Logorrhea is literally a flow of speech, or pressure of speech, denoting an excessive verbal output, an abnormal number of words produced during each utterance. Content is often irrelevant, disconnected and difficult to interpret. The term may be used of the output in the Wernicke/posterior type of aphasia, or of an output which superficially resembles Wernicke aphasia but in which syntax and morphology are intact, rhythm and articulation are usually normal, and paraphasias and neologisms are few. Moreover comprehension is better than anticipated in the Wernicke type of aphasia. Patients may be unaware of their impaired output (anosognosia) due to a failure of self-monitoring.
Logorrhea may be observed in subcortical (thalamic) aphasia, usually following recovery from lesions (usually hemorrhage) to the anterolateral nuclei. Similar speech output may be observed in psychiatric disorders, such as mania and schizophrenia.
Damasio AR. Aphasia. New England Journal of Medicine 1992; 326: 531-539