1. Deficits in Spatial Cognition After TBI Revealed By Virtual Morris Water Maze R.W. Skelton & S.P. Ross, Psychology, University of Victoria, Victoria, BC, CANADA

2. 1 Premises Traumatic brain injury (TBI) damages many neural structures and impairs many cognitive functions, including: Hippocampus, Episodic memory, Spatial memory. Animal research shows Morris water maze (MWM) useful for measuring deficits in spatial memory and hippocampal function. Previous study showed that survivors of TBI show deficits in Virtual MWM Present study uses more advanced 3D environment And distal cues for orientation

3. 2 Methods Participants TBI: 14 (11M, 3F) 23-67 years old, ½-48 years post-injury (9 MVA) Non-Injured: 12 (7M, 5F), 19 – 52 years old Virtual MWM Built with Unreal® Editor, shown on desktop system Large (~40 m) arena (circus ring) with 2 m circular platform Large square room with windows and world outside Room and world has “cardinal” orientation (North-South etc)

4. 3 Methods Trials Free time for orientation, mapping and joystick practice 4 with platform visible (varying locations) 10 with platform invisible (until tread upon) in fixed location, from varying start locations 1 Probe (no platform) Measures Distance and Latency (measured with TRAM®) Dwell time in correct quadrant on Probe trials Spatial Score: z-score average of invisible platform trial and probe trial data

5. 4 Methods Virtual MWM requires combinations of distal and proximal cues for navigation (not just single cues or landmarks) Views showing visible platform and outside scenery Views of the arena, room and visible platform

6. 5 Methods Trials start from 4 different positions. Visible platform Views of Arena from the 4 start positions. Invisible platform

7. 6 Results: Learning Trials Participant with no injury quickly learns to find the invisible platform Participant with brain injury takes longer to learn to find the platform Sample Data

8. 7 Results: Learning Trials TBI slows acquisition of platform location: Path lengths are longer Group Data Sample Individual Data TBI Control

9. 8 Results: Learning Trials Groups show large differences in ability to locate invisible platform Groups show only small differences in speed of movement Latency Distance Speed Efficacy

10. 9 Results: Probe Trials Those with TBI showed poor searches when platform absent. Control participant closest to group mean Participant with TBI closest to group mean

11. 10 Results: Group Differences Effect sizes reveal that most measures of spatial navigation show large differences between TBI and Controls

12. 11 Conclusions Virtual MWM reveals deficits in spatial navigation after TBI. Some measures show bigger effects. Study replicates previous finding. Impairment after TBI not due to primitive 3D rendering. Useful for studying TBI deficits and functions of human hippocampus.