Visual, Speech & Hearing Symptoms
A vision problem is the first symptom of multiple sclerosis (MS) for many people. The sudden onset of double vision, poor contrast, eye pain, or heavy blurring can be terrifying and the knowledge that one's vision may be compromised can make those with MS concerned about the future. Visual symptoms are common in people with MS, but rarely result in total blindness.

Speech and voice problems occur in around 25 to 40% of those with MS, particularly during relapses or periods of extreme fatigue. The problems are basically of two types:
Dysarthria - referring to changes in the production of speech, including slurring, unclear articulation of words, and difficulty controlling loudness.
Dysphonia - is the term used for changes in voice quality, including hoarseness, breathiness, nasality, poor control of pitch.

Hearing loss is not a common symptom of MS with only about 6% of those with have MS complain of impaired hearing. Deafness due to MS is exceedingly rare, and most acute episodes of hearing deficit caused by MS tend to improve.
Visual Symptoms
Optic Neuritis

Those with MS may experience double vision, eye discomfort and uncontrollable eye movements. Optic neuritis is a common first symptom of MS. The inflammation of the optic nerve is mainly due to demyelination and can be idiopathic and isolated. From 15 to 20% of cases of MS manifest as optic neuritis, and about 50% of patients with MS develop optic neuritis at some point during the course of their disease. Other than the visual issues, pain commonly occurs or is made worse with eye movement.

As a predictor of MS, it's been found that the presence of demyelinating white matter lesions on brain magnetic resonance imaging (MRI) at the time of presentation of optic neuritis is the strongest predictor for developing clinically definite MS. Almost half of the patients with optic neuritis have white matter lesions consistent with MS. At five years follow-up, the overall risk of developing MS is 30%, with or without MRI lesions. Patients with a normal MRI still develop MS, but at a lower rate compared to those patients with three or more MRI lesions. From the other perspective, however, almost half of patients with any demyelinating lesions on MRI at presentation will not have developed MS ten years later.

The classic triad of optic neuritis consists of (1) loss of vision, (2) eye pain, and (3) dyschromatopsia, which refers to the impairment of accurate color vision. 70% of cases in adults are unilateral or just affecting on eye. The typical clinical course is that of eye pain and worsening visual function, which progresses over days to weeks. The eye pain usually resolves over days, often as the visual loss begins. Usually recovery is spontaneous, with a reversal of the visual loss beginning within 2 to 3 weeks and stabilizing over months.

Major symptoms of optic neuritis are sudden loss of vision (partial or complete), or sudden blurred or "foggy" vision, and pain on movement of the affected eye. Many patients with optic neuritis may lose some of their color vision in the affected eye, with colors appearing subtly washed out compared to the other eye. Many others tend to have "floaters" (floating spots) in their vision that are more noticeable in brighter lighting conditions. These "floaters" or scotoma in the field of vision can be described as dark spots or gaps that appear to move with they eye, but are actually fixed blind spots due to optic nerve damage. They can range in number from a single spot to many and will typically show up unilaterally. Additional findings may include movement or sound induced phosphenes, described as brief flashes of light lasting 1-2 seconds. Reduction in vision may also worsen in bright light, a symptom that seems paradoxical.

Another condition that may appear is called closed-eye visualizations (CEV) where light appears when one's eyes are closed or when one is in a darkened room. The spots of light are a form of phosphene which are brief spots of light brought on by eye movement (movement phosphenes) or sudden noises (sound phosphenes). They can last for a few seconds to always being present. In the case of optic neuritis, they are caused by mechanical aggravation from a damaged or inflamed optic nerve. They are usually more obvious in low light to dark conditions.

Optic neuritis usually clears by itself within 4 to 12 weeks after appearing and generally causes no permanent damage. However, in some cases there may be a permanent reduction in sight, this is when continued episodes cause scarring on the optic nerve. Irreversible optic nerve damage occurs in up to 85% of those with optic neuritis; however, the damage is often early on and mild. As many as 80% of patients regain at least 20/30 vision, 45% within the first 4 months and 35% within 1 year. Long-term severe vision loss occurs in 20% of patients.

Diplopia

Diplopia (double vision) is a fairly common symptom of MS and is the result of lesions in the brainstem, where the cranial nerves serving the eye muscles originate. It usually goes away without treatment, but occasionally a course of corticosteroids are used to speed the process. Covering one eye with a patch eliminates the double vision and is useful for driving or other necessary tasks.

Nerve Palsy

Third nerve (oculomotor)

An irregular, uncertain, stamping gait. Legs are kept far apart, and either the ground or the feet are watched, because there has been a loss of knowledge of the position of the lower limbs. This gait is caused by an interruption of the afferent nerve fibers.

Forth nerve (trochlear)

Legs flexed slightly at the hips and knees, giving the appearance of crouching, with the knees and thighs hitting or crossing in a scissors-like movement.

Sixth nerve (abducens)

Slow, shuffling gait in which the patient appears to be wading in water. Knee and hip movements are restricted. Also referred to as creeping palsy.

All three of these cranial nerves originate in the brainstem - the third and forth in the midbrain and the sixth in the pons.

Nystagmus

Nystagmus is the involuntary, rapid repetitive movements of the eyes and is a common symptom of MS. These movements are usually from side to side, but can also be up and down. It can happen only when people look to the side or it can be severe and constant enough to impair vision.

In those with MS, nystagmus is often associated with a loss of coordination between the eyes, caused by a lesion in the part of the brain called the medial longitudinal fasciculus. It can also be due to a lesion in the cerebellum or the brainstem.

