Rajesh, a 58-year-old businessman, was having breakfast when his wife noticed that the right side of his face looked slightly droopy. He tried to reassure her.

"It's probably because I didn't sleep well."

A few minutes later, his teacup slipped from his right hand. His speech became slurred. His family wanted to rush him to the hospital, but Rajesh insisted on waiting for "the weakness to improve". By the time he reached the emergency department six hours later, the diagnosis was clear; he had suffered an acute ischemic stroke.

Unfortunately, he had missed the time window for clot-busting treatment (thrombolysis), which is most effective when given within the first few hours after symptom onset.

Fortunately, not every neurological symptom is an emergency. Many turn out to have benign causes. However, some symptoms are the nervous system's way of telling us that something important may be wrong. Recognising these warning signs and seeking timely medical attention can sometimes prevent permanent disability or even save a life.

Here are ten symptoms that should prompt neurological consultation.

1. Sudden weakness of the face, arm or leg

Weakness affecting one side of the body is the hallmark symptom of stroke. It may involve the face, arm, leg or all three. Sometimes, the weakness lasts only a few minutes before recovering completely. Even then, it should never be ignored because it may represent a transient ischemic attack (TIA), often called a 'mini-stroke'.

Remember the simple FAST test:

• Face drooping 

• Arm weakness 

• Speech difficulty 

• Time to call emergency services 

Every minute counts during a stroke.

2. Sudden difficulty speaking or understanding speech

If someone suddenly cannot find words, speaks gibberish, has slurred speech or cannot understand what others are saying, it is a medical emergency until proven otherwise. Stroke is the most important cause, but other neurological disorders may also present this way.

3. A sudden, severe headache unlike any before

Most headaches are not dangerous. However, a sudden 'thunderclap headache', often described as the worst headache of one's life, requires immediate medical evaluation. It may indicate bleeding around the brain (subarachnoid hemorrhage) or another serious condition. Headaches accompanied by fever, confusion, seizures, weakness or visual loss also warrant urgent assessment.

4. Sudden loss of vision or double vision

Vision problems are not always due to eye disease. Sudden loss of vision in one eye may be caused by interruption of blood supply to the retina and should be treated like a stroke. Persistent double vision may indicate a disorder affecting the brain, brainstem or nerves controlling eye movements. Both symptoms deserve prompt medical evaluation.

5. Persistent numbness or tingling

Many people experience temporary numbness after sitting awkwardly. Persistent numbness, especially if confined to one hand, one foot or one side of the body, should be evaluated. Conditions ranging from nerve compression, diabetes-related neuropathy and vitamin B12 deficiency to stroke or multiple sclerosis can present this way.

6. Difficulty walking or unexplained imbalance

Frequent falls, unsteadiness, veering to one side or difficulty coordinating movements are not a normal part of ageing. They may result from disorders affecting the brain, cerebellum, spinal cord, peripheral nerves or inner ear. If imbalance develops suddenly, especially along with double vision or weakness, seek emergency care.

7. Tremors or slowing of movement

Not every tremor is Parkinson's disease. However, a new tremor, stiffness, slowness in walking, reduced arm swing or difficulty performing everyday tasks should prompt neurological evaluation. Early diagnosis allows treatment to begin before symptoms significantly interfere with quality of life.

8. Memory problems affecting daily life

Occasionally forgetting names or misplacing keys is common, especially during stress. More concerning are memory problems that interfere with work, finances, driving or managing medications. Repeating the same questions, getting lost in familiar places or personality changes deserve medical attention. Importantly, memory impairment is not always dementia; it may be due to depression, thyroid disorders, vitamin deficiencies, sleep disorders or medication side effects, many of which are treatable.

9. Seizures or episodes of loss of consciousness

A first seizure always requires medical evaluation. Seizures may involve dramatic shaking movements, but they can also present as brief episodes of staring, sudden confusion or unexplained loss of awareness. Similarly, recurrent unexplained blackouts should never be dismissed as simple fainting without proper assessment.

10. Persistent dizziness or vertigo

Most dizziness is not due to a serious brain disorder, and common causes such as benign positional vertigo are highly treatable. However, dizziness accompanied by double vision, weakness, difficulty speaking, severe imbalance or inability to walk requires urgent neurological evaluation because it may indicate a stroke affecting the back of the brain.

Listen to your nervous system

The brain and nervous system often provide warning signals long before permanent damage occurs. While many neurological symptoms eventually prove to have harmless or treatable causes, ignoring them can sometimes lead to missed opportunities for early treatment.

The good news is that advances in neurology have transformed outcomes. Modern treatments are effective in reducing disability and improving quality of life, when started early and on time. 

The message is not to become anxious every time you develop a headache or feel dizzy. Rather, it is to recognise symptoms that are unusual, persistent, progressive or sudden in onset, and seek timely medical advice.

When it comes to neurological disease, time often matters as much as treatment. Listening to the warning signs your nervous system gives you may be one of the most important health decisions you ever make.

The opinions expressed in this article are those of the author and do not purport to reflect the opinions or views of THE WEEK.