Table 3. L-Kynurenine (L-KYN) and L-tryptophan (L-TRP) levels in the cerebrospinal fluid (CSF) and serum of the corresponding control subjects and patients with normal pressure hydrocephalus (NPH) and hydrocephalus e-vacuo (He-v). Data represent mean ± SEM. Number (N) of subjects is given in parentheses. % of corresponding control subjects is given in parentheses. Significance: *p < 0.05, **p<0.01 vs. control group age ≤ 50 years or ≥ 51 years, respectively, using a Student's t-test