Dictionary
inability to use or understand language (spoken or written) because of a brain lesion
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Wikipedia
Aphasia fn 1 (from Greek languageGreek privative α and !φασι&sigm af;,? speech) is a term which means literally inability to speak, and is used to denote various defects in the comprehension and expression of both spoken and written language which result from brain damagelesions of the brain. Aphasic disorders may be classed in two groups:--first, receptive or sensory aphasia, which comprises (''a'') inability to understand spoken language (auditory aphasia), and (''b'') inability to read (visual aphasia, or ''alexia''); second, emissive or motor aphasia, under which category are included (''a'') inability to speak (motor vocal aphasia, or ''aphemia''}, and (''b'') inability to write (motor graphic aphasia, or ''agraphia''). It has been shown that each of these defects is produced by destruction of a special region of the cortex of the brain. These regions, which are termed the speech centres, are, in right-handed people, situated in the left hemisphereleft cerebral hemisphere; this is the reason why aphasia is so commonly associated with paralysis of the right side of the body. A study of the acquisition of the faculty of speech throws light upon the education of the speech centres, and helps to elucidate their physiological interaction and the phenomena of aphasia. The auditory speech centre is the first to show signs of functional activity, for within a few months of birth the child begins to ''understand'' spoken language. Some months later the motor vocal speech centre begins to functionate. The memories of the auditory word images which are stored in the auditory speech centre play an important part in the process of learning to speak. The child born deaf grows up mute. The visual speech centre comes into activity when the child is taught to read. Again, when he learns to write and thus begins to educate his graphic centre, he is constantly calling upon his visual speech centre for the visual images of the words he wishes to produce. There is an intimate association between the auditory speech centre and the motor vocal speech centre, also between the visual speech centre and the graphic centre.
Auditory aphasia - The auditory speech centre is situated in the posterior part of the first and second temporo-sphenoidal convolutions on the left side of the brain. Destruction of this centre causes "auditory aphasia." Hearing is unimpaired but spoken language is quite unintelligible. The subject of auditory aphasia may be compared to an individual who is listening to a foreign language of which he does not understand a word. Word deafness, a term often used as synonymous with auditory aphasia, is misleading and should be abandoned. Auditory aphasia commonly interferes with vocal expression, for the majority of people when they speak do so by recalling the auditory memories of words stored up in the auditory speech centre. ''Amnesia verbalis'' is employed to designate failure to call up in the memory the images of words which are needed for purposes of vocal expression or silent thought.
Visual aphasia or Alexia - The visual speech centre, which is located in the left angular gyrus, is connected with the two centres for vision which are situated one in either occipital lobe. Destruction of the visual speech centre produces visual aphasia or alexia. Word blindness, sometimes used as the equivalent of visual aphasia, is, like word deafness, a misleading term. The individual is not blind, he sees the words and letters perfectly, but they appear to him as unintelligible cyphers. When the visual speech centre is destroyed, the memories of the visual images of words are obliterated and interference with writing, a consequence of ''amnesia verbalis'', results. On the other hand, when the lesion is situated deeply in the occipital lobe, and does not implicate the cortex, but merely cuts off the connexions of the angular gyrus with both visual centres, agraphia is not produced, for the visual word centre and its connexion with the graphic centre are still intact (pure, or sub-cortical word blindness).
Motor vocal aphasia or Aphemia - The centre for motor vocal speech is situated in the posterior part of the third left frontal convolution and extends on to the foot of the left ascending frontal convolution (Broca's convolution). Complete destruction of this region produces loss of speech, although it often happens that a few words, such as "yes" and "no," and, it may be, emotional exclamations such as "Oh! dear!" and the like are retained. The utterance of unintelligible sounds is still possible, however, and there is neither defective voice production (''aphonia'') nor paralysis of the mechanism of articulation. The individual can recall the auditory and visual images of the words which he wishes to use, but his memory for the complicated, co-ordinated movements which he acquired in the process of learning to speak, and which are necessary for vocal expression, has been blotted out. In the great majority of cases of motor vocal aphasia there is associated agraphia, a circumstance which is perhaps to be accounted for by the proximity of the graphic centre. When the lesion is situated below the cortex of Broca's convolution but destroys the fibres which pass from it towards the internal capsule, agraphia is not produced (sub-cortical or pure motor vocal aphasia). Destruction of the auditory speech centre is, as we have seen, commonly accompanied by more or less interference with vocal speech, a consequence of ''amnesia verbalis''.
