Cortical+Deafness

Causes
-When both primary auditory receiving areas   and their subcortical axonal connections have been destroyed (e.g. bilateral middle cerebral artery stroke)

Sounds continue to be processed subcortically. Hence the ability to hear sounds per se, is retained. Nevertheless, since the sounds which are heard are not received neocortically and thus cannot be transmitted to the adjacent associaiton areas, sounds become stripped of meaning.

Symptoms
-Auditory Agnosia (Sounds are heard but do not reach the association areas so meaning cannot be extracted or assigned) -Differences in auditory intensity can be discerned. Much like Cortical Blindness

-Patients cannot respond to questions -No startle responses to loud sounds -Lose the ability to discern the melody for music -Cannot recognize speech or environmental sounds -Tend to experience the sounds they do hear as distorted and disagreeable, e.g. like the banging of tin cans or buzzing -Retain ability to read, write, speak, comprehend pantomime, and are fully aware of their deficit (no aphasia) -Speech is sometimes noted to be hypophonic and contaminated by occasional literal paraphasias.
 * Bilateral Lesions **

<span style="font-family: Times New Roman,serif;">-Difficulty discriminating sequences of sound <span style="font-family: Times New Roman,serif;">-Detecting difference in temporal patterning <span style="font-family: Times New Roman,serif;">-Determining sound duration wheareas intensity discriminations are better preserved. <span style="font-family: Times New Roman,serif;">-Auditory inattention <span style="font-family: Times New Roman,serif;">-Failure to respond to loud sounds
 * <span style="font-family: Times New Roman,serif;">**May Have** **

<span style="font-family: Times New Roman,serif;">In some instances, a destructive lesion may be limited to the primary receiving area of just the right or left cerebral hemisphere. These patient's are not considered cortically deaf. When the auditory receiving area of the left temporal lobe is destroyed the patient suffers from pure word deafness <span style="font-family: Times New Roman,serif;">. If the lesion is in the right temporal receiving area, the patient is more likely to suffer a non-verbal auditory agnosia.
 * <span style="font-family: Times New Roman,serif;">Unilateral Lesions **