In multiple sclerosis, or MS, your immune system attacks myelin, the fatty tissue that surrounds and protects nerve fibers.
This causes scar tissue (sclerosis, also called plaque or lesions) to form on nerve fibers, disrupting the flow of electrical impulses throughout the nervous system.
This nerve damage can lead to a broad range of MS symptoms, from blurred vision to numbness to weakness to loss of balance and more.
For people with primary-progressive MS, symptoms get steadily worse from the beginning, although how quickly they get worse varies from person to person.
Overheating, caused by fever, hot baths, or sun exposure, and stress can also trigger or temporarily worsen MS symptoms. When the body cools back down, or the stress is alleviated, the symptoms generally abate as well.
Early Signs and Symptoms of MS
While some symptoms of multiple sclerosis are very common, there’s no typical pattern of symptoms that applies to everyone. In addition, any one person’s symptoms can fluctuate over time.
Still, the earliest symptoms of MS often include vision problems, such as blurred or double vision, color distortions, and a condition called optic neuritis, which causes eye pain and rapid loss of vision.
Other early symptoms can include:
- Balance problems and clumsiness
- Numbness, tingling, or prickling sensations ("pins and needles") in the arms, legs, torso, or face, known as paresthesia
- Heat sensitivity
A first episode of MS-like symptoms that lasts for at least 24 hours and is caused by inflammation or loss of myelin in the central nervous system is called clinically isolated syndrome (CIS).
In some cases, a person with CIS never has another such episode and does not develop MS. In others, a person does have another episode and is diagnosed with MS. And in still others, an MRI in a person with apparent CIS reveals lesions from earlier episodes, indicating that the person in fact has MS.
Given the nonspecific nature of all of these symptoms, many people with MS are initially diagnosed with something else.
Strategies for Dealing With MS Fatigue
Fatigue is one of the most common symptoms of MS, affecting about 80 percent of people who have the disease, according to the National Multiple Sclerosis Society.
You may experience being tired all day long or become easily fatigued from mental or physical exertion. When MS-related fatigue is severe, it’s called “lassitude.”
Some of the strategies people with MS use to minimize or at least manage their fatigue include:
- Following a healthy diet
- Pacing themselves and taking planned rests
- Exercising to maintain muscle strength and flexibility
- Getting adequate sleep by addressing any symptoms that are interrupting sleep
- Learning energy-conservation techniques
- Avoiding heat exposure
- Getting help for depression, which can cause fatigue
- Taking a medication that promotes wakefulness
An experimental, noninvasive form of brain stimulation called transcranial direct current stimulation (tDCS) has been shown in a few studies to reduce fatigue in people with MS. In tDCS, two electrodes are placed on the head over brain areas believed to be involved in MS fatigue, and a low-intensity electrical current is passed through the electrodes. For MS, an anodal, or positive, current is used to excite neuronal activity. (For other conditions, cathodal, or negative, current might be used to inhibit neuronal activity.)
A study published in September 2017 in Multiple Sclerosis Journal reported that 20 sessions of tDCS in 15 people with MS yielded statistically significant reduction of fatigue, compared with the group that received sham treatment. In a second study, in which 10 sessions of tDCS were delivered, the intervention had less of an effect. (1)
Additional studies of transcranial direct current stimulation and fatigue, cognition, pain, and walking ability in people with MS are ongoing.
Common and Uncommon Symptoms of MS
Other common MS symptoms include:
- Muscles that are weak, stiff, and sometimes painful
- Restless legs syndrome
- Difficulties controlling the bladder or urgency to urinate
- Difficulty walking due to muscle weakness, spasticity, loss of balance, sensory deficits, foot drop, and fatigue
- Constipation and bowel incontinence
- Cognitive impairments affecting concentration, attention, memory, problem-solving, and judgment
- Sexual problems, such as erectile dysfunction, vaginal dryness, and the inability to orgasm
- Clinical depression
- Emotional changes, such as mood swings, irritability, and uncontrolled laughing and crying (called pseudobulbar affect)
Less common symptoms of MS include:
- Slurred or difficult-to-understand speech, as well as the inability to produce voice sounds (dysphonia)
- Difficulty with fine motor control
- Uncontrollable shaking or tremor
- Respiratory problems
- Difficulty chewing and swallowing
- Altered or diminished sense of taste and smell
- Itchy skin (pruritus)
- Hearing problems
- Headaches, particularly migraines
- Psychosis, or loss of contact with reality
RELATED: When MS Attacks the Spinal Cord
Multiple Sclerosis Pain
Pain — including headaches, muscle pain, and chronic back or other musculoskeletal pain — is common among people with MS.
Neuropathic pain may be experienced as pain in the hands and feet, back pain, headaches, painful spasms, Lhermitte’s sign, and trigeminal neuralgia.
Lhermitte’s sign is a brief and sharp, electric shock–like sensation that runs from the back of the head down the spine and into the limbs. It is usually triggered by bending the neck forward.
Trigeminal neuralgia causes a sharp, stabbing pain in the face that originates from damage to the trigeminal nerve, which is responsible for facial motor functions and sensations. It's sometimes confused with dental pain.
