Reduced Peripheral Nerve Conduction Velocity is Associated with Alzheimer's Disease: A Cross-Sectional Study from China

Purpose: Elderly individuals with degenerative diseases of the central nervous system are more likely to develop peripheral neuropathy; however, research is limited as to whether the decline in peripheral nerve conduction can be used as a biomarker of Patients and Methods: This study enrolled 74 patients with mild cognitive impairment (MCI), 21 with AD, and 82 healthy elderly individuals. All participants underwent a peripheral nerve conduction and neuropsychological evaluation. Nicolet EDX was used to assess peripheral nerve conduction in the limbs and comparisons were made between the three cognitive groups. Furthermore, the relationship between peripheral nerve conduction and cognitive function was investigated. Results: A ladder-shaped difference was found in the median (p < 0.001) and common peroneal (p < 0.001) motor nerve velocity, with the control group > MCI group > AD group, even after controlling for variables. The median motor nerve amplitude in the AD group was lower than that in the control group (P = 0.017). After controlling for age, sex, education, and height, the median motor nerve velocity was positively correlated with the Montreal Cognitive Assessment (r = 0.196, p = 0.015), and the common peroneal motor nerve velocity was positively correlated with verbal fluency task-idioms (r = 0.184, p = 0.026). The median (AUC: 0.777, p < 0.001) and common peroneal motor nerve velocities (AUC: 0.862; p < 0.001) were significantly associated with the diagnosis of AD. The accuracy rate of these two motor nerve velocities to predict AD was 51.5%. Conclusion: Our study found that peripheral motor nerve velocity may correlate with early cognitive impairment in AD. However, the accuracy of different cognitive classifications and the value of early diagnosis are not ideal when peripheral motor nerve velocity is used alone. Whether peripheral nerve function can be used as a marker for early diagnosis of AD needs further clarification but provides a new possibility for the future of biomarker research.