Deterioration of vestibular motion perception: a risk factor for postural instability and falls in elderly with type 2 diabetes

Aims: To assess whether impaired vestibular perception of self-motion is a risk factor for unsteadiness and falls in elderly patients with type 2 diabetes (T2D). Materials and methods: 113 participants (65–75 years old) with T2D underwent tests of roll and pitch discrimination, postural stability (Berg Balance Scale, Modified Romberg Test, and quantitative posturography), clinical examination and blood chemistry analyses. Falls 1-year after enrolment were self-reported. We performed cluster analysis based on the values of the vestibular motion thresholds, and logistic stepwise regression to compare the clinical-biochemical parameters between clusters. Results: We identified two clusters (VC1 n = 65 and VC2 n = 48 participants). VC2 had significantly (p < 0.001) higher (poorer) thresholds than VC1: mean pitch threshold 1.62°/s (95% CI 1.48–1.78) in VC2 and 0.91°/s (95% CI 0.84–0.98) in VC1, mean roll threshold 1.34°/s (95% CI 1.21–1.48) in VC2 and 0.69°/s (95% CI 0.64–0.74) in VC1. Diabetes duration was significantly (p = 0.024) longer in VC2 (11.96 years, 95% CI 9.23–14.68) than in VC1 (8.37 years, 95% CI 6.85–9.88). Glycaemic control was significantly (p = 0.014) poorer in VC2 (mean HbA1c 6.74%, 95% CI 6.47–7.06) than in VC1 (mean HbA1c 6.34%, 95% CI 6.16–6.53). VC2 had a significantly higher incidence of postural instability than VC1, with a higher risk of failing the Modified Romberg Test C4 (RR = 1.57, χ2 = 5.33, p = 0.021), reporting falls during follow-up (RR = 11.48, χ2 = 9.40, p = 0.002), and greater postural sway in the medio-lateral direction (p < 0.025). Conclusions: Assessing vestibular motion thresholds identifies individuals with T2D at risk of postural instability due to altered motion perception and guides vestibular rehabilitation.