Upper Motor Neuron Lesions

Question 1

What is an upper motor neuron lesion?

Answer 1

damage or dysfunction in the central nervous system pathways that control voluntary movement

Question 2

Location of an upper motor neuron lesion

Answer 2

The lesion is within the central nervous system (brain and spinal cord), specifically in the upper motor neuron pathways

Question 3

Symptoms of upper motor neuron lesions

Answer 3

-hyperreflexia (overactive reflexes)
-spasticity (increased muscle tone)
-positive Babinski sign (upward extension of the big toe when the sole of the foot is stroked)

Question 4

Is weakness present?

Answer 4

Yes but not as severe as lower motor neuron lesions

Question 5

Other signs of upper motor neuron lesions?

Answer 5

Other signs include clonus (rhythmic muscle contractions) -potentially disuse atrophy (minimal) or contractures

Question 6

Pathways

Answer 6

involved in controlling voluntary movements, including fine motor skills, posture, and balance

Question 7

Differential diagnosis

Answer 7

The causes of UMN lesions can be varied, including cerebrovascular accidents (strokes), traumatic brain injury, infections, and neurodegenerative disorders

Question 8

Example of conditions of upper motor neuron lesions

Answer 8

-Multiple Sclerosis: UMN lesions are a common finding in MS, leading to spasticity, weakness, and impaired voluntary movement control.

-Stroke: Strokes can cause UMN lesions depending on the location of the damage in the brain.

-ALS (Amyotrophic Lateral Sclerosis): ALS affects both upper and lower motor neurons, but UMN damage causes spasticity and rigidity.

-Brain Injury: Traumatic brain injuries can result in UMN lesions.
Spinal Cord Injury: Lesions above the level of spinal cord injury can cause UMN signs

Question 9

What is an upper motor neuron lesion

Answer 9

UMN lesions, affecting the central nervous system (CNS) above the spinal cord, lead to increased tone, spasticity, hyperreflexia, and positive Babinski sign

Question 10

Location

Answer 10

Brain and spinal cord (central nervous system)

Question 11

Weakness?

Answer 11

-Yes but not as severe as lower motor neuron lesions

-weakness is often generalized, affecting multiple muscle groups, and may include extensor weakness in the arms and flexor weakness in the legs

Question 12

Reflexes

Answer 12

hyperreflexia (increased reflexes)

Question 14

Hyperflexia

Answer 14

Reflexes are often exaggerated in UMN lesions due to the loss of inhibitory influences from the UMN pathway

Question 15

Spasticity

Answer 15

Increased muscle tone, especially in the affected limbs, leads to resistance to movement, particularly at the beginning of movement (stiffness of muscle)

Question 16

Clonus

Answer 16

Involuntary rhythmic muscle contractions, often seen at the ankle, are common in UMN lesions

Question 17

Positive babinski reflex

Answer 17

The big toe extends upward, and the other toes fan out when the sole of the foot is stroked. This is a hallmark sign of UMN lesions

Question 18

Muscle wasting

Answer 18

Doesn’t tend to be associated with upper motor neuron lesions

Question 19

Other signs

Answer 19

Dysphasia (difficulty swallowing)