![]() ![]() ![]() Working memory is memory for the short term and operates to marshal the necessary neurocognitive resources to initiate a response as requested. Subordinate to this temporal gestalt are three separate, but highly integrated neurocognitive constructs that govern how time is allocated - working memory, preparatory set, and inhibitory control. This model views the time necessary to bring a task to fruition as a temporal gestalt. Past research demonstrating this time-related, dysexecutive impairment has been interpreted within the context of Fuster’s model of executive attention. Patients with VaD and some MCI patients tend to produce a negative slope on executive tests when outcome is measured as a function of time. Another heuristic mechanism that may be used to evaluate constructs that underlie executive difficulty in dementia and MCI is to assess performance as a function test epoch. The research reviewed above provides useful heuristics to understand the constructs that underlie executive difficulty in dementia and MCI. Focal deficits involving language and visuospatial operations can occur however, these syndromes are comparatively rare. Serial-list learning test performance is often replete with elements consistent with amnesia (see ref 1– 3 for a complete review). The errors made on tests assessing verbal concept formation tend to be vague, but retain some context to provide a supraordinate concept that binds the word pair (dog–lion: “I like them”). Among these patients, graphomotor perseverations have been shown to be highly associated with naming and lexical access problems. subordinate to other more pervasive neuropsychological problems. MEMORY PATIENT KF DIGIT SPAN SERIALWhen memory is assessed with the serial list-learning test, patients with executive impairment often present with retrieval, rather than consolidation problems.īy contrast, the dysexecutive syndrome associated with AD and other MCI patients is “context dependent”, i.e. On tests that assess verbal concept formation (e.g., the Similarities subtest) patients with VaD and some MCI patients demonstrate a gross inability to assume an abstract attitude and treat each element of the word pair as a separate test stimulus (e.g., dog–lion: “one is a pet and the other roars”). Thus, on tests examining the production of graphomotor perseveration, patients with VaD tend to produce errors suggesting an inability to desist from a motor act. This means that elements of a dysexecutive syndrome can be found across virtually all neurocognitive domains that might be assessed. Past research has shown that dysexecutive impairment in VaD associated with magnetic resonance imaging (MRI) white matter alterations and among some MCI patients is “context independent”. Dysexecutive impairment is common in patients with dementia syndromes such as Alzheimer’s disease (AD) and vascular dementia (VaD), and in patients with mild cognitive impairment (MCI). ![]()
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