Editing Expressive aphasia (section)

==Causes==

=== More common ===
* [[Stroke]] or brain [[Oxygen saturation (medicine)|anoxia]].
* Brain tumor
* Brain trauma

=== Less common ===
* [[Autoimmune disease]]
* [[Paraneoplastic syndrome]]
* [[Micrometastasis]]
* [[Neurodegeneration|neurodegenerative disorders]]
* Certain infections (e.g., ''[[Bartonella henselae]]''<ref>{{Cite journal|last1=Marienfeld|first1=Carla B.|last2=DiCapua|first2=Daniel B.|last3=Sze|first3=Gordon K.|last4=Goldstein|first4=Jonathan M.|date=June 2010|title=Expressive Aphasia as a Presentation of Encephalitis with Bartonella henselae Infection in an Immunocompetent Adult|journal=The Yale Journal of Biology and Medicine|volume=83|issue=2|pages=67–71|issn=0044-0086|pmc=2892771|pmid=20589186}}</ref>)
* Metabolic disease (e.g., [[hyperosmolar hyperglycemic state]]<ref>{{Cite journal|last1=Lee|first1=Ji Hyun|last2=Kim|first2=Ye An|last3=Moon|first3=Joon Ho|last4=Min|first4=Se Hee|last5=Song|first5=Young Shin|last6=Choi|first6=Sung Hee|date=November 2016|title=Expressive aphasia as the manifestation of hyperglycemic crisis in type 2 diabetes|journal=The Korean Journal of Internal Medicine|volume=31|issue=6|pages=1187–1190|doi=10.3904/kjim.2014.379|issn=1226-3303|pmc=5094916|pmid=26968185}}</ref>)

==== Common causes ====
The most common cause of expressive aphasia is [[stroke]]. A stroke is caused by hypoperfusion (lack of oxygen) to an area of the brain, which is commonly caused by [[thrombosis]] or [[embolism]]. Some form of aphasia occurs in 34 to 38% of stroke patients.<ref name="Bakheit">{{cite journal|last1=Bakheit|first1=AMO|last2=Shaw|first2=S|last3=Carrington|first3=S|last4=Griffiths|first4=S|year=2007|title=The rate and extent of improvement with therapy from the different types of aphasia in the first year of stroke|journal=Integumentary Rehabilitation|volume=21|issue=10|pages=941–949|doi=10.1177/0269215507078452|pmid=17981853|s2cid=25995618}}</ref> Expressive aphasia occurs in approximately 12% of new cases of aphasia caused by stroke.<ref name="Pedersen">{{cite journal|last1=Pedersen|first1=PM|last2=Vinter|first2=K|last3=Olsen|first3=TS|year=2004|title=Aphasia after stroke: Type, severity, and prognosis - The Copenhagen aphasia study|journal=Cerebrovascular Diseases|volume=17|issue=1|pages=35–43|doi=10.1159/000073896|pmid=14530636|s2cid=11754713}}</ref>

In most cases, expressive aphasia is caused by a stroke in Broca's area or the surrounding vicinity. Broca's area is in the lower part of the [[premotor cortex]] in the language dominant hemisphere and is responsible for planning motor speech movements. However, cases of expressive aphasia have been seen in patients with strokes in other areas of the brain.<ref name=":1" /> Patients with classic symptoms of expressive aphasia in general have more acute brain lesions, whereas patients with larger, widespread lesions exhibit a variety of symptoms that may be classified as [[global aphasia]] or left unclassified.<ref name="Bakheit" />

Expressive aphasia can also be caused by trauma to the brain, [[tumor]],  [[cerebral hemorrhage]]<ref name="Ozeren">{{cite journal|last=Orzeren|first=A|author2=F Koc|author3=M Demirkiran|author4=A Sonmezler|s2cid=23023504|year=2006|title=Global aphasia due to left thalamic hemorrhage|journal=Neurology India|volume=54|issue=4|pages=415–417|doi=10.4103/0028-3886.28118|pmid=17114855|doi-access=free}}</ref> and by [[extradural abscess]].<ref name="Commondoor">{{cite journal|author1=Commondoor, R.|author2=Eisenhut, M.|author3=Fowler, C.|author4=Kirollos, R. W.|author5=Nathwani, N.|name-list-style=amp|year=2009|title=Transient Broca's Aphasia as Feature of an Extradural Abscess|journal=Pediatric Neurology|volume=40|issue=1|pages=50–53|doi=10.1016/j.pediatrneurol.2008.06.018|pmid=19068255}}</ref>

