Characteristics of Dysarthria

Cranial nerve V

Trigeminal- Facial sensation

Innervation- Motor and Sensory

Cranial Nerve VII

Facial- facial expression, taste (anterior 2/3 tongue), tears/saliva

Innervation- Motor and Sensory

Cranial Nerve IX

Glossopharyngeal- Taste (posterior 1/3 tongue), swallowing, saliva production

Innervation- Motor and Sensory

Cranial Nerve X

Vagus- parasympathetic control (hear, lungs, gut), voice, swallowing

Innervation- Motor and Sensory

Cranial Nerve XI

Accessory- shoulder shrug, head turning (trapezius, SCM)

Innervation- Motor

Cranial Nerve XII

Hypoglossal- tongue movement

Innervation- Motor

Which type of motor neurons are affected in flaccid dysarthria?

lower motor neurons

How can CN 5 be affected in flaccid dysarthria?

• trigeminal neuralgia

• unilateral lesion of mandibular branch

• bilateral lesion

trigeminal neuralgia

• pain in one or more sensory divisions of CN 5

• can be triggered by movement- patients may avoid lip, face, or jaw movement to avoid pain

unilateral lesion of mandibular branch of CN 5

• jaw deviates to the weak side when opened

• limited effect on speech- stronger side is good at compensating for damage

• may have decreased masseter/temporalis contraction- weaker jaw movements when chewing

bilateral lesion of CN 5

• unable to close or lateralize jaw

• decreased mass ester/temporalis contraction

• loss of sensation to face and tongue

• inability to elevate jaw can cause devastating impact on articulation

unilateral lesion of CN 7 in flaccid dysarthria

• facial droop ipsilaterally; eye droop

• asymmetrical facial expression

• decreased/ absent lip movement- may not affect speech much but might cause distortion

bilateral lesion of CN 7 in flaccid dysarthria

• facial droop on both sides

• decreased/absent lip movement

• symmetrical facial expression

• may be harder to see the problem visually

• speech effects- distortion of labial sounds, cheek flutter during speech

• unusual movements to watch for- synkinesis, hemifacial spasm, facial myokymia

synkinesis

movements of muscles next to intended muscles

facial myokymia

similar to fasciculations but more prolonged

how is CN 9 affected in flaccid dysarthria?

possible reduction in gag relex

lesion affects of CN 10 affected in flaccid dysarthria?

• pharyngeal branch lesion- hypernasality/ nasal emission

• changes to phonation

  • SLN only affected- mild hoarseness, decrased pitch range (cricothyroid affected)

  • RLN only affected- breathy/hoarse voice, inhalitory stridor if lesion is bilateral (muscles for adduction/abduction)

pharyngeal banch of the vagus nerve

• motor innervation- most of pharynx and soft palate (not tensor palatini)

• pharyngeal constriction/ VP closure

superior laryngeal nerve branch (SLN)

• external laryngeal nerve- motor innervation to cricothyroid and inferior pharyngeal constrictor

• internal laryngeal nerve- sensory innervation to base of tongue and larynx

Recurrent laryngeal nerve branch (RLN)

• motor and sensory innervation to all intrinsic laryngeal muscles except cricothyroid which is vulnerable during thyroid surgery

how is CN 11 affected in flaccid dysarthria?

damage to the spinal part results in problems with head control and indirectly affects speech

unilateral lesion of CN 12 in flaccid dysarthria

• decrease in tongue bulk on side of lesion

• weakness

• tongue deviate to weak side

• speech effect- may have articulatory imprecision

bilateral lesion of CN 12 in flaccid dysarthria

• tongue atrophy

• faciculations

• symmetric but limited protrusion

• significant articulation problems for speech

which cranial nerve is most often damaged in flaccid dysarthria?

