92 Chapter 5
Aphasia can also be caused by traumatic brain injuries, which can be open or closed. An open
traumatic brain injury occurs when a missile or projectile enters the brain. In a closed head injury,
a foreign object does not enter the brain but brain tissue is damaged. Patients with traumatic brain
injuries often have reduced awareness, memory loss, and disorientation in addition to neurogenic
communication disorders.
Diseases can cause aphasia, the most serious of which is cancer of the brain. A malignant brain
tumor occupies space, and as it grows, it destroys brain cells. Surgery, radiation treatment, and
chemotherapy are used to combat the cancer. Tumors may also be noncancerous (benign) but still
cause aphasia if they affect the major speech and language centers and the tracts leading to and
from them. Virtually any disease or disorder that can damage or destroy the speech and language
centers of the brain, and the tracts leading to and from them, can cause aphasia.
Aphasia and Motor Speech Disorders
Apraxia of speech is often a component of aphasia. There are two primary neurogenic com-
munication disorders: aphasia and motor speech disorders. They occur when the ability to com-
municate is eliminated or impaired due to damage to the brain and/or ner vous system. As noted
earlier, aphasia is a language disorder in which semantic pro cessing and grammar can be impaired
to varying degrees for both expression and reception. Semantics deals with words and their mean-
ings. The word, whether written, gestured, or spoken, is a symbol, an arbitrary repre sen ta tion of
real ity used for communication and thought. The referent is that to which the symbol refers. It can
be a tangible aspect of real ity, such as chair, or an abstract concept, such as truthfulness. Semantics
is the relationship between the symbol and its referent. Grammar is the rules by which spoken,
written, or gestured language is constructed and understood. It includes rules for combining
and sequencing sounds into words and transforming words into sentences and phrases. Aphasia
can disrupt or eliminate these previously learned aspects of language. Apraxia of speech and the
dysarthrias are the motor speech disorders. Motor refers to the physical aspects of generating and
transmitting a neurological impulse for muscle movement. Motor speech disorders are discussed
in Chapter 6.
Aphasia as a Multimodality Disorder
There are several ave nues, or modalities, of communication. The linguistic modalities are
speaking, listening, writing, and reading. Aphasia impairs all modalities of communication to
varying degrees. According to Davis (2000), in aphasia “the modalities are not impaired equally,
and there is a typical pattern of comparative deficit” (p. 2). The general pattern of aphasic
impairment is, from the least to most impaired modality, listening, reading, speaking, and writ-
ing. In aphasia, the inability to read is called alexia; dyslexia is a less severe form of the disorder.
Agraphia and dysgraphia are the inability or impaired ability, respectively, to express oneself
using written symbols.
Persons also use gestural communication, which has both expressive and receptive modes.
They can express themselves using hand, fin ger, and, to a lesser extent, general body and facial ges-
tures, and the receiver can comprehend them. Aphasia usually impairs the ability to use gestures to
express and understand complex thoughts, but basic gestures are preserved in even the most severe
aphasia. For example, even a patient with severe aphasia can turn away to express refusal and can
appreciate a pat on the back for a job well done. As noted earlier, aphasia also impairs mathematical
abilities; this is because mathe matics is also a language. The impairment is not limited to complex
pro cesses such as those of algebra and statistics. It also affects simple prob lems such as knowing
how much change to give, that 2 + 4 = 6, and how many quarters there are in $2. In aphasia, the
inability to do and understand simple arithmetic is called acalculia; dyscalculia is a less severe
form of the disorder.