it can affect their prices in two different ways:
1. everyone knows that whenever bitcoin is falling everything else falls harder. so ICO tokens are no exceptions. they can fall hard because of it and never recover.
2. which is the most important one in my opinion is the fact that when bitcoin is rising like last year there are a lot of newbies coming in with a lot of dreams of getting rich overnight while having 0 understanding of the market. and when price drops like these days the same newbies are running away as fast as possible.
these newbies are the main bulk of investors in ICOs and when there are more of them around ICOs can have better days than when there is less of them around and they are running away.
I agree on how the price of bitcoin drops and everything now was unpredictable, but with regards to the ico I think that the opportunity now at low price could attract good investors. Having those newbies weren't a reliable assurance that makes bitcoin price rise even higher, but the most certain situation was more wise investors waited for that low price to buy. If you think that it will affect the ico, then I guess that's far behind all speculated ideas because most of those who used digital currency now preferred a cheaper bitcoin value for their purchases.