In this study, FAB was used due to the relevant role of frontal lobe syndrome in the symptomatology of PSP. The frontal lobe syndrome is generally associated with the Richardson–Steele variant of PSP, as patients affected by this disease often present rapidly progressing changes in behavior. In this context, FAB, regarding its simplicity and possible screening value, may be interpreted as a valuable supplement in the examination of PSP. As growing interest is related to boundaries between parkinsonian syndromes based on four-repeat tauopathies, in the opinion of the authors of the study, extended evaluation of similarities and differences regarding the frontal lobe in PSP-RS, PSP-P, and CBS seem to be an intriguing issue.