CN 10- Vagus

What is the order of cranial nerves that are most to least damaged in flaccid dysarthria

1. CN 10

2. CN 7

3. CN 12

4. CN 5

which cranial nerve is least often damaged in flaccid dysarthria

CN 5

distinctive speech characteristics in flaccid dysarthria

• hyper nasality- leads to distorted labial or lingual phonemes and distorted vowels

• breathiness

• nasal emission

• audible insiration

• short phrases

less disctinctive speech characteristics of flaccid dysarthrias that are also seen in other types of dysarthria

• imprecise consonants

• monopitch

• harsh or hoarse voice

• monoloudness

a study by Leveque et al. (2022) found that participants with spinal and bulbar muscular atrophy (SBMA) had

lower motor neuron problems

spastic dysarthria results from damage to

upper motor neurons

what is the hallmark characteristic of spastic dysarthria

spasticity- excess muscle tone, decreased muscle strength

spastic dysarthria may affect what speech subsystem

any

characteristics of direct activation pathway damage in spastic dysarthria

• loss of impairment in fine, discrete movements

• weakness with increased muscle tone (spasticity)

• pathological reflexes re-emerge

  • Babinski sign

  • oral reflexes

characteristics of indirect activation pathway damage in spastic dysarthria

• increased muscle tone/ spasticity- legs resist bending, arms resist extension

• hyperactive reflexes- hyperactive stretch reflex can lead to clonus, looks like rhythmic tremor due to a muscle kept under tension)

characteristics of direct AND indirect pathway damage in spastic dysarthria

• spasticity with weakness- more distal than proximal

• decreased ROM and slowness of movement

• abnormal reflexes

bilateral UMN symptoms in limbs in spastic dysarthria shows

bilateral involvement

clinical findings of spastic dysarthria- pseudobulbar palsy results from

• UMN bilateral lesions of corticobulbar fibers

• looks like LMN cranial nerve problems

nonspeech oral mech findings in spastic dysarthria

• drooling

• mild weakness

• symmetry observed but face is held in a somewhat fixed, subtle smile or pout

clinical findings of spastic dysarthria- emotional lability

• may seem to be on the verge of tears when talking

• may fluctuate between crying and laughing

• inner emotional state may not match emotional expression

distinctive speech features of spastic dysarthia

• low pitch

• slow rate

• strained strangled voice quality

other speech characteristics of spastic dysarthria

• short phrases

• monopitch

• monoloudness

• articulation problems- imprecise consonants, distorted vowels

• hypernasality

• excess and equal stress

• increased duration of phoneme to phoneme transitions

• reduced speech and range of tongue and jaw movements

• reduced rate and slope of second formant transitions

• smaller vowel space, and centralization of vowel formants

unilateral upper motor neuron disease

primarily articulation problems secondary to weakness, spasticity, and/or incorrdination

unilateal direct and indirect activation pathway damage to unilateral upper motor neuron disease

• contralateral innervation- most of the body

• bilateral innervation (except hypoglossal/facial)- most cranial nerves

clinical characteristics of unilateral upper motor neuron disease

• contralateral hemiplegia sometimes with sensory deficits

• weakness and spasticity, reflexes exaggerated/ abnormal

• often contralateral lower face weakness

patient perceptions of speech characteristics in unilateral upper motor neuron disease

• aware of their problems

• significant improvement in a first two days after stroke

• slow, slurred speech

• drooling, chewing, and swallowing problems

clinical symptoms of unilateral upper motor neuron disease

• loss of voluntary control

• initial muscle paralysis flaccid with emergence of spasticity within several weeks

• contralateral hyperactive reflexes

• altered reflexes- Babinski sign emergence and loss of abdominal and cremasteric reflexes

• no atrophy in paralyzed muscles

clinical findings of unilateral upper motor neuron disease

• language and/or cognitive problems likely

• imprecise consonants; slow, imprecise AMRs

• irregular articulatory breakdowns- unclear reason

• phonatory problems depending on where the damage is- CN 10= phonatory prob