Dysarthria is a condition that affects the ability to speak clearly and intelligibly. It is caused by weakness or paralysis of the muscles that control speech, including the tongue, lips, jaw, and vocal cords. Adults who have experienced brain damage such as strokes, brain injuries, brain tumors, or degenerative diseases such as Parkinson's disease or multiple sclerosis are more likely to develop dysarthria.
Dysarthria can result from damage to different parts of the nervous system that are involved in speech production. These include:
The brain, which controls the planning and coordination of speech movements.
The brainstem, which connects the brain to the spinal cord and regulates breathing and swallowing.
The cranial nerves, which carry signals from the brain to the muscles of the face, mouth, and throat.
The spinal cord, which transmits signals from the brain to the rest of the body.
The peripheral nerves, which connect the spinal cord to the muscles and organs.
Depending on the location and extent of the damage, dysarthria can be classified into six types:
The condition of flaccid dysarthria occurs when the lower motor neurons (the nerves that connect the spinal cord to the muscles) are damaged. This causes the speech muscles to become weak and floppy, resulting in breathy, nasal, and low-volume speech.
Spastic dysarthria occurs when the upper motor neurons (the nerves connecting the brain to the spinal cord) are damaged. This causes the muscles that control speech to be stiff and tight, causing strained, harsh, and slow speech.
When the cerebellum (the part of the brain that coordinates movement and balance) is damaged, the speech muscles become uncoordinated and inaccurate, resulting in slurred, distorted, and irregular speech.
In hypokinetic dysarthria, the speech muscles become rigid and restricted in range due to damage to the basal ganglia (the part of the brain that controls movement and muscle tone).
The condition of hyperkinetic dysarthria is also caused by damage to the basal ganglia, which causes the speech muscles to become involuntary and unpredictable, resulting in jerky, variable, and excessive speech movements.
Mixed dysarthria, which occurs when more than one part of the nervous system is damaged. This causes a combination of symptoms from different types of dysarthria.
The symptoms of dysarthria vary depending on the type and severity of the condition. Some of the common symptoms include:
Slurred, mumbled, or unclear speech.
Difficulty pronouncing certain sounds or words.
Difficulty controlling the pitch, loudness, or rhythm of speech.
Difficulty modulating the tone or emotion of speech.
Difficulty moving the tongue, lips, jaw, or facial muscles.
Drooling or difficulty swallowing.
Changes in voice quality, such as hoarseness, breathiness, or nasality.
It can affect not only the ability to communicate, but also eating, drinking, and socializing, as well as the person's self-esteem and emotional well-being.
A speech-language pathologist (SLP) is a healthcare professional who specializes in evaluating and treating speech, language, and swallowing disorders. The SLP will conduct a comprehensive assessment that may include:
A medical history, including the onset, duration, and progression of the symptoms, and any underlying conditions or medications that may affect speech.
A physical examination, including the observation and palpation of the speech muscles and structures, and the measurement of the strength, range, and coordination of the movements.
A speech and language evaluation, including the assessment of the articulation, fluency, voice, resonance, and prosody of speech, and the comprehension and expression of language.
A hearing screening, to rule out any hearing loss that may affect speech.
A swallowing evaluation, to determine if there is any difficulty or risk of aspiration (inhaling food or liquid into the lungs) during eating or drinking.
A cognitive evaluation, to assess the attention, memory, reasoning, and problem-solving skills that may affect speech.
A psychosocial evaluation, to assess the impact of dysarthria on the quality of life, mood, and coping strategies of the person and their family and friends.
The SLP will also use various tests and tools, such as:
Standardized tests, which measure the speech and language abilities of the person compared to the normative data of their age and gender group.
Instrumental tests, which use devices or machines to record and analyze the acoustic, aerodynamic, or physiological aspects of speech, such as the sound pressure level, airflow, air pressure, or muscle activity.
Imaging tests, which use techniques such as X-ray, MRI, CT scan, or ultrasound to visualize the structure and function of the speech organs and the brain.
Based on the results of the assessment, the SLP will determine the type, severity, and prognosis of dysarthria, and recommend the appropriate treatment plan.
