Movement Disorders

Question 1

What are symptoms of UMN being affected?

Answer 1

Tone increased spastic, clonus present, power weakness (pyramidal distribution: flexors stronger than extensors UL and extensors stronger than flexors in LL), reflexes brisk, extensor plantar responses, no wasting and no fasciculations.

Question 2

What are symptoms of LMN being affected?

Answer 2

Tone flaccid, power weakness (distal weaker than proximal), no clonus, reflexes reduced or absent, flexor plantar responses, wasting may be present, fasciculations may be present.

Question 3

What pathways are affected in ALS?

Answer 3

Pyramidal tracts (these are the corticospinal and corticobulbar tracts) providing voluntary motor commands to limbs/trunk and head/neck respectively.

Question 4

Why are abdominal reflexes (superficial reflexes) absent while the other reflexes (deep tendon reflexes) are brisk?

Answer 4

Hallmark of a corticospinal tract lesion. Stroking the skin of the abdomen causes the abdominal wall muscles to contract, sometimes pulling theumbilicustowards the stimulus. These reflexcontractions are often absent inupper motor neurone disorders.

Question 5

What is a fasciculation? What is its significance?

Answer 5

A fasciculation is an involuntary and abnormal firing of a single motor neuron and all its innervated muscle fibres. They are visible to the eye.