MAPT and Alzheimer disease: In the meantime, deposition of hyperphosphorylated tau was also sparsely detected in each segment of the spinal cord in 37 cases of nondementia patients with no diagnosis of any central nervous system diseases, indicating that accumulation of hyperphosphorylated tau may occur before dementia occurrence, and that hyperphosphorylation of tau may occur in the spinal cord in the preclinical phase of AD [18].