The virtual Morris water maze for cognitive function assessment in adolescents with type 1 diabetes.

AIMS/HYPOTHESIS: Neuropsychological assessments and neuroimaging techniques have indicated impaired spatial working memory in adolescents with type 1 diabetes. We investigated the influence of diabetes-related factors on their spatial navigation performance. METHODS: Spatial navigation performance on the virtual Morris water maze task (vMWMT) was evaluated in adolescents with type 1 diabetes and compared with that of healthy control adolescents of similar age and sex. Collected data on diabetes-related variables included disease duration, diabetic ketoacidosis (DKA) at diagnosis and continuous glucose monitoring (CGM) metrics during the 2 weeks preceding the assessment, with focus upon nocturnal values measured during the night before testing. Time to first move, time to platform and path length were measured in visible and hidden platform vMWMT stages. RESULTS: The 74 study participants (age 15.6 ± 3.1 years, 45 boys) with type 1 diabetes demonstrated sex-specific patterns of spatial navigation, comparable with those observed in the healthy control group. Both the boys and girls had longer time to first move than the control groups in the visible platform stage, which assessed motor control (p=0.036 and p=0.002, respectively). Test outcomes did not differ between the participants with and without type 1 diabetes in the hidden platform stages, which assessed spatial learning and memory. However, linear regression models adjusted for sex, age and DKA at diagnosis found that diabetes duration (β=0.464, p<0.001) independently predicted longer time to platform (R2=0.396, p=0.003), while nocturnal time spent in marked hypoglycaemia (β=0.397, p=0.002) predicted longer path length (R2=0.206, p=0.017). CONCLUSIONS/INTERPRETATION: Spatial navigation performance in adolescents with type 1 diabetes is influenced by both disease duration and recent glycaemic control. Glycaemic excursions, especially during the night, were shown to impair performance.