Second to that. They easily get spider mites which cause leaves to get pale, dry up, fall off. Mites create fine webbing and a dusty feel to the living leaves.
Having some new growth is a good sign.
Ivy (Hedera is the genus) are very tough outdoor plants, they can take a lot of cold and humidity and drought. But indoors, they typically don't get enough light or humidity ( don't bother misting, that won't work). They're really picky! and then there's the spider mite thing..
Can you put them outside?
