Cognitive Fog

What it is

Cognitive fog, sometimes called brain fog or cog fog, describes trouble with thinking clearly. It can include slower processing, losing your train of thought, struggling to find words, or having a hard time focusing. It often comes and goes, and can be worse during fatigue or heat.

What you might notice

Losing the thread of a conversation, forgetting a common word, struggling to multitask, or feeling like your thinking is a step slower than usual.

Why it matters for you

Cognitive fog can be frustrating because it is invisible to others. Giving it a name makes it easier to talk about with your care team, your workplace, or the people around you.

Questions to ask your doctor

• Is this brain fog from MS, or could something else be causing it?
• Can you refer me for formal neuropsych testing?
• Are there cognitive rehabilitation programs that actually help?
• Could my current medication be contributing to cognitive issues?
• Will my cognitive function get worse over time?

Related terms

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