Not that we have heard. While performing acoustic stimulation, only EMG is our primary monitor. Do you have any particular monitor for VEG simutaneously?

Dear Dr Yin-Cheng Huang   

When i have to measure SSVEP (Steady-state Visual Evoked Potential) for BCI (Brain Computer Interface) devices after visual stimulation, in that case, if subject is in the state of visual and acoustic stimulation simultaneously, then what will happen on SSVEP signal? Does it affect the performance of BCIs devices?

I wanna investigate that effect. 

There are most likely audiovisual interactons

http://www.ncbi.nlm.nih.gov/pubmed/17076810

http://www.ncbi.nlm.nih.gov/pubmed/22973204

As I know... auditory stimuli slightly affect the performance of BCIs based on ERP signals. However, it all depends on how you design the experiment.

There is definitely an effect in visual cortices during auditory stimulation: For example, Gregor Thut from Glasgow has a remarkable series of findings, initiated by the observation that the clicking sound of a TMS coil induces a phase reset in occipital alpha oscillations:

http://www.ncbi.nlm.nih.gov/pubmed/22503499

http://www.ncbi.nlm.nih.gov/pubmed/24858108

http://www.ncbi.nlm.nih.gov/pubmed/23384192

[etc]

There is also a large body on literature on crossmodal attention and multisensory perception. Just type these two terms in any search engine and you will be overwhelmed on the amount of work done in these topics. There is an awesome study by David Poeppel (http://www.psych.nyu.edu/poeppel/) showing that the jitter of the speech sound and the observation of someone speaking are highly interacting. Unfortunately I cannot find that study back right now. I bet if you search for "SSVEP and auditory" you will find a lot of literature more related to your particular research questions. I know for sure that similar investigations have been performed before.

In addition to the works mentioned by Dr. Horschig, there are a large number of studies showing there to be early-latency multisensory interactions within low-level cortices, including primary visual cortices. You can find a couple of reviews here:

http://journal.frontiersin.org/article/10.3389/fnint.2015.00017/full

There are also a couple of books on this topic:

The Neural Bases of Multisensory Processes (Murray & Wallace, Eds)

http://www.ncbi.nlm.nih.gov/books/NBK92848/

(this is available online via PubMed)

The New Handbook of Multisensory Processing (Stein, Ed)

don't hesitate with any further questions.