Mixed transcortical aphasia is the least common of the three transcortical aphasias (behind transcortical motor aphasia and transcortical sensory aphasia, respectively). This type of aphasia can also be referred to as "Isolation Aphasia". This type of aphasia is a result of damage that isolates the language areas (Broca's, Wernicke’s, and the arcuate fasciculus) from other brain regions. Broca's, Wernicke's, and the arcuate fasiculus are left intact; however, they are isolated from other brain regions. [2]
A stroke is one of the leading causes of disability in the United States. [3] Following a stroke, 40% of stroke patients are left with moderate functional impairment and 15% to 30% have a severe disability as a result of a stroke. [4] A neurogenic cognitive-communicative disorder is one possible result of a stroke, with neuro- meaning related to nerves or the nervous system and -genic meaning resulting from or caused by. [2] Aphasia is one type of a neurogenic cognitive-communicative disorder which presents with impaired comprehension and production of speech and language, usually caused by damage in the language-dominant, left hemisphere of the brain. [2] Aphasia is any disorder of language that causes the patient to have the inability to communicate, whether it is through writing, speaking, or sign language. [5]
Mixed transcortical aphasia is characterized by severe speaking and comprehension impairment, but with preserved repetition. [6] People who suffer mixed transcortical aphasia struggle greatly to produce propositional language or to understand what is being said to them, yet they can repeat long, complex utterances or finish a song once they hear the first part. Persons with mixed transcortical aphasia are often nonfluent, and in most cases do not speak unless they are spoken to, do not comprehend spoken language, cannot name objects, and cannot read or write. However, they often have the ability to repeat what is said to them. In fact, persons with mixed transcortical aphasia often repeat in a parrot-like fashion. [2] Some patients with this disorder can experience many different types neurological symptoms including, bilateral paralysis, lack of voluntary speech, and difficulty with producing spontaneous speech. [7]
A conversation between a clinician and person with transcortical mixed aphasia would have similar characteristics to the conversation below: [2]
Clinician: Hello, Mrs. Fenton Patient: Mrs. Fenton. Yes. Clinician: How are you doing today? Patient: How are you doing today? Clinician: I'm very fine, thank you. How are you doing? Patient: I'm very fine, thank you. Clinician: My name is Mary. I'll be working with you today. Patient: My name is Mary. I'm working today.
In this rare type of aphasia, Broca's area, Wernicke's area, and the arcuate fasciculus are intact but the watershed region around them is damaged. [8] This damage isolates these areas from the rest of the brain. The most frequent etiology of mixed transcortical aphasia is stenosis (narrowing) of the internal carotid artery. Mixed transcortical aphasia can also occur after cerebral hypoxia, cerebral swelling, and any stroke that affects the cerebral artery. [9] Often lesions that cause mixed transcortical aphasia affect both the anterior and posterior perisylvian border zones. [10] Some times the type of aphasia can be determined just by knowing the lesion location. [5] In order for a patient to be diagnosed with mixed transcortical aphasia all other forms of transcortical must be ruled out. [11] Using WAB or the BDAE can rule out global aphasia if the ability to repeat is present. [11] If verbal fluency is depressed transcortical aphasia gets ruled out and if auditory processing and comprehension is weak then it cannot be transcortical motor aphasia. [11]
After a stroke, many patients feel the devastating impacts of the loss of language. Studies have looked into ways to enhance verbal communication with therapy, and one of the treatment approaches that proved to be successful is "Drawing Therapy". Drawing offers an alternative route to access semantic information. Because of this, it provides adults who have lost language with a means to access and express their ideas, emotions, and feelings. Drawing has also been shown to activate right hemisphere regions. This makes drawing a non-linguistic intervention that can access semantic knowledge in the right hemisphere. [12] The study conducted on drawing therapy found that it increased naming abilities in patients with acute and chronic aphasia. It also produced fewer error attempts during naming tasks. [12] The study also found that the act of drawing itself, not the quality, was critical for the activation of the semantic-lexical network required for naming tasks. [12] Other studies have also reported that family members have seen the effects of therapy at home. [13] The gains made from drawing therapy were not ones that could have been made from spontaneous recovery. [13] Drawing therapy was especially found to be useful in individuals with global and anomic aphasia. Both of these individuals were found to have produced more verbalizations post-therapy. [12] This reinforces the idea that drawing provides a mean of recruiting areas or networks that were not otherwise sufficient for producing speech. Across the majority of patients, the quality of drawing improved as well as written output and sentence structure. [14] Drawing therapy has proved to be effective even after a few periods of therapy. [15]
Although this therapy is aimed at patients with aphasia, it can be implemented for any patient with expressive deficits. [12]
Drawing therapy can be implemented in the following hierarchy:
1. Clinician gives patient a prompt and asks them to draw a response 2. Clinician asks for clarification of drawing if it is unclear (add more detail, enlarge one aspect of the drawing) 3. If possible, patient verbalizes about their drawing and assigns language
Drawing therapy can also be made harder through the type of prompt given and the task difficulty. Prompts and questions that are opened ended and with broad semantic categories are going to be harder to conceptualize and draw. [12] It is a harder task when the client is asked to draw abstract concepts or sequenced actions/events.
