Aphasia : A Language Disorder after a Stroke

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What is Aphasia?

Aphasia often arises as a result of damage to Broca’s area or Wernicke’s area.

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 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 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 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.

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How is aphasia diagnosed?

Aphasia is usually first recognized by the physician who treats the individual for his or her brain injury, usually a neurologist. 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.

Family members are encouraged to:

  • Simplify language by using short, uncomplicated sentences.
  • Repeat the content words or write down key words to clarify meaning as needed.
  • Maintain a natural conversational manner appropriate for an adult.
  • Minimize distractions, such as a blaring radio, whenever possible.
  • Include the person with aphasia in conversations.
  • Ask for and value the opinion of the person with aphasia, especially regarding family matters.
  • Encourage any type of communication, whether it is speech, gesture, pointing, or drawing.
  • Avoid correcting the individual’s speech.
  • Allow the individual plenty of time to talk.
  • Help the individual become involved outside the home. Seek out support groups such as stroke clubs.

What are researchers investigating about aphasia?
Aphasia research is exploring new ways to evaluate and treat aphasia as well as to further understand 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 (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 also being studied. Promising new drugs administered shortly after some types of stroke are being investigated as ways to reduce the severity of aphasia.

source : http://www.strokecenter.org/

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Language and Brain Connection

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Do you know that a part of the brain is responsible for your Language and Speech Areas?

Lateralization of the brain:

In human beings, it is the left hemisphere that usually contains the specialized language areas.

While this holds true for 97% of right-handed people, about 19% of left-handed people have their language areas in the right hemisphere and as many as 68% of them have some  language abilities in both the left and the right hemispheres.

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Broca (1861):

The first language area within the left hemisphere to be discovered is called Broca’s Area, after Paul Broca. Broca was a French neurologist who had a patient with severe language problems: Although he could understand the speech of others with little difficulty, the only word he could produce was “tan.” After the patient died, Broca performed an autopsy, and discovered that an area of the frontal lobe, had been seriously damaged. He correctly hypothesized that this area was responsible for speech
production.
Wernicke (1876):

The second language area to be discovered is called Wernicke’s Area, after Carl Wernicke, a German neurologist. Wernicke had a
patient who could speak quite well, but was unable to understand the speech of others. After the patient’s death, Wernicke performed an autopsy and found damage to an area at the upper portion of the temporal lobe, just behind the auditory cortex. He correctly hypothesized that this area was responsible for speech comprehension.

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How the two Areas Work together:
Broca’s area processes the information received from Wernicke’s area into a detailed and coordinated pattern for vocalization and then projects the pattern via a speech articulation area in the insula to the motor cortex, which initiates the appropriate movements of the lips, tongue, and larynx to produce speech. The angular gyrus behind Wernicke’s area appears to process information from words that are read in such away that they can be converted into the auditory forms of the words in Wernicke’s area.

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How these  areas of the brain  play  critical roles  in speech and language.

Broca’s Area

Broca’s area, located in the left hemisphere, is associated with speech production and articulation. Our ability to articulate ideas, as well as use words accurately in spoken and written language, has been attributed to this crucial area.

Wernicke’s Area

This critical language area in the posterior superior temporal lobe connects to Broca’s area via a neural pathway. Wernicke’s area is primarily involved in the comprehension. Historically, this area has been associated with language processing, whether it is written or spoken.

Angular Gyrus

The angular gyrus allows us to associate multiple types of language-related information whether auditory, visual or sensory. It is located in close proximity to other critical brain regions such as the parietal lobe which processes tactile sensation, the occipital lobe which is involved in visual analyses and the temporal lobe which processes sounds. The angular gyrus allows us to associate a perceived word with different images, sensations and ideas.

references:  Boeree, C. G. (2004). Speech and the brain.

Reading a good book may make permanent changes to your brain

Reading novel

The new research, carried out at Emory University in the US, found that reading a good book may cause heightened connectivity in the brain and neurological changes that persist in a similar way to muscle memory.

