Flaccid dysarthria

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Flaccid dysarthria
Specialty Neurology

Flaccid dysarthria is a motor speech disorder resulting from damage to peripheral nervous system (cranial or spinal nerves) or lower motor neuron system. Depending on which nerves are damaged, flaccid dysarthria affects respiration, phonation, resonance, and articulation. It also causes weakness, hypotonia (low-muscle tone), and diminished reflexes. [1] [2] Perceptual effects of flaccid dysarthria can include hypernasality, imprecise consonant productions, breathiness of voice, and affected nasal emission. [3]

Contents

Causes

Flaccid dysarthria is caused when damage occurs to the motor unit (one or more cranial or spinal nerves). Processes that can cause this include: [1]

Diagnosis

The hallmark of flaccid dysarthria is weakness, affecting different muscles, depending on where the damage has occurred. Some common signs include the following [4]

Phonation and prosody:

Damage to cranial nerve X can present as changes in voice quality. One or both vocal folds may be effectively paralyzed, or have diminished function. If a vocal fold is stuck in an adducted or closed position, the voice will be harsh and low in volume. A vocal fold stuck in an abducted or open position may cause breathiness and low volume. Listen for vocal flutter and diplophonia. Having both vocal folds stuck in an abducted position creates a breathy voice, with potential inspiratory stridor. Having both vocal folds stuck in an adducted or closed position compromises the airway significantly. In addition to these changes in phonation, someone may have issues changing their pitch or loudness. Or, they may speak in short phrases, as they release more air than normal through their larynx while speaking.[ citation needed ]

Resonance:

Damage to the cranial nerves innervating muscles that control the velum may result in hypernasal speech. This can sound like someone is saying things through their nose, making oral sounds like "b" or "d" sound more like "m" or "n", respectively. Or, there may be air release through the nose that is audible, as in an attempt to say "s".

Articulation:

Damage to the cranial nerves innervating the lips, tongue and other key muscles for making speech sounds may result in inaccurate or imprecise articulation. This may improve with rest.

Other:

Flaccid paralysis can cause muscles to atrophy or lose mass over time. Twitches in the affected muscle fibres (fasciculations) may be present. In the tongue, this resembles worms moving in the tissue. If the muscles of the face are affected (i.e. if there is damage to cranial nerve VII; V for the jaw in mastication), there may be drooping, sagging or drooling. When the tongue moves forward (as in a protrusion exercise), it will move to the stronger side. If the person is asked to move their jaw, it will be opposite (toward the weaker side). Other visible signs that accompany flaccid dysarthria include facial or soft palate droop, or nasal regurgitation with eating (again, if the velum is an affected area). Issues with eating are common, given the shared nature of the muscles for talking and those for chewing and swallowing. These require evaluation alongside any speech difficulties, and if present, may be medically serious (i.e. if material enters the lungs, or if not enough food is able to be eaten).[ citation needed ]

Treatment

Treatment may be carried out by a range of professionals (i.e. speech-language pathologists/therapists, rehabilitation specialists, or others with training in this area). Treatments may include direct work on the nerves and muscles involved (see below, organised by affected component of speech); counselling; partner training (i.e. to improve their ability to understand the affected person, or implement exercises); or, training aimed at helping the person themselves compensate for their condition (i.e. using gestures to supplement a message; using a device to talk; advocating for others to wait while they get their message across). [1] [5] Note that treatment should be planned and supervised by a trained professional, and tailored to the individual's specific profile.[ citation needed ]

Phonation and prosody: Behavioural treatments may include turning one's head to the affected side during speech or lateralizing the thyroid cartilage; making an effortful closure of the vocal folds or an abrupt glottal attack; or, producing intense high-level phonation. Medical treatments may include surgery such as medialization laryngoplasty; arytenoid adduction; or, fat/collagen injections. Prosthetic approaches may include artificial larynges; or abdominal binders/corsets (to provide best posture for speech, and support stronger exhalation, if affected muscles include those controlling breathing).[ citation needed ]

Resonance: Behavioural treatments may include use of CPAP machines, supine positioning (lying down, to help train velum closure), or reducing pressure during held consonants (i.e. 's' or 'z' sounds). Again, some medical or prosthetic approaches may be utilised, including palatal lifts, or pharyngeal flap procedures.[ citation needed ]

Articulation: Behavioural treatments may include various speech sound strengthening or accuracy re-training exercises.[ citation needed ]

Related Research Articles

Phonetics is a branch of linguistics that studies how humans produce and perceive sounds or, in the case of sign languages, the equivalent aspects of sign. Linguists who specialize in studying the physical properties of speech are phoneticians. The field of phonetics is traditionally divided into three sub-disciplines on questions involved such as how humans plan and execute movements to produce speech, how various movements affect the properties of the resulting sound or how humans convert sound waves to linguistic information. Traditionally, the minimal linguistic unit of phonetics is the phone—a speech sound in a language which differs from the phonological unit of phoneme; the phoneme is an abstract categorization of phones and it is also defined as the smallest unit that discerns meaning between sounds in any given language.

