MAPT and Parkinson disease: The PSP‐tau score significantly correlated with the PSP rating scale (t[44] = 2.38; rs = 0.34; P = 0.02), Unified Parkinson's Disease Rating Scale [UPDRS] Part III (t[41] = 2.51; rs = 0.37; P = 0.02), and Frontal Assessment Battery (t[38] = −2.27; rs = −0.35; P = 0.03), which indicate the severity of PSP‐RS, and the distribution of accumulation was expanded when the scores were divided into low, moderate, and high groups (Fig. 4 and Fig. S1E).