Tell-tale signs of a looming stroke often fall under the radar, experts say.
One in seven stroke patients does not experience any of the symptoms which make up the FAST acronym, most commonly associated with the condition.
They remind family and friends to look out for the face to drop on one side, the patient to struggle to lift both arms and have slurred speech, while time is essential.
But additional signs can be just as dangerous, experts say. These include difficulty swallowing and loss of sight in one or both eyes.
Strokes affect more than 100,000 Brits annually — one every five minutes — and claim 38,000 lives every year.
Professor Martin Dennis, an expert in stroke medicine at the University of Edinburgh, told Mail Online it is essential stroke sufferers are treated quickly to avoid further health problems, disabilities or even death.
Sudden numbness on one side of the body
Numbness that affects the hand, arm, leg or part of the face are very common.
Prof Dennis said the symptom is often due to nerve compression, especially if it occurs while sitting or laying down, as this can put pressure on nerves.
If sudden numbness occurs in the face and arm or the arm and leg, "at the same time", this could be a cause for concern.
Not everyone will experience all of the signs of stroke.
But if you experience numbness alongside any one of those under the FAST acronym, help should be sought immediately.
Sudden memory loss
Someone who appears to be suffering from memory loss may be experiencing the life-threatening condition too.
Confusion and difficulty understanding speech are signs of a stroke, which to a normal person, may seem like someone has lost their memory.
Therefore, sudden memory loss can appear to be a 'rare' sign of a stroke, according to Prof Dennis.
"People who develop aphasia or dysphasia (difficulties understanding language) will jumble their words, and may not be able to say anything, or understand anything," Professor Dennis said.
"Their reading and writing may be affected. They may be described by lay peoples as being confused or having loss of memory because they cannot answer questions."
Loss of sight in one or both eyes
While stroke can cause blurred vision, or loss of vision in one eye or both eyes, this symptom may not be as well recognised as facial weakness.
A 2017 study, published in the journal Stroke, concluding that, of the one in seven stroke sufferers who do not experience FAST symptoms, four in 10 list visual problems as one of their stroke symptoms.
Loss of sight can indicate a loss of circulation to the eye, which may be caused by a stroke.
Sudden Vertigo
Vertigo, which is the sensation that you, or the environment around you, is spinning, is a symptom caused by an array of health conditions.
It is often harmless and the sign of an ear infection or headache.
When coupled though with double vision, weakness or clumsiness of the limbs and slurred speech, it can be a sign of a stroke.
One 2016 study even suggested that between 15,000 to 25,000 people annually who suffer a stroke and present with dizziness or vertigo symptoms, may suffer serious or potentially preventable harms from initial misdiagnosis.
A separate 2017 study suggested four in 10 stroke victims, who did not experience typical symptoms, said they suffered from vertigo.
Difficulty swallowing
Professor Martin James, a consultant stroke physician at the Royal Devon & Exeter NHS Foundation Trust in Devon, warned difficulty swallowing should still be taken seriously.
But he told the publication it is "very very rarely a sign of a stroke on its own".
Swallowing problems are also known as dysphagia.
Dysphagia is thought to affect up to 15million adults in the US and around 4million in the UK.
A sudden, severe headache
A sudden, severe headache may indicate signs of a stroke but this is uncommon.
Often associated with migraines, it could in some rarer cases "be a feature of a subarachnoid or intracerebral bleed," Prof Dennis said.
A subarachnoid haemorrhage, an uncommon type of stroke, is bleeding in the space around the brain.
This bleeding between the thin layers of tissue that cover the brain can often cause serious side effects, including disability or can even prove to be fatal.
Stroke is UK's fourth biggest killer and a leading cause of disability.
Age, high blood pressure, smoking, obesity, sedentary lifestyle and diabetes are all known to increase the risk of stroke.
