© Sweet Livin, Inc.  2011 Chronic Fatigue and Fibro Living Brain Fog Overview Brain fog (also called fibro fog or cognitive dysfunction) is one of the most common complaints of people with fibromyalgia  (FMS) and chronic fatigue syndrome (CFS or ME/CFS). For many, it can be severe and can have just as big an impact on their lives as pain or fatigue. In fact, some people say brain fog is more of a disability than their physical symptoms. The difficulties, which many people find very distressing, include being forgetful, feeling confused, difficulty concentrating and the inability to speak clearly. Causes Cognitive problems can have a variety of causes, including:   Overexertion    Being too active, living "outside energy envelope"   Fatigue              Hard to be alert when tired    Over-stimulation   Sense information from multiple sources    Multi-tasking    Doing more than one task at the same time   Stress              Stress increases CFS/FM symptoms   Poor Sleep              Not getting restorative sleep   Medications    Side effects include confusion