Biomedical subjects

Jan B F van Erp

Publications and source records attributed to Jan B F van Erp.

5 recordsLinked to original sources

PubMed2006

Touch down: the effect of artificial touch cues on orientation in microgravity.

Orienting oneself in space is not an easy task. On Earth, we combine visual, vestibular and pressure cues into a coherent concept of up and down. Since there are no cues from gravity in space, astronauts have to adjust the way they determine up from down, with the possible risk of space motion sickness. In three tasks performed by one astronaut in the International Space Station (ISS), we examined the effect of artificial touch cues presented to the torso. The role of "natural" touch cues on spatial orientation in microgravity, such as pressure presented to the sole of the feet, has already been shown, but it is not trivial whether the brain can also integrate artificial orientation information that has no real life equivalent. We find that artificial touch information in the form of a localised vibration on the torso that indicates down can make orienting in microgravity faster, better and easier. The importance of the artificial touch information seems to increase over the initial 7 days of staying in microgravity while the weight of visual information decreases over the same period. The results underline the capacity of the brain to adapt to unusual environments and to use and integrate artificial cues. Besides astronauts, pilots, divers and people with a vestibular dysfunction may benefit from this technology.

Cues↗

PubMed2006

A tactile cockpit instrument supports the control of self-motion during spatial disorientation.

OBJECTIVE: We investigated the effectiveness of a tactile torso display as a countermeasure to spatial disorientation (SD) and compared inside-out and outside-in codings. BACKGROUND: SD is a serious threat to military as well as civilian pilots and aircraft. Considerable effort has been put into SD countermeasures such as training programs and advanced cockpit displays. Tactile displays have been considered a promising technology. METHOD: Twenty-four participants were assigned to the two coding groups (12 per group and matched for age and gender). We used a rotating chair to build up a state of SD by rotating participants around their yaw axis followed by a sudden stop. During the following recovery phase a random disturbance signal was added to the chair's orientation. Participants actively controlled their orientation and were instructed to maintain a stable orientation. RESULTS: Statistical analyses revealed that recovery from SD was improved with support of the tactile instrument, but tracking performance was reduced. The effects were the same whether the instrument was available full time or during the recovery phase only. There were no differences between outside-in and inside-out coding. CONCLUSION: The present study demonstrates the potential of tactile cockpit instruments in controlling SD, even in the presence of strong but misleading self-motion information from the vestibular sense. APPLICATION: Actual or potential applications of this research include spatial disorientation countermeasures for pilots, divers, and astronauts.

Adult↗

PubMed2004

Cross-modal visual and vibrotactile tracking.

The present study investigates tracking performance with tactile and/or visual presentation of target and cursor. The tactile display consisted of vibrators in a horizontal linear array on the torso, the visual display consisted of dots projected on a horizontal plane surrounding the observer. Both displays presented qualitatively identical information: direction in a horizontal plane. Participants performed two different tracking tasks with target and cursor presented to the same modality (either visual or tactile) or to different modalities (a visual target and a tactile cursor or vice versa). The errors in both cross-modal settings were well predicted by the uni-modal errors. This indicates that no additional costs are involved in cross-modal visual-vibrotactile tracking. Closer inspection of the data reveals that the tactile modality is less suited for processing external disturbances. These results give directions on how to allocate information to the visual and tactile modalities in a multi-modal tracking interface, such as those applied in military cockpits.

Adult↗

PubMed2004

Vibro-tactile and visual asynchronies: sensitivity and consistency.

We investigated the consistency between tactually and visually designated empty time intervals. In a forced-choice discrimination task, participants judged whether the second of two intervals was shorter or longer than the first interval. Two pulses defined the intervals. The pulse was either a vibro-tactile burst presented to the fingertip, or a foveally presented white square. The comparisons were made for uni-modal and cross-modal intervals. We used four levels of standard interval durations in the range of 100- 800 ms. The results showed that tactile empty intervals must be 8.5% shorter to be perceived as long as visual intervals. This cross-modal bias is larger for small intervals and decreases with increasing standard intervals. The Weber fractions (the threshold divided by the standard interval) are 20% and are constant over the standard intervals. This indicates that the Weber law holds for the range of interval lengths tested. Furthermore, the Weber fractions are consistent over uni-modal and cross-modal comparisons, which indicates that there is no additional noise involved in the cross-modal comparisons.

Adult↗

PubMed2003

Image parameters for driving with indirect viewing systems.

Indirect viewing systems such as tv cameras can potentially support drivers under low visibility conditions or when the driver's field of view (FOV) is restricted. In three experiments, we identified the critical image parameters of such systems on vehicle control. We used a taskbattery that measured lateral and longitudinal vehicle control in both simulated and real world driving. Important parameters are magnification factor (compared to unity, a magnification of 0.5 leads to a lower course stability and overestimation of speed and distance) and FOV (increasing the FOV from 50 degrees to 100 degrees improves performance in lateral control tasks). However, the positive effects of a doubled FOV cannot outweigh the negative effects of magnification 0.5, when both factors are confounded. Less critical is the image resolution (lowering the image resolution leads to distance overestimation and degraded longitudinal control) and image update rate (rates below 5 - 10 Hz decrease lateral control). Camera viewpoint (i.e., the location of the camera) is not critical for vehicle control. Overall, we can conclude that vehicle control with an indirect viewing system is proficient when the image parameters are adequately chosen. This supports the further development of these kind of driver support systems.

Accidents, Traffic↗