Additionally, a study of 39 participants using phosphorylated tau and amyloid beta 1–42 ratio as measure of AD pathology in ventricular CSF showed less improvement in gait and cognition among participants with high ratio [21], while another small study of 10 participants using PET amyloid beta (Aβ) imaging showed less cognitive improvement in participants with high Aβ [22]. Here, MAPT is linked to Alzheimer disease.