	O
of	O
brainstem	O
lesions	O
,	O
evoked	B-Algorithm
potentials	I-Algorithm
measurements	O
are	O
also	O
an	O
electrophysiological	B-Application
technique	O
that	O
has	O
been	O
used	O
for	O
over	O
30	O
years	O
in	O
this	O
context	O
.	O
</s>
<s>
This	O
method	O
differs	O
from	O
magnetic	B-Algorithm
resonance	I-Algorithm
imaging	I-Algorithm
in	O
that	O
it	O
passively	O
measures	O
the	O
magnetic	O
fields	O
without	O
altering	O
the	O
body	O
's	O
magnetization	O
.	O
</s>
<s>
However	O
,	O
data	O
from	O
MEG	O
and	O
MRI	B-Algorithm
can	O
be	O
combined	O
to	O
create	O
images	O
that	O
approximately	O
map	O
the	O
estimated	O
location	O
of	O
the	O
natural	O
magnetic	O
fields	O
.	O
</s>
<s>
In	O
order	O
for	O
the	O
heart	O
to	O
contract	O
in	O
a	O
regular	O
,	O
organized	O
manner	O
,	O
specific	O
electrical	O
signals	O
are	O
sent	O
to	O
the	O
myocardium	O
from	O
the	O
pacemaker	B-Algorithm
cells	I-Algorithm
.	O
</s>
<s>
EKGs	O
can	O
be	O
used	O
to	O
aid	O
in	O
the	O
diagnosis	O
of	O
myocardial	O
infarction	O
,	O
arrhythmia	B-Application
,	O
left	O
ventricular	O
hyptertrophy	O
,	O
valvulopathies	O
,	O
and	O
coronary	O
artery	O
disease	O
.	O
</s>
<s>
Nerve	O
conduction	O
studies	O
have	O
been	O
used	O
as	O
a	O
control	O
electrophysiological	B-Application
method	O
in	O
the	O
development	O
of	O
better	O
CTS	O
diagnostic	O
techniques	O
.	O
</s>
<s>
The	O
demyelination	O
and	O
scarring	O
of	O
axons	B-Algorithm
in	O
the	O
neurons	O
of	O
the	O
nervous	O
system	O
can	O
affect	O
their	O
conduction	O
properties	O
and	O
seriously	O
harm	O
the	O
normal	O
communication	O
of	O
the	O
brain	O
with	O
the	O
rest	O
of	O
the	O
body	O
.	O
</s>
<s>
However	O
,	O
visual	O
evoked	B-Algorithm
potentials	I-Algorithm
do	O
play	O
a	O
role	O
in	O
the	O
whole	O
diagnostic	O
process	O
.	O
</s>
