Editing Aphasia (section)

=== Classification ===
Aphasia is best thought of as a collection of different disorders, rather than a single problem. Each individual with aphasia will present with their own particular combination of language strengths and weaknesses. Consequently, it is a major challenge just to document the various difficulties that can occur in different people, let alone decide how they might best be treated. Most classifications of the aphasias tend to divide the various symptoms into broad classes. A common approach is to distinguish between the fluent aphasias (where speech remains fluent, but content may be lacking, and the person may have difficulties understanding others), and the nonfluent aphasias (where speech is very halting and effortful, and may consist of just one or two words at a time).<ref>{{cite journal |last1=Damasio |first1=Antonio |title=Aphasia |journal=The New England Journal of Medicine |date=1992 |volume=326 |issue=8 |pages=531–539 |doi=10.1056/NEJM199202203260806 |pmid=1732792 |url=https://www.nejm.org/doi/full/10.1056/NEJM199202203260806 |access-date=21 February 2022}}</ref>

However, no such broad-based grouping has proven fully adequate, or reliable. There is wide variation among people even within the same broad grouping, and aphasias can be highly selective. For instance, people with naming deficits (anomic aphasia) might show an inability only for naming buildings, or people, or colors.<ref>{{cite book |author1=Kolb, Bryan |author2=Whishaw, Ian Q. |title=Fundamentals of human neuropsychology |publisher=Worth |location=[New York] |year=2003 |pages= 502, 505, 511|isbn=978-0-7167-5300-1 |oclc=464808209 }}</ref> Unfortunately, assessments that characterize aphasia in these groupings have persisted. This is not helpful to people living with aphasia, and provides inaccurate descriptions of an individual pattern of difficulties.

There are typical difficulties with speech and language that come with normal aging as well. As we age, language can become more difficult to process, resulting in a slowing of verbal comprehension, reading abilities and more likely word finding difficulties. With each of these, though, unlike some aphasias, functionality within daily life remains intact.<ref name="Manasco" />{{Reference page|7}}