The changes were registered in the left temporal cortex, an area of the brain associated with receptivity for language, as well as the the primary sensory motor region of the brain.

Neurons of this region have been associated with tricking the mind into thinking it is doing something it is not, a phenomenon known as grounded cognition – for example, just thinking about running, can activate the neurons associated with the physical act of running.

“The neural changes that we found associated with physical sensation and movement systems suggest that reading a novel can transport you into the body of the protagonist,” said neuro scientist Professor Gregory Berns, lead author of the study.

“We already knew that good stories can put you in someone else’s shoes in a figurative sense. Now we’re seeing that something may also be happening biologically.”

21 students took part in the study, with all participants reading the same book – Pompeii, a 2003 thriller by Robert Harris, which was chosen for its page turning plot.

“The story follows a protagonist, who is outside the city of Pompeii and notices steam and strange things happening around the volcano,” said Prof Berns. “It depicts true events in a fictional and dramatic way. It was important to us that the book had a strong narrative line.”

Over 19 days the students read a portion of the book in the evening then had MRI scans the following morning. Once the book was finished, their brains were scanned for five days after.

The neurological changes were found to have continued for all the five days after finishing, proving that the impact was not just an immediate reaction but has a lasting influence.

“Even though the participants were not actually reading the novel while they were in the scanner, they retained this heightened connectivity,” added Prof Berns. “We call that a ‘shadow activity,’ almost like a muscle memory.”

Speaking A Second Language May Delay Dementia, or Alzheimer’s Disease

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Polyglot!!  This is a term for a person who knows how to speak different language.
It has its Health Benefits, Cognitively.

Scientists have long known that certain lifestyle routines, levels of intelligence, education, and even exercise could potentially play a role in delaying the onset of certain dementias like Alzheimer’s disease. Now, a researcher from Nizam’s Institute of Medical Sciences in India has released a new study that highlights the protective ability of bilingualism, or speaking two languages, in delaying certain kinds of dementias.

“Our study is the first to report an advantage of speaking two languages in people who are unable to read, suggesting that a person’s level of education is not a sufficient explanation for this difference,” Suvarna Alladi, author of the study, said in a press release. “Speaking more than one language is thought to lead to better development of the areas of the brain that handle executive functions and attention tasks, which may help protect from the onset of dementia.”

This was the largest study completed on the topic to date, and it was published in an online issue of Neurology. The study reviewed 648 people from India, who had an average age of 66 and a dementia diagnosis. Out of the 648, around 391 spoke two or more languages, and 14 percent could not read. Alladi discovered that people who spoke two languages had delayed onsets of Alzheimer’s disease, frontotemporal dementia, as well as vascular dementia — even if the bilingual person was illiterate. However, the study did not find any extra benefit in multilingualism, or speaking more than two languages.

“These results offer strong evidence for the protective effect of bilingualism against dementia in a population very different from those studied so far in terms of its ethnicity, culture and patterns of language use,” Alladi said in the press release.

Though perhaps the largest study completed so far about bilingualism’s effect on dementia, it is far from the first. In the past, scientists found that speaking two languages may delay dementia by up to four years. This phenomenon has been linked to what is known as the brain’s cognitive reserve or behavioral brain reserve, which has been described as being similar to a car’s reserve tank in providing the brain with “fuel,” which can be expanded by bilingualism or sustained complex mental activity. The authors of a 2003 study wrote that “[t]he concept of cognitive reserve (CR) suggests that innate intelligence or aspects of life experience like educational or occupational attainments may supply reserve, in the form of a set of skills or repertoires that allows some people to cope with progressing Alzheimer’s disease (AD) pathology better than others.” The study went on to state that there is epidemiological evidence that a lifestyle defined by the engagement in intellectual and social activities is linked to slower cognitive decline.

source: medicaldaily.com