Appendix: Common Classifications of Aphasiaa
- A type of nonfluent aphasia, so called because speech production is halting and effortful. Damage is typically in the anterior portion of the left hemisphere. The dominant feature is agrammatism (impaired syntax). Content words (nouns, verbs) may be preserved but sentences are difficult to produce due to the problems with grammar, resulting in "telegraphic speech." In its more severe form, spoken utterances may be reduced to single words. Comprehension is typically only mildly to moderately impaired, and impairments are primarily due to difficulty understanding complex grammar. Repetition of words and sentences is usually poor.
- A type of fluent aphasia. Damage is typically in the posterior portion of the left hemisphere. Comprehension is poor and the person often produces jargon, or nonsensical words and phrases when attempting to speak. These utterances typically retain sentence structure but lack meaning. The person is usually unaware of how they are speaking and may continue to talk even when they should pause to allow others to speak; this is often referred to as "press of speech." Repetition of words and sentences is poor.
- A type of nonfluent aphasia with severe impairment of both expressive and receptive skills. Usually associated with a large left hemisphere lesion. People are often alert and may be able to express themselves through facial expressions, intonation, and gestures.
- A type of fluent aphasia with a prominent impairment with repetition. Damage typically involves the arcuate fasciculus and the left parietal region. The patient may be able to express him- or herself fairly well, with some word-finding issues, and comprehension can be functional. However, the patient will show significant difficulty repeating phrases, particularly as the phrases increase in length and complexity and as they stumble over words they are attempting to pronounce. This type of aphasia is rare.
- A mild form of aphasia. The most prominent difficulty is in word-finding, with the person using generic fillers in utterances, such as nonspecific nouns and pronouns (e.g., "thing"), or circumlocution, where the person describes the intended word. Comprehension and repetition of words and sentences is typically good; however, the person may not always recognize that a word they have successfully retrieved is the correct word, indicating some difficulty with word recognition.
- Transcortical Sensory
- A type of fluent aphasia similar to Wernicke's with the exception of a strong ability to repeat words and phrases. The person may repeat questions rather than answer them ("echolalia").
- Transcortical Motor
- A type of nonfluent aphasia similar to Broca's aphasia, but again with strong repetition skills. The person may have difficulty spontaneously answering a question but can repeat long utterances without difficulty.
- Mixed Transcortical
- A combination of the two transcortical aphasias where both reception and expression are severely impaired but repetition remains intact.
- A type of aphasia that occurs when a person's language centers are not in the expected hemisphere. In most right-handed individuals, language centers are located in the left hemisphere. This is also true for a majority of left-handed people, although there are exceptions for both groups. An example of crossed aphasia would be a right-handed person who has a right hemisphere stroke which results in aphasia.
- A form of aphasia that results from damage to subcortical regions such as the thalamus, internal capsule, and the basal ganglia. The symptoms can mirror those arising from cortical lesions, and subcortical damage can also co-occur with cortical lesions. Aphasic symptoms can arise from diaschisis (remote effects), such as subcortical inputs to the frontal lobe being altered, or may directly stem from damage to subcortical areas that support language processing.
- Primary Progressive Aphasia (ppA)
- Primary Progressive Aphasia (PPA): A focal dementia (or focal cortical atrophy syndrome) characterized by gradual loss of language function in the context of relatively well-preserved memory, visual processing, and personality until the advanced stages. Symptoms usually begin with word-finding problems and progress to impaired grammar (syntax) and comprehension (sentence processing and semantics). Symptoms associated with impaired speech production can also accompany PPA, such as dysarthria and apraxia of speech. Typically, a diagnosis of PPA is made following a 2-year decline in language function not accompanied by any marked decline in other cognitive functions. (However, a 2-year hiatus in making a definitive diagnosis should not delay proactive management of the aphasia and general life planning.) Structural and physiological abnormalities are typically noted only in the left hemisphere language-related cortices (i.e., frontal, parietal and temporal regions). PPA is not due to neoplastic, vascular, or metabolic etiologies nor to infectious disease (Mesulam, 2001; Rogers, 2004).
Note. From Aphasiology: Disorders and Clinical Practice p. 33-39, by G. A. Davis, 2007, Boston, MA: Allyn & Bacon. Copyright 2007 by Allyn & Bacon. Adapted with permission.
a It is important to note that written language deficits tend to be similar in nature to the spoken language deficits described in the table, although the severity of written and spoken language problems may not be exact.