Aphasia Health Article

Definition

Aphasia is an impairment of spoken language understanding and expression associated with brain damage.

Description

Neurologic etiologies that affect the left cerebral cortex can lead to aphasia (sometimes termed dysphasia). Aphasia is a language disturbance affecting the use of words and sentences; it is not simply difficulty with speech articulation. Aphasia is usually accompanied by difficulties with reading (dyslexia/alexia) and writing (dysgraphia/agraphia) and may also co-occur with speech articulation difficulties (apraxia of speech and dysarthria). Though more common in adults, aphasia can arise in children who incur brain damage or who fail to develop language abilities related to left hemisphere neurologic dysfunction, sometimes termed developmental dysphasia.

Causes and symptoms

Stroke leads to approximately 80,000 new cases of aphasia each year. Tumor, dementia, trauma, anoxic events (lack of oxygen), and infections affecting the left cerebral hemisphere also may lead to aphasia.

Approximately one million people in the United States live with aphasia.

The symptoms of aphasia vary depending upon the portion of the brain that is damaged. Fluency of verbal expression in aphasia refers to the ease with which individuals initiate and fill time with words, form grammatical and melodious sentences, and articulate speech sounds. Disruption of any one of these characteristics associated with damage anterior to the left Rolandic/central sulcus parts of the brain can lead to nonfluency. Comprehension of messages can be disrupted, especially with damage affecting the left superior temporal gyrus. Repetition of spoken messages can be impaired, particularly with damage surrounding the left Sylvian/lateral fissure. The patterns of preserved or impaired abilities in fluency, comprehension, and repetition lead to different syndromes of aphasia (for example, Broca's aphasia: nonfluent, impaired repetition, relatively spared comprehension;

Wernicke's aphasia: fluent, impaired repetition and comprehension). Anomia, or difficulty thinking of specific words (for example, knife), can occur across syndromes of aphasia. Instead, individuals may provide a description (it's for cutting), a paraphasia related by meaning (fork) or sound (night or nipe), a meaningless word or neologism (sparn), or no response.

Diagnosis

Following a clinical neurological examination, patients with aphasia are referred to speech-language pathologists or neuropsychologists trained in the administration of standardized language assessments to identify the patterns of aphasia. Most aphasia assessments include subtests to evaluate fluency, comprehension, repetition, and word retrieval (for example, Boston Diagnostic Aphasia Examination). Other tests allow assessment of specific symptoms of aphasia (for example, word retrieval: Boston Naming Test; reading: Reading Comprehension Battery for Aphasia). Assessment of aphasia, which occurs in acute through chronic stages of the disorder, takes one to three hours to complete. Trained professionals are reimbursed for assessment and treatment of aphasia at the rate consistent with Medicare allowances.

Treatment

Patients with aphasia participate in speech-language treatment to alleviate its consequences for communication. A number of studies have indicated the efficacy of behavioral treatments for aphasia. Some treatment methods use drills and practice with language activities to restore skills or to engage other neural regions to mediate language abilities. In other treatments, clinicians teach patients to compensate for the symptoms of aphasia using alternative modalities to communicate including writing, gesture, musical abilities, pointing boards, or speech-generation devices. Speech-language pathologists also provide consultation to patients and family members on strategies to improve communication. Pharmacologic treatments for aphasia (for example, bromocriptine, amphetamines) primarily are experimental in nature and are not used in standard clinical practice.

Prognosis

The prognosis for recovery of aphasia relates to a number of medical, neurological, behavioral, and psychosocial factors. Positive indicators include acute neurologic conditions (for example, stroke) over degenerative conditions, hemorrhagic over ischemic stroke, unilateral left hemisphere lesion sparing subcortical white matter, onset within the past six to 12 months, and mild form of aphasia at onset. Psychosocial factors such as age, gender, intelligence, emotional state, and family support may also contribute to recovery to a lesser degree. The majority of individuals demonstrate some language recovery; fewer completely regain their previous language levels.

Health care team roles

Nursing and medical staff providing medical care for individuals with aphasia implement strategies recommended by speech-language pathologists to foster communication with patients. Nursing staff monitors changes in patient communication status, often noting the need for referral to speech-language pathology services. In performing their unique roles to assist neurological recovery, the rehabilitation team (for example, physical therapist, occupational therapist, psychiatrist, social worker), implement strategies to maximize communication skills.

Prevention

Avoiding the neurologic event that causes aphasia is the only way to prevent its occurrence. For example, since strokes are a leading cause of aphasia, reducing the chances of having a stroke by not smoking cigarettes also reduces the chances of developing aphasia.