Spruce Needle Cast
There are a few possibilities here, and without culturing in a lab or looking with a microscope it's impossible to know for sure what's causing the problems you see on your spruce tree. There are two needle cast diseases that cause the older spruce foliage to turn purple or brown and then die. Stigmina needle cast and Rhizosphaera Needle Cast. Both can be severe problems for spruce and treatment is difficult. You would need a definite diagnosis from your local extension service or a certified arborist, and treatment with a fungicide labeled for the fungus you have is usually done in the spring.
Spruce can also lose needles due to drought and many parts of the Northeast were dry this past summer and early fall. Sometimes drought works in combination with other situations such as spruce spider mites and the damage seen is a result of the two things combined. Yellowing needles on spruce can be caused by too dry, too wet, or soil that is too compact such as areas where recent activity from construction machinery have pressed soil into place.
If this spruce is recently planted, and it was a balled and burlaped plant, that too might be playing a role because B&B plants have had a great deal of their roots cut off, and the plant will drop the older needles if it doesn't have the root system to sustain all the plant.
If this is an important plant in your landscape you might want to have a certified arborist come and look at it.