Motion sickness caused by roll-compensated lateral acceleration: Effects of centre-of-rotation and subject demographics

Abstract

The combination of low-frequency lateral and roll motions experienced in tilting trains can provoke motion sickness. The incidence of sickness depends on vehicle design and subject demographics. Vehicle design affects the location of the centre-of-roll, which influences passenger perception of motion. Age and gender have large influences on susceptibility to sickness, but little is known about the effects of ethnicity and body size. This study investigated the influence of both the vertical position of the centre-of-roll and subject characteristics (ethnicity, weight, stature and sickness susceptibility) on sickness caused by fully roll-compensated lateral oscillation. It was hypothesised that sickness would be greater when full compensation occurred at the head than when full compensation occurred at the seat. Sixty subjects experienced a 0.2-Hz lateral oscillation combined with ±7.3° of roll, so that the lateral acceleration was fully compensated at either the seat surface or 800 mm above the seat (i.e. average head height). Illness ratings and symptom scores were recorded every minute for 50 min (i.e. during a 5-min acclimatisation period, a 30-min exposure period and a 15-min recovery period). Although the mean illness ratings were greater when full compensation occurred at the head than at the seat, the difference was not statistically significant. Weight and stature were not associated with motion sickness, but illness ratings were much greater in Asian subjects than in European subjects. It is concluded that differences in susceptibility between Asians and Europeans have a greater effect on motion sickness than the height of the centre-of-rotation during roll-compensated lateral acceleration.