Aphasia

Definition

Aphasia is condition characterized by either partial or total loss of the ability to communicate verbally or using written words. A person with aphasia may have difficulty speaking, reading, writing, recognizing the names of objects, or understanding what other people have said. Aphasia is caused by a brain injury, as may occur during a traumatic accident or when the brain is deprived of oxygen during a stroke. It may also be caused by a brain tumor, a disease such as Alzheimer's, or an infection, like encephalitis. Aphasia may be temporary or permanent. Aphasia does not include speech impediments caused by loss of muscle control.

Description

To understand and use language effectively, an individual draws upon word memory-stored information on what certain words mean, how to put them together, and how and when to use them properly. For a majority of people, these and other language functions are located in the left side (hemisphere) of the brain. Damage to this side of the brain is most commonly linked to the development of aphasia. Interestingly, however, left-handed people appear to have language areas in both the left and right hemispheres of the brain and, as a result, may develop aphasia from damage to either side of the brain.

Stroke is the most common cause of aphasia in the United States. Approximately 500,000 individuals suffer strokes each year, and 20% of these individuals develop some type of aphasia. Other causes of brain damage include head injuries, brain tumors, and infection. About half of the people who show signs of aphasia have what is called temporary or transient aphasia and recover completely within a few days. An estimated one million Americans suffer from some form of permanent aphasia. As yet, no connection between aphasia and age, gender, or race has been found.

Aphasia is sometimes confused with other conditions that affect speech, such as dysarthria and apraxia. These condition affect the muscles used in speaking rather than language function itself. Dysarthria is a speech disturbance caused by lack of control over the muscles used in speaking, perhaps due to nerve damage. Speech apraxia is a speech disturbance in which language comprehension and muscle control are retained, but the memory of how to use the muscles to form words is not.

Causes and symptoms

Aphasia can develop after an individual sustains a brain injury from a stroke, head trauma, tumor, or infection, such as herpes encephalitis. As a result of this injury, the pathways for language comprehension or production are disrupted or destroyed. For most people, this means damage to the left hemisphere of the brain. (In 95 to 99% of right-handed people, language centers are in the left hemisphere, and up to 70% of left-handed people also have left-hemisphere language dominance.) According to the traditional classification scheme, each form of aphasia is caused by damage to a different part of the left hemisphere of the brain. This damage affects one or more of the basic language functions: speech, naming (the ability to identify an object, color, or other item with an appropriate word or term), repetition (the ability to repeat words, phrases, and sentences), hearing comprehension (the ability to understand spoken language), reading (the ability to understand written words and their meaning), and writing (the ability to communicate and record events with text).

KEY TERMS

Anomic aphasia— A condition characterized by either partial or total loss of the ability to recall the names of persons or things as a result of a stroke, head injury, brain tumor, or infection.

Broca's aphasia— A condition characterized by either partial or total loss of the ability to express oneself, either through speech or writing. Hearing comprehension is not affected. This condition may result from a stroke, head injury, brain tumor, or infection.

Computed tomography (CT)— An imaging technique that uses cross-sectional x rays of the body to create a three-dimensional image of the body's internal structures.

Conduction aphasia— A condition characterized by the inability to repeat words, sentences, or phrases as a result of a stroke, head injury, brain tumor, or infection.

Frontal lobe— The largest, most forward-facing part of each side or hemisphere of the brain.

Global aphasia— A condition characterized by either partial or total loss of the ability to communicate verbally or using written words as a result of widespread injury to the language areas of the brain. This condition may be caused by a stroke, head injury, brain tumor, or infection. The exact language abilities affected vary depending on the location and extent of injury.

Hemisphere— One of the two halves or sides-the left and the right-of the brain.

Magnetic resonance imaging (MRI)— An imaging technique that uses a large circular magnet and radio waves to generate signals from atoms in the body. These signals are used to construct images of internal structures.

Subcortical aphasia— A condition characterized by either partial or total loss of the ability to communicate verbally or using written words as a result of damage to non language-dominated areas of the brain. This condition may be caused by a stroke, head injury, brain tumor, or infection.

Temporal lobe— The part of each side or hemisphere of the brain that is on the side of the head, nearest the ears.

