1. the coordination of sensory inputs involving different brain regions. It is usually required in tasks that involve matching auditory and visual inputs, tactile and visual inputs, or a similar combination of cognitive functions. Lesions in the temporal, parietal, or occipital lobes may be diagnosed by cross-modal association testing. See perceptual synthesis; sensory interaction.

2. a phenomenon in which the input to one sense reliably generates an additional sensory output that is usually generated by the input to a separate sense.