Receptive aphasia

Overview
Receptive aphasia, also known as Wernicke’s aphasia, fluent aphasia, or sensory aphasia in clinical neuropsychology and cognitive neuropsychology, is a type of aphasia often (but not always) caused by neurological damage to Wernicke’s area in the brain (Brodman area 22, in the posterior part of the superior temporal gyrus of the dominant hemisphere). This is not to be confused with Wernicke’s encephalopathy or Wernicke-Korsakoff syndrome. The aphasia was first described by Carl Wernicke and its understanding substantially advanced by Norman Geschwind.

Presentation
If Wernicke’s area is damaged in the non-dominant hemisphere, the syndrome resulting will be sensory dysprosody - the lack of ability to perceive the pitch, rhythm, and emotional tone of speech.

Speech is preserved, but language content is incorrect. This may vary from the insertion of a few incorrect or nonexistent words to a profuse outpouring of jargon. Grammar, syntax, rate, intonation and stress are normal. Substitutions of one word for another (paraphasias, e.g. “telephone” for “television”) are common. Comprehension and repetition are poor.

Example:


 * I called my mother on the television and did not understand the door. It was too breakfast, but they came from far to near. My mother is not too old for me to be young.

If excessive, this may be confused with the psychiatric signs of “pressure of speech” and “word salad.”

Patients who recover from Wernicke’s aphasia report that, while aphasic, they found the speech of others to be unintelligible and, despite being cognizant of that fact that they were speaking, they could neither stop themselves nor understand their own words.

The ability to understand and repeat songs is usually unaffected, as these are processed by the opposite hemisphere. "Melodic intonation therapy" had been pursued for some years with aphasic patients under the belief that it helps stimulate the ability to speak normally, but in 2003 this was found to not be so. Patients also generally have no trouble purposefully reciting anything they have memorized. The ability to utter profanity is also left unaffected, however the patient typically has no control over it, and may not even understand their own profanity.

Luria's theory on Wernicke's aphasia
Luria proposed that this type of aphasia has three characteristics.


 * 1) A deficit in the categorization of sounds. In order to hear and understand what is said, one must be able to recognize the different sounds of spoken language. For example, hearing the difference between bad and bed is easy for native English speakers. The Dutch language however, makes no difference between these vowels, and therefore the Dutch have difficulties hearing the difference between them. This problem is exactly what patients with Wernicke’s aphasia have in their own language: they can't isolate significant sound characteristics and classify them into known meaningful systems.


 * 2) A defect in speech. A patient with Wernicke's aphasia can and may speak a great deal, but he or she confuses sound characteristics, producing “word salad”: intelligible words that appear to be strung together randomly.


 * 3) An impairment in writing. A person who cannot discern sounds cannot be expected to write.