Neurogenic Voice Disorders

CDIS 700

Review of the Nervous System

Review your motor speech and anatomy/physiology notes. Neurotransmitter issues in the CNS can cause hypo- and

hyperkinetic dysarthrias. Spasticity of vocal folds results from UMN lesions Flaccidity of VFs and VF paralysis result from LMN lesions The PNS cranial nerves can have an effect on the voice if

they are damaged: IX (Glossopharyngeal)—taste, sensation, innervation of pharynx X (Vagus)—SLN and RLN branches affect sensory and motor

systems related to the pharynx, larynx, and respiratory structures

XI (Spinal Accessory)—resonance/respiration XII (Hypoglossal)—resonance and quality of the voice;

positioning of the larynx and tongue

SLN and RLN

SLN innervates the cricothyroid muscles. Recall that CT contraction lengthens the VFs and increases pitch and contribute to VF adduction.

RLN innervates the thyroarytenoid, lateral cricoarytneoid, transverse/oblique arytenoids, and the posterior cricoarytenoid muscles.

Dysarthrias

Flaccid Unilateral upper motor neuron Spastic Ataxic Hypokinetic Hperkinetic Mixed

Flaccid DysarthriaDisorder Cause Effects Treatment

Bilateral vocal fold paralysis

Lesions to Vagus nerve

VFs paralyzed in adducted or abducted position

Medical and/or surgical

Unilateral vocal fold paralysis

Surgical trauma to left RLN, also viral infections, smoking

Aphonia, monotone, hoarse/breathy voice, pitch breaks, vocal hyperfunction

Voice therapy; perhaps surgery

Cricothyroid paralysis

Viral infection of SLN

Difficulty with pitch change; breathiness

Resolves in time; voice therapy helps

Myasthenia Gravis Antibodies block acetylcholine from binding to muscles

Dysphonia and voice fatigue; weakness increases with use

Medical. SLP may recognize symptoms and refer; could monitor symptoms

Guillain-Barre Syndrome

Body’s immune system attacks nerves

Possibly dysarthric speech and weak voice

Focus on clear speech and safe swallowing

Unilateral Upper Motor Neuron Dysarthria

Often due to unilateral lesions in the CNS, caused by CVAs, tumors, or trauma.

Symptoms include a harsh, strained voice that may be accompanied by reduced loudness.

Good breath support is an essential form of voice therapy for these patients.

Hypokinetic Dysarthria Occurs when there is not enough dopamine to regulate

basal ganglia functioning = Parkinson’s disease. Physical manifestations include rigidity, bradykinesia,

limited range of motion, and tremor. Voice symptoms include decreased loudness, breathy

voice, monotone, rapid rushes of speech, and soft/imprecise consonants.

Bowed vocal folds accompanied by respiration difficulties may accompany voice symptoms.

Treatments include the Lee Silverman Voice Treatment program for increased loudness, quality, and intelligibility. The Pitch Limiting Voice Treatment also has good results.

Hyperkinetic DysarthriaDisorder Cause Effects Treatment

Huntington’s Disease

Overabundance of dopamine

Jerky, irregular bursts of loud voice; strained/strangled voice; monopitch; poor breath control.

Behavioral voice therapy in early stages (slower speech and easier voice production)

Adductor Spasmodic Dysphonia

Generally neurogenic

Strained, tight voice produced when VFs (true and sometimes false) adduct during phonation

Vocal hygiene therapy, including easy voice production); Botox injections

Abductor Spasmodic Dysphonia

Generally neurogenic

Intermittent aphonia Botox, possible voice therapy

Essential tremor Neurogenic Alternating changes in pitch; shaky voice quality

Behavioral voice therapy-talk less loudly with a higher pitch and shortened vowel duration

Mixed Dysarthrias Amyotrophic Lateral Sclerosis (ALS) and

Multiple Sclerosis (MS) are examples. A hoarse voice due to hyperfunction is

typical of both of these disorders. Breath support and easy onset of voice is recommended.

Voice symptoms associated with Traumatic Brain Injuries (TBIs) are typically treated behaviorally.