Brain Fog
"Brain fog" is a symptom -- not a formal medical diagnosis -- describing a cluster of complaints around attention, memory, and mental clarity, per current neurology literature.
Symptoms
Difficulty concentrating, feeling mentally slow or "foggy," word-finding trouble, and short-term memory lapses that interfere with daily tasks.
Causes and risk
Brain fog is associated with a wide range of conditions, including post-COVID syndrome, ME/CFS, fibromyalgia, thyroid and autoimmune disease, poor sleep, certain medications, and mood disorders, per current neurology research.
How it is evaluated
Because brain fog can stem from many causes, evaluation focuses on screening for reversible contributors -- reviewing medications, checking thyroid function and other labs, and screening for sleep and mood disorders -- following multidisciplinary consensus guidance developed for post-COVID cognitive symptoms.
Treatment
Treatment targets the underlying cause once identified; cognitive rehabilitation strategies and addressing sleep, mood, and pacing (particularly if ME/CFS or post-COVID syndrome is present) are the most evidence-supported general approaches.
When to seek care
Sudden-onset confusion, difficulty speaking, weakness on one side of the body, or a severe headache are not typical brain fog and require emergency evaluation -- call 911, since these can signal a stroke or other acute neurological event.