==== Boston classification ====
{| class="wikitable sortable"
|+ Major characteristics of different types of aphasia according to the Boston classification<ref name="Ref4 from the Broca's area article">{{Cite web|url=http://www.atlantaaphasia.org|title=What is Aphasia|year=2006|publisher=Atlanta Aphasia Association|access-date=2008-12-01}}</ref><ref>{{Cite book|title=Acquired Speech and Language Disorders| vauthors = Murdoch BE |date=1990|publisher=Springer, Boston, MA|isbn=9780412334405|pages=60–96|language=en|doi=10.1007/978-1-4899-3458-1_2|chapter = Bostonian and Lurian aphasia syndromes}}</ref>
! Type of aphasia
! [[Speech repetition]]
! Naming
! Auditory comprehension
! Fluency
|-
| [[Expressive aphasia]] (Broca's aphasia)
| Moderate–severe
| Moderate–severe
| Mild difficulty
| Non-fluent, effortful, slow
|-
| [[Receptive aphasia]] (Wernicke's aphasia)
| Mild–severe
| Mild–severe
| Defective
| Fluent paraphasic
|-
| [[Conduction aphasia]]
| Poor
| Poor
| Relatively good
| Fluent
|-
| [[Mixed transcortical aphasia]]
| Moderate
| Poor
| Poor
| Non-fluent
|-
| [[Transcortical motor aphasia]]
| Good
| Mild–severe
| Mild
| Non-fluent
|-
| [[Transcortical sensory aphasia]]
| Good
| Moderate–severe
| Poor
| Fluent
|-
| [[Global aphasia]]
| Poor
| Poor
| Poor
| Non-fluent
|-
| [[Anomic aphasia]]
| Mild
| Moderate–severe
| Mild
| Fluent
|}
* Individuals with [[receptive aphasia]] ([[Wernicke's area|Wernicke's]] aphasia), also referred to as fluent aphasia, may speak in long sentences that have no meaning, add unnecessary words, and even create new "words" ([[neologism]]s). For example, someone with receptive aphasia may say, "delicious taco", meaning "The dog needs to go out so I will take him for a walk". They have poor auditory and reading comprehension, and fluent, but nonsensical, oral and written expression. Individuals with receptive aphasia usually have great difficulty understanding the speech of both themselves and others and are, therefore, often unaware of their mistakes. Receptive language deficits usually arise from lesions in the posterior portion of the left hemisphere at or near Wernicke's area.<ref name="Manasco" /><ref>{{cite journal | vauthors = DeWitt I, Rauschecker JP | title = Wernicke's area revisited: parallel streams and word processing | journal = Brain and Language | volume = 127 | issue = 2 | pages = 181–191 | date = November 2013 | pmid = 24404576 | pmc = 4098851 | doi = 10.1016/j.bandl.2013.09.014 }}</ref>{{Reference page|71}} It is often the result of trauma to the temporal region of the brain, specifically damage to [[Wernicke's area]].<ref>{{Cite news|url=https://www.nidcd.nih.gov/health/aphasia|title=Aphasia|date=2015-08-18|work=NIDCD|access-date=2017-05-02|language=en}}</ref> Trauma can be the result from an array of problems, however it is most commonly seen as a result of stroke<ref name=":0">{{Cite web|url=http://www.asha.org/Practice-Portal/Clinical-Topics/Aphasia/Common-Classifications-of-Aphasia/|title=Common Classifications of Aphasia|website=www.asha.org|language=en|access-date=2017-05-02}}</ref>
* Individuals with [[expressive aphasia]] ([[Broca's area|Broca's]] aphasia) frequently speak short, meaningful phrases that are produced with great effort. It is thus characterized as a nonfluent aphasia. Affected people often omit small words such as "is", "and", and "the". For example, a person with expressive aphasia may say, "walk dog", which could mean "I will take the dog for a walk", "you take the dog for a walk" or even "the dog walked out of the yard." Individuals with expressive aphasia are able to understand the speech of others to varying degrees. Because of this, they are often aware of their difficulties and can become easily frustrated by their speaking problems.<ref name="Brookshire 2007">{{cite book |author=Brookshire R |url=https://archive.org/details/introductiontone0000broo_i6r7|title=Introduction to neurogenic communication disorders|edition=7th|year=2007|location=St. Louis, MO|publisher=Mosby|isbn=978-0-323-07867-2}}{{page needed|date=August 2023}}</ref> While Broca's aphasia may appear to be solely an issue with language production, evidence suggests that it may be rooted in an inability to process syntactical information.<ref>{{cite journal | vauthors = Embick D, Marantz A, Miyashita Y, O'Neil W, Sakai KL | year = 2000 | title = A syntactic specialization for Broca's area | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 97 | issue = 11| pages = 6150–6154 | doi = 10.1073/pnas.100098897 | pmid = 10811887 | pmc = 18573 | bibcode = 2000PNAS...97.6150E | doi-access = free }}</ref> Individuals with expressive aphasia may have a speech automatism (also called recurring or recurrent utterance). These speech automatisms can be repeated lexical speech automatisms; ''e.g.'', modalisations ('I can't&nbsp;..., I can't&nbsp;...'), expletives/swearwords, numbers ('one two, one two') or non-lexical utterances made up of repeated, legal, but meaningless, consonant-vowel syllables (e.g.., /tan tan/, /bi bi/). In severe cases, the individual may be able to utter only the same speech automatism each time they attempt speech.<ref name="Code">{{cite journal | author = Code C | year = 1982 | title = Neurolinguistic analysis of recurrent utterances in aphasia | journal = Cortex | volume = 18 | issue = 1 | pages = 141–152 | doi = 10.1016/s0010-9452(82)80025-7 | pmid = 6197231 | s2cid = 4487128 | doi-access = free }}</ref>
