11 Symptoms Neurologists Say Never to Ignore

It can be hard to wrap your head around all the conditions neurologists treat: cerebrovascular disorders like stroke and carotid artery disease, seizure disorders, neurodegenerative diseases such as Alzheimer’s and frontotemporal dementia, headache and facial pain disorders, movement disorders including Parkinson’s, muscle diseases, sleep-related conditions like narcolepsy, and much more.

“If there’s a nerve somewhere, a neurologist could get involved,” says Dr. Andrew Dorsch, division chief for general neurology at Rush University System for Health and a neurologic rehabilitation specialist. “And there’s nerves everywhere in the body. There’s a lot of things that can go wrong with the nervous system, and it can take quite the detective work to figure it out.”

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Often, he adds, people brush off neurological symptoms for a long time, pinning their symptoms on age-related aches and pains or assuming they’ll resolve on their own. That’s a mistake.

We asked four neurologists which symptoms you should never ignore—and what they might signal.

Double vision in one eye

One common symptom that people often overlook is double vision in one eye. There are a number of potential causes, including multiple sclerosis, a stroke or aneurysm, myasthenia gravis, a brain tumor, or a brain infection, says Dr. Luis Cruz-Saavedra, a neurologist with Memorial Hermann Health System. 

When should you take it seriously? “Immediately,” he says. “If you develop sudden-onset double vision, it’s a reason to go to the emergency department.” The doctors there will check vitals and look for stroke red flags, do eye and neurologic exams, and may order imaging like a CT scan of the head or a brain MRI.

Weakness in one hand or leg

Have you ever noticed that you’re dragging one leg behind you, or maybe limping around? Do you have difficulty picking up your morning coffee or writing with your dominant hand? If the answer is yes, schedule a doctor’s appointment.

“I’ve been impressed in my clinics by how many people ignore weakness in one hand or one leg,” Cruz-Saavedra says. (That is: impressed in a bad way.) “People come months after their symptoms start—but weakness is one you can’t ignore. A lot of people think, ‘Oh, it’s just a pinched nerve,’ but it could actually be a stroke, it could be a brain tumor, it could be a disorder like multiple sclerosis, it could be any sort of brain inflammation.”

When neurologists see patients with this type of weakness, they typically test strength, reflexes, coordination, and gait, which can help rule out potential causes and point them in the right diagnostic direction.

Transient unresponsiveness

Sometimes people with neurological problems go blank for a few seconds, and then return to their normal selves with no recollection of what just happened. This experience is commonly associated with temporal lobe seizures, which happen in the parts of the brain that are important for short-term memory and processing emotions, Cruz-Saavedra says. 

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“Sometimes family members describe it because the patient might not really notice,” he adds. “They’ll say, ‘I was speaking to him, and he was just staring off, and then after 10-15 seconds, he was back to normal.’ Or the patient might say, ‘Hey, sometimes I lose track of time. It’s almost like I lost a little part of my day.’”

Problems with speech

Stroke is a major cause of death in the U.S., yet people often don’t recognize the symptoms and delay seeking care as quickly as they should. “I hear all the time how someone’s having stroke symptoms, and their reaction is, ‘Well, I’m going to take a nap and see if they go away,’” says Dr. Enrique Leira, director of the division of cerebrovascular diseases at the University of Iowa in Iowa City.

Stroke symptoms tend to appear abruptly and involve a lack of function stemming from brain injury. One way that manifests: trouble speaking. People might start slurring their words, speaking slowly, experience difficulty with word finding, or even be unable to comprehend what others are saying, Leira says. In that situation, seek care urgently, he advises.

Sudden headache during physical effort

Headaches are a pain for neurologists to evaluate—there are dozens of potential causes, and many are innocuous. But some warrant fast attention. A headache could raise suspicions of a stroke if “it’s unusually strong and sudden—it doesn’t build up over minutes or hours,” Leira says. “And if it strikes when you’re doing some physical effort, that’s enough of a concern that it should be checked out right away.”

