Lecture 26: reflexes and muscle tone - CLINICAL

Question 1

Tendon Jerks?

Answer 1

• Involutary
• stereotyped (same jerk)
• non-fatiguing
• increased by reinforcement (eg. clenching teeth)

Question 2

Abnormalities of tendon reflexes?

Answer 2

LMN lesion = decreased of absent

UMN lesion = Increased ‘brisk’

basal ganglia = No change

Question 3

Abnormalities of tone?

Answer 3

LMN lesion = decreased / hypotonia or normal

UMN lesion = Increased / spasticity**

Basal ganglia = Increased / rigidity

Spacticity = slow stretch has little resistance but faster stretch has increased resistance before at very fast speeds the resistance comes on and off

Question 4

Plantar respnse?

Answer 4

Stroking the underside of the foot will normally cause a flexor response (plantarflexion)

In UMN lesion we get a extensor response = dorsiflexion

In LMN lesion or extra-pyramidal we get flexor response