07 Sensory Components

Among the most common symptoms in multiple sclerosis are the sensory symptoms. They are often the first symptoms of MS and while invisible to the naked eye, can be among the most bothersome. The list is long and may involve every inch of the human body. While ever present, these symptoms usually do not predict a poor prognosis.  Nonetheless they are important to understand and manage as best as possible. 

For many the first sign of MS is a blurring of vision indicative of an inflammation of the optic nerve, an optic neuritis or if behind the nerve, a retrobulbar neuritis. That nerve in the eye is extremely sensitive and bursting with myelin. It is a common target of the immune system in MS. When inflamed, vision blurs, colors become bleached, and pain in the eye often accompanies the visual difficulties.  This often is diagnosed simply by looking in the eye with an instrument (ophthalmoscope) and the pupil becomes less sensitive to light shined into it.  If left alone the majority will improve over time but with steroid treatment, vision and pain improve much faster.  When healed there often remains patches of decreased vision which can be accommodated by the brain.  Blindness is rarely a complication. 

Sometimes the muscles (six of them) of the eye are weakened by demyelination in the brainstem. The result is double vision. This obviously makes reading, driving or even walking difficult, if not impossible. This frightening symptom often improves over time as the brain develops compensation.  It often also clears when the inflammation subsides. Patching an eye allows for single vision for tasks but slows the compensation that the brain can develop if allowed. Sometimes special gasses (prism glasses) can help merge the images into one. Neurologists can sometimes see the eyes moving in directions not normal and may diagnose an internuclear ophthalmoplegia which is indicative of MS at an early stage. This fairly specific MS finding has the eyes going in opposite directions but, surprisingly, is not usually disabling to the individual. There are other visual problems as well eg difficulty maintaining focus on a moving target or rhythmical oscillation of the eyes. To address persistent visual issues, your neurologist may refer you to a neuroptometrist or neuropthamologist or even an occupational therapist who has a specialty certification in Low Vision. The occupational therapist can trial low or high tech equipment to help you compensate for your visual deficits.

Numbness, tingling, itching, crawly sensations, and burning pain in the arms and legs are variations of a theme of disturbed electrical conduction in demyelinated nerves within the brain and spinal cord. Like so many sensory symptoms, these usually do not portend a bad long-term prognosis but can be very disturbing. A lot has been said about a band like sensation around the chest, “the MS Hug”. Some have said that it may portend a bad prognosis but that is not the experience of others.  Usually this is due to demyelination in the spinal cord and, like so many sensory symptoms, clears with time. Little can be done for numbness but to develop a conscious denial of their presence and compensatory techniques. Occupational or physical therapists are helpful with teaching those techniques. Pain may be treated with medications developed for neuropathic pain and seizures. Biofeedback and meditation techniques can be helpful as well. Sometimes topical creams are useful.

 Dizziness or light headedness is very common in MS and may be the initial symptom of the disease. Unfortunately for the clinician, dizziness is not very specific and is commonly seen with a variety of dysfunctions involving eyes, ears, brain, metabolism, heart and other organs.  Specific treatment should be aimed at the exact cause but if that is not found there are exercises (provided by a physical therapist) and medications available. Vertigo is a spinning sensation and often is associated with the dizziness. Treatment may be similar but often it is easier to pin down the cause of the vertigo and treat that specifically. Again, these symptoms are common to many disorders so a diagnostic work up may be necessary if the cause is not obvious.

Balance and coordination are motor abnormalities that involve the sensory system greatly.  To keep one’s balance effectively requires input from the eyes, the vestibular (balance) part of ears, sensation in the legs (position sense in the feet), and muscle strength. Disturbance along any of these pathways will have an effect on balance and result in an impaired walking with fall potential. Physical and occupational therapy are essential to the treatment of these issues.  There is a whole specialization to therapy of the balance system, vestibular rehabilitation. At times, a physical therapist may need to guide you to use mobility devices eg a cane or walker to compensate for these balance issues or even instruct you in other compensatory techniques.

Some will feel a lightning like sensation down the spine when the head is bent forward.  This is called a L’Hermitte’s sign and occurs because of demyelination in the spinal cord in the neck. Neuropathic pain medications may alleviate this symptom, but it routinely clears on its own. It can be a frightening sensation if not understood.

Severe stabbing pain in the face can occasionally be associated with MS.  This severe pain is called trigeminal neuralgia and sometimes occurs in the elderly without MS.  When it occurs in people below 50, one should look for demyelination.  It is treated with neuropathic pain medications and occasionally may require a surgical intervention, of which there are many.

Surprisingly, hearing is not a common problem caused by MS but occasionally occurs.  Hearing goes from one ear to both sides of the brain (vision does not operate in that manner) so hearing problems are usually transient unless caused by other causes e.g. aging. 

Dyspareunia is the term given to painful intercourse. This is not common in MS but when present deserves a work-up including gynecological evaluation and potential sexual therapist evaluation and treatment.    

Dysuria means painful urination and is common in MS associated with bladder infections and requires medical intervention with antibiotics, vitamin C, or other management strategies. 

Cold feet may be the result of disrupted nerve pathway of the part of the nervous system that controls blood flow to the skin and/or changes in sensation due to the MS.  Management my involve warming the feet or the use of niacin as a blood vessel dilator.

As you can see, there are many sensory disturbances than may happen in MS. It is very important to note that every person with MS is different and will not be experiencing these, even if they are common. It is also important to understand that most of the time, these are more of a nuisance than disabling. However, if one is bothered by any of them there are management approaches for each of them