Attentional bias to drug cues is thought to contribute to maintenance of drug-use behavior among chronic drug users. Studies assessing this bias traditionally have assessed drug cues that are explicitly presented in a laboratory setting. This study tested the use of a mobile eye-tracking procedure to assess visual attention to smoking cues by smokers and non-smokers in a more naturalized environment.A mobile eye-tracker was used to assess the number and duration of fixations made to smoking cues located in an office space environment by smokers and non-smokers while completing a sham experimental task. Smokers completed two sessions, once after 12 h of abstinence and once after smoking.Results indicated that smokers made significantly more fixations to the smoking cues than non-smokers, regardless of smoking condition though the mean amount of time spent fixating on the cues did not differ significantly. Smokers did not differ in the number of fixations or mean fixation duration across the two smoking conditions, suggesting in this sample that a 12-h period of abstinence did not make the smoking cues more salient in this context.This study demonstrates the successful use of mobile eye-tracking to assess attentional biases to environmental drug cues. Results suggest that smoking cues in the environment are potentially more attention grabbing for smokers compared to non-smokers but these cues do not necessarily hold visual attention of smokers longer than that of non-smokers.

Although assistive devices, such as walkers and canes are often prescribed to aid in balance control, recent studies have suggested that such devices may actually increase risk of falling. In this study, we investigated one possible mechanism: the potential for walkers or canes to interfere with, or constrain, lateral movement of the feet and thereby impede execution of compensatory stepping reactions during lateral loss of balance. Lateral stepping reactions were evoked, in 10 healthy young adults (ages 22–27 years), by means of sudden unpredictable medio-lateral support surface translation. Subjects were tested while holding and loading a standard pickup walker or single-tip cane or while using no assistive device (hands free or holding an object). Results supported the hypothesis that using a walker or cane can interfere with compensatory stepping. Collisions between the swing-foot and mobility aid were remarkably frequent when using the walker (60% of stepping reactions) and also occurred in cane trials (11% of stepping reactions). Furthermore, such collisions were associated with a significant reduction (26–37%) in lateral step length. It appeared that subjects were sometimes able to avoid collision by increasing the forward or backward displacement of the swing-foot or by moving the cane; however, attempts to lift the walker out of the way occurred rarely and were usually impeded due to collision between the contralateral walker post and stance foot. The fact that compensatory stepping behavior was altered significantly in such a healthy cohort clearly demonstrates some of the safety limitations inherent to these assistive devices, as currently designed.

This study investigated the adaptive changes in the compensatory stepping response that occur with repeated exposure to the same postural perturbation. Perturbations were applied as forward platform translations (which evoked backward stepping), and responses were characterized using videorecordings, surface EMG, and ground reaction forces. Testing of seven healthy young adults demonstrated that the first exposure to a novel perturbation tends to evoke a stereotypical compensatory stepping response that shows some distinct differences when compared to 'volitional' stepping. Although individual subjects varied, increasing practice and familiarity often led to: (1) reduction in the incidence of stepping, (2) reduction in the number and/or length of steps needed to regain stability, and (3) the introduction of an anticipatory postural adjustment that procedes the unloading of the swing leg. These adaptations highlight the need to maintain adequate levels of unpredictability during balance assessment, in order to evoke the compensatory behaviour that may be characteristic of responses occurring in the unpredictable circumstances of everyday life.