What does my abnormal (almost non-existent) knee reflex indicate to a physician?

What does my abnormal (almost non-existent) knee reflex indicate to a physician?
I've been out of work due to both a mental and physical illnesses for nearly two years, and have been awaiting a Social Security disability decision. I'm in the appeal phase, and recently had to go for a second medical examination with one of their doctors. My diagnoses include bipolar & panic disorders, personality disorder-NOS, PTSD, severe sleep deprivation and chronic fatigue syndrome. During this most recent exam, the doctor did the usual tapping to check my knee reflexes, and I must admit to never having known exactly what normal is supposed to be for these things. But both of my legs remained virtually motionless after being tapped. There was movement so slight (and a bit delayed) that it was barely noticeable. I know that in the past my legs have moved quite a bit more than that, and sometimes VERY briskly. What could be going on?

I'm only curious because I've noticed my reflexes in general are slower. I've had to stop driving because of it. Sometimes I wonder if it's because of the meds I'm on.

It's a tumor!

Wow you are certainly different about worrying about your reflexes when you have all of those illnesses!
There is no cause for concern - I have no reflexes all the time and my dad, the doctor, checks them often. He is sometimes curious about why they don't reflex but there is nothing wrong with me and having constant good reflexes, there is bound to have something go wrong at least in one medical check.
Well, good luck for the disability decision, and have good reflexes soon!