If a client has deficits in the following areas, drawing therapy might be an appropriate therapy technique:
Western Aphasia Battery (WAB) 1. Responsive Speech ("What do you write with?") 2. Spontaneous Speech a. Conversational questions b. Picture descriptions
Boston Diagnostic Aphasia Examination (BDAE) 1. Oral expression (word reading, sentence reading) 2. Written section (writing to dictation, writing to describe a picture)
Overall, drawing therapy offers a means of accessing language to patients with aphasia who have difficulty expressing themselves with different modalities. [12]
For most patients, formal and informal language assessments are initially administered during his/her acute hospital stay by a licensed speech-language pathologist. However, a standardized assessment may provide further information regarding an aphasia classification. While there are different classifications of aphasia (i.e., Broca's, Wernicke's, Conduction, Anomia), they each have hallmark deficits. Research has shown, a patient presenting with mixed transcortical aphasia will have impairments in all communicative areas, with the exception of the preserved ability to repeat a person's words or phrases. [16] Patients with mixed transcortical aphasia demonstrate similar deficits as those seen in patients with global aphasia. Therefore, assessment of repetition is most critical in order to differentially diagnose. Specifically, language based standardized assessments such as the Western Aphasia Battery (WAB), and the Folstein Mini Mental State Exam include a repetition subtest amongst all other language-related areas.
Other possible assessments that can provide further differentiation include: Magnetic Resonance Imaging (MRI) Magnetic Resonance Angiography (MRA) CT scan Informal observation
It is important to remain diligent in providing therapy regardless of aphasia classification.
If brain damage is minimal then a patient may recover language skills over time without treatment, however if the damage is severe it may be necessary to receive speech and language therapy. [5] Recovery from this type of brain injury is a slow process and very few patients regain the same level of language and communication skills that they have before the injury. Patients with aphasia usually undergo speech therapy where they relearn and practice supplementary communication methods. [5] Speech therapy is not a cure for the aphasia, but instead helps patients use skills that remain intact. [5] When considering the prognosis for individuals with aphasia it is necessary to consider internal factors, patient specific factors, and external factors as these factors are considered most critical to post-stroke recovery. [17] Internal factors are factors related to the stroke such as aphasia severity, lesion site and lesion size . Individuals with milder forms of aphasia, lesions that insignificantly impact language function and smaller lesions tend to have a higher degree of aphasia recovery. [18] Lesions in the superior temporal gyrus (STG) produce a more persistent global aphasia, which is associated with poor aphasia recovery. [19] [20] Patient specific factors relate to the patient's age of onset, education level and motivation for recovery. Younger patients have been reported to demonstrate a higher recovery rate than older patients. [21] Those with more years of education are less vulnerable to language disruption by stroke. [19] External factors include environmental factors such as type and amount of language treatment provided. [17] Stroke patients who are generally aware of their handicap and receive good support show more motivation and are more likely to have a better outcome. [22]
In aphasia, a person may be unable to comprehend or unable to formulate language because of damage to specific brain regions. The major causes are stroke and head trauma; prevalence is hard to determine, but aphasia due to stroke is estimated to be 0.1–0.4% in the Global North. Aphasia can also be the result of brain tumors, epilepsy, autoimmune neurological diseases, brain infections, or neurodegenerative diseases.
