Journal of the Neurological Sciences (2006) Author: Ergun Y. Uc, Matthew Rizzo, Steven W. Anderson, Qian Shia, Jeffrey D. Dawson

Introduction Avoiding a crash continuous monitoring of neighboring vehicles anticipating and adjusting to changes in their speeds positions under pressure of time, which relies on multiple cognitive abilities

Introduction Alzheimer disease (AD), the most common cause of dementia in older adults AD were impairs these abilities with clear implications for increased crash risk

Introduction Rear-end collision (REC) is defined as a collision type in which one vehicle collides with the rear of another vehicle In 2003, RECs accounted for 29.6% of all crashes, 29.6% of injuries, 29.8% of property damage, and 5.4% of fatalities in traffic accidents

Introduction About 44% of all rear-end crashes are intersection- related The drivers with highest propensity for rear-end crashes are younger than 18 years old or older than 69 years of age

Materials and methods Subjects were 61 participants with mild AD and 115 neurologically normal control participants. Both groups had comparable years of education, but AD subjects were older

Driving simulator assessment 收集以下參數 (30Hz) 方向盤角度 煞車加速度 速度 (mph) 橫向加速度 線道位置 駕駛行為之拍攝，拍攝頻率為 30Hz ，紀錄駕駛軌跡

Training and adaptation 適應及訓練最少需要 5 分鐘，請參考 [Quantitative analysis of steering adaptation on a high performance fixed-base driving simulator; part F] 車內有裝置對講機及螢幕，來觀察駕駛者是否不舒服 及疲勞

Rear-end collision avoidance scenario

Binary outcome measures

Predictors of unsafe outcomes across groups

Predictors of unsafe outcomes adjusted for groups

Analyses of collisions In 5 of 6 crashes, the DV slowed down abruptly and was struck by the FV (e.g., Fig. 2B) Only in one case (a driver with AD), the DV crashed into the stopped LV at the intersection (at 48.6 mph=78.2 kmh).

Performances of AD and control group

Discussion Although the likelihood of REC was not significantly higher in AD, these drivers reacted slower and were more likely to respond unsafely by slowing down abruptly or stopping prematurely before reaching the intersection Slowing abruptly increased the odds of being struck from behind by the FV

Discussion Visual perception is impaired in early AD and influences cognition and performance of the patients with AD Reduced UFOV, which depends on processing speed and attention, was a strong predictor of unsafe outcomes, consistent with earlier findings on prediction of crashes and driving errors in AD and aging [5,8,10,11,18–20].

In this study, slowing down abruptly, a quite common occurrence with increased odds for a potential crash, was associated with being struck by the following vehicle in the REC avoidance scenario in the simulator.