Unilateral UMN Dysarthria

Question 1

Advantage of unilateral UMN Innervation
Bilateral , Unilateral And ???

Answer 1

Bilateral
UMNs on each side of the brain synapses with LMNs on
both sides of the body. Found in many cranial nerves

Unilateral
UMN damage will not completely disrupt innervation, since the UMN on the undamaged side will still send signals to LMN on both sides of the body

Contralateral
UMN innervates LMN on opposite side of the body

Question 2

UNILATERAL UPPER MOTOR
NEURON DYSARTHRIA
What are some bilateral and unilateral Intervation and correspondent cranial nerve ?
What type of damage when it’s unilateral?

Answer 2

 Damage to upper motor neurons on one side of brain that innervate
cranial and spinal nerves

 Weakness in lower face, lips, and tongue on opposite side of lesion
 Weakness
 Incoordination
 Spasticity

 Lower face (VII)
 Tongue (XII)

Bilateral UMN
 Jaw (V)
 Upper face (VII)
 Velum(X)
 Pharynx (IX, X) Freed, 2020
 Larynx (X)

Question 3

NEUROLOGIC BASIS
Where are innervation unilateral or bilateral?
How is the Speech deficit by unilateral ?
Most cranial nerves what ?

Answer 3

 Most cranial nerves serving speech muscles (except lower face and tongue)
receive bilateral innervation from upper motor neurons

 Speech deficits due to unilateral upper motor neuron damage are less severe
than with bilateral damage

 Damage to muscles of lower face and tongue

Severe cases of unilateral damage

Since upper motor neurons bilaterally innervate velum, pharynx, and larynx:

Question 4

NEUROLOGIC BASIS
Severe cases of unilateral damage

Answer 4

Lower face and tongue may be paralyzed on affected side

Question 5

NEUROLOGIC BASIS
Since upper motor neurons bilaterally innervates
What Is expected with unilateral ?
What can happens sometimes in unilateral damage ?

Answer 5

Since upper motor neurons bilaterally innervate velum, pharynx, and larynx

should not be affected by unilateral upper motor neuron damage as sufficiently innervated
from unaffected side
 At times unilateral upper motor neuron damage appears to affect function of bilaterally
innervated structures

Question 6

CAUSES OF UNILATERAL UPPER MOTOR
NEURON DYSARTHRIA
Any condition that what ?

Answer 6

 Any condition that damages upper motor neurons on one side of brain after
damage to either left or right hemisphere
 Pathologies causing focal lesions are most common cause
 Stroke
Brain Tumor
 Traumatic Brain Injury

Question 7

CAUSES OF UNILATERAL UPPER MOTOR
NEURON DYSARTHRIA
Brain Tumor

Answer 7

Focal damage. Not a common cause of this dysarthria

Question 8

CAUSES OF UNILATERAL UPPER MOTOR
NEURON DYSARTHRIA
 Traumatic Brain Injury

Answer 8

Most traumatic brain injury results in diffuse damage in both hemispheres
Head injury with lesion in one side of brain
cortical
Subcortical
brainstem level
Freed, 2020

Question 9

CAUSES OF UNILATERAL UPPER MOTOR
NEURON DYSARTHRIA
Strokes
Any danger that occurs where ?

Answer 9

Frontal lobe is a leading cause
can occur almost anywhere in brain that contains upper motor neurons: many cortical and subcortical
areas, brainstem, internal capsule.

Question 10

SPEECH CHARACTERISTICS OF UNILATERAL
UPPER MOTOR NEURON DYSARTHRIA
Mild vs moderate?
Why is it hard to diagnose ?

Answer 10

 Mild or moderate speech production errors
Often short-term with recovery over days or weeks

 More serious cases
Co-occurs with other disorders, such as aphasia, apraxia, limb hemiparesis, visual
deficits, or cognitive impairments
difficult to diagnose this dysarthria because patient’s language may be limited
Freed, 2020

Question 11

Speech Characteristics
Articulation
What type of problems ?

Answer 11

Articulation
(primarily articulation disorder)
Imprecise consonant production
irregular articulatory breakdowns
Slow alternate motion rates (AMRs)
Irregular AMRs

Question 12

Speech Characteristics
Phonation
And why ?
What can happen sometimes with unilateral UMN damage ?

Answer 12

Phonation
Mild to moderate harsh vocal quality
larynx sometimes can be affected by unilateral upper motor neuron damage
even though bilaterally innervated
Reasons for harsh vocal quality
Result of mild vocal-fold weakness or spasticity
Previously unknown lesion present with new
Dysphonia
General medical condition not attributed to upper motor neuron damage

Question 13

Speech Characteristics
Resonance

Answer 13

Resonance
Hypernasality
Unilateral upper motor neuron damage may cause mild muscular weakness in velum

Question 14

Speech Characteristics
Prosody and Respiration
Speech Rate ?

Answer 14

Prosody and Respiration
Rarely impaired in this dysarthria
slightly slow rate of speech
Respiration rarely affected due to strong innervation of intercostal muscles
and bilateral innervation of diaphragm