Equipping People To Make Sense Of What They Are Told
In MS Ataxia may manifest itself as
Clumsiness.
Unsteady gait.
Impaired eye movement.
Impaired limb movement.
Speech problems.
In more advanced cases, a lack of coordination is seen as tremor.
The Cerebellum
Responsible for coordinating movement, planning, motor activities, learning and remembering
of physical skills and for some cognitive abilities. The cerebellum controls movement
by collecting sensory nerve inputs, such as limb position, balance information and
vision, and synthesising them together to control movement by sending nerve transmissions
down motor nerve outputs. The learning of physical tasks is done by trial and error
and then stored into cerebellar memory.
There is some evidence that mental activities are also coordinated in the cerebellum
which could explain why cognitive dysfunction is sometimes associated with damage
to the cerebellum.
The cerebellum is divided into two hemispheres by the central "vermis" (the cerebellar
vermis is a narrow, wormlike structure between the hemispheres of the cerebellum).
The surface of each hemisphere is made up of grey matter surrounding a large mass
of white matter - nerve cells with myelinated axons.
The whole structure is connected to the rest of the central nervous system by three
very broad tracts of white matter called the cerebellar peduncles. Damage to the
cerebellum or the cerebellar peduncles is very common in multiple sclerosis.
Ataxia in MS - As the body carries out a function such as walking or speaking, it
involves a complicated interaction of signals between the brain and feedback from
the nerves in the limbs or organs involved.
Ataxia often occurs when parts of the nervous system that control movement are damaged.
People with ataxia experience a failure of muscle control in their arms and legs,
resulting in a lack of balance and coordination or a disturbance of gait. While the
term ataxia is primarily used to describe this set of symptoms, it is sometimes also
used to refer to a family of disorders. It is not, however, a specific diagnosis.
Most disorders that result in ataxia cause cells in the part of the brain called
the cerebellum to degenerate, or atrophy (ataxia cerebellar). Sometimes the spine
is also affected.
The phrases cerebellar degeneration and spinocerebellar degeneration are used to
describe changes that have taken place in a person’s nervous system; neither term
constitutes a specific diagnosis.
These outgoing and incoming messages are coordinated in the area of the brain called
the cerebellum. Inflammation of the nerve fibres in the cerebellum may interfere
with the matching of signals which then causes ataxia.
Cerebellar and spinocerebellar degeneration have many different causes.
The age of onset of the resulting ataxia varies depending on the underlying cause
of the degeneration.
Other symptoms associated with damage to the cerebellum or the nervous tracts leading
to it:
Dysarthria - loss of coordination of the muscles controlling speech.
Dysdiadokokinesia - difficulty in performing rapid alternating movements.
