Paraphasias are a feature of aphasias (disorders of language), particularly (but not exclusively) fluent aphasias resulting from posterior dominant temporal lobe lesions (cf. anterior lesions which tend to produce nonfluent aphasias with agrammatism). Paraphasias refer to a range of speech output errors including substitution, addition, duplication, omission and transposition of linguistic units, affecting letters within words, letters within syllables, or words within sentences. Paraphasic errors may be categorized as:
- Phonemic or literal:
Errors involve individual phonemes; impaired phonology (i.e., sound based) causing approximations to real words; nonwords resulting from phonemic paraphasia may be referred to as neologisms. Phonemic paraphasias may be encountered in Broca’s aphasia and conduction aphasia, when the patient may recognize them to be errors, and Wernicke’s aphasia.
Target word is replaced by another word that is phonemically similar.
Errors involving word stems, suffixes, prefixes, inflections and other parts of words.
Errors involving whole words. These may be further classified as:
Semantic or categoric: substitution of a different exemplar from the same category (e.g., "orange" for "apple"; paradig-matic) or of a thematically related word (e.g., "sit" for "chair’; syntagmatic). Verbal paraphasias showing both semantic and phonemic resemblance to the target word are called mixed errors. These types may be observed in patients with Wernicke’s aphasia, who often seem unaware of their paraphasias due to a failure of self-monitoring of output.
Buckingham HW, Kertesz A. Neologistic jargon aphasia. Amsterdam: Swets & Zeitlinger, 1976