speech, also known as verbal apraxia or dyspraxia, is a speech
disorder in which a person has trouble saying what he or she wants
to say correctly and consistently. It is not due to weakness or
paralysis of the speech muscles (the muscles of the face, tongue,
and lips). The severity of apraxia of speech can range from mild
What are the
two main types of speech apraxia: acquired apraxia of speech and
developmental apraxia of speech. Acquired apraxia of speech can
affect a person at any age, although it most typically occurs
in adults. It is caused by damage to the parts of the brain that
are involved in speaking, and involves the loss or impairment
of existing speech abilities. The disorder may result from a stroke,
head injury, tumor, or other illness affecting the brain. Acquired
apraxia of speech may occur together with muscle weakness affecting
speech production or language difficulties caused by damage to
the nervous system.
apraxia of speech (DAS) occurs in children and is present from
birth. It appears to affect more boys than girls. This speech
disorder goes by several other names, including developmental
verbal apraxia, developmental verbal dyspraxia, articulatory apraxia,
and childhood apraxia of speech. DAS is different from what is
known as a developmental delay of speech, in which a child follows
the "typical" path of speech development but does so
more slowly than normal.
or causes of DAS are not yet known. Some scientists believe that
DAS is a disorder related to a child's overall language development.
Others believe it is a neurological disorder that affects the
brain's ability to send the proper signals to move the muscles
involved in speech. However, brain imaging and other studies have
not found evidence of specific brain lesions or differences in
brain structure in children with DAS. Children with DAS often
have family members who have a history of communication disorders
or learning disabilities. This observation and recent research
findings suggest that genetic factors may play a role in the disorder.
What Are the
either form of apraxia of speech may have a number of different
speech characteristics, or symptoms. One of the most notable symptoms
is difficulty putting sounds and syllables together in the correct
order to form words. Longer or more complex words are usually
harder to say than shorter or simpler words. People with apraxia
of speech also tend to make inconsistent mistakes when speaking.
For example, they may say a difficult word correctly but then
have trouble repeating it, or they may be able to say a particular
sound one day and have trouble with the same sound the next day.
People with apraxia of speech often appear to be groping for the
right sound or word, and may try saying a word several times before
they say it correctly. Another common characteristic of apraxia
of speech is the incorrect use of "prosody" -- that
is, the varying rhythms, stresses, and inflections of speech that
are used to help express meaning.
developmental apraxia of speech generally can understand language
much better than they are able to use language to express themselves.
Some children with the disorder may also have other problems.
These can include other speech problems, such as dysarthria; language
problems such as poor vocabulary, incorrect grammar, and difficulty
in clearly organizing spoken information; problems with reading,
writing, spelling, or math; coordination or "motor-skill"
problems; and chewing and swallowing difficulties.
of both acquired and developmental apraxia of speech varies from
person to person. Apraxia can be so mild that a person has trouble
with very few speech sounds or only has occasional problems pronouncing
words with many syllables. In the most severe cases, a person
may not be able to communicate effectively with speech, and may
need the help of alternative or additional communication methods.
on Deafness and Other Communication Disorders
National Institutes of Health