Transcortical aphasia— A condition characterized by either partial or total loss of the ability to communicate verbally or using written words that does not affect an individual's ability to repeat words, phrases, and sentences.

Wernicke's aphasia— A condition characterized by either partial or total loss of the ability to understand what is being said or read. The individual maintains the ability to speak, but speech may contain unnecessary or made-up words.

The traditional classification scheme includes eight types of aphasia:

• Broca's aphasia, also called motor aphasia, results from damage to the front portion or frontal lobe of the language-dominant area of the brain. Individuals with Broca's aphasia may be completely unable to use speech (mutism ) or may be able to use single-word statements or even full sentences, though these sentences may require a great deal of effort to construct. Small words, such as conjunctions (and, or, but) and articles (the, an, a), may be omitted, leading to a "telegraph" quality in their speech. Hearing comprehension is usually not affected, so they are able to understand other people's speech and conversation and can follow commands. Often, they may experience weakness on the right side of their bodies, which can make it difficult to write. Reading ability is impaired, and they may have difficulty finding the right word when speaking. Individuals with Broca's aphasia may become frustrated and depressed because they are aware of their language difficulties.
• Wernicke's aphasia is caused by damage to the side portion or temporal lobe of the language-dominant area of the brain. Individuals with Wernicke's aphasia speak in long, uninterrupted sentences; however, the words used are frequently unnecessary or even made-up. They have a great deal of difficulty understanding other people's speech, sometimes to the point of being unable to understand spoken language at all. Reading ability is diminished, and although writing ability is retained, what is written may be abnormal. No physical symptoms, such as the right-sided weakness seen with Broca's aphasia, are typically observed. Also, in contrast to Broca's aphasia, individuals with Wernicke's aphasia are not aware of their language errors.
• Global aphasia is caused by widespread damage to the language areas of the left hemisphere. As a result, all basic language functions are affected, but some areas may be more affected than others. For example, an individual may have difficulty speaking but may be able to write well. The individual may experience weakness and loss of feeling on the right side of their body.
• Conduction aphasia, also called associative aphasia, is rather uncommon. Individuals with conduction aphasia are unable to repeat words, sentences, and phrases. Speech is fairly unbroken, although individuals may frequently correct themselves and words may be skipped or repeated. Although able to understand spoken language, it may also be difficult for the individual with conduction aphasia to find the right word to describe a person or object. The impact of this condition on reading and writing ability varies. As with other types of aphasia, right-sided weakness or sensory loss may be present.
• Anomic or nominal aphasia primarily influences an individual's ability to find the right name for a person or object. As a result, an object may be described rather than named. Hearing comprehension, repetition, reading, and writing are not affected, other than by this inability to find the right name. Speech is fluent, except for pauses as the individual tries to recall the right name. Physical symptoms are variable, and some individuals have no symptoms of one-sided weakness or sensory loss.
• Transcortical aphasia is caused by damage to the language areas of the left hemisphere outside the primary language areas. There are three types of aphasia: transcortical motor aphasia, transcortical sensory aphasia, and mixed transcortical aphasia. All of the transcortical aphasias are distinguished from other types by the individual's ability to repeat words, phrases, or sentences. Other language functions may also be impaired to varying degrees, depending on the extent and particular location of brain damage.

As researchers continue to learn more about the brain's structure and function, new types of aphasia are being recognized. One newly recognized type of aphasia, subcortical aphasia, mimics the symptoms of other traditional types of aphasia but involves language disorders that are not typical. This type of aphasia is associated with injuries to areas of the brain typically not identified with language and language processing.

Diagnosis

Following brain injury, an initial bedside assessment is made to determine whether language function has been affected. If the individual experiences difficulty communicating, attempts are made to determine whether this difficulty arises from impaired language comprehension or an impaired ability to speak. A typical examination involves listening to spontaneous speech and evaluating the individual's ability to recognize and name objects, comprehend what is heard, and repeat sample words and phrases. The individual may also be asked to read text aloud and explain what the passage means. In addition, writing ability is evaluated by having the individual copy text, transcribe dictated text, and write something without prompting.

A speech pathologist or neuropsychologist may be asked to conduct more extensive examinations using in-depth, standardized tests. Commonly used tests include the Boston Diagnostic Aphasia Examination, the Western Aphasia Battery, and possibly, the Porch Index of Speech Ability.