The term phonation has slightly different meanings depending on the subfield of phonetics. Among some phoneticians, phonation is the process by which the vocal folds produce certain sounds through quasi-periodic vibration. This is the definition used among those who study laryngeal anatomy and physiology and speech production in general. Phoneticians in other subfields, such as linguistic phonetics, call this process voicing, and use the term phonation to refer to any oscillatory state of any part of the larynx that modifies the airstream, of which voicing is just one example. Voiceless and supra-glottal phonations are included under this definition.

This is a glossary of medical terms related to communication disorders which are psychological or medical conditions that could have the potential to affect the ways in which individuals can hear, listen, understand, speak and respond to others.

The field of articulatory phonetics is a subfield of phonetics that studies articulation and ways that humans produce speech. Articulatory phoneticians explain how humans produce speech sounds via the interaction of different physiological structures. Generally, articulatory phonetics is concerned with the transformation of aerodynamic energy into acoustic energy. Aerodynamic energy refers to the airflow through the vocal tract. Its potential form is air pressure; its kinetic form is the actual dynamic airflow. Acoustic energy is variation in the air pressure that can be represented as sound waves, which are then perceived by the human auditory system as sound.

Speech disorders, impairments, or impediments, are a type of communication disorder in which normal speech is disrupted. This can mean fluency disorders like stuttering, cluttering or lisps. Someone who is unable to speak due to a speech disorder is considered mute. Speech skills are vital to social relationships and learning, and delays or disorders that relate to developing these skills can impact individuals function. For many children and adolescents, this can present as issues with academics. Speech disorders affect roughly 11.5% of the US population, and 5% of the primary school population. Speech is a complex process that requires precise timing, nerve and muscle control, and as a result is susceptible to impairments. A person who has a stroke, an accident or birth defect may have speech and language problems.

Dysarthria is a speech sound disorder resulting from neurological injury of the motor component of the motor–speech system and is characterized by poor articulation of phonemes. It is a condition in which problems effectively occur with the muscles that help produce speech, often making it very difficult to pronounce words. It is unrelated to problems with understanding language, although a person can have both. Any of the speech subsystems can be affected, leading to impairments in intelligibility, audibility, naturalness, and efficiency of vocal communication. Dysarthria that has progressed to a total loss of speech is referred to as anarthria. The term dysarthria was formed from the Greek components dys- "dysfunctional, impaired" and arthr- "joint, vocal articulation".

<span class="mw-page-title-main">Vocal register</span> Range of tones a certain voice type can reliably produce

A vocal register is a range of tones in the human voice produced by a particular vibratory pattern of the vocal folds. These registers include modal voice, vocal fry, falsetto, and the whistle register. Registers originate in laryngeal function. They occur because the vocal folds are capable of producing several different vibratory patterns. Each of these vibratory patterns appears within a particular range of pitches and produces certain characteristic sounds.

A hoarse voice, also known as dysphonia or hoarseness, is when the voice involuntarily sounds breathy, raspy, or strained, or is softer in volume or lower in pitch. A hoarse voice can be associated with a feeling of unease or scratchiness in the throat. Hoarseness is often a symptom of problems in the vocal folds of the larynx. It may be caused by laryngitis, which in turn may be caused by an upper respiratory infection, a cold, or allergies. Cheering at sporting events, speaking loudly in noisy environments, talking for too long without resting one's voice, singing loudly, or speaking with a voice that is too high or too low can also cause temporary hoarseness. A number of other causes for losing one's voice exist, and treatment is generally by resting the voice and treating the underlying cause. If the cause is misuse or overuse of the voice, drinking plenty of water may alleviate the problems.

Pharyngeal flap surgery is a procedure to correct the airflow during speech. The procedure is common among people with cleft palate and some types of dysarthria.

Velopharyngeal insufficiency is a disorder of structure that causes a failure of the velum to close against the posterior pharyngeal wall during speech in order to close off the nasal cavity during oral speech production. This is important because speech requires sound from the vocal folds and airflow from the lungs to be directed into the oral cavity (mouth) for the production of all speech sounds, with the exception of nasal consonants. If complete closure does not occur during speech, this can cause hypernasality and/or audible nasal emission during speech. In addition, there may be inadequate airflow to produce most consonants, making them sound weak or omitted.

