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.
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
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
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 (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.
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
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
All three of these cranial nerves originate in the brainstem - the third and
forth in the midbrain and the sixth in the pons.
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
There are no effective symptomatic treatments for nystagmus, although corticosteroids
are sometimes given to reduce the severity or duration of this symptom.
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.
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:
||Unilateral upper motor neuron
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
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
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.
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 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.