The minimal interpretation of the atmospheric neutrino data suggests that the muon neutrino oscillates into another species with a mixing angle close to the maximal π/4. In the Exact Parity Symmetric Model, both the muon and electron neutrinos are expected to be maximally mixed with essentially sterile partners 9ν μ and ν e respectively). We examine the impact of maximal ν e - ν e oscillations on the atmospheric neutrino experiments. We estimate that maximal ν e - ν e oscillations will have effects on atmospheric neutrino data for δm 2 (ν e - ν e ) > 7 10 - 5 eV 2 . For δm 2 in this range, a slight but distinctive rise in the ratio of muon-like to electron-like events is predicted for the low-energy sample. Furthermore, the ratio of low-energy electron-like events with zenith angles less than 90° to those with zenith angles greater than 90° should be greater than 1.