Agraphia - Debate still rages as to the presence of a special writing centre. Those who favour the separate existence of a graphic centre locate it in the second left frontal convolution. It may be that the want of unanimity as to the graphic centre is to be explained by an anatomical relationship so close between the graphic centre and that for the fine movement of the hand that a lesion in this situation which produces agraphia must at the same time cause a paralysis of the hand. Destruction of the visual speech centre by obliterating the visual memories of words (''amnesia verbalis'') produces agraphia. Further, several instances are on record in which agraphia has followed destruction of the commissure between the visual speech centre and the graphic centre. As already mentioned, agraphia is very often associated with motor vocal aphasia. A number of aphasic defects are met with in addition to those already mentioned. Thus ''paraphasia'' is a condition in which the patient makes use of words other than those he intends. He may mix up his words so that his conversation is quite unintelligible. In the most pronounced forms he gabbles away, employing unrecognizable sounds in place of words (''jargon and gibberish aphasia''). ''Paragraphia'' is a similar defect which occurs in writing. Both paraphasia and paragraphia may be produced by partial lesions of the sensory speech centres or of the commissures which connect these with the motor centres. ''Object blindness'' (syn. mind-blindness) refers to an inability to recognize an object or its uses by the aid of sight alone. The probable explanation would seem to be that the ordinary centre for vision has been isolated from the other sensory centres with which it is connected. Not uncommonly there is associated visual aphasia. ''Optic aphasia'' was introduced to designate a somewhat similar state in which, although the uses of an object are recognized, the patient cannot name it at sight, yet, if it is of such a nature that it appeals directly to one of the other senses, he may at once be able to name it. ''Tactile aphasia'' is a rare defect in which there exists an inability to recognize an object by touch alone although the qualities which, under normal circumstances, suffice for its detection can be accurately described. ''Amusia'', or loss of the musical faculty, may occur in association with or independent of aphasia. It may be that special receptive and emissive centres exist for the musical sense exactly analogous to those for speech. The speech centres are all supplied by the left middle cerebral artery. When this artery is blocked close to its origin by an ''embolus'' or ''thrombus'', total aphasia results. It may be, however, that only one of the smaller branches of the artery is obstructed, and, according to the region of the brain to which this branch is distributed, one or more of the speech centres may be destroyed. Occlusion of the left posterior cerebral artery causes extensive softening of the occipital lobe and produces pure word blindness. Further, a tumour, abscess, haemorrhage or meningitis may be so situated as to damage or destroy the individual speech centres or their connecting commissures. The amount of recovery to be expected in any given case depends upon the nature, situation and extent of the lesion, and upon the age of the patient. Even after complete destruction of the speech centres, perfect recovery may take place, for the centres in the right hemisphere of the brain are capable of education. This is only possible in young individuals. In the great majority of instances the nature of the lesion is such as to render futile all treatment directed towards its removal. In suitable cases, however, the education of the right side of the brain may be very greatly assisted by an intelligent application of scientific methods. Aphasia is usually a result of damage to the language centres of the brain (like Broca's area). These areas are always located in the left hemisphere and in most people this is where the ability to produce and comprehend language is found. However in a very small number of people language ability is found in the right hemisphere. Damage to these language areas can be caused by a stroke or physical injury. Depending on the area and extent of the damage, someone may be able to speak but not write, or vice versa, or understand more complex sentences than he can produce. The brains of young children with brain damage sometimes restructure themselves to use different areas for speech processing, and regain lost function; adult brains are less "plastic" and lack this ability.Aphasia can be assessed in a variety of ways, from quick clinical screening at the bedside to several-hour-long batteries of tasks that examine the key components of language and communication.Aphasia is a language disorder that results from damage to portions of the brain that are responsible for language. For most people, these are parts of the left side (hemisphere) of the brain. Aphasia usually occurs suddenly, often as the result of a stroke or traumatic brain injury or other head injury, but it may also develop slowly, as in the case of a brain tumor. The disorder impairs both the expression and understanding of language as well as reading and writing. Aphasia may co-occur with speech disorders such as dysarthria or apraxia of speech, which also result from brain damage.
Who has aphasia? - Anyone can acquire aphasia, but most people who have aphasia are in their middle to late years. Men and women are equally affected. It is estimated that approximately 80,000 individuals in the United States acquire aphasia each year. About one million persons in the United States currently have aphasia.
