Development of a questionnaire on everyday navigational ability to assess topographical disorientation in Alzheimer's disease.

We developed a Questionnaire on Everyday Navigational Ability (QuENA) to detect topographical disorientation (TD) in patients with Alzheimer's disease (PwAD). In the QuENA, 3 items were designed to assess landmark agnosia, 2 for egocentric disorientation, 3 for heading disorientation, and 2 for inattention. The PwAD and their caregivers rated QuENA according to which TD symptoms would occur. Regarding the construct validity, confirmatory factor analysis showed that the caregiver version of the QuENA fits the proposed TD model well but the patient version does not. Regarding the internal consistency, the Cronbach's α for the caregiver version was 0.91 and that for the patient version was 0.87. A discrepancy existed between the appraisal of navigational abilities by PwAD and by caregivers, and it was correlated with the number of getting lost (GL) events. The caregiver version of QuENA is a feasible, reliable, and valid instrument to assess TD and it also discriminates well between the PwAD with GL and those without.

Recognition of personally familiar scenes in patients with very mild Alzheimer's disease: effects of spatial frequency and luminance.

Many community-residing patients with Alzheimer's disease (AD) have way-finding problems, particularly at twilight or on rainy days. In an attempt to understand the mechanism, we prepared pictures of street scenes, including 8 personally familiar and 8 unfamiliar, divided into Low Spatial Frequency (LSF) and Low Luminance (LL) conditions to simulate foggy or rainy days and nighttime. Each picture was presented from the most difficult (level 10) to the easiest (level 1). The participants, including 20 very mild AD patients and 20 normal controls (NC) with equal basic visual acuity, were asked to judge whether a picture was familiar or not and to describe how they came to that conclusion. The accuracy of familiar scene recognition was measured by the number of pictures successfully recognized and the ability thereof by the level needed. Compared with NC, AD patients showed poorer accuracy (2.7 ± 0.2 versus 3.6 ± 0.1, mean ± SEM, p = 0.003 under LSF; 2.8 ± 0.2 versus 3.8 ± 0.1, p = 0.001 under LL) and poorer ability (2.2 ± 0.4 versus 4.3 ± 0.4 p = 0.000 under LSF; 2.9 ± 0.3 versus 5.2 ± 0.5, p = 0.000 under LL) for both conditions. The AD patients used a global element to help judge when personally familiar scenes were displayed, which was the method NC usually adopted when presented with novel scenes. In summary, this study demonstrated poorer recognition ability in very mild AD patients when personally familiar street scenes were displayed, and the underlying mechanisms may include impaired visual search performance and efficiency. The deficits also reflect their difficulty in real life situations when their familiar environments become blurred or dark.

Effects of escapable and inescapable stressors on behavior and interleukin-2 in the brain.

This study aimed to clarify the effects of inescapable and escapable stressors on behavior and interleukin-2 (IL-2) levels in the brain. Inescapable trials, consisting of pairings of conditioned and unconditioned stimuli, were used to induce fear-conditioned stress, whereas trials of escapable pairings of conditioned and unconditioned stimuli in an active avoidance test were used as acute and conditioned stressors. IL-2 levels in the brain were analyzed by enzyme-linked immunoadsorbent assays. Inescapable and escapable stressors had different effects on behavior in the modified active avoidance test and on IL-2 levels in brain areas that are known to be involved in emotional processes. These data provide insight into the pathophysiological role of IL-2 in stress-related disorders.