The results of these tests indicate the severity of the aphasia and may also provide information regarding the exact location of the brain damage. This more extensive testing is also designed to provide the information necessary to design an individualized speech therapy program. Further information about the location of the damage is gained through the use of imaging technology, such as magnetic resonance imaging (MRI) and computed tomography scans (CT).

Treatment

Initially, the underlying cause of aphasia must be treated or stabilized. To regain language function, therapy must begin as soon as possible following the injury. Although there are no medical or surgical procedures currently available to treat this condition, aphasia resulting from stroke or head injury may improve through the use of speech therapy. For most individuals, however, the primary emphasis is placed on making the most of retained language abilities and learning to use other means of communication to compensate for lost language abilities.

Speech therapy is tailored to meet individual needs, but activities and tools that are frequently used include the following:

• Exercise and practice. Weakened muscles are exercised by repetitively speaking certain words or making facial expressions, such as smiling.
• Picture cards. Pictures of everyday objects are used to improve word recall and increase vocabulary. The names of the objects may also be repetitively spoken aloud as part of an exercise and practice routine.
• Picture boards. Pictures of everyday objects and activities are placed together, and the individual points to certain pictures to convey ideas and communicate with others.
• Workbooks. Reading and writing exercises are used to sharpen word recall and regain reading and writing abilities. Hearing comprehension is also redeveloped using these exercises.
• Computers. Computer software can be used to improve speech, reading, recall, and hearing comprehension by, for example, displaying pictures and having the individual find the right word.

Prognosis

The degree to which an individual can recover language abilities is highly dependent on how much brain damage occurred and the location and cause of the original brain injury. Other factors include the individual's age, general health, motivation and willingness to participate in speech therapy, and whether the individual is left or right handed. Language areas may be located in both the left and right hemispheres in left-handed individuals. Left-handed individuals are, therefore, more likely to develop aphasia following brain injury, but because they have two language centers, may recover more fully because language abilities can be recovered from either side of the brain. The intensity of therapy and the time between diagnosis and the start of therapy may also affect the eventual outcome.

Prevention

Because there is no way of knowing when a stroke, traumatic head injury, or disease will occur, very little can be done to prevent aphasia. The extent of recovery, however, in some cases, can be affected by an individual's willingness to cooperate and participate in speech therapy directly following the injury.

Resources

BOOKS

Lyon, Jon G., and Marianne B. Simpson. Coping with Aphasia. San Diego: Singular Publishing Group, 1998.

ORGANIZATIONS

National Aphasia Association. 156 5th Ave., Suite 707, New York, NY 10010. (800) 922-4622. 〈http://www.aphasia.org〉.

Aphasia

A condition, caused by neurological damage or disease, in which a person's previous capacity to understand or express language is impaired. The ability to speak, listen, read, or write may be affected depending on the type of aphasia involved.

In contrast to neurological problems that affect the physical ability to speak or perform other linguistic functions, aphasia involves the mental ability to manipulate speech sounds, vocabulary, grammar, and meaning. There are several different types of aphasia. Each has different symptoms and is caused by damage to a different part of the brain .

The great majority of aphasias are caused by damage to the left hemisphere of the brain, which is the dominant

language hemisphere for approximately 95 percent of right-handed people and 60 to 70 percent of left-handed people. Two areas in the left hemisphere—Broca's area and Wernicke's area—and the pathways connecting them are especially important to linguistic ability, and damage to these areas is the most common cause of aphasia. Broca's area, located in the frontal lobe of the left hemisphere, is named for the 19th-century French physician Paul Broca (1824-1880), an early pioneer in the study of lateralization (the specialized functioning of the right and left sides of the brain). Aphasia resulting from damage to this area, called Broca's aphasia, is characterized by slow, labored, "telegraphic" speech, from which common grammatical function words, such as prepositions and articles, are missing ("I went doctor"). In general, however, comprehension of spoken and written language is relatively unaffected.

