Stops for Cops: Impaired Response Implementation for Older Drivers with Cognitive Decline

Response to an emergency vehicle requires detection and recognition of an object in peripheral vision, situation recognition, and a rapid response to execute a safety maneuver to decrease the potential for crashing into the vehicle or striking people situated near it. To investigate situation awareness and response to a roadway emergency in at-risk elderly drivers, 149 licensed older drivers were tested with a battery of visual and cognitive tests and in a driving simulator scenario in which drivers encountered a police car on the shoulder of the road. Forty-eight drivers (mean age of 73.5) had cognitive impairments caused by mild to moderate Alzheimer's disease, and 101 (mean age of 69.3 years) were neurologically normal. Results showed that compared with controls, drivers with Alzheimer's reacted more slowly (P = 0.0008)—with abrupt decelerations resulting—or failed to steer clear of the police car (P = 0.0036). Several older drivers stopped in the middle of the road. Poorer scores on neuropsychological tests of perception, attention, memory, and executive function predicted slower first reactions and increased the risk of inappropriate and potentially unsafe reactions. These results provide evidence that cognitive errors leading to unsafe driver behaviors can be tested safely in a simulator. The findings suggest that there is decreased situation awareness or poor executive control over response implementation in older drivers with cognitive decline, possibly at the level of selecting one of several possible learned evasive motor actions.