There are no effective symptomatic treatments for nystagmus, although corticosteroids are sometimes given to reduce the severity or duration of this symptom.
Speech & Swallowing
Speech disorders are fairly common in MS. Speech patterns are controlled by many areas in the brain, especially the brainstem. Lesions in different parts of the brain can cause several types of changes in normal speech patterns. They range from mild difficulties to severe problems that make it difficult to speak and be understood. Medically, speech disorders are called dysarthrias.

Like other symptoms of MS, speech or swallowing difficulties are due to an area of damaged nerves that normally aid in performing these tasks.

Speech

Dysarthria is a speech diagnostic term that can be used to classify various types of neuromuscular speech disturbances. Dysarthria results from notable degrees of one or more abnormalities involving speech musculature, including weakness, paralysis, incoordination, sensory deprivation, exaggerated reflex patterns, uncontrollable movement activities, and excess or reduced tone.

The dysarthrias are considered motor speech disorders because speaking difficulties are largely due to breakdowns in movement control of one or more muscle groups that compose the speech mechanism. The name of each dysarthria subtype is partially derived from the basic characteristics of the overlying movement disturbances. Normal speech production involves the integration and coordination of five primary physiological subsystems.

The five primary physiological subsystems:
Respiration - breath support
Phonation - voice production
Articulation - pronunciation of words
Resonation - nasal versus oral voice quality
Prosody - rate, rhythm, and inflection patterns of speech

Locating the damaged areas responsible for the speech problem is often difficult. Many areas in the brain, especially the brainstem, control speech patterns. Thus, lesions in different parts of the brain can cause several types of changes in normal speech patterns. They range from mild difficulties to severe problems that make it difficult to speak and be understood.

The seven subtypes of dysarthria:
Spastic
Unilateral upper motor neuron
Ataxic
Hypokinetic
Hyperkinetic
Flaccid
Mixed

One pattern of speech that is commonly associated with MS is called "scanning" speech. This type of speech produces speech in which the normal "melody" or speech pattern is disrupted, with abnormally long pauses between words or individual syllables of words. People with MS may also slur words as a result of weak tongue, lip, and mouth muscles. Other speech problems include explosive dysarthrias, or nasal speech, which can sound as though the person has a cold or nasal obstruction.

Different types of dysarthria, related to the type of speech produced:
Clipped - speech where words are slurred over and uncompleted
Cerebellar - varying from jerky or scanning speech to explosive
Explosive - speech uttered with more force than necessary
Scanning - slurring, monotonous speech
Staccato - speech in which each syllable is uttered separately

Dysphonia is an impairment with the voice or difficulty speaking. This can include hoarseness, raspy speech or a change in pitch when the person tries to talk. In MS, dysphonia often means that the person has trouble controlling the volume of speech, meaning that they speak too softly to be heard or more loudly than is appropriate. Dysphonia should be differentiated from dysphasia or aphasia, both of which refer to problems understanding or communicating spoken or written words and will be discussed later in the Cognitive Issues section.

Difficulties produced by speech problems:
Slurring of words
Mispronunciation of words
Monotonous tone of voice
Failure to complete words
Long pauses between words or syllables

Other people struggle with understanding language or find that they “lose words” mid-sentence, or switch words or syllables when speaking. These difficulties are probably related to the cognitive symptoms and again will be discussed later in the Cognitive Issues section.

A speech therapist (or speech and language pathologist) help people with MS improve speech patterns, enunciation, and oral communication in general.

Swallowing

Dysphagia, or difficulty in swallowing, can occur among people with MS. While more frequent in advanced disease, it can occur at any stage. This may cause a person may cough after drinking liquids, or choke while eating certain foods, particularly those with crumbly textures.

Some symptoms of a swallowing problem are:
Coughing or choking when eating
Feeling like food is lodged in the throat
Unexplained recurrent lung infections (pneumonia)
Otherwise unexplained malnutrition or dehydration

When swallowing difficulties are present, food or liquids that you eat may be inhaled into the trachea (windpipe) instead of going down the esophagus and into the stomach. Once in the lungs, the inhaled food or liquids can cause pneumonia or abscesses. Because the food or drink isn't reaching the stomach, a person may also be at risk for malnutrition or dehydration.

A speech therapist or pathologist can usually treat swallowing problems. Treatment typically consists of changes in diet, positioning of the head, exercises, or stimulation designed to improve swallowing. In very severe cases that don't respond to these measures, feeding tubes may be inserted directly into the stomach to provide the necessary fluids and nutrition.
Hearing Loss
Hearing loss is an uncommon symptom of MS. About 6% of people who have MS complain of impaired hearing. Hearing loss is usually associated with other symptoms that suggest damage to the brainstem. This is the part of the nervous system that contains the nerves that help to control vision, hearing, balance, and equilibrium. Hearing deficits caused by MS are thought to be due to inflammation and/or scarring around the eighth cranial nerve (the auditory nerve) as it enters the brainstem, although plaques at other sites along the auditory pathways could also contribute to hearing problems.

In addition to hearing loss, MS can also cause abnormal sensitivity or intolerance to everyday sound levels or noises. This sensitivity to sound is called hyperacusis and is often present without hearing loss. Hyperacusis often accompanies tinnitus. Unilateral or bilateral hyperacusis or deafness in people with normal sound audiometry is often attributed to lesions in the ipsilateral pons and in the central auditory pathway.

Tinnitus is the perception of sound in the ears or head where no external source is present. Vibratory tinnitus is caused by transmission to the cochlea of vibrations from adjacent tissues or organs. Non-vibratory tinnitus is produced by biochemical changes in the nerve mechanism of hearing.

Hyperacusis and Tinnitus can also be caused by side effects of medications.