  Quantum gravity may involve models with stochastic fluctuations of the
associated metric field, around some fixed background value. Such stochastic
models of gravity may induce decoherence for matter propagating in such
fluctuating space time. In most cases, this leads to fewer neutrinos of all
active flavours being detected in a long baseline experiment as compared to
three-flavour standard neutrino oscillations. We discuss the potential of the
CNGS and J-PARC beams in constraining models of quantum-gravity induced
decoherence using neutrino oscillations as a probe. We use as much as possible
model-independent parameterizations, even though they are motivated by specific
microscopic models, for fits to the expected experimental data which yield
bounds on quantum-gravity decoherence parameters.