Wernicke's area, in the upper rear part of the left temporal lobe, is named for Carl Wernicke (1848-1905), who first described it in 1874. Aphasia associated with this area—called Wernicke's aphasia—differs dramatically from Broca's aphasia. While speech in Broca's aphasia is overly concise, in Wernicke's aphasia it is filled with an abundance of words (logorrhea), but they are words which fail to convey the speaker's meaning. Even though their pitch and rhythm sound normal, many of the words are used incorrectly or are made-up words with no meaning (aphasic jargon). Besides their speech difficulties, persons with Wernicke's aphasia also have trouble comprehending language, repeating speech, naming objects, reading, and writing. An interesting exception to their comprehension impairment is their ability to respond readily to direct commands that involve bodily movement, such as "Close your eyes."

Certain types of aphasia—called disconnection aphasias—are caused by damage to the connections of Broca's or Wernicke's areas to each other or to other parts of the brain. Conduction aphasia results from damage to the fiber bundles connecting the two language areas and is characterized by fluent but somewhat meaningless speech and an inability to repeat phrases correctly. In transcortical sensory aphasia, the connections between Wernicke's area and the rest of the brain are severed, but the area itself is left intact. Persons with this condition have trouble understanding language and expressing their thoughts but can repeat speech without any trouble. Another type of aphasia, word deafness, occurs when auditory information is prevented from reaching Wernicke's area. Persons affected by word deafness can hear sounds of all kinds and understand written language, but spoken language is incomprehensible to them, since the auditory signals cannot reach the part of the brain that decodes them.

Most types of aphasia are accompanied by some difficulty in naming objects. However, when this problem is the only symptom, the condition is called anomic aphasia. Persons with anomic aphasia can comprehend and repeat the speech of others and express themselves fairly well, although they are unable to find some of the words they need. However, they do poorly when asked to name specific objects. Anomic aphasia is caused by left hemisphere damage that does not affect either Broca's or Wernicke's area. It commonly occurs after a head injury and also in Alzheimer's disease . Global aphasia is caused by widespread damage to the dominant cerebral hemisphere, either left or right. This condition is characterized by an almost total loss of all types of verbal ability—speech, comprehension, reading, and writing.

It is possible for people suffering from aphasia following a stroke or head injury to recover some of their language abilities with the aid of a speech therapist. However, there is little chance of recovery from severe cases of aphasia.

See also Left-brain hemisphere; Right-brain hemisphere

Further Reading

Browning, Elizabeth. I Can't See What You're Saying. New York: Coward, McCann & Geoghegan, 1973.

Hughes, Kathy. God Isn't Finished With Me Yet. Nashville: Winston-Derek, 1990.

Howard, David. Aphasia Therapy: Historical and Contemporary Issues. Hillsdale, NJ: Erlbaum, 1987.

APHASIA

Aphasia, a word proposed by Armand Trousseau to replace the term "aphemia," created by Paul Broca, refers to language disturbances that arise from specific cerebral lesions, most often in the cortex. Between 1861 and 1865, when the dispute ended concerning the question of determining whether the cerebral cortex operated as a unit or as a collection of separate elements, Paul Broca showed, through a series of anatomical and clinical observations, that the destruction of the left side of the base of the third circumvolution of the frontal lobe in a right-handed subject who until then was able to speak normally led to the loss of articulate language. The subject was unable to express himself using a sequence of words or phrases.

In 1874 Carl Wernicke extended the field of research by describing two other types of aphasia, all caused by a lesion in the left hemisphere: sensory aphasia from damage to the posterior areas of the second and third circumvolution of the cortex, and conduction aphasia, arising from the disconnection of the bundles connecting this region to the base of the third circumvolution of the frontal lobe. Afterwards, the disturbance identified by Broca would be known as "motor aphasia." Later Wernicke identified two other types of aphasia: "motor transcortical aphasia" and "sensory transcortical aphasia."

By the end of the nineteenth century, three separate approaches to the problem had been developed. Some researchers, such as Jean Martin Charcot and Joseph Grasset, increased the number of types of aphasia; others, like Alfred Vulpian, and later Pierre Marie, renewed the "unitarian" position; the third group, following the important work by Jules Déjerine, demonstrated through the use of clinical and anatomical arguments that the nature of the aphasia would change with the nature and location of the lesion. For example, frontal lesions seemed to primarily affect speech production, posterior lesions seemed to affect speech recognition, and the destruction of the cortex resulted in disturbances of internal language, which affected the subject's autonomy.