What causes aphasia? - Aphasia is caused by damage to one or more of the language areas of the brain. Many times, the cause of the brain injury is a stroke. A stroke occurs when, for some reason, blood is unable to reach a part of the brain. Brain cells die when they do not receive their normal supply of blood, which carries oxygen and important nutrients. Other causes of brain injury are severe blows to the head, brain tumors, brain infections, and other conditions of the brain.Individuals with Broca's aphasia have damage to the frontal lobe of the brain. These individuals frequently speak in short, meaningful phrases that are produced with great effort. Broca's aphasia is thus characterized as a nonfluent aphasia. Affected people often omit small words such as "is," "and," and "the." For example, a person with Broca's aphasia may say, "Walk dog" meaning, "I will take the dog for a walk." The same sentence could also mean "You take the dog for a walk," or "The dog walked out of the yard," depending on the circumstances. Individuals with Broca's aphasia are able to understand the speech of others to varying degrees. Because of this, they are often aware of their difficulties and can become easily frustrated by their speaking problems. Individuals with Broca's aphasia often have right-sided weakness or paralysis of the arm and leg because the frontal lobe is also important for body movement.In contrast to Broca's aphasia, damage to the temporal lobe may result in a fluent aphasia that is called Wernicke's aphasia. Individuals with Wernicke's aphasia may speak in long sentences that have no meaning, add unnecessary words, and even create new "words." For example, someone with Wernicke's aphasia may say, "You know that smoodle pinkered and that I want to get him round and take care of him like you want before," meaning "The dog needs to go out so I will take him for a walk." Individuals with Wernicke's aphasia usually have great difficulty understanding speech and are therefore often unaware of their mistakes. These individuals usually have no body weakness because their brain injury is not near the parts of the brain that control movement.A third type of aphasia, global aphasia, results from damage to extensive portions of the language areas of the brain. Individuals with global aphasia have severe communication difficulties and may be extremely limited in their ability to speak or comprehend language.
How is aphasia diagnosed? - Aphasia is usually first recognized by the physician who treats the individual for his or her brain injury. Usually this is a neurologist or a neuropsychologist. The physician typically performs tests that require the individual to follow commands, answer questions, name objects, and converse. If the physician suspects aphasia, the individual is often referred to a speech-language pathologist, who performs a comprehensive examination of the person's ability to understand, speak, read, and write.
How is aphasia treated? - In some instances an individual will completely recover from aphasia without treatment. This type of "spontaneous recovery" usually occurs following a transient ischemic attack (TIA), a kind of stroke in which the blood flow to the brain is temporarily interrupted but quickly restored. In these circumstances, language abilities may return in a few hours or a few days. For most cases of aphasia, however, language recovery is not as quick or as complete. While many individuals with aphasia also experience a period of partial spontaneous recovery (in which some language abilities return over a period of a few days to a month after the brain injury), some amount of aphasia typically remains. In these instances, speech-language therapy is often helpful. Recovery usually continues over a 2-year period. Most people believe that the most effective treatment begins early in the recovery process. Some of the factors that influence the amount of improvement include the cause of the brain damage, the area of the brain that was damaged, the extent of the brain injury, and the age and health of the individual. Additional factors include motivation, handedness, and educational level.Aphasia therapy strives to improve an individual's ability to communicate by helping the person to use remaining abilities, to restore language abilities as much as possible, to compensate for language problems, and to learn other methods of communicating. Treatment may be offered in individual or group settings. Individual therapy focuses on the specific needs of the person. Group therapy offers the opportunity to use new communication skills in a comfortable setting. Stroke clubs, which are regional support groups formed by individuals who have had a stroke, are available in most major cities. These clubs also offer the opportunity for individuals with aphasia to try new communication skills. In addition, stroke clubs can help the individual and his or her family adjust to the life changes that accompany stroke and aphasia. Family involvement is often a crucial component of aphasia treatment so that family members can learn the best way to communicate with their loved one.
What research is being done for aphasia? - Aphasia research is exploring new ways to evaluate and treat aphasia as well as to further understanding of the function of the brain. Brain imaging techniques are helping to define brain function, determine the severity of brain damage, and predict the severity of the aphasia. These procedures include PET (positron emission tomography), CT (computed tomography), and MRI (magnetic resonance imaging) as well as the new functional magnetic resonance imaging (fMRI), which identifies areas of the brain that are used during activities such as speaking or listening. In-depth testing of the language ability of individuals with the various aphasic syndromes is helping to design effective treatment strategies. The use of computers in aphasia treatment is being studied. Promising new drugs administered shortly after some types of stroke are being investigated as ways to reduce the severity of aphasia.
