Developing a Spatial Navigation Screening Tool Sensitive to the Preclinical Alzheimer Disease Continuum

Abstract

Objective There remains a need for a non-invasive and cost-effective screening measure that could be administered prior to the provision of a lumbar puncture or positron emission tomography scan for the detection of preclinical Alzheimer disease (AD). Previous findings suggest that a hippocampally-based spatial navigation task may be effective for screening individuals for the preclinical AD continuum (i.e., low cerebrospinal fluid (CSF) Aβ42). Unfortunately, this task took 1.5–2 hours to administer, which would be time-prohibitive in a clinical setting. Therefore, the goal of this study was to compare psychometric properties of six spatial navigation-related tasks in order to take the next steps in developing a clinically appropriate screening measure. Methods Psychometric properties (i.e., reliability, diagnostic accuracy, validity) of a modified version of the cognitive mapping task, two binding tasks, a visual perspective taking task, and self- and informant report versions of a questionnaire were examined in a sample of 91 clinically normal (CN) individuals. CSF Aβ42 and ptau181 were available for 30 individuals. Results The learning phase of the cognitive mapping task and the self-report questionnaire were sensitive to identifying individuals in the preclinical AD continuum (93% and 87% sensitivity, 60% and 67% specificity, respectively). These two measures also demonstrated good test-retest stability (intraclass correlation coefficients = .719 and .838, respectively) and internal consistency (Cronbach’s αs = .825 and .965, respectively). Conclusions These findings suggest that a self-report questionnaire and aspects of a cognitive mapping task may be particularly appropriate for development as screening tools for identifying individuals in the preclinical AD continuum.

Spatial navigation ability predicts progression of dementia symptomatology

“…Measures of CM may be particularly useful considering evidence that these may be more powerful than standard episodic memory measures. Furthermore, recent work has established strong psychometric properties of CM . Longitudinal investigations of spatial navigation would be important to determine its ability to track subtle cognitive changes in the preclinical AD phase .…”

“…Participants were recruited from the Knight Alzheimer's Disease Research Center (ADRC) at Washington University and initially participated in previous spatial navigation studies . Ninety‐eight participants completed the CM task and 67 completed the RL task.…”

“…There were three study‐test trials during the learning phase. During study, participants freely explored the environment for 7 or 4 minutes . Participants were then given a blank two‐dimensional (2D) map of the environment and placed X's at landmark locations.…”

“…Participants were then given a blank two‐dimensional (2D) map of the environment and placed X's at landmark locations. The learning score (CM‐Learning) was the average number of correct locations across trials (: range = 0–20; : range = 0–18). After a 10‐minute or 15‐minute delay, participants completed 12 or 6 trials in which they were presented with a picture of a landmark and navigated to the landmark using the shortest path as quickly as possible.…”

“…It is notable that recent work suggests that individuals in the preclinical AD continuum (ie, low CSF Aβ 42 ) have differential deficits in cognitive map formation relative to RL . This CM task demonstrated high sensitivity (92%; 57% specificity) in detecting the preclinical AD continuum, was more sensitive than a standard episodic memory task or RL, and had strong psychometric properties …”