* Individuals with [[anomic aphasia]] have difficulty with naming. People with this aphasia may have difficulties naming certain words, linked by their grammatical type (''e.g.'', difficulty naming verbs and not nouns) or by their [[semantic]] category (''e.g.'', difficulty naming words relating to photography, but nothing else) or a more general naming difficulty. People tend to produce grammatic, yet empty, speech. Auditory comprehension tends to be preserved.<ref name="Squire 2009">{{cite encyclopedia |editor=Squire LR |author1=Dronkers NF |author2=Baldo JV |title=Language: Aphasia|encyclopedia=Encyclopedia of neuroscience |year=2009 |pages=343–348|doi=10.1016/B978-008045046-9.01876-3 |isbn=978-0-08-045046-9}}</ref> Anomic aphasia is the aphasial presentation of tumors in the language zone; it is the aphasial presentation of Alzheimer's disease.<ref>{{cite book|title=Aphasia| vauthors = Alexander MP, Hillis AE | chapter = Chapter 14 Aphasia |series=Handbook of Clinical Neurology|year=2008<!--|access-date = 2013-06-09 -->| isbn=9780444518972|editor=Georg Goldenberg |editor2=Bruce L Miller |editor3=Michael J Aminoff |editor4=Francois Boller |editor5=D F Swaab|edition=1|volume=88|pages=287–310|doi=10.1016/S0072-9752(07)88014-6|pmid=18631697|oclc=733092630}}</ref> Anomic aphasia is the mildest form of aphasia, indicating a likely possibility for better recovery.<ref name="Squire 2009" />{{Additional citation needed|date= April 2022|reason= source does not mention possibility for better recovery}}
* Individuals with transcortical sensory aphasia, in principle the most general and potentially among the most complex forms of aphasia, may have similar deficits as in receptive aphasia, but their repetition ability may remain intact.
* Global aphasia is considered a severe impairment in many language aspects since it impacts expressive and receptive language, reading, and writing.<ref>{{cite journal |author1=Demeurisse G. |author2=Capon A. | year = 1987 | title = Language recovery in aphasic stroke patients: Clinical, CT and CBF studies | journal = Aphasiology | volume = 1 | issue = 4| pages = 301–315 | doi=10.1080/02687038708248851}}</ref> Despite these many deficits, there is evidence that has shown individuals benefited from speech language therapy.<ref name="Basso 2011">{{cite journal | vauthors = Basso A, Macis M | title = Therapy efficacy in chronic aphasia | journal = Behavioural Neurology | volume = 24 | issue = 4 | pages = 317–325 | year = 2001 | pmc = 5377972 | doi = 10.1155/2011/313480 | pmid = 22063820 | doi-access = free }}</ref> Even though individuals with global aphasia will not become competent speakers, listeners, writers, or readers, goals can be created to improve the individual's quality of life.<ref name="Brookshire 2007" /> Individuals with global aphasia usually respond well to treatment that includes personally relevant information, which is also important to consider for therapy.<ref name="Brookshire 2007" />
* Individuals with conduction aphasia have deficits in the connections between the speech-comprehension and speech-production areas. This might be caused by damage to the [[arcuate fasciculus]], the structure that transmits information between [[Wernicke's area]] and [[Broca's area]]. Similar symptoms, however, can be present after damage to the [[insular cortex|insula]] or to the [[auditory cortex]]. Auditory comprehension is near normal, and oral expression is fluent with occasional paraphasic errors. Paraphasic errors include phonemic/literal or semantic/verbal. Repetition ability is poor. Conduction and transcortical aphasias are caused by damage to the white matter tracts. These aphasias spare the cortex of the [[language center]]s, but instead create a disconnection between them. Conduction aphasia is caused by damage to the arcuate fasciculus. The arcuate fasciculus is a white matter tract that connects Broca's and Wernicke's areas. People with conduction aphasia typically have good language comprehension, but poor speech repetition and mild difficulty with word retrieval and speech production. People with conduction aphasia are typically aware of their errors.<ref name="Brookshire 2007" /> Two forms of conduction aphasia have been described: ''reproduction conduction aphasia'' (repetition of a single relatively unfamiliar multisyllabic word) and ''repetition conduction aphasia'' (repetition of unconnected short familiar words.<ref>{{Cite journal|last1=Shallice|first1=Tim|last2=Warrington|first2=Elizabeth K.|date=October 1977|title=Auditory-verbal short-term memory impairment and conduction aphasia|journal=Brain and Language|volume=4|issue=4|pages=479–491|doi=10.1016/0093-934x(77)90040-2|pmid=922463|s2cid=40665691|issn=0093-934X}}</ref>
* Transcortical aphasias include transcortical motor aphasia, transcortical sensory aphasia, and mixed transcortical aphasia. People with transcortical motor aphasia typically have intact comprehension and awareness of their errors, but poor word finding and speech production. People with transcortical sensory and mixed transcortical aphasia have poor comprehension and unawareness of their errors.<ref name="Brookshire 2007" /> Despite poor comprehension and more severe deficits in some transcortical aphasias, small studies have indicated that full recovery is possible for all types of transcortical aphasia.<ref>{{cite journal | vauthors = Flamand-Roze C, Cauquil-Michon C, Roze E, Souillard-Scemama R, Maintigneux L, Ducreux D, Adams D, Denier C | display-authors = 6 | title = Aphasia in border-zone infarcts has a specific initial pattern and good long-term prognosis | journal = European Journal of Neurology | volume = 18 | issue = 12 | pages = 1397–1401 | date = December 2011 | pmid = 21554494 | doi = 10.1111/j.1468-1331.2011.03422.x | s2cid = 26120952 }}</ref>

