|
Aphasiology
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 (Broca's aphasia) and receptive aphasia (Wernicke's or sensory aphasia). Acute aphasias Acute aphasias are often the result of tissue damage following a stroke. Expressive aphasia First described by the French neurologist Paul Broca in the nineteenth century, expressive aphasia causes the speech of those affected to display a considerable vocabulary but to show grammatical deficits. It is characterized by a halting speech consisting mainly of content words, i.e. n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aphasia
Aphasia is an inability to comprehend or 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, brain infections, or neurodegenerative diseases (such as dementias). To be diagnosed with aphasia, a person's speech or language must be significantly impaired in one (or more) of the four aspects of communication following acquired brain injury. Alternatively, in the case of progressive aphasia, it must have significantly declined over a short period of time. The four aspects of communication are auditory comprehension, verbal expression, reading and writing, and functional communication. The difficulties of people with aphasia can range from occasional trouble finding words, to losing the ability to speak, read, or write; intelligence, however, is unaffected. Expressive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anomic Aphasia
Anomic aphasia (also known as dysnomia, nominal aphasia, and amnesic aphasia) is a mild, fluent type of aphasia where individuals have word retrieval failures and cannot express the words they want to say (particularly nouns and verbs). 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. Types * Word selection anomia is caused by damage to the posterior inferior temporal area. This type of anomia occurs when the patient knows how to use an object and can correctly select the target object from a group of objects, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Expressive Aphasia
Expressive aphasia, also known as Broca's aphasia, is a type of aphasia characterized by partial loss of the ability to produce language ( spoken, manual, or written), 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.ASHA.orgAppendix: Common Classifications of Aphasia. (n.d.). Retrieved from http://www.asha.org/Practice-Portal/Clinical-Topics/Aphasia/Common-Classifications-of-Aphasia/ Typically, comprehension is mildly to moderately impaired in expressive aphasia due to difficulty understanding complex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Global Aphasia
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 (needed for both written and oral language) as well as auditory and visual comprehension.Brookshire, R. H. (2007). Introduction to neurogenic communication disorders (Seventh edition.). St. Louis, Mo.: Mosby Elsevier. Acquired impairments of communicative abilities are present across all language modalities, impacting language production, comprehension, and repetition.Goodglass, H., and Kaplan, E. (1983). The assessment of aphasia and related disorders. Philadelphia: Lea and Febiger. Patients with global aphasia may be able to verbalize a few short utterances and use non-word neologisms,Manasco, H. M. (2014). Introduction to Neurogenic Communication Disorders. Burlington, MA: Jones & Barlett Learning. but their overall production ability is limited. Their ability to repeat words, utterances, or phrases is also affected. Due to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Language
Language is a structured system of communication. The structure of a language is its grammar and the free components are its vocabulary. Languages are the primary means by which humans communicate, and may be conveyed through a variety of methods, including spoken, sign, and written language. Many languages, including the most widely-spoken ones, have writing systems that enable sounds or signs to be recorded for later reactivation. Human language is highly variable between cultures and across time. Human languages have the properties of productivity and displacement, and rely on social convention and learning. Estimates of the number of human languages in the world vary between and . Precise estimates depend on an arbitrary distinction (dichotomy) established between languages and dialects. Natural languages are spoken, signed, or both; however, any language can be encoded into secondary media using auditory, visual, or tactile stimuli – for example, writing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Passive Voice
A passive voice construction is a grammatical voice construction that is found in many languages. In a clause with passive voice, the grammatical subject expresses the ''theme'' or '' patient'' of the main verb – that is, the person or thing that undergoes the action or has its state changed. This contrasts with active voice, in which the subject has the agent role. For example, in the passive sentence "The tree was pulled down", the subject (''the tree'') denotes the patient rather than the agent of the action. In contrast, the sentences "Someone pulled down the tree" and "The tree is down" are active sentences. Typically, in passive clauses, what is usually expressed by the object (or sometimes another argument) of the verb is now expressed by the subject, while what is usually expressed by the subject is either omitted or is indicated by some adjunct of the clause. Thus, turning an active sense of a verb into a passive sense is a valence-decreasing process ("detransiti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Superior Longitudinal Fasciculus
