Table 2.
Performance on the mental navigation tasks.
| Spatial task | Description | Dominant reference frame1 | Type of score | H.C.’s score | Healthy controls’ mean score (SD) |
|---|---|---|---|---|---|
| Sketch mapping | Draw a detailed map of the streets and landmarks located in well-known neighborhood and downtown environments | A | a) Total landmarks b) Total street segments c) Total details (landmarks + segments) |
a) 20** b) 34 c) 54** |
a) 44.833 (8.660) b) 106.167 (35.254) c) 151 (35.254) |
| Landmark localization | Locate landmarks on an outline map | A | a) Mean distance error (km) for neighborhood landmarks b) Mean distance error (km) for city core landmarks c) Total mean distance error (km) |
a) 0.37* b) 0.762*** c) 0.566*** |
a) 0.247 (0.072) b) 0.273 (0.118) c) 0.26 (0.086) |
| Proximity judgments | Of two landmarks, select the one that is closest to a third, reference landmark | A | Accuracy (Proportion correct) | 0.7 | 0.817 (0.075) |
| Distance judgments | Provide distances between pairs of landmarks | A | Mean distance error (km) | 0.7 | 1.806 (2.117) |
| Landmark sequencing | Place a series of 15 landmarks in the correct order from north to south | E | Accuracy (Proportion in correct sequence) | 0.8* | 0.933 (0.073) |
| Vector mapping | Draw a line indicating distance and direction from a specified landmark to a second named landmark | A | a) Mean distance error (km) b) Mean angle error (degrees) |
a) 0.197 b) 13.5 |
a) 0.239 (0.076) b) 13.638 (6.089) |
| Blocked route2 | Describe most efficient detour between 2 landmarks, given that the most direct route is blocked | A/E | a) Proportion correct (# correct/total) b) Proportion correct, outlier removed |
a) 0.6 b) 0.6** |
a) 0.763 (0.204) b) 0.84 (0.082) |
| Landmark recognition | Of two landmarks, select the one that is located in the neighborhood or downtown environment | NA | Accuracy (Hit rate—false alarm rate) | 0.973 | 0.95 (0.032) |
Note. A, allocentric; E, egocentric
1As reported in Ciaramelli et al. (2010) and Rosenbaum et al. (2004, 2007).
2One outlier was identified in the control sample and included in analysis a) but removed from analysis b).
***Significant difference at p < 0.01; **Significant difference at p < 0.05; *Approaching significance (p < 0.1).