Department of Psychology, University of Utah, 380 S. 1500 E. Room 502, Salt Lake City, UT, 84112, USA.
Interdisciplinary Program in Neuroscience, University of Utah, Salt Lake City, USA.
Exp Brain Res. 2024 Jun;242(6):1277-1289. doi: 10.1007/s00221-024-06818-7. Epub 2024 Mar 28.
Older adults demonstrate impairments in navigation that cannot be explained by general cognitive and motor declines. Previous work has shown that older adults may combine sensory cues during navigation differently than younger adults, though this work has largely been done in dark environments where sensory integration may differ from full-cue environments. Here, we test whether aging adults optimally combine cues from two sensory systems critical for navigation: vision (landmarks) and body-based self-motion cues. Participants completed a homing (triangle completion) task using immersive virtual reality to offer the ability to navigate in a well-lit environment including visibility of the ground plane. An optimal model, based on principles of maximum-likelihood estimation, predicts that precision in homing should increase with multisensory information in a manner consistent with each individual sensory cue's perceived reliability (measured by variability). We found that well-aging adults (with normal or corrected-to-normal sensory acuity and active lifestyles) were more variable and less accurate than younger adults during navigation. Both older and younger adults relied more on their visual systems than a maximum likelihood estimation model would suggest. Overall, younger adults' visual weighting matched the model's predictions whereas older adults showed sub-optimal sensory weighting. In addition, high inter-individual differences were seen in both younger and older adults. These results suggest that older adults do not optimally weight each sensory system when combined during navigation, and that older adults may benefit from interventions that help them recalibrate the combination of visual and self-motion cues for navigation.
老年人在导航方面表现出的障碍不能用一般的认知和运动能力下降来解释。先前的研究表明，老年人在导航时可能会以不同于年轻人的方式组合感觉线索，尽管这项工作主要是在黑暗环境中进行的，在这种环境中，感觉整合可能与全线索环境不同。在这里，我们测试老年人是否能最佳地组合两种对导航至关重要的感觉系统的线索：视觉（地标）和基于身体的自身运动线索。参与者使用沉浸式虚拟现实完成了归巢（三角形完成）任务，以便在光线充足的环境中导航，包括可以看到地面。基于最大似然估计原理的最优模型预测，归巢的精度应该随着多感觉信息的增加而增加，其方式与每个单独感觉线索的感知可靠性（通过变异性来衡量）一致。我们发现，与年轻人相比，身体状况良好的老年人（视力正常或矫正正常且生活方式积极）在导航过程中更不稳定，准确性也更低。老年人和年轻人在导航时都比最大似然估计模型所建议的更依赖于他们的视觉系统。总的来说，年轻人的视觉权重与模型的预测相符，而老年人则表现出次优的感觉权重。此外，在年轻人和老年人中都观察到了很高的个体间差异。这些结果表明，老年人在导航时不会最佳地组合每个感觉系统，而且老年人可能会受益于帮助他们重新校准视觉和自身运动线索组合的干预措施。
