voice tracing

Types of Voice Disorders


Dysarthria is a speech disorder resulting from neurological injury including amyotrophic lateral sclerosis (ALS or Lou Gehrig’s disease), cerebral palsy, Parkinson’s disease, locked-in syndrome, multiple sclerosis and traumatic brain injury. It may also arise from other diseases with neurological sequelae, including tumor, postoperative complications, inflammatory and metabolic diseases, and other sporadic, degenerative neurological conditions.
After a stroke or other brain injury, the muscles of the mouth, face, and respiratory system may become weak, move slowly, or not move at all, resulting in dysarthria. 
An individual with severe dysarthria is able to formulate intent to communicate (i.e., to formulate a thought, linguistically encode it appropriately as a message, and program the motor sequence necessary to produce the message as speech). However, that individual’s body is unable, because of the disability, to execute those commands that control speech production.

The type and severity of dysarthria depends on which area of the nervous system is affected. The complete loss of speech is called "anarthria". Dysarthric speech is characterized by problems with articulation (i.e., production of speech sounds), voicing (i.e., volume and quality of speech) and prosody (i.e., speech rate, rhythm and naturalness). The symptoms include: "slurred" speech, slow rate of speech, rapid rate of speech with a "mumbling" quality, speaking softly or barely able to whisper, limited tongue, lip, and jaw movement, abnormal intonation, changes in vocal quality ("nasal" speech or sounding "stuffy"),  hoarseness, breathiness, drooling or poor control of saliva, chewing and swallowing difficulty.

Vocal Cord Impairments

Vocal fold motion impairment is of two major types: unilateral (more common) and bilateral. These types differ in their seriousness, symptoms, and treatment.

Patients with unilateral paralysis may exhibit a weak and "breathy" voice, and speaking may require considerable effort. Because the vocal folds are unable to close completely during swallowing, patients may also experience coughing and choking while eating or drinking. Patients with bilateral paralysis may experience these symptoms, but the possibility of a compromised airway is a more serious threat. The muscles which normally abduct the folds and provide for a patent airway are unable to function. Thus, the folds may remain adducted in the airway and block normal respiration.

The most common cause of vocal fold motion impairment is injury to the recurrent laryngeal nerve, the nerve responsible for controlling the intrinsic muscles of the larynx. This may be due to trauma, surgery, viral infection, a tumor pressing on the recurrent laryngeal nerve, or other causes. Occasionally, injury or diseases of the brain, including stroke, result in impaired motion. Mechanical obstruction can also result in vocal fold motion impairment. The arytenoid cartilages can become "locked" and restrict movement. Scar tissue may also accumulate and inhibit vocal fold movement.

Spasmodic dysphonia

What is spasmodic dysphonia?
Spasmodic dysphonia (SD), a focal form of dystonia, is a neurological voice disorder that involves involuntary "spasms" of the vocal cords causing interruptions of speech and affecting the voice quality.

Types of spasmodic dysphonia
The two types of recognized spasmodic dysphonia are adductor spasmodic dysphonia and abductor spasmodic dysphonia. Adductor SD causes an intermittent excessive closing of the vocal folds during vowel sounds in speech; while in abductor SD, there is a prolonged vocal-fold opening during voiceless consonants. The control problems of the vocal cords result in different speech symptoms in the two types of disorder. There are three subtypes of SD which have been identified by clinicians. One is a combination of adductor and abductor symptoms in which an individual may demonstrate both types of spasms as he/she speaks. In a second subtype, SD symptoms are accompanied by a voice tremor. A third subtype involves a primary voice tremor that is so severe the patient experiences adductor voice stoppages during the tremor.

What causes spasmodic dysphonia?
The cause of spasmodic dysphonia is unknown. The general medical consensus is that SD is a central nervous system disorder and a focal form of dystonia. Dystonia is the general neurological term for a variety of problems characterized by excessive contraction of muscles with associated abnormal movements and postures. Dystonia disorders are thought to originate in the area of the brain called the basal ganglia, which are that help coordinate movements of the muscles throughout the body.

Treatment for spasmodic dysphonia

Botulinum toxin injections
Local injections of botulinum toxin (BTX) into the vocal cord muscles have proven to be the most effective treatment for spasmodic dysphonia. The treatment weakens the vocal muscles so that spasms are greatly diminished and speech is greatly improved. The treatment can also reduce the breathiness and help decrease the effort required to speak


Surgery may be performed for people for whom botulinum toxin injections are no longer providing relief of symptoms.Selective Laryngeal Adductor Denervation-Reinnervation surgery involves cutting the nerve to the affected vocal cord and re-innervating the muscle with another muscle to prevent muscle atrophy.

Speech Therapy
General voice relaxation techniques and speech therapy may play an adjunct role in the treatment of spasmodic dysphonia. These include reducing one's vocal effort, loudness, intonation, and rate of utterance while increasing pause time between phrases. These techniques can only be reinforced and adapted if they do not intrude on the vocal naturalness.


Aphonia refers to an inability to produce voice naturally (i.e., due to physical impairment) and/or inability to produce voice by using a speech prosthesis (e.g., Passy-Muir valve, electrolarynx, tracheoesophageal puncture) due to physical disability or absence of larynx.



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