==== Classical-localizationist approaches ====
[[File:Brain - Broca's and Wernicke's area Diagram.svg|thumb|Cortex]]
Localizationist approaches aim to classify the aphasias according to their major presenting characteristics and the regions of the brain that most probably gave rise to them.<ref name="Goodglass, H. 2001">Goodglass, H., Kaplan, E., & Barresi, B. (2001). The assessment of aphasia and related disorders. Lippincott Williams & Wilkins.</ref><ref>Kertesz, A. (2006). Western Aphasia Battery-Revised (WAB-R). Austin, TX: Pro-Ed.</ref> Inspired by the early work of nineteenth-century neurologists [[Paul Broca]] and [[Carl Wernicke]], these approaches identify two major subtypes of aphasia and several more minor subtypes:
* [[Expressive aphasia]] (also known as "motor aphasia" or "Broca's aphasia"), which is characterized by halted, fragmented, effortful speech, but well-preserved comprehension ''relative to expression''. Damage is typically in the anterior portion of the left hemisphere,<ref name="Common Classifications of Aphasia">{{Cite web|title = Common Classifications of Aphasia|url = http://www.asha.org/Practice-Portal/Clinical-Topics/Aphasia/Common-Classifications-of-Aphasia/|website = www.asha.org|access-date = 2015-11-19}}</ref> most notably [[Broca's area]]. Individuals with Broca's aphasia often have [[hemiplegia|right-sided weakness]] or paralysis of the arm and leg, because the left frontal lobe is also important for body movement, particularly on the right side.
* [[Receptive aphasia]] (also known as "sensory aphasia" or "Wernicke's aphasia"), which is characterized by fluent speech, but marked difficulties understanding words and sentences. Although fluent, the speech may lack in key substantive words (nouns, verbs, adjectives), and may contain incorrect words or even nonsense words. This subtype has been associated with damage to the posterior left temporal cortex, most notably Wernicke's area. These individuals usually have no body weakness, because their brain injury is not near the parts of the brain that control movement.
* [[Conduction aphasia]], where speech remains fluent, and comprehension is preserved, but the person may have disproportionate difficulty repeating words or sentences. Damage typically involves the [[arcuate fasciculus]] and the left parietal region.<ref name="Common Classifications of Aphasia" />
* [[Transcortical motor aphasia]] and [[transcortical sensory aphasia]], which are similar to Broca's and Wernicke's aphasia respectively, but the ability to repeat words and sentences is disproportionately preserved.