The superior longitudinal fasciculus (SLF) is an association tract in the brain that is composed of three separate components. It is present in both hemispheres and can be found lateral to the centrum semiovale and connects the frontal, occipital, parietal, and temporal lobes. This bundle of tracts (fasciculus) passes from the frontal lobe through the operculum to the posterior end of the lateral sulcus where they either radiate to and synapse on neurons in the occipital lobe, or turn downward and forward around the putamen and then radiate to and synapse on neurons in anterior portions of the temporal lobe. The SLF is composed of three distinct components SLF I, SLF II, and SLF III. SLF I SLF I is the dorsal component and originates in the superior and medial parietal cortex, passes around the cingulate sulcus and in the superior parietal and frontal white matter, and terminates in the dorsal and medial cortex of the frontal lobe ( Brodmann 6, 8, and 9) and in the supplem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cerebral Cortex
The cerebral cortex, also known as the cerebral mantle, is the outer layer of neural tissue of the cerebrum of the brain in humans and other mammals. The cerebral cortex mostly consists of the six-layered neocortex, with just 10% consisting of allocortex. It is separated into two cortices, by the longitudinal fissure that divides the cerebrum into the left and right cerebral hemispheres. The two hemispheres are joined beneath the cortex by the corpus callosum. The cerebral cortex is the largest site of neural integration in the central nervous system. It plays a key role in attention, perception, awareness, thought, memory, language, and consciousness. The cerebral cortex is part of the brain responsible for cognition. In most mammals, apart from small mammals that have small brains, the cerebral cortex is folded, providing a greater surface area in the confined volume of the cranium. Apart from minimising brain and cranial volume, cortical folding is crucial for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wernicke's Area
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, which is 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. Damage caused to Wernicke's area results in receptive, fluent aphasia. This means that the person with aphasia will be able to fluently connect words, but the phrases will lack meaning. This is unlike non-fluent aphasia, in which the person will use meaningful words, but in a non-fluent, telegraphic manner. Structure Wernicke's area is traditionally viewed as being located in the posterior section of the superior tem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middle Cerebral Artery
The middle cerebral artery (MCA) is one of the three major paired cerebral arteries that supply blood to the cerebrum. The MCA arises from the internal carotid artery and continues into the lateral sulcus where it then branches and projects to many parts of the lateral cerebral cortex. It also supplies blood to the anterior temporal lobes and the insular cortices. The left and right MCAs rise from trifurcations of the internal carotid arteries and thus are connected to the anterior cerebral arteries and the posterior communicating arteries, which connect to the posterior cerebral arteries. The MCAs are not considered a part of the Circle of Willis. Structure The middle cerebral artery divides into four segments, named by the region they supply as opposed to order of branching as the latter can be somewhat variable: *M1: The ''sphenoidal'' segment (stem), receiving its name due to its course along the adjacent sphenoid bone. It is also referred to as the ''horizontal'' segment, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Superior Temporal Gyrus
The superior temporal gyrus (STG) is one of three (sometimes two) gyri in the temporal lobe of the human brain, which is located laterally to the head, situated somewhat above the external ear. The superior temporal gyrus is bounded by: * the lateral sulcus above; * the superior temporal sulcus (not always present or visible) below; * an imaginary line drawn from the preoccipital notch to the lateral sulcus posteriorly. The superior temporal gyrus contains several important structures of the brain, including: * Brodmann areas 41 and 42, marking the location of the auditory cortex, the cortical region responsible for the sensation of sound; * Wernicke's area, Brodmann 22p, an important region for the processing of speech so that it can be understood as language. The superior temporal gyrus contains the auditory cortex, which is responsible for processing sounds. Specific sound frequencies map precisely onto the auditory cortex. This auditory (or tonotopic) map is similar to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Karl Wernicke
Carl (or Karl) Wernicke (; ; 15 May 1848 – 15 June 1905) was a German physician, anatomist, psychiatrist and neuropathologist. He is known for his influential research into the pathological effects of specific forms of encephalopathy and also the study of receptive aphasia, both of which are commonly associated with Wernicke's name and referred to as Wernicke encephalopathy and Wernicke's aphasia, respectively. His research, along with that of Paul Broca, led to groundbreaking realizations of the localization of brain function, specifically in speech. As such, Wernicke's area (a.k.a. Wernicke's Speech Area) has been named after the scientist. Biography Wernicke was born on May 15, 1848, in Tarnowitz, a small town in Upper Silesia, Prussia, now Tarnowskie Góry, Poland. He obtained his secondary education at the gymnasium in Oppeln, which is a school near the university of Breslau. Wernicke then studied medicine at the University of Breslau and did graduate work st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