Sigmund Freud's work on aphasia, published in 1891, accepts the work of Paul Broca but questions Wernicke's research, which Freud criticizes for being excessively schematic and lacking in clinical observations. Freud did not question the relationship of language function with the brain but was cautious about hastily assigning specific locations to specific functions. Although he accepts that certain clinically based forms of aphasia—"verbal aphasia," "asymbolic aphasia," "agnosic aphasia"—can be used to localize the cortical lesion with certainty (which was later confirmed by neurosurgery during the First World War), he refused to extrapolate from pathology to physiology and deduced a cerebral concept of the normal operation of language, with a critical position that was far removed from the scientism that is often attributed to him in this field. In the descriptive sections of his work, Freud distinguished between the representation of words and the representation of things, and their links with auditory images, visual images, and the motor images at work in these phenomena.

Georges LantÉri-Laura

See also: Brain and psychoanalysis, the; Language and disturbances of language; memory; Thing-presentation; Word-presentation.

Bibliography

Freud, Sigmund. (1891b [1953]), On aphasia (A critical study) (E. Stengel, Trans.). New York: International Universities Press.

Hécaen, H. and Lantéri-Laura, Georges. (1977).Évolution des connaissances et des doctrines sur les localisations cérébrales. Paris: Desclée de Brouwer.

——. (1989). Les fonctions du cerveau. Paris: Masson.

Lantéri-Laura, Geoerges. (1993). Histoire de la phrénologie. Paris: Presses Universitaires de France.

Further Reading

Miller, Laurence (1991). On aphasia at 100: the neuropsychodynamic legacy of Freud. Psychoanalytic Review, 78, 365-378.

Rizzuto, Anna-Marie. (1990). Origin of Freud's concept of object representation: "On Aphasia." International Journal of Psychoanalysis, 71, 241-248.

aphasia , language disturbance caused by a lesion of the brain, making an individual partially or totally impaired in his ability to speak, write, or comprehend the meaning of spoken or written words. It is distinguished from functional disorders such as stammering or stuttering, and from impaired speech due to physical defects in the organs used for speaking. Treatment consists of reeducation; the oral and lip-reading methods employed in the education of deaf and mute children have been found to be of assistance in therapy.

aphasia (dysphasia) (ă-fay-ziă) n. a disorder of language affecting the generation and content of speech and its understanding. It is caused by damage to the language-dominant half of the brain, usually the left hemisphere in a right-handed person. expressive a. difficulty in producing language. receptive a. difficulty with comprehension of the spoken word.
—aphasic adj.

a·pha·sia / əˈfāzhə/ • n. Med. loss of ability to understand or express speech, caused by brain damage.Compare with aphonia. DERIVATIVES: a·pha·sic / -zik/ adj. & n.

aphasia Group of disorders of language arising from disease of or damage to the brain. In aphasia, a person has problems formulating or comprehending speech and difficulty in reading and writing. See also brain disorders

aphasia (med.) loss of speech. XIX. — modL. — Gr. aphasíā, f. A-4 + phánai speak; see -IA1.

aphasia •astrantia • Bastia •Dei gratia, hamartia •poinsettia •in absentia, Parmentier •Izvestia •meteor, wheatear •Whittier • cottier • Ostia •consortia, courtier •protea • Yakutia • frontier • Althea •Anthea • Parthia •Pythia, stichomythia •Carinthia, Cynthia •forsythia • Scythia • clothier • salvia •Latvia • Yugoslavia • envier •Flavia, Moldavia, Moravia, Octavia, paviour (US pavior), Scandinavia, Xavier •Bolivia, Livia, Olivia, trivia •Sylvia • Guinevere • Elzevir •Monrovia, Segovia •Retrovir • effluvia • colloquia •Goodyear • yesteryear • brassiere •Abkhazia •Anastasia, aphasia, brazier, dysphasia, dysplasia, euthanasia, fantasia, Frazier, glazier, grazier, gymnasia, Malaysia •amnesia, anaesthesia (US anesthesia), analgesia, freesia, Indonesia, Silesia, synaesthesia •artemisia, Kirghizia, Tunisia •ambrosia, crozier, hosier, osier, symposia