Recent classification schemes adopting this approach, such as the Boston-Neoclassical Model,<ref name="Goodglass, H. 2001" /> also group these classical aphasia subtypes into two larger classes: the nonfluent aphasias (which encompasses Broca's aphasia and transcortical motor aphasia) and the fluent aphasias (which encompasses Wernicke's aphasia, conduction aphasia and transcortical sensory aphasia). These schemes also identify several further aphasia subtypes, including: [[anomic aphasia]], which is characterized by a selective difficulty finding the names for things; and [[global aphasia]], where both expression and comprehension of speech are severely compromised.

Many localizationist approaches also recognize the existence of additional, more "pure" forms of language disorder that may affect only a single language skill.<ref name="KolbWhishaw1">{{cite book|title=Fundamentals of human neuropsychology|author1=Kolb, Bryan|author2=Whishaw, Ian Q.|publisher=Worth|year=2003|isbn=978-0-7167-5300-1|location=[New York]|pages=502–504|oclc=464808209}}<!-- The whole paragraph "fluent, non-fluent and pure aphasias" is written with help of this reference.--></ref> For example, in [[pure alexia]], a person may be able to write, but not read, and in [[pure word deafness]], they may be able to produce speech and to read, but not understand speech when it is spoken to them.

==== Cognitive neuropsychological approaches ====
Although localizationist approaches provide a useful way of classifying the different patterns of language difficulty into broad groups, one problem is that most individuals do not fit neatly into one category or another.<ref>{{cite journal | vauthors = Godefroy O, Dubois C, Debachy B, Leclerc M, Kreisler A | title = Vascular aphasias: main characteristics of patients hospitalized in acute stroke units | journal = Stroke | volume = 33 | issue = 3 | pages = 702–705 | date = March 2002 | pmid = 11872891 | doi = 10.1161/hs0302.103653 | doi-access = free }}</ref><ref>{{cite journal |author1=Ross K.B. |author2=Wertz R.T. | year = 2001 | title = Type and severity of aphasia during the first seven months poststroke | journal = Journal of Medical Speech-Language Pathology | volume = 9 | pages = 31–53 }}</ref> Another problem is that the categories, particularly the major ones such as Broca's and Wernicke's aphasia, still remain quite broad and do not meaningfully reflect a person's difficulties. Consequently, even amongst those who meet the criteria for classification into a subtype, there can be enormous variability in the types of difficulties they experience.<ref>{{Cite web |title=What Is Aphasia? — Types, Causes and Treatment |url=https://www.nidcd.nih.gov/health/aphasia |access-date=2022-06-17 |website=NIDCD |date=6 March 2017 |language=en}}</ref>

Instead of categorizing every individual into a specific subtype, cognitive neuropsychological approaches aim to identify the key language skills or "modules" that are not functioning properly in each individual. A person could potentially have difficulty with just one module, or with a number of modules. This type of approach requires a framework or theory as to what skills/modules are needed to perform different kinds of language tasks. For example, the model of [[Max Coltheart]] identifies a module that recognizes [[phonemes]] as they are spoken, which is essential for any task involving recognition of words. Similarly, there is a module that stores phonemes that the person is planning to produce in speech, and this module is critical for any task involving the production of long words or long strings of speech. Once a theoretical framework has been established, the functioning of each module can then be assessed using a specific test or set of tests. In the clinical setting, use of this model usually involves conducting a battery of assessments,<ref>{{cite book |author1=Coltheart, Max |author2=Kay, Janice |author3=Lesser, Ruth |title=PALPA psycholinguistic assessments of language processing in aphasia |publisher=Lawrence Erlbaum Associates |location=Hillsdale, N.J |year=1992 |isbn=978-0-86377-166-8 }}</ref><ref>Porter, G., & Howard, D. (2004). CAT: comprehensive aphasia test. Psychology Press.</ref> each of which tests one or a number of these modules. Once a diagnosis is reached as to the skills/modules where the most significant impairment lies, therapy can proceed to treat these skills.

==== Progressive aphasias ====
[[Primary progressive aphasia]] (PPA) is a neurodegenerative focal dementia that can be associated with progressive illnesses or dementia, such as [[frontotemporal dementia]] / [[Pick's disease|Pick Complex]] [[Motor neuron disease]], [[Progressive supranuclear palsy]], and [[Alzheimer's disease]], which is the gradual process of progressively losing the ability to think. Gradual loss of language function occurs in the context of relatively well-preserved memory, visual processing, and personality until the advanced stages. Symptoms usually begin with word-finding problems (naming) and progress to impaired grammar (syntax) and comprehension (sentence processing and semantics). The loss of language before the loss of memory differentiates PPA from typical dementias. People with PPA may have difficulties comprehending what others are saying. They can also have difficulty trying to find the right words to make a sentence.<ref>{{cite journal | vauthors = Mesulam MM | title = Primary progressive aphasia | journal = Annals of Neurology | volume = 49 | issue = 4 | pages = 425–432 | date = April 2001 | pmid = 11310619 | doi = 10.1002/ana.91 | s2cid = 35528862 }}</ref><ref>{{cite journal | vauthors = Wilson SM, Henry ML, Besbris M, Ogar JM, Dronkers NF, Jarrold W, Miller BL, Gorno-Tempini ML | display-authors = 6 | title = Connected speech production in three variants of primary progressive aphasia | journal = Brain | volume = 133 | issue = Pt 7 | pages = 2069–2088 | date = July 2010 | pmid = 20542982 | pmc = 2892940 | doi = 10.1093/brain/awq129 | url = }}</ref><ref name="Harciarek Kertesz 2011">{{cite journal | vauthors = Harciarek M, Kertesz A | title = Primary progressive aphasias and their contribution to the contemporary knowledge about the brain-language relationship | journal = Neuropsychology Review | volume = 21 | issue = 3 | pages = 271–287 | date = September 2011 | pmid = 21809067 | pmc = 3158975 | doi = 10.1007/s11065-011-9175-9 }}</ref> There are three classifications of Primary Progressive Aphasia : [[Progressive nonfluent aphasia]] (PNFA), [[Semantic Dementia]] (SD), and [[Logopenic progressive aphasia]] (LPA).<ref name="Harciarek Kertesz 2011" /><ref name="Gorno-Tempini 2011">{{cite journal | vauthors = Gorno-Tempini ML, Hillis AE, Weintraub S, Kertesz A, Mendez M, Cappa SF, Ogar JM, Rohrer JD, Black S, Boeve BF, Manes F, Dronkers NF, Vandenberghe R, Rascovsky K, Patterson K, Miller BL, Knopman DS, Hodges JR, Mesulam MM, Grossman M | display-authors = 6 | title = Classification of primary progressive aphasia and its variants | journal = Neurology | volume = 76 | issue = 11 | pages = 1006–1014 | date = March 2011 | pmid = 21325651 | pmc = 3059138 | doi = 10.1212/WNL.0b013e31821103e6 }}</ref>

