Previous dual-task research pairing complex visual tasks involving non-spatial cognitive processes during dichotic listening have shown effects on the late component (Ndl) of the negative difference selective attention waveform but no effects on the early (Nde) response suggesting that the Ndl, but not the Nde, is affected by non-spatial processing in a dual-task. Thus to further explore the nature of this dissociation and whether the Nd waveform is affected by spatial processing; fourteen adult participants performed auditory dichotic listening in conjunction with visuo-spatial memory in a cross-modal dual-task paradigm. The results showed that the visuo-spatial memory task decreased both the Nde and Ndl waveforms, and also attenuated P300 and increased its latency. This pattern of results suggests that: (1) the Nde reflects a memory trace that is shared with vision when the information is spatial in nature, and (2) P300 latency appears to be influenced by the discriminability of stimuli underlying the Nde and Ndl memory trace. (Contains 1 table and 4 figures.)