HOW ELECTROENCEPHALOGRAPHY IS DONE
A number of small electrodes are
attached to the scalp. Shaving of the
scalp is unnecessary. The electrodes
are connected to an instrument that
measures the brain’s impulses in
microvolts and amplifies them for
recording purposes. The technique
is painless, produces no side effects,
and takes about
Recordings are taken while the
subject is at rest, with the eyes open
and then shut, during and after
and while looking at a flashing light.
Electroencephalography is also
helpful to record activity as the
patient goes to sleep, especially
when epilepsy is suspected.
E l e c t r o d e s
c o n n e c t e d t o
c o n t r o l p a n e l
EEG WAVE PATTERNS
The prominent pattern of an awake, relaxed adult
whose eyes are closed.
The lower, faster oscillation of a person who is
concentrating on an external stimulus.
The typical pattern of sleep, also found in young
infants; rarely, delta waves indicate the presence
ofa brain tumour.
The dominant waves ofyoung children. In adults,
they may indicate an abnormality ofthe brain.
M o n it o r
The process by w hich fluid escapes. The
term effusion also describes an abnor-
mal collection of fluid (such as blood,
in the tissues or a body
cavity. An effusion can form as a result
of inflammation or changes in pressure
w ithin blood vessels; alternatively, it can
be due to changes in the blood con-
stituents, such as in
(a kidney disorder).
Effusion commonly occurs around the
or heart (see
or within joints, caus-
ing swelling (see
The accumulation of fluid in the space
resulting in swelling,
limitation of movement, and usually
also pain and tenderness. All joints are
enclosed by a capsule lined with a
membrane called the
. T h e
vium normally secretes small amounts
of fluid (known as synovial fluid) to
synovium is damaged or inflamed (for
example, as a result of
duces excessive fluid.
The pain and inflammation may be
nonsteroidal anti-inflammatory drugs
and by having injections of
The swelling usually reduces if
Location of knee joint effusion
Excessive production and accumulation of fluid
within the right knee joint (left in image) as a
result of injury or inflammation.
the affected joint is rested, bandaged
firmly, cooled with ice-packs, and kept
elevated. In some cases, the excess fluid
is drawn out of the joint using a needle
maintains a balance between the prim i-
tive, unconscious instincts of the
controls of the
and the de-
mands of the outside world.
An inherited disorder of
most important structural protein in the
body Individuals with Ehlers-Danlos
thin skin that bruises easily Wounds are
slow to heal and leave paper-thin scars,
and the joints are loose and prone
to recurrent dislocation. Sufferers bleed
easily from the gums and digestive tract.
commonly inherited in an autosomal
dominant pattern (see
There is no known specific treatment
for the condition, although unnecessary
accidental injury, such as that w hich
may occur in contact sports, should be
avoided by sufferers.
A condition in w hich deoxygenated
blood flows directly back into the circu-
lation rather than through the lungs.
This is due to an abnormal connection
between the left and right sides of the
w hich there is abnormally high blood
pressure in the arteries supplying the
lungs). The resultant
oxygen in the blood) causes
(bluish coloration of the skin), fainting,
and difficulty in breathing.
Eisenmenger complex occurs most
commonly in individuals
heart disease, congenital
such as ventricular
The diagnosis of Eisenmenger com-
(the insertion, under X-ray
control, of a thin tube into the heart via
a blood vessel). Once the condition has
developed, surgical correction of the
original defect w ill not help. Drug treat-
ment may help control the symptoms.