aphasia aphasia aphasia is an inability to comprehend or formulate language because of damage to specific brain regions. the major causes are stroke and head trauma; prevalence is hard to determine but aphasia due to stroke is estimated to be 0.1–0.4% in the global north. aphasia can also be the result of brain tumors, brain infections, or neurodegenerative diseases (such as dementias). not to be confused with aphakia, aphagia, or aphantasia. aphasiaregions of the left hemisphere that can give rise to aphasia when damagedpronunciation/əˈfeɪʒə/, /əˈfeɪziə/ or /eɪˈfeɪziə/ specialtyneurology, psychiatrytreatmentspeech therapy to be diagnosed with aphasia, a person's speech or language must be significantly impaired in one (or more) of the four aspects of communication following acquired brain injury. alternatively, in the case of progressive aphasia, it must have significantly declined over a short period of time. the four aspects of communication are auditory comprehension, verbal expression, reading and writing, and functional communication. the difficulties of people with aphasia can range from occasional trouble finding words, to losing the ability to speak, read, or write; intelligence, however, is unaffected. expressive language and receptive language can both be affected as well. aphasia also affects visual language such as sign language. in contrast, the use of formulaic expressions in everyday communication is often preserved. for example, while a person with aphasia, particularly expressive aphasia (broca's aphasia), may not be able to ask a loved one when their birthday is, they may still be able to sing "happy birthday". one prevalent deficit in the aphasias is anomia, which is a difficulty in finding the correct word.: 72 with aphasia, one or more modes of communication in the brain have been damaged and are therefore functioning incorrectly. aphasia is not caused by damage to the brain that results in motor or sensory deficits, which produces abnormal speech; that is, aphasia is not related to the mechanics of speech but rather the individual's language cognition (although a person can have both problems, as an example, if they have a haemorrhage that damaged a large area of the brain). an individual's language is the socially shared set of rules, as well as the thought processes that go behind communication (as it affects both verbal and nonverbal language). it is not a result of a more peripheral motor or sensory difficulty, such as paralysis affecting the speech muscles or a general hearing impairment. neurodevelopmental forms of auditory processing disorder are differentiable from aphasia in that aphasia is by definition caused by acquired brain injury, but acquired epileptic aphasia has been viewed as a form of apd. prevalence aphasia affects about two million people in the u.s. and 250,000 people in great britain. nearly 180,000 people acquire the disorder every year in the u.s., 170,000 due to stroke. any person of any age can develop aphasia, given that it is often caused by a traumatic injury. however, people who are middle aged and older are the most likely to acquire aphasia, as the other etiologies are more likely at older ages. for example, approximately 75% of all strokes occur in individuals over the age of 65. strokes account for most documented cases of aphasia: 25% to 40% of people who survive a stroke develop aphasia as a result of damage to the language-processing regions of the brain. aphasia and dysphasia "dysphasia" redirects here. not to be confused with dysphagia. technically, dysphasia means impaired language and aphasia means lack of language. there have been calls to use the term 'aphasia' regardless of severity. reasons for doing so include dysphasia being easily confused with the swallowing disorder dysphagia, consumers and speech pathologists preferring the term aphasia, and many languages other than english using a word similar to aphasia. the term "aphasia" is more commonly used in north america, while "dysphasia" is more frequently used elsewhere. signs and symptoms people with aphasia may experience any of the following behaviors due to an acquired brain injury, although some of these symptoms may be due to related or concomitant problems, such as dysarthria or apraxia, and not primarily due to aphasia. aphasia symptoms can vary based on the location of damage in the brain. signs and symptoms may or may not be present in individuals with aphasia and may vary in severity and level of disruption to communication. often those with aphasia may have a difficulty with naming objects, so they might use words such as thing or point at the objects. when asked to name a pencil they may say it is a “thing used to write”. inability to comprehend language inability to pronounce, not due to muscle paralysis or weakness inability to form words inability to recall words (anomia) poor enunciation excessive creation and use of personal neologisms inability to repeat a phrase persistent repetition of one syllable, word, or phrase (stereotypies, recurrent/recurring utterances/speech automatism) also known as perseveration. paraphasia (substituting letters, syllables or words) agrammatism (inability to speak in a grammatically correct fashion) speaking in incomplete sentences inability to read inability to write limited verbal output difficulty in naming speech disorder speaking gibberish inability to follow or understand simple requests related behaviors given the previously stated signs and symptoms, the following behaviors are often seen in people with aphasia as a result of attempted compensation for incurred speech and language deficits: self-repairs: further disruptions in fluent speech as a result of mis-attempts to repair erred speech production. struggle in non-fluent aphasias: a severe increase in expelled effort to speak after a life where talking and communicating was an ability that came so easily can cause visible frustration. preserved and automatic language: a behavior in which some language or language sequences that were used so frequently prior to onset are still produced with more ease than other language post onset. subcortical subcortical aphasias characteristics and symptoms depend upon the site and size of subcortical lesion. possible sites of lesions include the thalamus, internal capsule, and basal ganglia. causes aphasia is most often caused by stroke, where about a quarter of patients who experience an acute stroke develop aphasia. 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, and progressive neurological disorders. in rare cases, aphasia may also result from herpesviral encephalitis. the herpes simplex virus affects the frontal and temporal lobes, subcortical structures, and the hippocampal tissue, which can trigger aphasia. 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. substantial damage to tissue anywhere within the region shown in blue (on the figure in the infobox above) can potentially result in aphasia. aphasia can also sometimes be caused by damage to subcortical structures deep within the left hemisphere, including the thalamus, the internal and external capsules, and the caudate nucleus of the basal ganglia. the area and extent of brain damage or atrophy will determine the type of aphasia and its symptoms. 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. 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. epilepsy can also include transient aphasia as a prodromal or episodic symptom. aphasia is also listed as a rare side-effect of the fentanyl patch, an opioid used to control chronic pain. 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). however, no such broad-based grouping has proven fully adequate. 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. it is important to note that 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.: 7 boston classification major characteristics of different types of aphasia according to the boston classification 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 aphasia), also referred to as fluent aphasia, may speak in long sentences that have no meaning, add unnecessary words, and even create new "words" (neologisms). 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.: 71 it is often the result of trauma to the temporal region of the brain, specifically damage to wernicke's area. trauma can be the result from an array of problems, however it is most commonly seen as a result of stroke individuals with expressive aphasia (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. 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. 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..., i can't...'), 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. individuals with anomic aphasia have difficulty with naming. people with this aphasia may have