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.
Cognitive flexibility
Diminished cognitive flexibility has been noted in a variety of neuropsychiatric disorders such as anorexia nervosa, obsessive–compulsive disorder, schizophrenia, autism, and in a subset of people with ADHD. Each of these disorders exhibit varying aspects of cognitive inflexibility. For example, those with obsessive–compulsive disorder experience difficulty shifting their attentional focus as well as inhibiting motor responses. Children with autism show a slightly different profile with deficits in adjusting to changing task contingencies, while often maintaining the ability to respond in the face of competing responses. Potential treatments may lie in neurochemical modulation. Juveniles with Anorexia nervosa have marked decreases in set-shifting abilities, possibly associated with incomplete maturation of prefrontal cortices associated with malnutrition. One can also consider people with addictions to be limited in cognitive flexibility, in that they are unable to flexibly respond to stimuli previously associated with the drug.