Purpose: Goal-directed walking requires an estimation of the goal's location in space relative to one's body. Information for this estimation could come from various sources, e.g. visual, efferent, vestibular, and somatosensory signals. In this study we determined whether there is a gender difference in the effect of visual and non-visual information on action-task performance—walking to a briefly exposed target. Methods: Subjects were 10 men and 10 women. An immersive virtual environment was used to present a scene of a room with a ball in a doorway. The ball was positioned at −3 , 0 , or 3 relative to the subject's midline, and the doorway was either centered on the subject's midline or offset 5. The scene was displayed for 1 sec, replaced with a uniform field, and the subjects were to walk to the ball (4 m). In Exp. 2, subjects began walking at display onset. In Exp. 3, the positions of the subject's head and/or eyes were rotated relative to straight-ahead as they viewed the scene. Results: Doorway offsets affected the women's paths significantly more than the men's, t(18)=−2.3, p<.05. Nine of 10 women had errors of 2.8–22.7. The majority of the men (7/10) had errors of 0.1 – 1.4. With rotated head and/or eyes (Exp. 3), the women had significantly larger path errors than the men. With visual feedback (Exp. 2), the magnitude of the women's errors decreased to the range of the men's. Conclusions: Women are more affected than are men by the context of a target and by the positions of their head and eyes in determining the spatial position of a target to self.

In this study we investigated whether a visual illusion located in far space alters a person's open-loop, target-directed walking path in the same manner as it alters the perception of the target's position. Through the use of immersive VR the subject was able to walk physically to the location of a target embedded in a scene that was manipulated to create a visual illusion, known as the induced Roelofs effect. This illusion has been shown to alter the perception of a target's position. The experiment consisted of two tasks: a perception task and an action task. In the perception task, subjects viewed the scene for 1 s, it disappeared, and they were to report the target's location verbally. The results showed that the visual illusion altered the reported positions in all but one subject. In the action task, subjects viewed the scene for 1 s, it disappeared, and the subjects were asked to walk to the target's location. The results showed that the illusion significantly altered the walking paths of most of the women and less than half of the men. A significant gender effect was observed; women's walking paths deviated, on average, by 7.1 degrees and men's, by only 2.0 degrees . These results indicate that action tasks in far space are susceptible to the effects of visual illusions, unlike the action tasks in near space that reportedly have been resistant to them. Furthermore, the significant gender effect suggests that men and women either have different strategies and/or employ different mechanisms when executing a visually guided task in far space.

Study Design. A cross-sectional study was conducted to analyze a convenience sample of patients seeking treatment for cervical spine conditions. Objective. To develop and evaluate the psychometric properties of a comprehensive, disease-specific questionnaire for characterizing complaints of neck pain and evaluating the outcomes of treatments for these complaints. Summary of Background Data. There currently are a number of generic and disease-specific instruments for assessing complaints of neck pain. None comprehensively cover the wide range of factors considered essential in evaluating treatment outcomes. Methods. The authors developed a comprehensive, disease-specific questionnaire for characterizing complaints of neck pain and evaluating the outcomes of treatments for these complaints. In this study, 216 patients who underwent surgery for cervical spine disorders completed the Cervical Spine Outcomes Questionnaire before treatment, then at 3 and 6 months after treatment. The data were used to evaluate the reliability, validity, and responsiveness of the questionnaire. Results. The authors have shown that the Cervical Spine Outcomes Questionnaire has high test–retest reliability, good construct validity, and responsiveness to change after treatment. Conclusions. The Cervical Spine Outcomes Questionnaire is a comprehensive, disease-specific instrument for assessing complaints of neck pain and evaluating the outcomes of treatments for these complaints. It provides information on demographics, pain severity, functional disability, psychological distress, physical symptoms, health care utilization, and satisfaction. It appears to be acceptable to patients, easy to administer, highly reliable, valid, and responsive. It should be considered for use in monitoring patients with cervical spine conditions and in studies of cervical spine disorders and their treatments.

Spatial context has been shown to affect the perceived location of an object. An object surrounded by a frame that is offset relative to one's midline is perceived to be more centrally located than it actually is (induced Roelof's effect). Remarkably, that same object will be accurately localized when subjects must point to it (Bridgeman et al., 1979). Differences in perception and action responses have been used to support the view that visual information is processed differently depending on whether the information is used for perception or action. Here we show a sex difference in the effects of context on spatial localization, predominantly revealed by an action response. Ten subjects wearing a head-mounted display, and viewing a virtual environment, were briefly presented (1 s) a scene of an object (2°-diameter ball) in a doorway (20.5° wide). Subjects were instructed to either verbally report the object's position relative to themselves or to walk to it. The object was positioned at −3°, 0°, or 3° relative to the subject's midline, and the doorway was either centered or offset by 5° to the left or right of the subject's midline. All subjects exhibited the typical Roelof's effect in their verbal report, with average object mislocalizations of 2.2° (men) and 4.2° (women) for the offset doorway conditions. However, when the subjects had to walk to the object, spatial context had little effect on the men's endpoints (average deviation <1°) but had significant effects on the endpoints of the women (average deviation >4°). These findings suggest a basic difference in men and women with respect to the effects of context on spatial processing as it relates to navigation and may help explain reported sex differences in navigation ability. Bridgeman, B. et al. (1979). Relation between cognitive and motor-oriented systems of visual position perception. Journal of Experimental Psychology: Human Perception and Performance, 5, 692–700.