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Background: Spatial navigation performance in the Hidden Goal Task (HGT), a real-space human analogue of the Morris Water Maze, can identify amnestic mild cognitive impairment (aMCI) patients with memory impairment of the hippocampal type, a known indicator of incipient Alzheimer's disease (AD). Objective: Contrast results from computer versus real-space versions of the HGT. Methods: A total of 42 aMCI patients were clinically and neuropsychologically classified into: (1) memory impairment of the hippocampal type - the hippocampal aMCI (HaMCI; n = 10) and (2) isolated retrieval impairment - the nonhippocampal aMCI (NHaMCI; n = 32). Results were compared to the control (n = 28) and AD (n = 21) groups. Results: The HaMCI group, although similar to the NHaMCI group with respect to overall cognitive impairment, performed poorer on the computer version of the HGT and yielded parallel results to the real-space version. The two versions were strongly correlated. Conclusions: Both versions of the HGT can reliably identify aMCI with pronounced memory impairment of the hippocampal type. The computer version of the HGT may be a useful, relatively inexpensive screening tool for early detection of individuals at a high risk of AD. Copyright © 2011 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Background: Patients with Alzheimer’s disease (AD) and amnestic mild cognitive impairment (MCI) have difficulties with spatial orientation. Objective: To test hypothesis that spatial navigation is impaired early in MCI patients representing the presymptomatic stage of AD. Methods: We tested patients with probable AD (n = 21), MCI, further classified according to Petersen’s criteria as amnestic MCI (aMCI) single domain (n = 11), aMCI multiple domain (n = 31), or nonamnestic MCI (n = 7). The aMCI group was also stratified using cued recall according to Dubois’ criteria into memory impairment of the hippocampal type (n = 10) and isolated memory retrieval impairment-nonhippocampal (n = 32) and also according to ApoE4 status into E4+ (n = 12) and E4– (n = 30). These patients and controls (n = 28) were tested in the human variant of the Morris water maze. Depending on the subtest, the subjects could use the egocentric or allocentric (hippocampus-dependent) navigation. Results: The AD and aMCI multiple domain groups were impaired in all subtests. The aMCI single domain group was impaired in allocentric subtests. The hippocampal MCI group performed poorer than the nonhippocampal MCI group and similarly to the AD group. The ApoE4+ group was as bad as the AD group when compared with the E4– group. Conclusion: aMCI subjects represent a very heterogeneous population, and spatial memory or cued recall examination can add more value to aMCI classification. ApoE4+ patients are more impaired than ApoE4– patients. Copyright © 2010 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

The results of neuropsychological tests may be distorted by patients who exaggerate cognitive deficits. Eighty-three patients with cognitive deficit [Amnestic Mild Cognitive Impairment (aMCI), n = 53; Alzheimer's disease (AD) dementia, n = 30], 44 healthy older adults (HA), and 30 simulators of AD (s-AD) underwent comprehensive neuropsychological assessment. Receiver Operating Characteristic (ROC) analysis revealed high specificity but low sensitivity of the Delayed Matching to Sample Task (DMS48) in differentiating s-AD from AD dementia (87 and 53%, respectively) and from aMCI (96 and 57%). The sensitivity was considerably increased by using the DMS48/Rey Auditory Verbal Learning Test (RAVLT) ratio (specificity and sensitivity 93% and 93% for AD dementia and 96% and 80% for aMCI). The DMS48 differentiates s-AD from both aMCI and AD dementia with high specificity but low sensitivity. Its predictive value greatly increased when evaluated together with the RAVLT. [ABSTRACT FROM AUTHOR]

Introduction Path integration (PI) is an important component of spatial navigation that integrates self-motion cues to allow the subject to return to a starting point. PI depends on the structures affected early in the course of Alzheimer’s disease (AD) such as the medial temporal lobe and the parietal cortex. Objectives To assess whether PI is impaired in patients with mild AD and amnestic mild cognitive impairment (aMCI) and to investigate the role of the hippocampus, entorhinal and inferior parietal cortex in this association. Methods 27 patients with aMCI, 14 with mild AD and 18 controls completed eight trials of Arena Path Integration Task. The task required subjects with a mask covering their eyes to follow an enclosed triangle pathway through two previously seen places: start–place1–place2–start. Brains were scanned at 1.5T MRI and respective volumes and thicknesses were derived using FreeSurfer algorithm. Results Controlling for age, education, gender and Mini-Mental State Examination score the aMCI and AD subjects were impaired in PI accuracy on the pathway endpoint (p = 0.042 and p = 0.013) compared to controls. Hippocampal volume and thickness of entorhinal and parietal cortices explained separately 36–45% of the differences in PI accuracy between controls and aMCI and 28–31% of the differences between controls and AD subjects. Conclusions PI is affected in aMCI and AD, possibly as a function of neurodegeneration in the medial temporal lobe structures and the parietal cortex. PI assessment (as a part of spatial navigation testing) may be useful for identification of patients with incipient AD. [ABSTRACT FROM AUTHOR]