|Clip art: Clker|
It is an important study, reportedly one of the first to establish that empirically. The trick apparently is just how closely related the two tasks are. If they are sufficiently distinct, either in terms of intra-modality contrast (like two pictures) or inter-modality (like singing and knitting), go to it! Any number of previous posts have looked at the interplay among visual and auditory and haptic modalities, coming to much the same conclusion: that we can, under the right circumstances attend quite well to both haptic and auditory (and in controlled contexts, visual) simultaneously.
HICP/EHIEP is based on the idea of continuous, simultaneous engagement of multiple modalities (what we often refer to with the acronym "CHI"--for continuous haptic integration, haptic having the primary function of anchoring and integrating.) In other words, doing pedagogical movement patterning and seeing (tracking those movements of the hands across the visual field) and speaking at the same time should be a piece of cake. If not, we may just have too much time on our hands--or not enough. Certainly nothing to HICP at!