CAT and Alzheimer disease: The assessment of salivary CAT, GPx and GSH (sensitivity = 82.61%, specificity = 84.00%, p < 0.0001; sensitivity = 73.91%, specificity = 72.00%, p = 0.0043; sensitivity = 72.73%, specificity = 72.00%, p = 0.0313) clearly differentiates the AD patients from the control.