Speech perception
Agnosia is "the loss or diminution of the ability to recognize familiar objects or stimuli usually as a result of brain damage". There are several different kinds of agnosia that affect every one of our senses, but the two most common related to speech are speech agnosia and phonagnosia.
Auditory agnosia
Auerbach et al considered word deafness and general auditory agnosia as two separate disorders, and labelled general auditory agnosia as pre-phonemic auditory agnosia and word deafness as post-phonemic auditory agnosia. They suggested that pre-phonemic auditory agnosia manifests because of general damage to the auditory cortex of both hemispheres, and that post-phonemic auditory agnosia manifests because of damage to a spoken word recognition center in the left hemisphere. Recent evidence, possibly verified Auerbach hypothesis, since an epileptic patient who undergone electro-stimulation to the anterior superior temporal gyrus was demonstrated a transient loss of speech comprehension, but with intact perception of environmental sounds and music.