Cognitive impairment is very common and is associated with many neurological and systemic disorders. Cognitive impairment is an umbrella term that comprises a number of conditions ranging from confusional state (or delirium) to severe dementia in patients with Alzheimer’s disease (AD). Neurologists together with primary care physicians play an important role in the assessment, interpretation, and treatment of symptoms, disability, and needs of patients with cognitive deficits. Delirium is discussed in Chapter 2. The present chapter is focused on clinical disorders associated with cognitive impairment leading to dementia (Table 3.1) and comprises three sections. In the first, the main cognitive functions are reviewed along with their anatomical correlates, and the most important (and common) cognitive deficits are defined. In the second, basic clinical, cognitive, and laboratory investigations recommended in the assessment of patients with cognitive impairment are described, with a particular focus on neuroimaging techniques. In the last section, clinical and cognitive findings and diagnostic work-up of the principal treatable, vascular, and neurodegenerative causes of cognitive impairment are discussed. Cognitive functions and impairment Memory “Leonard Shelby: Burt. I’m not sure, I think I may have asked you to hold my calls. Burt: You don’t know? Leonard Shelby: Well, I think I may have. I’m not too good on the phone. Burt: Right, you said you like to look people in the eye when you talk to them. Leonard Shelby: Yeah, yeah. Burt: You don’t remember saying that. Leonard Shelby: Well, that’s the thing. I have this condition. Burt: A condition? Leonard Shelby: It’s my memory […]. I have no short-term memory. I know who I am, I know all about myself. I just… since my injury I can’t make new memories. Everything fades. If we talk for too long I’ll forget how we started and next time I see you I’m not gonna remember this conversation. I don’t even know if I’ve met you before. So if I seem a little strange or rude, or something, uh… [He notices Burt is staring at him strangely] Leonard Shelby: I’ve told you this before, haven’t I? Burt: Yeah… I don’t mean to mess with you but it’s so weird. You don’t remember me at all? Leonard Shelby: No. Burt: We’ve talked a bunch of times. Leonard Shelby: I’m sure we have.” From “Memento”, a Christopher Nolan movie.
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