The treatment of dysarthria depends on the cause, type, and severity of the condition, and the goals and preferences of the person with dysarthria and their family and friends. The treatment may include:
Medical treatment, which aims to address the underlying cause of dysarthria, such as medication, surgery, or radiation therapy for stroke, brain tumor, or Parkinson’s disease.
Speech therapy, which aims to improve the speech and communication skills of the person with dysarthria, by using various techniques and strategies, such as:
Exercises, which help to strengthen, stretch, or relax the speech muscles, and improve the coordination, accuracy, and timing of the movements.
Drills, which help to practice and reinforce the correct production of sounds, words, phrases, or sentences.
Feedback, which helps to monitor and correct the errors or deviations in speech, by using auditory, visual, or tactile cues, such as a mirror, a recorder, or a touch.
Modification, which helps to adjust the rate, loudness, or pitch of speech, by using devices or methods, such as a metronome, a microphone, or a pacing board.
Through compensatory strategies or aids, such as speaking slowly, clearly, and loudly, using gestures, facial expressions, or writing, or utilizing augmentative and alternative communication (AAC) devices, such as a picture board, tablet, or speech-generating device, speech is made more intelligible and effective.
Swallowing therapy, which aims to improve the swallowing function and prevent aspiration, by using techniques and strategies, such as:
Exercises, which help to strengthen, stretch, or relax the swallowing muscles, and improve the coordination, accuracy, and timing of the movements.
Maneuvers, which help to modify the position, posture, or movement of the head, neck, or tongue during swallowing, to facilitate the passage of food or liquid from the mouth to the stomach.
Modification, which helps to adjust the texture, consistency, or temperature of food or liquid, to make it easier or safer to swallow.
Compensation, which helps to reduce the risk of aspiration, by using strategies or aids, such as eating slowly, taking small bites or sips, or using a suction machine or a feeding tube.
Using exercises, games, or tasks that challenge and stimulate the brain, cognitive therapy seeks to improve the cognitive skills that may affect speech, such as attention, memory, reasoning, and problem-solving.
Through counseling, support, education, or referrals to other resources or services, psychosocial therapy aims to improve the emotional and social well-being of people with dysarthria and their families.
The treatment of dysarthria is usually provided by a multidisciplinary team, which may include the SLP, the neurologist, the physiatrist, the occupational therapist, the physical therapist, the psychologist, the social worker, and the nurse. There are a number of settings that can be used for the treatment, including hospitals, clinics, homes, and schools. In the case of dysarthria, treatment may be individual or group-based, short-term or long-term, depending on the individual's needs and goals.
However, certain risk factors that may increase the likelihood of developing dysarthria can be reduced or avoided, such as:
High blood pressure, high cholesterol, diabetes, and obesity, which can increase the risk of stroke and cardiovascular diseases that can damage the brain and the nervous system.
Smoking, alcohol, and drug abuse, which can impair the blood flow and oxygen supply to the brain and the nervous system, and cause toxicity or side effects that can affect speech.
Head or neck injury, which can result from accidents, falls, or violence, and cause trauma or compression to the brain and the nervous system.
Infection or inflammation, which can be caused by bacteria, viruses, fungi, or parasites, and affect the brain and the nervous system.
Some of the preventive measures that can help to lower the risk of dysarthria include:
Being healthy involves eating a balanced diet, exercising regularly, drinking plenty of water, and avoiding or limiting caffeine, salt, sugar, and fat consumption.
By taking prescribed medications, monitoring vital signs, and following the doctor's advice, blood pressure, cholesterol, and blood sugar levels can be controlled.
By seeking professional assistance, joining a support group, or using alternative methods, such as nicotine patches, gum, or lozenges, you can quit or reduce smoking, alcohol, and drug use.
Wearing a helmet, seat belt, or protective gear when playing sports, driving, or riding a bike or motorcycle, as well as avoiding risky or violent situations.
Infections and inflammation can be prevented or treated by maintaining good hygiene, washing hands frequently, avoiding contact with sick people, getting vaccinated, and taking antibiotics or anti-inflammatory medications.
It is a challenging condition that can impact a person's quality of life and relationships as well as their speech and communication abilities. Dysarthria can, however, be managed, improved, and regained independence and confidence with proper diagnosis, treatment, and prevention.
