Unsafe rear-end collision avoidance in Alzheimer’s disease

Journal of the Neurological Sciences (2006)

Author: Ergun Y. Uc, Matthew Rizzo, Steven W. Anderson, Qian

Shia, Jeffrey D. Dawson

IntroductionAvoiding a crash

continuous monitoring of neighboring vehiclesanticipating and adjusting to changes in their

speedspositions under pressure of time, which relies

on multiple cognitive abilities

IntroductionAlzheimer disease (AD), the most common

cause of dementia in older adults

AD were impairs these abilities with clear implications for increased crash risk

IntroductionRear-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

IntroductionAbout 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 methodsSubjects 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 collisionsIn 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

DiscussionAlthough 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

DiscussionVisual 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.