Editing Aphasia (section)

==Causes==
Aphasia is most often caused by stroke, where about a quarter of patients who experience an acute stroke develop aphasia.<ref name=":4">{{Cite journal|last=Berthier|first=Marcelo L.|date=2005-02-01|title=Poststroke Aphasia|url=https://doi.org/10.2165/00002512-200522020-00006|journal=Drugs & Aging|language=en|volume=22|issue=2|pages=163–182|doi=10.2165/00002512-200522020-00006|pmid=15733022|s2cid=22725166|issn=1179-1969}}</ref> However, any disease or damage to the parts of the brain that control language can cause aphasia. Some of these can include brain tumors, traumatic brain injury, epilepsy and progressive neurological disorders.<ref>{{Cite web|title = Aphasia|url = http://www.asha.org/public/speech/disorders/Aphasia/|website = www.asha.org|access-date = 2015-11-18}}</ref> In rare cases, aphasia may also result from [[herpesviral encephalitis]].<ref>{{cite journal | vauthors = Soares-Ishigaki EC, Cera ML, Pieri A, Ortiz KZ | title = Aphasia and herpes virus encephalitis: a case study | journal = Sao Paulo Medical Journal| volume = 130 | issue = 5 | pages = 336–341 | year = 2012 | pmid = 23174874 | doi = 10.1590/S1516-31802012000500011 | doi-access = free | pmc = 10836473 }}</ref> The [[herpes simplex virus]] affects the frontal and temporal lobes, subcortical structures, and the hippocampal tissue, which can trigger aphasia.<ref>{{cite journal | vauthors = Naudé H, Pretorius E | title = Can herpes simplex virus encephalitis cause aphasia? | journal = Early Child Development and Care | date = 3 Jun 2010 | volume = 173 | issue = 6 | pages = 669–679 | doi = 10.1080/0300443032000088285 | s2cid = 143811627 }}</ref> In acute disorders, such as head injury or stroke, aphasia usually develops quickly. When caused by brain tumor, [[infection]], or [[dementia]], it develops more slowly.<ref name="ASHA Aphasia" /><ref name="medicinenet.com">{{cite web | url = http://www.medicinenet.com/aphasia/article.htm | title = Aphasia | access-date = 2011-05-23 | work = MedicineNet.com}}</ref>

Substantial damage to tissue anywhere within the region shown in blue (on the figure in the infobox above) can potentially result in aphasia.<ref name="Lesion correlates of patholinguisti" /> Aphasia can also sometimes be caused by damage to subcortical structures deep within the left hemisphere, including the thalamus, the [[Internal capsule|internal]] and [[external capsule]]s, and the [[caudate nucleus]] of the basal ganglia.<ref>{{cite journal | vauthors = Kuljic-Obradovic DC | title = Subcortical aphasia: three different language disorder syndromes? | journal = European Journal of Neurology | volume = 10 | issue = 4 | pages = 445–448 | date = July 2003 | pmid = 12823499 | doi = 10.1046/j.1468-1331.2003.00604.x | s2cid = 19945519 }}</ref><ref>{{cite journal | vauthors = Kreisler A, Godefroy O, Delmaire C, Debachy B, Leclercq M, Pruvo JP, Leys D | title = The anatomy of aphasia revisited | journal = Neurology | volume = 54 | issue = 5 | pages = 1117–1123 | date = March 2000 | pmid = 10720284 | doi = 10.1212/wnl.54.5.1117 | s2cid = 21847976 }}</ref> The area and extent of brain damage or [[atrophy]] will determine the type of aphasia and its symptoms.<ref name="ASHA Aphasia" /><ref name="medicinenet.com" /> A very small number of people can experience aphasia after damage to the [[right hemisphere]] only. It has been suggested that these individuals may have had an unusual brain organization prior to their illness or injury, with perhaps greater overall reliance on the right hemisphere for language skills than in the general population.<ref>{{cite journal | vauthors = Coppens P, Hungerford S, Yamaguchi S, Yamadori A | title = Crossed aphasia: an analysis of the symptoms, their frequency, and a comparison with left-hemisphere aphasia symptomatology | journal = Brain and Language | volume = 83 | issue = 3 | pages = 425–463 | date = December 2002 | pmid = 12468397 | doi = 10.1016/s0093-934x(02)00510-2 | s2cid = 46650843 }}</ref><ref>{{cite journal | vauthors = Mariën P, Paghera B, De Deyn PP, Vignolo LA | title = Adult crossed aphasia in dextrals revisited | journal = Cortex; A Journal Devoted to the Study of the Nervous System and Behavior | volume = 40 | issue = 1 | pages = 41–74 | date = February 2004 | pmid = 15070002 | doi = 10.1016/s0010-9452(08)70920-1 | s2cid = 4481435 }}</ref>

[[Primary progressive aphasia]] (PPA), while its name can be misleading, is actually a form of dementia that has some symptoms closely related to several forms of aphasia. It is characterized by a gradual loss in language functioning while other cognitive domains are mostly preserved, such as memory and personality. PPA usually initiates with sudden word-finding difficulties in an individual and progresses to a reduced ability to formulate grammatically correct sentences (syntax) and impaired comprehension. The etiology of PPA is not due to a stroke, traumatic brain injury (TBI), or infectious disease; it is still uncertain what initiates the onset of PPA in those affected by it.<ref>{{Cite web|title = Primary Progressive Aphasia|url = http://www.asha.org/Glossary/Primary-Progressive-Aphasia/|website = www.asha.org|access-date = 2015-11-15}}</ref>

[[Epilepsy]] can also include transient aphasia as a [[prodromal]] or episodic symptom.<ref>{{cite journal | vauthors = Blumenfeld H, Meador KJ | title = Consciousness as a useful concept in epilepsy classification | journal = Epilepsia | volume = 55 | issue = 8 | pages = 1145–1150 | date = August 2014 | pmid = 24981294 | pmc = 4149314 | doi = 10.1111/epi.12588 }}</ref> However, the repeated seizure activity within language regions may also lead to chronic, and progressive aphasia. Aphasia is also listed as a rare side-effect of the [[fentanyl]] patch, an opioid used to control chronic pain.<ref>{{cite web |url=https://www.drugs.com/pro/fentanyl-transdermal.html#A02A9CB6-35CF-4F01-A980-C3733E0F861A |title=Fentanyl Transdermal Official FDA information, side effects and uses |work=Drug Information Online }}</ref>