L15 - Disorders of Motor control Flashcards
What is Ataxia?
- Group of disorders that affect:
a) co-ordination
b) balance
c) speech - Impaired calibration of movement.
Briefly state the different categories of ataxia?
- Acquired ataxia
- symptoms develop as result of trauma, stroke, MS - Hereditary ataxia
- symptoms develop slowly over many year, caused by faulty genes a person inherits from parents e.g. Friedreich’s ataxia - Idiopathic late-onset cerebellar ataxia
- brain progressively damaged for unclear reasons
What is sensory ataxia?
- Loss of coordination
- caused by loss of sensory input into control of movement
NOT BY cerebellar dysfunction.
How may sensory ataxia be distinguished from cerebellar ataxia?
- Patient has near-normal coordination when movement is visually observed by patient
- but marked worsening of coordination when eyes are shut
- indicating positive Rhomberg’s sign.
Hypokinesia
Motor activity is reduced or slowed, except for the resting tremor.
e.g. Parkinson’s
Akinesia
No movement
Diskinesia
Bad movement
Apraxia
Brains inability to select correct movement.
What causes ataxia?
Lesions of the cerebellum or its connections.
What may cause hypokinesia / hyperkinesia?
Lesions of the Basal ganglia.
What may cause apraxia?
Lesions of the motor association cortices.
Describe central ataxia?
impaired ……..? processing
Impaired cerebellar processing.
State some signs of sensory ataxia?
- Discrepancy in finger-nose performance when performed with eyes closed then open.
- Psuedoathetosis
- Romberg sign
What is Psuedoathetosis?
Inability to maintain posture with eyes closed, giving rise to a wandering movement of the fingers or hands)
Recap: Romberg’s sign
Inability to remain standing when eyes are closed.
What may cause sensory ataxia?
Damage to nerves in spinal cord or nerves leading to extremities such as the feet and legs.
What does cerebellar ataxia lead to?
- Lack of muscle movement coordination
- caused by a dysfunction in cerebellum.
- Cerebellum controls timing and force of muscle movement.
State some common symptoms of ataxia?
- Incoordination of hands, arms and legs
- Slurring of speech
- Wide-based gait
- Difficulty with writing and eating
- Slow eye movements.
Dysmetria
Lack of coordination of movement.
Undershoot or Overshoot
Dysdiadochokinesia
Medical term for an impaired ability to perform rapid, alternating movements.
Complete inability - adiadochokinesia
Nystagmus
Vision condition in which the eyes make repetitive, uncontrolled movements.
- result in reduced vision
- depth perception
- can affect balance and coordination