Numb feet and fingers

When Dorsch’s patients come in for numbness, it’s typically affecting their feet or fingers. “That usually tells us that the nerves are not sending information back to the brain like they should,” he says. “The nerve is asleep. It’s stunned, or unfortunately in some cases, it’s dead. There’s no information getting to the body or up to the brain.” That makes numbness different from tingling, a prickly sensation that indicates that a nerve is irritated.

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When someone is experiencing numbness, the first step is typically doing a full workup to figure out which nerves are dysfunctioning, what’s causing the problem, and how to best treat it. While some patients end up having diabetes, there are many possibilities; others might have a genetic condition, or their immune system could be attacking their nerves, Dorsch says.

A sense of déjà vu

Everybody experiences déjà vu—the uncanny sense that something has happened before—from time to time. “But if you’re having episodes of déjà vu on a regular basis, you probably want to come in and get checked out,” Dorsch says. That’s because it could be a warning sign for a temporal lobe seizure. Dorsch recently treated a patient who was “having recurring episodes every week, or every couple of weeks, which is not how often people usually get déjà vu,” he says.

Difficulty getting out of a chair on a regular basis

As people get older, they tend to develop problems with daily movement, like stiffness or slowing down. Some complaints stand apart, however. If you’re regularly having trouble getting out of your chair, it’s a good idea to schedule a doctor appointment. 

“Sure, there could be some joint issues, but we really want to take a look and make sure you don’t have an issue with your muscles or your nerves or your spinal cord,” Dorsch says, like Parkinson’s or amyotrophic lateral sclerosis (ALS). “That’s something I would want a family member to go get checked out.”

Changes in voice

Neurologists are alert to several kinds of vocal changes. One is hypophonic speech, which means the voice is abnormally soft or breathy; it can indicate Parkinson’s disease, says Dr. Alexandru Olaru, a neurologist at University of Maryland St. Joseph Medical Center. Another is slurred speech, which could point to a stroke. 

Another concerning change, Olaru says, is wet dysarthria: when your voice sounds gurgly, likely because of excess saliva or phlegm. “People lose the muscle mass in the back of their throat, and they lose the ability to handle the saliva,” he says. That means it pools in the back of the throat, “so when you talk, it’s almost like you have water in your mouth.” Some of the most common causes include Parkinson’s disease, ALS, and multiple sclerosis.

Persistent muscle twitches

Everyone’s muscles twitch from time to time, usually at various locations. Sometimes you can actually see the muscles “rippling under the skin,” Olaru says. “Or, if you put your hand onto the muscle, you can feel it.” 

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If you experience these fasciculations—the medical term for muscle twitches—in the same place consistently, however, it’s worth bringing up to your doctor. It’s possible you could have benign fascicular syndrome, which is harmless, or a more serious condition like spinal stenosis, ALS, or chronic inflammatory demyelinating polyneuropathy (an autoimmune condition that targets the protective covering around your peripheral nerves). Neurologists usually recommend an electromyography (EMG), which is an electrical test for the nerves and muscles that can help pinpoint what’s going on.

Paranoia

Abrupt behavior and personality changes can be the result of conditions like autoimmune encephalitis, frontotemporal dementia, or other cognitive disorders. One common example is newfound paranoia. Someone might “feel like they’re being persecuted, or like somebody’s plotting against them or their loved one is being unfaithful, when it just makes no sense,” Cruz-Saavedra says.

Neurologists also pay close attention when someone who has been quiet and serious their whole life suddenly takes on a boisterous personality, talking nonstop. “Sometimes people even become hypersexual, and make inappropriate comments or jokes,” he says. “Or the other way around: a person who has been outgoing and very vocal is now just withdrawn.”

Dementia can also manifest as uncharacteristic-obsessive compulsive disorder or hoarding behavior, Cruz-Saavedra adds.