Webster's New World Medical Dictionary

sedimentation rate
A blood test that detects and
monitors inflammation in the body. Abbreviated sed
rate. The sed rate measures the rate at which red
blood cells in a test tube separate from blood serum
over time, becoming sediment at the bottom of the
test tube. The sed rate increases as inflammation
increases. The sed rate can also become elevated in
diseases that feature the production of abnormal
proteins, such as multiple myeloma. Also known as
erythrocyte sedimentation rate, or ESR.
Segawa dystonia
See 
dopa-responsive dystonia.
seizure
Uncontrolled electrical activity in the brain
that may produce a physical convulsion, minor phys-
ical signs, thought disturbances, or a combination of
symptoms. The type of symptoms and seizures expe-
rienced depend on where the abnormal electrical
activity takes place in the brain, what its root cause is,
and such factors as the patient’s age and general state
of health. Seizures can be caused by head injuries,
brain tumors, lead poisoning, maldevelopment of the
brain, genetic and infectious illnesses, and fevers. In
half of patients with seizures, no cause can yet be
found. See also 
epilepsy; seizure disorder.
seizure, absence
A seizure that takes the form
of a staring spell: The person suddenly seems to be
“absent.” There is a brief loss of awareness, which
can be accompanied by blinking or mouth twitch-
ing. Absence seizures have a very characteristic
appearance on an EEG. Also known as petit mal
seizure.
seizure, atonic
A seizure in which the person
suddenly loses muscle tone and cannot sit or stand
upright. Also known as drop attack and drop
seizure.
seizure, complex partial
A form of partial
seizure during which the person loses awareness.
The patient does not actually become unconscious,
and he or she may carry out actions as complex as
walking, talking, or driving. The patient may have
physical, sensory, and thought disturbances. When
the seizure ends, the patient has no memory of those
actions. See also 
seizure, partial; fugue state.