It often develops after a stroke or brain injury. The patient's speech is fluent but is error-prone, e.g. 'treen' instead of 'train'.
Paraphasia can be further sub-divided into 3 categories: Literal/phonological paraphasia, neologistic paraphasias and verbal paraphasias. In literal/phonological paraphasia, more than half of the spoken word is said correctly. An example could be saying pun instead of spun. Neologistic refers to a spoken word that is said less than half correct. Occasionally the word is not said correctly at all, for example Balenti for Banana. This sometimes occurs in the speech of patients with schizophrenia. The last is verbal paraphasia where another word is substituted for the target word. A common example is saying dog instead of cat.
While low-frequency paraphasic errors can occur in normal speech, paraphasias (particularly phonological paraphasias) are considerably more common in Wernicke's aphasia and in Sensory Transcortical Aphasia.
- Phonemic paraphasia, also literal paraphasia - Mispronunciation, syllables out of sequence. e.g. "I slipped on the lice (ice) and broke my arm."
- Verbal paraphasia - Substitution of words
- Semantic paraphasia - The substituted word is related to the intended word. e.g. "I spent the whole day working on the television, I mean, computer."
- Remote paraphasia - The substituted word is, at most, distantly related to the intended word. e.g. "You forgot your musketeer, I mean, umbrella."
- Neologistic paraphasia - More severe mispronunciation, in which less than half the word is said correctly.
Perseverative paraphasia - previous response persists, interferes with retrieval of new responses. For an example please see the experimental case study D.L.A published by Dennis in 1976