What is aphasia?

Aphasia is defined as impaired language ability.  It
ranges from forgetting names (nominal aphasia) to complete inability to speak, read or
write (global aphasia).

A neurologist and/or speech
pathologist should evaluate a patient with aphasia.  The commonest cause of aphasia is
brain damage from a stroke (cerebrovascular accident or CVA).  Strokes occur from
thrombosis (clotting) of vessels supplying blood to the brain, hemorrhage (bleeding)
from vessels within the brain, or clots originating elsewhere in the circulatory system
which then lodge in the vessels of the brain.

Aphasia
patients are given a thorough neurologic examination.  An MRI (Magnetic Resonance
Imaging) scan is used to detect areas of brain
injury.

Early neurologists Paul Broca and Carl Wernicke
described aphasia and identified areas of brain injury responsible for the condition. 
Some of their work has been superseded by modern imaging studies, and it is currently
felt that assigning specific brain injury sites to aphasia type is
difficult.

One useful classification of aphasia is as
follows:

1.  Receptive
Aphasia

a.  Word deafness (patient hears but does not
understand words)

b.  Alexia (patient reads but does not
understand words)

c.  Visual asymbolia (words are
disorganized and can not be recognized)

2.  Intermediate
Aphasia:  Nominal amnestic aphasia (patient can not remember
names)

3.  Expressive Aphasia, also called Broca’s aphasia
(patient has difficulty putting thoughts into words)