Vocal cord paresis, also known as recurrent laryngeal nerve paralysis or vocal fold paralysis, is an injury to one or both recurrent laryngeal nerves (RLNs), which control all intrinsic muscles of the larynx except for the cricothyroid muscle. The RLN is important for speaking, breathing and swallowing.

Bulbar palsy refers to a range of different signs and symptoms linked to impairment of function of the glossopharyngeal nerve, the vagus nerve, the accessory nerve, and the hypoglossal nerve. It is caused by a lower motor neuron lesion in the medulla oblongata, or from lesions to these nerves outside the brainstem, and also botulism. This may be caused by any of a number of genetic, vascular, degenerative, inflammatory, and other underlying conditions. It can be differentiated from pseudobulbar palsy. When there is airway obstruction, intubation is used.

A speech sound disorder (SSD) is a speech disorder affecting the ability to pronounce speech sounds, which includes speech articulation disorders and phonemic disorders, the latter referring to some sounds (phonemes) not being produced or used correctly. The term "protracted phonological development" is sometimes preferred when describing children's speech, to emphasize the continuing development while acknowledging the delay.

Apraxia of speech (AOS), also called verbal apraxia, is a speech sound disorder affecting an individual's ability to translate conscious speech plans into motor plans, which results in limited and difficult speech ability. By the definition of apraxia, AOS affects volitional movement pattern. However, AOS usually also affects automatic speech.

<span class="mw-page-title-main">Myelomalacia</span> Medical condition

Myelomalacia is a pathological term referring to the softening of the spinal cord. Possible causes of myelomalacia include cervical myelopathy, hemorrhagic infarction, or acute injury, such as that caused by intervertebral disc extrusion.

<span class="mw-page-title-main">Voice therapy</span> Used to aid voice disorders or altering quality of voice

Voice therapy consists of techniques and procedures that target vocal parameters, such as vocal fold closure, pitch, volume, and quality. This therapy is provided by speech-language pathologists and is primarily used to aid in the management of voice disorders, or for altering the overall quality of voice, as in the case of transgender voice therapy. Vocal pedagogy is a related field to alter voice for the purpose of singing. Voice therapy may also serve to teach preventive measures such as vocal hygiene and other safe speaking or singing practices.

Speech and language impairment are basic categories that might be drawn in issues of communication involve hearing, speech, language, and fluency.

<span class="mw-page-title-main">Hypernasal speech</span> Abnormal vocal sound due to excess airflow through the nose during speech

Hypernasal speech is a disorder that causes abnormal resonance in a human's voice due to increased airflow through the nose during speech. It is caused by an open nasal cavity resulting from an incomplete closure of the soft palate and/or velopharyngeal sphincter. In normal speech, nasality is referred to as nasalization and is a linguistic category that can apply to vowels or consonants in a specific language. The primary underlying physical variable determining the degree of nasality in normal speech is the opening and closing of a velopharyngeal passageway between the oral vocal tract and the nasal vocal tract. In the normal vocal tract anatomy, this opening is controlled by lowering and raising the velum or soft palate, to open or close, respectively, the velopharyngeal passageway.

<span class="mw-page-title-main">Velopharyngeal consonant</span>

The velopharyngeal fricatives, also known as the posterior nasal fricatives, are a family of sounds sound produced by some children with speech disorders, including some with a cleft palate, as a substitute for sibilants, which cannot be produced with a cleft palate. It results from "the approximation but inadequate closure of the upper border of the velum and the posterior pharyngeal wall." To produce a velopharyngeal fricative, the soft palate approaches the pharyngeal wall and narrows the velopharyngeal port, such that the restricted port creates fricative turbulence in air forced through it into the nasal cavity. The articulation may be aided by a posterior positioning of the tongue and may involve velar flutter.

<span class="mw-page-title-main">Congenital bilateral perisylvian syndrome</span> Medical condition

Congenital bilateral perisylvian syndrome (CBPS) is a rare neurological disease characterized by paralysis of certain facial muscles and epileptic seizures.

References

  1. 1 2 3 Duffy, Joseph (June 6, 2013). Motor Speech Disorders: Substrates, Differential Diagnosis, and Management. Elsevier Health Sciences. ISBN   9780323242646.
  2. ↑ Manasco, H. (2014). Introduction to neurogenic communication disorders. Burlington, MA: Jones & Bartlett Learning.
  3. ↑ University of Minnesota Duluth. (2014). Dysarthria. http://www.d.umn.edu/~mmizuko/2230/msd.htm
  4. ↑ "Dysarthria Characteristics". www.csuchico.edu. Retrieved 2019-08-01.
  5. ↑ Swigert, Nancy B. (2010). The Source for Dysarthria: Second Edition. Austin, Texas: Pro-Ed.
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