The Association of Impaired Vibration Sensation in the Lower Limb with Tests of Cognition in Older People: The Cardiovascular Health Study.

Introduction: The prevalence of peripheral neuropathy (PN) in the lower limb increases with age and with the presence of diabetes. Studies show an association of PN with advanced cognitive impairment. Here we examine the association of PN with measures of early cognitive deficits in a cohort of older adults without apparent cognitive impairment, with or without diabetes.

Methods: A total of 2,798 participants from the Cardiovascular Health Study were examined, mean age 80 years. All underwent tests of overall cognition (3MSE), executive function (DSST), and visual memory (BVRT). Impairment of vibration sensation in the toes, ankles, and tibial tuberosities was ascertained. Participants were graded according to the extent of impairment. Adjusted linear regression analyses of the extent of impaired vibration sensation with cognitive tests were performed. Results were further categorized by the presence or absence of diabetes.

Results: 70% of participants had intact vibration sensation in the toes; 8% had no vibration sensation in the tibial tuberosities or below. Compared to participants with intact vibration sensation in the toes, those with no vibration sensation in the tibial tuberosities had lower 3MSE scores. Tests of executive function were lower in a stepwise manner with greater impaired vibration sensation. Visual memory was less strongly associated with impaired vibration sensation. Findings did not differ significantly by diabetes status.

Conclusion: In older adults, impaired vibration sensation in the lower limb is associated with impaired executive function and visual memory. These findings did not differ by diabetes status.