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.
Memory disorder
Alzheimer's disease (AD) is a progressive, degenerative and fatal brain disease, in which cell to cell connections in the brain are lost. Alzheimer's disease is the most common form of dementia. Globally approximately 1–5% of the population is affected by Alzheimer's disease. Women are disproportionately the victims of Alzheimer's disease, with evidence suggesting that women with AD display more severe cognitive impairment relative to age-matched males with AD, as well as a more rapid rate of cognitive decline.
Amnesia is an abnormal mental state in which memory and learning are affected out of all proportion to other cognitive functions in an otherwise alert and responsive patient. There are two forms of amnesia: Anterograde amnesia and retrograde amnesia, that show hippocampal or medial temporal lobe damage. Anterograde amnesics show difficulty in the learning and retention of information encountered after brain damage. Retrograde Amnesics generally have memories spared about personal experiences or context independent semantic information.