[[Jargon aphasia|Progressive Jargon Aphasia]]{{citation needed|date=August 2012}} is a fluent or receptive aphasia in which the person's speech is incomprehensible, but appears to make sense to them. Speech is fluent and effortless with intact [[syntax]] and [[grammar]], but the person has problems with the selection of [[noun]]s. Either they will replace the desired word with another that sounds or looks like the original one or has some other connection or they will replace it with sounds. As such, people with jargon aphasia often use [[neologism]]s, and may [[perseveration|perseverate]] if they try to replace the words they cannot find with sounds. Substitutions commonly involve picking another (actual) word starting with the same sound (e.g., clocktower – colander), picking another semantically related to the first (e.g., letter – scroll), or picking one phonetically similar to the intended one (e.g., lane – late).

==== Deaf aphasia ====
There have been many instances showing that there is a form of aphasia among deaf individuals. Sign languages are, after all, forms of language that have been shown to use the same areas of the brain as verbal forms of language. Mirror neurons become activated when an animal is acting in a particular way or watching another individual act in the same manner. These mirror neurons are important in giving an individual the ability to mimic movements of hands. Broca's area of speech production has been shown to contain several of these mirror neurons resulting in significant similarities of brain activity between sign language and vocal speech communication. People use facial movements to create, what other people perceive, to be faces of emotions. While combining these facial movements with speech, a more full form of language is created which enables the species to interact with a much more complex and detailed form of communication. Sign language also uses these facial movements and emotions along with the primary hand movement way of communicating. These facial movement forms of communication come from the same areas of the brain. When dealing with damages to certain areas of the brain, vocal forms of communication are in jeopardy of severe forms of aphasia. Since these same areas of the brain are being used for sign language, these same, at least very similar, forms of aphasia can show in the Deaf community. Individuals can show a form of Wernicke's aphasia with sign language and they show deficits in their abilities in being able to produce any form of expressions. Broca's aphasia shows up in some people, as well. These individuals find tremendous difficulty in being able to actually sign the linguistic concepts they are trying to express.<ref>{{cite book |last=Carlson |first=Neil| name-list-style = vanc |title=Physiology of Behavior |url=https://archive.org/details/physiologybehavi00carl_811 |url-access=limited |year=2013 |publisher=Pearson |location=New York |pages=[https://archive.org/details/physiologybehavi00carl_811/page/n514 494]–496 |isbn=9780205239399}}</ref>

==== Severity ====
The severity of the type of aphasia varies depending on the size of the stroke. However, there is much variance between how often one type of severity occurs in certain types of aphasia. For instance, any type of aphasia can range from mild to profound. Regardless of the severity of aphasia, people can make improvements due to spontaneous recovery and treatment in the acute stages of recovery.<ref name=":5">{{cite journal |vauthors=Robey RR |date=February 1998 |title=A meta-analysis of clinical outcomes in the treatment of aphasia |journal=Journal of Speech, Language, and Hearing Research |volume=41 |issue=1 |pages=172–187 |doi=10.1044/jslhr.4101.172 |pmid=9493743}}</ref> Additionally, while most studies propose that the greatest outcomes occur in people with severe aphasia when treatment is provided in the acute stages of recovery, Robey (1998) also found that those with severe aphasia are capable of making strong language gains in the chronic stage of recovery as well.<ref name=":5" /> This finding implies that persons with aphasia have the potential to have functional outcomes regardless of how severe their aphasia may be.<ref name=":5" /> While there is no distinct pattern of the outcomes of aphasia based on severity alone, global aphasia typically makes functional language gains, but may be gradual since global aphasia affects many language areas.{{citation needed|date=August 2021}}