Using the gait disorientation test to measure spatial navigation in children with cochlear implants

The vestibular system is a collection of inertial organs that allow humans, and most other organisms, to remain appropriately oriented relative to earth's gravitational forces. A growing body of literature has identified a link between vestibular dysfunction and spatial cognitive abilities in both asymptomatic older adults and adults with confirmed vestibular loss. However, vestibular loss is also common among children with cochlear implants (CCI), with as many as 50 % showing evidence of concurrent vestibular dysfunction. Yet, how vestibular loss influences spatial cognition in CCI is limited. The primary objective of this study was to determine the impact of hearing loss and combined hearing plus vestibular loss on spatial cognitive performance by administering a mobility-based test of spatial navigation, the Gait Disorientation Test (GDT), in CCI and children with normal hearing and vestibular function.

This was a cross-sectional study involving 84 children: 36 children with normal hearing (CNH), 31 CCI and normal vestibular function (CCI-NV), 9 CCI and unilateral vestibular loss (CCI-UVL) and 8 CCI and bilateral vestibular loss (CCI-BVL). The Bruininks Oseretsky Test of motor proficiency, 2nd edition (BOT-2) and the video head impulse test (vHIT) were performed alongside a measure of spatial navigation, the GDT, which was determined for each child by measuring differences in gait speed between eyes open and eyes closed walking conditions.

There was no significant difference in GDT scores between the CNH (1.89 s), CCI-NV (1.91 s), CCI-UVL (2.28 s), and CCI-BVL (1.52 s) groups (Kruskal Wallis, H = 0.29, p = 0.96). Gait speed during the eyes closed portion of the GDT was not significantly different between the four groups (Kruskal Wallis, H = 1.53, p = 0.68); however, CNH (5.9 s) and CCI-BVL (6.21 s) each walked significantly slower than the CCI-NV (5.09 s) in the eyes open portion of the GDT. There was however an apparent stepwise change in BOT-2 balance scores, with lower performance amongst children with CCI and vestibular loss (Kruskal Wallis, H = 37.91, p < 0.001).

Unlike adults with vestibular loss, these data show that children with vestibular loss do not display significantly impaired spatial navigation relative to CNH and normal vestibular function. These data are consistent with the existence of unique compensatory responses to vestibular loss occurring later in life compared to at birth or early in development.