  We analyze recent results concerning the hypothesis of a privileged direction
in the space-time that is made by considering a background of the Lorentz
symmetry violation determined by a fixed spacelike vector field and the
analysis of quantum effects of this background on the interaction of a
nonrelativistic electron with a nonuniform electric field produced by a uniform
electric charge distribution. We show that the conclusions derived by the
authors are an artifact of the truncation of the Frobenius series by means of
the tree-term recurrence relation for the expansion coefficients. Thus, the
existence of allowed angular frequencies stemming from this procedure is
meaningless and unphysical.
