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.
Associative visual agnosia
Most cases have injury to the occipital and temporal lobes and the critical site of injury appears to be in the left occipito-temporal region, often with involvement of the splenium of the corpus callosum. The etiology of the cognitive impairment, as well the areas of the brain affected by lesions and stage of recovery are the primary determinants of the pattern of deficit. More generalized recognition impairments, such as, animate object deficits, are associated with diffuse hypoxic damage, like carbon monoxide poisoning; more selective deficits are correlated with more isolated damage due to focal stroke.