ALB and Parkinson disease: We identified a weak correlation of the CSF‐to‐serum albumin concentration quotients (Qalb) with the amide I maximum positions in ALS (P = 0.03, r = −0.36) and Ctrl (P = 0.03, r = −0.55), but not within the PD group (P = 0.18, r = −0.25).