Wernicke’s aphasia is the classical "receptive aphasia", in distinction to the "expressive aphasia" of Broca, although this classification is problematic since there are concurrent "expressive" problems in Wernicke’s aphasia.
Considering each of the features suggested for the clinical classification of aphasias (see Aphasia), Wernicke’s aphasia is characterized by:
- Fluency: fluent speech with phonemic and semantic paraphasias and paragrammatism (inappropriate use of syntax); "empty speech" with few verbs and nouns; prosody usually preserved; at worst, flowing speech (logorrhea) devoid of semantic meaning (jargon aphasia, semantic aphasia); automatic speech is often better preserved than spontaneous, e.g., counting, days of week, overlearned phrases ("I’m fine").
- Comprehension: impaired auditory comprehension (sine qua non; "word deafness"); impaired reading comprehension probably also required (not specifically discussed by Wernicke).
- Repetition: impaired.
- Naming: severely impaired (anomia) and not aided by cueing (cf. Broca’s aphasia).
- Reading: usually impaired, with numerous paralexic errors, and impaired reading comprehension (cf. pure word deafness).
- Writing: similarly affected.
There may be associated anxiety, with or without agitation and paranoia, and concurrent auditory agnosia.
The neuroanatomical substrate of Wernicke’s aphasia has been a subject of debate. Wernicke placed it in the posterior two-thirds of the superior temporal gyrus and planum temporale (Brodmann area 22), but more recent neuroradiological studies (structural and functional imaging) suggest that this area may be more associated with the generation of paraphasia whereas more ventral areas of temporal lobe and angular gyrus (Brodmann areas 37, 39 and 40) may be associated with disturbance of comprehension. A correlation exists between the size of the lesion and the extent of the aphasia. A similar clinical picture may occur with infarcts of the head of the left caudate nucleus and left thalamic nuclei.
The differential diagnosis of Wernicke’s aphasia includes delirium and schizophasia.
Binder JR. Wernicke aphasia: a disorder of central language processing. . In: D’Esposito M (ed.). Neurological foundations of cognitive neuroscience. Cambridge: MIT Press, 2003: 175-238
Wise RJS, Scott SK, Blank SC, Mummery CJ, Murphy K, Warburton EA. Separate neural subsystems within "Wernicke’s area." Brain 2001; 124: 83-95