Another type of pain associated with MS is the MS hug, or a feeling of squeezing or constriction around the chest or abdomen. The MS hug is caused by spasms in the muscles surrounding the rib cage, and in some people, it can cause difficulty breathing.
Some forms of pain related to MS tend to be short lived, while others can become chronic. Neuropathic pain, pain caused by spasticity, and pain associated with immobility and fatigue tend to become chronic and require ongoing efforts to manage.
Cognitive Impairment Caused by Multiple Sclerosis
Cognitive deficits, or problems with thinking or memory tasks, are common in people with MS. Often described by those experiencing them as "cog fog," cognitive impairments do not appear to be related to the amount of time a person has had MS, the degree of MS-related physical disability a person has, or the appearance of MS lesions on them. (3) However, at least one study has found that cognitive impairment tends to be worse among people with primary-progressive MS than among those with relapse-remitting MS. (4) And another has found that older age and a higher score on the Expanded Disability Status Scale (EDSS) is associated with more severe cognitive impairment. (5)
While there is some variety in the types of cognitive problems people with MS typically have, researchers have found the follow to the most common:
- Slowed processing of new information
- Difficulty learning and remembering new information
- Difficulty with organizing information and problem-solving
- Trouble focusing and maintaining attention
- Deficits in visuospatial skills, or the ability to properly perceive the world around them
- Problems understanding and using language
- Difficulty doing calculations
Cognitive dysfunction is a major cause of unemployment in people with MS and can also interfere with daily tasks such as cooking, driving, or holding a conversation. (6) It can cause tension in personal relationships and may make accessing healthcare more difficult.
Various cognitive function tests can identify the specific deficits a person is experiencing. In 2018, a group of experts brought together by the National Multiple Sclerosis Society published recommendations for cognitive screening for people MS. (7) They recommended:
- Early baseline testing for all adults and children with MS
- Annual reassessment with the same test as used for baseline screening
- More comprehensive testing for adults whose tests have revealed cognitive deficits or who have demonstrated cognitive decline
- Neuropsychological evaluation for children with MS under age 18 who have an unexplained change in function at school
- Interventions for adults and children to improve functioning at home, work, or school
Generally, such tests are administered by a neuropsychologist, a specialist who studies how brain function affects cognitive function and behavior. But since traditional testing can be time-consuming, and not all neurology offices employ a neuropsychologist, an initiative known as BICAMS (Brief International Cognitive Assessment for MS) has been working to develop a cognitive assessment test that takes less time and can be administered by non-neuropsychologists. The test, which has been in development since 2012, is currently being used in research on cognitive disability.
In some cases, cognitive rehabilitation can improve cognitive function, or individuals can learn to compensate for deficits by, for example, setting alarms, writing reminder notes, or minimizing distractions.
The Challenge of MS Diagnosis
Multiple sclerosis can be difficult to diagnose, in large part because it can cause so many different symptoms, some of which mimic the symptoms of a number of other conditions.
MS symptoms can also come and go from one day or week to the next, as well as change gradually over time. And there is no single test that can definitively diagnose the disease.
For all of these reasons, people with MS often go for months, years, or even decades not knowing the cause of their symptoms or believing they have some other condition. That's unfortunate, because early treatment with MS disease-modifying medication can slow the overall progression of the disease.
Other forms of treatment, such as a variety of rehabilitative therapies, can similarly improve physical and cognitive functioning and quality of life.
Editorial Sources and Fact-Checking
- Charvet L, Dobbs B, Shaw MT, et al. Remotely Supervised Transcranial Direct Current Stimulation for the Treatment of Fatigue in Multiple Sclerosis: Results From a Randomized, Sham-Controlled Trial. Multiple Sclerosis Journal. September 2017.
- Urits I, Adamian L, Fiocchi J, et al. Advances in the Understanding and Management of Chronic Pain in Multiple Sclerosis: a Comprehensive Review. Current Headache and Pain Reports. July 2019.
- Westervelt HJ. Dementia in Multiple Sclerosis: Why Is It Rarely Discussed? Archives of Clinical Neuropsychology. January 2015.
- Johnen A, Landmeyer NC, Burkner PC, et al. Distinct Cognitive Impairments in Different Disease Courses of Multiple Sclerosis: A Systematic Review and Meta-Analysis. Neuroscience and Biobehavioral Reviews. December 2017.
- Ruano L, Portaccio E, Goretti B, et al. Age and Disability Drive Cognitive Impairment in Multiple Sclerosis Across Disease Subtypes. Multiple Sclerosis. August 2017.
- Campbell J, Rashid W, Cercignani M, Langdon D. Cognitive Impairment Among Patients With Multiple Sclerosis: Associations With Employment and Quality of Life. Postgraduate Medical Journal. March 2017.
- Kalb R, Beier M, Benedict RHB, et al. Recommendations for Cognitive Screening and Management in Multiple Sclerosis Care. Multiple Sclerosis Journal. October 2018.
- MS Symptoms. National Multiple Sclerosis Society.
- Multiple Sclerosis Information Page. National Institute of Neurological Disorders and Stroke. August 5, 2019.
- Pain and Itching. National Multiple Sclerosis Society.