The iron-based superconductors are at the forefront of the research on unconventional superconductivity. The Barium-122 systems, doped with electrons, reveal a non-trivial behavior, above the superconducting transition (Tc), in nuclear magnetic resonance (NMR) relaxation times. 75As NMR spin-spin relaxation time in the normal phase of 122 iron-based superconductors shows very slow spin fluctuations, which are absent in the high temperature superconducting cuprates. Recent experiments show the presence of nematic charge fluctuations, in the same observed temperature/doping range. We thereby propose a muon spin rotation experiment to characterize the spin fluctuations, in a zero field and transverse field environment, in order to extend our previous NMR study, carried out in a broad range of magnetic fields, as well as to investigate the in-plane anisotropy of such slow dynamics.