Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
1
Is any of this happening now?
Call 911
Seek emergency help for:
Sudden confusion or a rapid change from the person’s usual state
New facial drooping, arm weakness, speech difficulty, or other stroke signs
A seizure, collapse, severe head injury, or loss of consciousness
Severe headache with new neurological symptoms
Difficulty breathing or being impossible to wake
Immediate risk of self-harm, harm to others, or unsafe wandering
And for anyone, someone who:
has sudden weakness or drooping on one side of the face or body, slurred speech, or sudden confusion
Other emergency signs, for anyone
Someone who is struggling to breathe, gasping, choking, or cannot get words out
Someone who has chest pain, tightness or pressure lasting more than a few minutes
Someone who is unconscious, or cannot be woken
Someone who is bleeding heavily and it will not stop with firm pressure
Someone who has had a seizure that will not stop, or does not wake up afterwards
Someone who has lips or skin that look pale, blue, grey or blotchy
Someone who you believe has taken an overdose or swallowed something poisonous
2
Is any of this happening?
Be seen today
Seek prompt medical advice for a noticeable change over days, new hallucinations, repeated falls, a major change in behaviour, or increasing difficulty eating, drinking, taking medicines, or staying safe.
And for anyone, someone who:
has a new severe headache unlike any they have had before
3
Does any of this apply?
Book an appointment
Arrange a routine medical assessment if memory or other thinking changes are persistent, worsening, or interfering with everyday activities.
Earlier assessment can identify treatable contributors and allow time for support and planning.
The article also says
Sudden symptoms should not be assumed to be part of a long-term neurocognitive disorder.
Every sign above is quoted from the sofidex article on Neurocognitive disorder. If you are not sure, err upward — it is always reasonable to be checked.