Impairment of human spatial orientation in the horizontal, but not the vertical plane, due to aging, cognitive decline, or chronic peripheral vestibular loss

Aging, cognitive decline, or chronic peripheral vestibular loss selectively impair human spatial orientation in the horizontal, but not the vertical plane. A possible explanation is that vertical and horizontal orientation in ground-based species use separate operational modes of spatial memory encoding. The continuous updating of the internal model of the body in space is realized through egocentric representation in the vertical plane and allocentric, that is world-based, representation in the horizontal plane. Additionally, heterogenous ageing patterns of relevant brain structures, and training effects could play a role.