Understanding [[lateralization of brain function]] is important for understanding which areas of the brain cause expressive aphasia when damaged. In the past, it has been believed that the area for language production differs between left and right-handed individuals. If this were true, damage to the homologous region of Broca's area in the right hemisphere should cause aphasia in a left-handed individual. More recent studies have shown that even left-handed individuals typically have language functions only in the left hemisphere. However, left-handed individuals are more likely to have a dominance of language in the right hemisphere.<ref name="Purves" />

==== Uncommon causes ====
Less common causes of expressive aphasia include primary [[Autoimmune encephalitis|autoimmune phenomenon]] and autoimmune phenomenon that are secondary to cancer (as a [[paraneoplastic syndrome]]) have been listed as the primary hypothesis for several cases of aphasia, especially when presenting with other psychiatric disturbances and focal neurological deficits. Many case reports exist describing paraneoplastic aphasia, and the reports that are specific tend to describe expressive aphasia.<ref>{{Cite journal|last=McKeon|first=Andrew|date=April 2013|title=Paraneoplastic and Other Autoimmune Disorders of the Central Nervous System|journal=The Neurohospitalist|volume=3|issue=2|pages=53–64|doi=10.1177/1941874412453339|issn=1941-8744|pmc=3726118|pmid=23983888}}</ref><ref>{{Cite journal|last1=Yeung|first1=Darwin F|last2=Hsu|first2=Rose|date=2014-08-05|title=Expressive aphasia in a patient with chronic myelomonocytic leukemia|journal=SpringerPlus|volume=3|pages=406|doi=10.1186/2193-1801-3-406|issn=2193-1801|pmc=4130962|pmid=25126489 |doi-access=free }}</ref><ref>{{Cite journal|last1=Will|first1=A.|last2=Akalin|first2=Murat|date=2012-04-24|title=Paraneoplastic Limbic Encephalitis with NMDA Receptor (NR1) Antibodies in Breast Cancer (S08.007)|url=http://n.neurology.org/content/78/1_Supplement/S08.007|journal=Neurology|language=en|volume=78|issue=1 Supplement|pages=S08.007|doi=10.1212/WNL.78.1_MeetingAbstracts.S08.007|issn=0028-3878}}</ref><ref name=":9">{{Cite book|url=https://books.google.com/books?id=H5XLSPrCtB4C&q=paraneoplastic+aphasia&pg=PA8|title=Paraneoplastic Syndromes|last1=Darnell|first1=Robert|last2=Darnell|first2=Robert B.|last3=Posner|first3=Jerome B.|date=2011-08-22|publisher=Oxford University Press, USA|isbn=9780199772735|language=en}}</ref><ref>{{Cite journal|last=Lancaster|first=Eric|date=April 2015|title=Continuum: The Paraneoplastic Disorders|journal=Continuum (Minneapolis, Minn.)|volume=21|issue=2 0|pages=452–475|doi=10.1212/01.CON.0000464180.89580.88|issn=1080-2371|pmc=4443809|pmid=25837906}}</ref>  Although most cases attempt to exclude micro-metastasis, it is likely that some cases of paraneoplastic aphasia are actually extremely small metastasis to the vocal motor regions.<ref name=":9" />

Neurodegenerative disorders may present with aphasia. [[Alzheimer's disease]] may present with either [[fluent aphasia]] or expressive aphasia. There are case reports of [[Creutzfeldt-Jakob disease]] presenting with expressive aphasia.<ref>{{Cite journal|last1=Mahboob|first1=Hafiz B.|last2=Kaokaf|first2=Kazi H.|last3=Gonda|first3=Jeremy M.|date=2018-02-14|title=Creutzfeldt-Jakob Disease Presenting as Expressive Aphasia and Nonconvulsive Status Epilepticus|journal=Case Reports in Critical Care|volume=2018|pages=5053175|doi=10.1155/2018/5053175|issn=2090-6420|pmc=5832162|pmid=29666711|doi-access=free }}</ref><ref>{{Cite news|url=https://www.aphasia.org/aphasia-resources/primary-progressive-aphasia/|title=Primary Progressive Aphasia - National Aphasia Association|work=National Aphasia Association|access-date=2018-11-26|language=en-US}}</ref>