Background: The walking gait of older adults with balance impairment is affected by dual tasking. Several studies have shown that external cues can stimulate improvement in older adults' performance. There is, however, no current evidence to support the usefulness of external cues, such as audio-visual cueing, in dual task walking in older adults. Thus, the aim of this study was to investigate the influence of an audio-visual cue (simulated traffic light) on dual task walking in healthy older adults and in older adults with balance impairments.Methods: A two-way repeated measures study was conducted on 14 healthy older adults and 14 older adults with balance impairment, who were recruited from the community in Chiang Rai, Thailand. Their walking performance was assessed using a four-metre walking test at their preferred gait speed and while walking under two further gait conditions, in randomised order: dual task walking and dual task walking with a simulated traffic light. Each participant was tested individually, with the testing taking between 15 and 20 minutes to perform, including two-minute rest periods between walking conditions. Two Kinect cameras recorded the spatio-temporal parameters using MFU gait analysis software. Each participant was tested for each condition twice. The mean parameters for each condition were analysed using a two-way repeated measures analysis of variance (ANOVA) with participant group and gait condition as factors.Result: There was no significant between-group effect for walking speed, stride length and cadence. There were also no significant effects between gait condition and stride length or cadence. However, the effect between gait condition and walking speed was found to be significant [F(1.557, 40.485) = 4.568, P = 0.024, η = 0.149]. Since walking requires the ability to interact with the external environment, external cues are needed to control and adjust walking kinematics. Many walking variables, such as walking speed, are important for rehabilitation and predict successful community ambulation. Previous reviews have stated that walking speed is the sixth vital life sign in humans because it is associated with functional ability and, more importantly, it could be used to predict the future health status and functional decline of an individual (9). Other gait variables such as stride length and cadence were also found to be affected by performing a dual task (10). When walking in an outdoor environment, many older adults were found to decrease both their preferred walking speed as well as their walking speed in potentially hazardous situations, such as walking while talking when crossing the street. It is therefore important to improve the physical capabilities of older adults by promoting a healthy lifestyle.Promoting the use of external cues is important in improving physical function in older adults. A previous study reported that older adults made more kinematic errors while performing a goal directed movement when the visual cues were lost (11). Similarly, Mah...