We show that the conditions for total neutrino conversion found in [ 1 ] are equivalent to the conditions of maximal depth ( parametric resonance ) and ( \pi / 2 + \pi k ) - phase of parametric oscillations .
Therefore the effects considered in [ 1 ] are a particular case of the parametric resonance in neutrino oscillations .
The existence of strong enhancement peaks in transition probability P rather than the condition P = 1 is of physical relevance .
We comment on possible realizations and implications of the parametric enhancement of neutrino oscillations .