Expressive aphasia is a type of aphasia characterized by partial loss of the ability to produce language, although comprehension generally remains intact. A person with expressive aphasia will exhibit effortful speech. Speech generally includes important content words but leaves out function words that have more grammatical significance than physical meaning, such as prepositions and articles. This is known as "telegraphic speech". The person's intended message may still be understood, but their sentence will not be grammatically correct. In very severe forms of expressive aphasia, a person may only speak using single word utterances. Typically, comprehension is mildly to moderately impaired in expressive aphasia due to difficulty understanding complex grammar.
In neuroscience and psychology, the term language center refers collectively to the areas of the brain which serve a particular function for speech processing and production. Language is a core system that gives humans the capacity to solve difficult problems and provides them with a unique type of social interaction. Language allows individuals to attribute symbols to specific concepts, and utilize them through sentences and phrases that follow proper grammatical rules. Finally, speech is the mechanism by which language is orally expressed.
Wernicke's aphasia, also known as receptive aphasia, sensory aphasia, fluent aphasia, or posterior aphasia, is a type of aphasia in which individuals have difficulty understanding written and spoken language. Patients with Wernicke's aphasia demonstrate fluent speech, which is characterized by typical speech rate, intact syntactic abilities and effortless speech output. Writing often reflects speech in that it tends to lack content or meaning. In most cases, motor deficits do not occur in individuals with Wernicke's aphasia. Therefore, they may produce a large amount of speech without much meaning. Individuals with Wernicke's aphasia often suffer of anosognosia – they are unaware of their errors in speech and do not realize their speech may lack meaning. They typically remain unaware of even their most profound language deficits.
A head injury is any injury that results in trauma to the skull or brain. The terms traumatic brain injury and head injury are often used interchangeably in the medical literature. Because head injuries cover such a broad scope of injuries, there are many causes—including accidents, falls, physical assault, or traffic accidents—that can cause head injuries.
Aphasiology is the study of language impairment usually resulting from brain damage, due to neurovascular accident—hemorrhage, stroke—or associated with a variety of neurodegenerative diseases, including different types of dementia. These specific language deficits, termed aphasias, may be defined as impairments of language production or comprehension that cannot be attributed to trivial causes such as deafness or oral paralysis. A number of aphasias have been described, but two are best known: expressive aphasia and receptive aphasia.
Brain injury (BI) is the destruction or degeneration of brain cells. Brain injuries occur due to a wide range of internal and external factors. In general, brain damage refers to significant, undiscriminating trauma-induced damage.
Anomic aphasia is a mild, fluent type of aphasia where individuals have word retrieval failures and cannot express the words they want to say. By contrast, anomia is a deficit of expressive language, and a symptom of all forms of aphasia, but patients whose primary deficit is word retrieval are diagnosed with anomic aphasia. Individuals with aphasia who display anomia can often describe an object in detail and maybe even use hand gestures to demonstrate how the object is used, but cannot find the appropriate word to name the object. Patients with anomic aphasia have relatively preserved speech fluency, repetition, comprehension, and grammatical speech.
Wernicke's area, also called Wernicke's speech area, is one of the two parts of the cerebral cortex that are linked to speech, the other being Broca's area. It is involved in the comprehension of written and spoken language, in contrast to Broca's area, which is primarily involved in the production of language. It is traditionally thought to reside in Brodmann area 22, located in the superior temporal gyrus in the dominant cerebral hemisphere, which is the left hemisphere in about 95% of right-handed individuals and 70% of left-handed individuals.
In neurology, conduction aphasia, also called associative aphasia, is an uncommon form of difficulty in speaking (aphasia). It is caused by damage to the parietal lobe of the brain. An acquired language disorder, it is characterised by intact auditory comprehension, coherent speech production, but poor speech repetition. Affected people are fully capable of understanding what they are hearing, but fail to encode phonological information for production. This deficit is load-sensitive as the person shows significant difficulty repeating phrases, particularly as the phrases increase in length and complexity and as they stumble over words they are attempting to pronounce. People have frequent errors during spontaneous speech, such as substituting or transposing sounds. They are also aware of their errors and will show significant difficulty correcting them.
