How to know if I loseing memory is related any illness?

Tests. When someone has memory loss, that person's doc will usually do a history and physical exam to rule out any illness, or depression. Tests may be done to make sure there is not a vitamin deficiency, thyroid disorder, or tumour. The doctor may review meds taken to make sure these are not causing memory loss. So begin the assessment by first going to your doctor.
Doctor. You should see a neurologist who will examine you for secondary causes of memory loss.