Aphasia (pronounced /əˈfeɪʒə/ or pronounced /əˈfeɪziə/), from the Greek root word "aphatos", meaning speechless, is an acquired language disorder in which there is an impairment of any language modality. This may include difficulty in producing or comprehending spoken or written language.
Traditionally, aphasia suggests the total impairment of language ability, and dysphasia a degree of impairment less than total. However, the term dysphasia is commonly confused with dysphagia, a swallowing disorder, and thus aphasia has come to mean both partial and total language impairment in common use.
Depending on the area and extent of brain damage, someone suffering from aphasia may be able to speak but not write, or vice versa, or display any of a wide variety of other deficiencies in language comprehension and production, such as being able to sing but not speak.Aphasia can be assessed in a variety of ways, from quick clinical screening at the bedside to several-hour-long batteries of tasks that examine the key components of language and communication. The prognosis of those with aphasia varies widely, and is dependent upon age of the patient, site and size of lesion, and type of aphasia.
Fluent, non-fluent and "pure" aphasias
The different types of aphasia can be divided into three categories: fluent, non-fluent and "pure" aphasias.
Fluent aphasias, also called receptive aphasias, are impairments related mostly to the input or reception of language, with difficulties either in auditory verbal comprehension or in the repetition of words, phrases, or sentences spoken by others. Speech is easy and fluent, but there are difficulties related to the output of language as well, such as paraphasia. Examples of fluent aphasias are: Wernicke's aphasia, Transcortical sensory aphasia, Conduction aphasia, Anomic aphasia
Non fluent aphasias, also called expressive aphasias are difficulties in articulating, but in most cases there is relatively good auditory verbal comprehension. Examples of nonfluent aphasias are: Broca's aphasia, Transcortical motor aphasia, Global aphasia
"Pure" aphasias are selective impairments in reading, writing, or the recognition of words. These disorders may be quite selective. For example, a person is able to read but not write, or is able to write but not read. Examples of pure aphasias are: Pure alexia, Agraphia, Pure word deafness
Primary and secondary aphasia
Aphasia can be divided into primary and secondary aphasia.
Primary aphasia is due to problems with language-processing mechanisms.
Secondary aphasia is the result of other problems, like memory impairments, attention disorders, or perceptual problems.
Acquired childhood aphasia
Acquired childhood aphasia (ACA) is a language impairment resulting from some kind of brain damage. This brain damage can have different causes, such as head trauma, tumors, cerebrovascular accidents, or seizure disorders. Most, but not all authors state that ACA is preceded by a period of normal language development. Age of onset is usually defined as from infancy until but not including adolescence.
ACA should be distinguished from developmental aphasia or developmental dysphasia, which is a primary delay or failure in language acquisition.[4] An important difference between ACA and developmental childhood aphasia is that in the latter there is no apparent neurological basis for the language deficit.
ACA is one of the more rare language problems in children and is notable because of its contribution to theories on language and the brain.[4] Because there are so few children with ACA, not much is known about what types of linguistic problems these children have. However, many authors report a marked decrease in the use of all expressive language. Children can just stop talking for a period of weeks or even years, and when they start to talk again, they need a lot of encouragement. Problems with language comprehension are less common in ACA, and don't last as long.
