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Expressive aphasia, also known as Broca's 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 which 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.
Broca's area, or the Broca area, is a region in the frontal lobe of the dominant hemisphere, usually the left, of the brain with functions linked to speech production.
Pierre Paul Broca was a French physician, anatomist and anthropologist. He is best known for his research on Broca's area, a region of the frontal lobe that is named after him. Broca's area is involved with language. His work revealed that the brains of patients with aphasia contained lesions in a particular part of the cortex, in the left frontal region. This was the first anatomical proof of localization of brain function.
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.
Agraphia is an acquired neurological disorder causing a loss in the ability to communicate through writing, either due to some form of motor dysfunction or an inability to spell. The loss of writing ability may present with other language or neurological disorders; disorders appearing commonly with agraphia are alexia, aphasia, dysarthria, agnosia, acalculia and apraxia. The study of individuals with agraphia may provide more information about the pathways involved in writing, both language related and motoric. Agraphia cannot be directly treated, but individuals can learn techniques to help regain and rehabilitate some of their previous writing abilities. These techniques differ depending on the type of agraphia.
Neuropsychology is a branch of psychology concerned with how a person's cognition and behavior are related to the brain and the rest of the nervous system. Professionals in this branch of psychology often focus on how injuries or illnesses of the brain affect cognitive and behavioral functions.
The temporal lobe is one of the four major lobes of the cerebral cortex in the brain of mammals. The temporal lobe is located beneath the lateral fissure on both cerebral hemispheres of the mammalian brain.
The cerebrum, telencephalon or endbrain is the largest part of the brain containing the cerebral cortex, as well as several subcortical structures, including the hippocampus, basal ganglia, and olfactory bulb. In the human brain, the cerebrum is the uppermost region of the central nervous system. The cerebrum develops prenatally from the forebrain (prosencephalon). In mammals, the dorsal telencephalon, or pallium, develops into the cerebral cortex, and the ventral telencephalon, or subpallium, becomes the basal ganglia. The cerebrum is also divided into approximately symmetric left and right cerebral hemispheres.
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.
The term laterality refers to the preference most humans show for one side of their body over the other. Examples include left-handedness/right-handedness and left/right-footedness; it may also refer to the primary use of the left or right hemisphere in the brain. It may also apply to animals or plants. The majority of tests have been conducted on humans, specifically to determine the effects on language.
Expressive language disorder is one of the "specific developmental disorders of speech and language" recognised by the tenth edition of the International Classification of Diseases (ICD-10). As of the eleventh edition, it is considered to be covered by the various categories of developmental language disorder. Transition to the ICD-11 will take place at a different time in different countries.
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.
Pierre Marie was a French neurologist and political journalist close to the SFIO.
Middle cerebral artery syndrome is a condition whereby the blood supply from the middle cerebral artery (MCA) is restricted, leading to a reduction of the function of the portions of the brain supplied by that vessel: the lateral aspects of frontal, temporal and parietal lobes, the corona radiata, globus pallidus, caudate and putamen. The MCA is the most common site for the occurrence of ischemic stroke.
Speech science refers to the study of production, transmission and perception of speech. Speech science involves anatomy, in particular the anatomy of the oro-facial region and neuroanatomy, physiology, and acoustics.
In human neuroanatomy, brain asymmetry can refer to at least two quite distinct findings:
Amorphosynthesis, also called a hemi-sensory deficit, is a neuropsychological condition in which a patient experiences unilateral inattention to sensory input. This phenomenon is frequently associated with damage to the right cerebral hemisphere resulting in severe sensory deficits that are observed on the contralesional (left) side of the body. A right-sided deficit is less commonly observed and the effects are reported to be temporary and minor. Evidence suggests that the right cerebral hemisphere has a dominant role in attention and awareness to somatic sensations through ipsilateral and contralateral stimulation. In contrast, the left cerebral hemisphere is activated only by contralateral stimuli. Thus, the left and right cerebral hemispheres exhibit redundant processing to the right-side of the body and a lesion to the left cerebral hemisphere can be compensated by the ipsiversive processes of the right cerebral hemisphere. For this reason, right-sided amorphosynthesis is less often observed and is generally associated with bilateral lesions.
Dichotic listening is a psychological test commonly used to investigate selective attention and the lateralization of brain function within the auditory system. It is used within the fields of cognitive psychology and neuroscience.
Disconnection syndrome is a general term for a collection of neurological symptoms caused – via lesions to associational or commissural nerve fibres – by damage to the white matter axons of communication pathways in the cerebrum, independent of any lesions to the cortex. The behavioral effects of such disconnections are relatively predictable in adults. Disconnection syndromes usually reflect circumstances where regions A and B still have their functional specializations except in domains that depend on the interconnections between the two regions.
References
- ↑ Broca, Paul (1861a). Perte de la parole, ramollissement chronique et destruction partielle du lobe antérieur gauche du cerveau Bulletin de la Société Anthropologique, 2, 235-238
