Editing Aphasiology (section)

==Acute aphasias==
'''Acute aphasias''' are often the result of tissue damage following a [[stroke]].{{citation needed|date=August 2021}}

===Expressive aphasia===
{{Main article|Expressive aphasia}}
First described by the [[France|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.<ref name="Burns 2010">{{cite journal |vauthors=Burns MS, Fahy J |title=Broca's area: rethinking classical concepts from a neuroscience perspective |journal=Top Stroke Rehabil |volume=17 |issue=6 |pages=401–10 |year=2010 |pmid=21239364 |doi=10.1310/tsr1706-401 |s2cid=45975702 }}</ref> It is characterized by a halting speech consisting mainly of content words, i.e. nouns and verbs, and, at least in [[English language|English]], distinctly lacking small grammatical function words such as articles and prepositions.  This observation gave rise to the terms telegraphic speech and, more recently, [[agrammatism]].  The extent to which expressive aphasics retain knowledge of grammar is a matter of considerable controversy.  Nonetheless, because their comprehension of spoken language is mostly preserved, and because their speech is usually good enough to get their point across, the agrammatic nature of their speech suggests that the disorder chiefly involves the expressive mechanisms of language that turn thoughts into well-formed sentences.<ref name="Hillis 2007">{{cite journal |author=Hillis AE |title=Aphasia: progress in the last quarter of a century |journal=Neurology |volume=69 |issue=2 |pages=200–13 |date=July 2007 |pmid=17620554 |doi=10.1212/01.wnl.0000265600.69385.6f |s2cid=219199296 |url=http://cel.huji.ac.il/courses/structureandprocesses/Bibliography/Hillis_2007.pdf}}</ref>

The view of expressive aphasia as an expressive disorder is supported by its frequent co-occurrence with facial motor difficulties, and its anatomical localization.  Although expressive aphasia may be caused by brain damage to many regions, it is most commonly associated with the [[inferior frontal gyrus]], a region that overlaps with [[motor cortex]] controlling the [[Human mouth|mouth]] and [[tongue]], extending into the periventricular white matter.<ref name="Helm-Estabrooks 2004">{{cite book |author1=Albert, Martin L. |author2=Helm-Estabrooks, Nancy |title=Manual of aphasia and aphasia therapy |publisher=Pro-Ed |location=Austin, Tex |year=2004 |isbn=0-89079-963-6 |oclc=51009586 }}</ref> Not surprisingly, this region has come to be known as "[[Broca's area]]".  However, an intriguing line of research has demonstrated specific comprehension deficits in expressive aphasics as well.  These deficits generally involve sentences that are grammatical, but atypical in their word order.  The simplest example is sentences in the [[passive voice]], such as "The boy was chased by the girl."  Expressive aphasics may have quite a hard time realizing that the girl is doing the chasing, but they do much better with "The mouse was chased by the cat," where world knowledge constraints contribute to the correct interpretation.  However, "The cat was chased by the mouse" would likewise be incomprehensible.  This evidence suggests that grammatical competence may be a specific function of Broca's area.{{citation needed|date=August 2021}}

Lesions exclusive to Broca's area (the foot of the [[inferior frontal gyrus]]) do not produce Broca's aphasia but instead mild [[dysprosody]] and [[agraphia]], sometimes accompanied by word-finding pauses and mild [[dysarthria]]. Not much is known about what other areas must be damaged in order to produce Broca's aphasia, but some maintain damage to the inferior pre-Rolandic motor strip (the motor cortex region responsible [[glossopharyngeal]] muscle control) is also necessary.{{cn|date=January 2024}}

===Receptive aphasia===
{{Main article|Receptive aphasia}}
Receptive aphasia was originally described by the German neurologist [[Karl Wernicke]], a contemporary of Broca.  Receptive aphasics produce speech that seems fluent and grammatical, but is largely devoid of sensible content.  Comprehension is severely impaired, but while patients display a great deal of difficulty comprehending individual words, they can more easily understand words in context.<ref name="Helm-Estabrooks 2004" />  Receptive aphasia is associated with the posterior third of the [[superior temporal gyrus]] in the distribution of the inferior division of the [[middle cerebral artery]],<ref name="Helm-Estabrooks 2004" /> known as "[[Wernicke's area]]", an area adjacent to the [[Cerebral cortex|cortex]] responsible for auditory processing.  If the damage extends posteriorly, visual connections are disrupted, and the patient will have difficulty understanding written language. Therefore, the localization of the two best-known aphasias mirrors the grossest dichotomy in brain organization:  anterior areas are specialized for motor output, and posterior areas for sensory processing.{{citation needed|date=August 2021}}

A fascinating corollary of this has come from research on aphasias in deaf users of sign language, who show deficits in signing and comprehension analogous to Expressive and Receptive aphasias in hearing populations.  These studies demonstrate that the grammatical functions of Broca's area and the semantic functions of Wernicke's area are indeed deep, abstract properties of the language system independent of its modality of expression.{{cn|date=January 2024}}

===Global aphasia===
{{Main article|Global aphasia}}
Another less commonly known aphasia is [[global aphasia]], which generally manifests itself after a stroke affecting an extensive portion of the brain occurs, including infarction of both divisions of the [[middle cerebral artery]] and generally both Broca's area and Wernicke's area.<ref name="Helm-Estabrooks 2004" /> Survivors with global aphasia may have great difficulty understanding and forming words and sentences, and generally experience a great deal of difficulty when trying to communicate.<ref name="Hillis 2007"/> With considerable speech therapy rehabilitation, global aphasia may progress into expressive aphasia or receptive aphasia.{{citation needed|date=August 2021}}

===Anomic aphasia===
{{Main article|Anomic aphasia}}
A person with [[anomic aphasia]] have word-finding difficulties. Anomic aphasia, also known as anomia, is a non-fluent aphasia, which means the person speaks hesitantly because of a difficulty naming words or producing correct syntax.{{medical citation needed|date=July 2023}}  The person struggles to find the right words for speaking and writing.<ref name="Maher 2004">{{cite journal |vauthors=Maher LM, Raymer AM |title=Management of anomia |journal=Top Stroke Rehabil |volume=11 |issue=1 |pages=10–21 |year=2004 |pmid=14872396 |doi= 10.1310/318R-RMD5-055J-PQ40|s2cid=40998077 }}</ref> Subjects tend to use circumlocutions, in which they speak around the word they can not find, to make up for their loss. People also with anomic aphasia tend to know how to use an object, but rather can not name the aforementioned object.  Any damage in or near the zone of language can result in anomic aphasia. Other forms of aphasia often transition into a syndrome of primarily anomic aphasia in the process of recovery.<ref name="Helm-Estabrooks 2004" />

===Conduction aphasia===
{{Main article|Conduction aphasia}}
Conduction Aphasia is a rare form of aphasia in which fibres in the arcuate fasciculus and [[superior longitudinal fasciculus]] are damaged.<ref name="Helm-Estabrooks 2004" /> These fibres are the link between the Wernicke's and Broca's area. Damage to the area connecting comprehension and expression together has the following symptoms: fluent speech, good comprehension, poor oral reading, repetition is poor and transpositions of sounds within words is very common.{{citation needed|date=August 2021}}