Types of aphasia - Any of the following can be considered aphasia: inability to comprehend speech inability to read (alexia (disorder)alexia) inability to write (agraphia) inability to speak, without muscle paralysis inability to form words inability to name objects (anomia) poor enunciation excessive creation and use of personal neologisms (jargon aphasia) inability to repeat a phrase persistent repetition of phrases other language impairmentThe common types of aphasia are Broca's aphasia (expressive aphasia)Wernicke's aphasia (receptive aphasia)Nominal aphasia (anomic aphasia)Global aphasiaConduction aphasiaA few less common varieties includeSign language aphasiaTranscortical motor aphasiaSubcortical motor aphasiaTranscortical sensory aphasiaSubcortical sensory aphasiaMixed transcortical aphasiaAcquired eleptiform aphasia (Landau Kleffner Syndrome)
References - Broca, ''Bulletin de la Société anatomique'' (1861) Wernicke, ''Der Aphasische Symptomen-complex'' (Breslau, 1874) Kussmaul, ''Ziemssen's Cyclopaedia'', vol. xiv. p. 759 Wyllie, ''The Disorders of Speech'' (1895) Elder, ''Aphasia and the Cerebral Speech Mechanism'' (1897) Collins, ''The Faculty of Speech'' (1897) Bastian, ''Aphasia and other Speech Defects'' (1898) Byrom Bramwell, "Will-making and Aphasia," ''British Medical Journal'' (1897) "The Morison Lectures on Aphasia," ''The Lancet'' (1906) 1911 Luria, A. R. Title=Traumatic Aphasia: Its Syndromes, Psychology, and Treatment Publisher=Mouton de Gruyter Year=1970 ID=ISBN 90-279-0717-X See also the works of Charcot, Hughlings Jackson, Dejerine, Lichtheim, Pitres, Grasset, Ross, Broadbent, Mills, Bateman, Mirallié, Exner, Marie and others.
Footnotes - fnb1 In 1906 Pierre Marie of Paris expressed views (''La Semaine medicale'', May 23 and October 17, and elsewhere) upon the question of aphasia which have given rise to much animated controversy, since they are in many respects at complete variance with the classical conception which has been represented in the present article. Marie holds that Broca's convolution plays no special role in the function of speech. He admits that a lesion in the region of the lenticular nucleus is followed by inability to speak, but this defect is, in his opinion, to be regarded as an anarthria. He further admits the production of sensory aphasia--the aphasia of Wernicke, as he prefers to call it after its discoverer--by lesions which destroy the angular and supramarginal gyri, and the upper two temporo-sphenoidal convolutions, but he regards the essential foundation of sensory aphasia as a diminution of intelligence. There are, in his opinion, no sensory images of language. Motor aphasia is, he believes, nothing more than a combination of sensory aphasia and anarthria. These conclusions have been vigorously attacked, more especially by Dejerine of Paris (''La Presse medicale'', July 1906 and elsewhere).
External links - nidcd.nih.gov - NIDCD health information: Aphasia (public domain source) nlm.nih.gov - National Institute of Health: MEDLINEplus Medical Encyclopdia entry on Speech Impairment (adult) (note: ''not'' public domain, even though it is on a .gov website) ? media.cbc.ca:8080 - "In So Many Words" Radio documentary broadcast on the Canadian Broadcasting Corporation's "The Sunday Edition" program on Sunday, December 15, 2002. Co-produced by Teresa Goff and telling the story of her father Steve Goff, who suffers from aphasia as a result of a stroke. 23nlpeople.com - Aphasia and Dysphasia - Ideas and Considerations aphasia.tv - "Picturing Aphasia" Documentary film about aphasia that uses drawings to help bridge the gap between hearing, seeing, and comprehending. The video is designed to function as a part of therapy for people with aphasia and to educate people of all language abilities about the condition. Directed by Mores McWreath. !braininfo.rprc.washington.edu< /a> - Read some of Luria's book on traumatic aphasia on-line at !BrainInfoCategory:AphasiaCateg ory:Communication? !disordersde:Aphasiees:Afasiafr :Aphasiegl:Afasiams:Aphasianl: Afasieno:Afasipl:Afazjaru:
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Websites
National Aphasia Association
Nonprofit organization devoted to assisting people with aphasia and their families. Its online offerings include fact sheets on aphasia, support group listings, reviews of research, tips for finding a speech-language pathologist, and information on upcoming NAA conferences.
http://www.aphasia.org/
Aphasia Hope Foundation
A 501(c)(3) nonprofit foundation promoting aphasia research and working to ensure that all aphasia survivors and caregivers have an awareness of, and access to, appropriate therapy.
http://www.aphasiahope.org/
National Institute on Deafness and Other Communication Disorders
Supports and conducts research in, and distributes information on, the disorders of human communication, including hearing, balance, smell, taste, voice, speech, and language.
http://www.nidcd.nih.gov/
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