Word Deafness

WORD DEAFNESS, WORD BLINDNESS (sur-ditas, cecitas verbalis), symptoms characterized by the inability to understand heard speech (W. d.) or written text (W. b., or alexia); both of these symptoms are observed in sensory aphasia (see Aphasia); the more pronounced of these symptoms gives a specific coloring to the clinical picture. In polyglots, W. d. may occur only with respect to one language. When understanding of music is impaired, it is called amusia. A patient with word blindness, while maintaining visual acuity, can well differentiate various handwriting styles, noting their characteristic features, but does not understand the meaning of what is written. Various degrees of intensity of word blindness are observed; when the patient does not understand the meaning of the individual letters, this disorder is classified under the concept of 'letter blindness' (cecitas litteralis): the inability to connect letters into syllables gives asyllabia (asyllabia). Word blindness can also extend to understanding of numbers, with inability to perform numerical operations (acalculia); finally, word blindness can also occur with respect to musical signs - inability to read music - cecitas musicalis. It is hypothesized that word blindness is caused by a lesion of the gyrus angularis or the underlying white matter, while word deafness is caused by a lesion of the gyrus temporalis superior or the white matter of the same area.