Global aphasia is a severe form of nonfluent aphasia, caused by damage to the left side of the brain, that affects receptive and expressive language skills as well as auditory and visual comprehension. Acquired impairments of communicative abilities are present across all language modalities, impacting language production, comprehension, and repetition. Patients with global aphasia may be able to verbalize a few short utterances and use non-word neologisms, but their overall production ability is limited. Their ability to repeat words, utterances, or phrases is also affected. Due to the preservation of the right hemisphere, an individual with global aphasia may still be able to express themselves through facial expressions, gestures, and intonation. This type of aphasia often results from a large lesion of the left perisylvian cortex. The lesion is caused by an occlusion of the left middle cerebral artery and is associated with damage to Broca's area, Wernicke's area, and insular regions which are associated with aspects of language.
Transcortical sensory aphasia (TSA) is a kind of aphasia that involves damage to specific areas of the temporal lobe of the brain, resulting in symptoms such as poor auditory comprehension, relatively intact repetition, and fluent speech with semantic paraphasias present. TSA is a fluent aphasia similar to Wernicke's aphasia, with the exception of a strong ability to repeat words and phrases. The person may repeat questions rather than answer them ("echolalia").
Brodmann area 22 is a Brodmann's area that is cytoarchitecturally located in the posterior superior temporal gyrus of the brain. In the left cerebral hemisphere, it is one portion of Wernicke's area. The left hemisphere BA22 helps with generation and understanding of individual words. On the right side of the brain, BA22 helps to discriminate pitch and sound intensity, both of which are necessary to perceive melody and prosody. Wernicke's area is active in processing language and consists of the left Brodmann area 22 and Brodmann area 40, the supramarginal gyrus.
Transcortical motor aphasia (TMoA), also known as commissural dysphasia or white matter dysphasia, results from damage in the anterior superior frontal lobe of the language-dominant hemisphere. This damage is typically due to cerebrovascular accident (CVA). TMoA is generally characterized by reduced speech output, which is a result of dysfunction of the affected region of the brain. The left hemisphere is usually responsible for performing language functions, although left-handed individuals have been shown to perform language functions using either their left or right hemisphere depending on the individual. The anterior frontal lobes of the language-dominant hemisphere are essential for initiating and maintaining speech. Because of this, individuals with TMoA often present with difficulty in speech maintenance and initiation.
In neuropathy, primary progressive aphasia (PPA) is a type of neurological syndrome in which language capabilities slowly and progressively become impaired. As with other types of aphasia, the symptoms that accompany PPA depend on what parts of the brain's left hemisphere are significantly damaged. However, unlike most other aphasias, PPA results from continuous deterioration in brain tissue, which leads to early symptoms being far less detrimental than later symptoms.
The lateralization of brain function is the tendency for some neural functions or cognitive processes to be specialized to one side of the brain or the other. The median longitudinal fissure separates the human brain into two distinct cerebral hemispheres, connected by the corpus callosum. Although the macrostructure of the two hemispheres appears to be almost identical, different composition of neuronal networks allows for specialized function that is different in each hemisphere.
Language disorders or language impairments are disorders that involve the processing of linguistic information. Problems that may be experienced can involve grammar, semantics (meaning), or other aspects of language. These problems may be receptive, expressive, or a combination of both. Examples include specific language impairment, better defined as developmental language disorder, or DLD, and aphasia, among others. Language disorders can affect both spoken and written language, and can also affect sign language; typically, all forms of language will be impaired.
Paraphasia is a type of language output error commonly associated with aphasia and characterized by the production of unintended syllables, words, or phrases during the effort to speak. Paraphasic errors are most common in patients with fluent forms of aphasia, and come in three forms: phonemic or literal, neologistic, and verbal. Paraphasias can affect metrical information, segmental information, number of syllables, or both. Some paraphasias preserve the meter without segmentation, and some do the opposite. However, most paraphasias affect both partially.
In psychology, logorrhea or logorrhoea is a communication disorder that causes excessive wordiness and repetitiveness, which can cause incoherency. Logorrhea is sometimes classified as a mental illness, though it is more commonly classified as a symptom of mental illness or brain injury. This ailment is often reported as a symptom of Wernicke's aphasia, where damage to the language processing center of the brain creates difficulty in self-centered speech.
Right hemisphere brain damage (RHD) is the result of injury to the right cerebral hemisphere. The right hemisphere of the brain coordinates tasks for functional communication, which include problem solving, memory, and reasoning. Deficits caused by right hemisphere brain damage vary depending on the location of the damage.
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