This paper utilizes an ontogenetically validated personality test, the Meta-Contrast Technique (MCT). The instrument focuses on the microdevelopment of perception (percept genesis) reflecting the process of individual adaptation to and construction of reality. Empirical evidence for the adequacy of the MCT paradigm in neuropsychological personality research is presented. In all, 45 patients were tested; thirty-three patients with various forms of supra-tentorial brain tumors were examined and compared with a group of 12 cerebrovascular disease (CVD) patients. Without the examiner's knowledge of degree of tumor malignancy, the MCT results allowed differentiation among tumors of various histological types. Uninformed of the final diagnosis, patients with highly malignant gliomas showed panic-related anxiety and schizoid-like regressions, in contrast both to patients with low and nonmalignant brain tumors and to the group of CVD patients.