In Electric Dipole Moment search experiments with polarized beams the coherence of spin oscillations of particles has a crucial role. The decoherent effects arise due to spin tune dependence on particle energy and particle trajectory in focusing-deflecting fields. They are described through the n-th order spin tune aberrations. Since the first order is suppressed by RF field, the second order plays crucial role. It depends on the orbit lengthening and on the odd order field components. We consider the spin decoherence effects and methods of their compensation in different channels, electrostatic, magnetostatic linking the decoherence effects with common characteristics such as the momentum compaction factor, the chromaticity and others
