  The problem how to approximately determine the absolute value of the Fisher
information measure for a general parametric probabilistic system is
considered. Having available the first and second moment of the system output
in a parametric form, it is shown that the information measure can be bounded
from below through a replacement of the original system by a Gaussian system
with equivalent moments. The presented technique is applied to a system of
practical importance and the potential quality of the bound is demonstrated.
