Neuropathologies of Speech Exam 2

Flaccid Dysarthria is caused by damage to...

LMNs

Hallmark resonance of flaccid dysarthria

hypernasality

A breathy voice in flaccid dysarthria is due to...

incomplete vocal fold adduction

Which CN leads to breathy phonation?

Vagus Nerve (X)

What is the strongest diagnostic sign of flaccid dysarthria?

hypernasality + phonatory incompetence

Myasthenia gravis affects _________

the neuromuscular junction

What is the best test for Myasthenia Gravis specifically in flaccid dysarthria?

stress test

LMN damage leads to...

hypotonia (low muscle tone)

Why do patients with flaccid dysarthria struggle with loudness?

They have a hard time building subglottic pressure due to incomplete vocal fold adduction.

What is flaccid dysarthria

Dysarthria caused by impairments of lower motor neurons in cranial or spinal nerves (damage toPNS)

Signs and symptoms of flaccid dysarthria

- Paralysis, weakness, hypotonicity, atrophy, and hypoactive reflexes of involved speech subsystem musculature

- Weakness in speech or respiratory musculature results in distinctive qualities

List 3 speech characteristics of flaccid dysarthria

- Slow-labored articulation

- Marked degrees of hypernasal resonance

- Hoarse, breathy phonation

Explain hypernasality

Excessive nasal resonance during speech, especially on vowels, due to incomplete closure between the oral and nasal cavities.

Explain nasal emission

Escape of air through the nose during production of pressure consonants due to inadequate velopharyngeal closure.

What 3 cranial nerves are affected in flaccid dysarthria?

- trigeminal (V)

- Facial (VII)

- Vagus (X)

Final common neural pathway in flaccid dysarthria

LMNs in the brainstem

Compare flaccid and spastic dysarthria

- Flaccid dysarthria: Caused by lower motor neuron (LMN) damage → muscles are weak, floppy (hypotonic) Speech: breathy voice, hypernasality, imprecise articulation

- Spastic dysarthria: Caused by upper motor neuron (UMN) damage → muscles are tight, stiff (hypertonic) Speech: strained-strangled voice, slow rate, reduced pitch variation

What happens if the vagus nerve gets damaged?

vagus nerve damage causes voice and resonance problems because the larynx and velum are weakened.

Define spastic dysarthria

a motor speech disorder caused by bilateral upper motor neuron (UMN) damage, leading to increased muscle tone (spasticity) and reduced control of speech muscles.

Why is there bilateral damage in spastic dysarthria?

Due to bilateral innervation of UMNs

4 features of spastic dysarthria

- spasticity

- weakness

- limited range of motion

- slow movement

spasticity

increased muscle tone

weakness

reduced strength of the speech muscles

Limited range of motion

movements are small and restricted

slowness of movement

speech is slow and effortful

How does hypernasality differ between flaccid and spastic dysarthria

Both have hypernasality in resonance but flaccid dysarthria has hypernasality with nasal emissions and spastic dysarthria does not have nasal emissions

What is the cause of monopitch in spastic dysarthria?

Pitch deficits are due to the vocal folds being stiff (spasticity) and not being able to stretch and contract which is how prosody is created.

Compare the affects flaccid and spastic dysarthria have on vocal quality.

In flaccid dysarthria, the vocal folds are paralyzed or the vocal fold closure is incomplete. This causes airflow to escape which creates a breathy voice. In spastic dysarthria the vocal folds are tense (spastic) which creates a strained voice because air has less space to flow through.

What is pseudobulbar palsy?

paralysis of the pseudobulbar system which results from damage to the corticobulbar passage ways, a neurological condition caused by damage to the upper motor neurons that control the muscles used for speaking, swallowing, and facial movement. (causes inappropriate emotions)

Is respiration less affected in spastic dysarthria?

No

What is unilateral upper motor neuron dysarthria caused by?

Unilateral damage to UMNs

What area of speech is most affected in UUMN dysarthria?

Articulation

Why is articulation the most affected area of UUMN dysarthria?

Affects tongue and lower face much more than any other speech structure due to...

- Weakness

- Reduced range of motion

- Decreased fine motor control of tongue

Imprecise consonant production: primary difficulty

• Irregular articulatory breakdowns

• Slow alternate motion rates (AMRs) • Irregular AMRs

What area is weak in UUMN dysarthria?

lower face and tongue

Most common cause of UUMN dysarthria

stroke

UUMN dysarthria severity

mild-moderate

What area of speech is not affected by UUMN dysarthria?

respiration

What type of vocal quality do people with UUMN dysarthria experience?

Harsh due to mild laryngeal involvment

What disorder co-occurs with UUMN dysarthria?

apraxia or aphasia

Why is UUMN dysarthria less severe than other dysarthrias?

Due to bilateral innervation

What is bilateral innervation?

Bilateral innervation means that a muscle receives nerve signals from both the left and right sides of the brain.

Why does UUMN dysarthria sometimes take a "back seat?"

Because it usually co-occurs with other disorders and therapy is focused elsewhere. In some cases, patients do not realize they have UUMN dysarthria because it can be temporary and may go away.

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