Speech may be jerky, staccato, breathy, irregular, imprecise, or monotonous, but people can understand language and use it correctly.
Practitioners evaluate muscle strength and movement by asking the person to do some simple tasks involving their mouth and tongue and to repeat words and sentences.
Speech therapy helps some people with dysarthria.
Although dysarthria seems to be a language problem, it is really a problem with controlling the muscles of speech (a motor problem).
Dysarthria may be caused by damage to the following:
Parts of the brain that control muscle movement.
Cerebellum Cerebellum The brain’s functions are both mysterious and remarkable, relying on billions of nerve cells and the internal communication between them. All thoughts, beliefs, memories, behaviors, and moods... read more : The cerebellum, which is located between the cerebrum and brain stem, coordinates the body’s movements.
Basal ganglia: These large collections of nerve cells help coordinate and smooth out movements (see figure Locating the Basal Ganglia Locating the Basal Ganglia Every body movement, from raising a hand to smiling, involves a complex interaction between the central nervous system (brain and spinal cord), nerves, and muscles. Damage to or malfunction... read more ).
Brain stem Brain stem The brain’s functions are both mysterious and remarkable, relying on billions of nerve cells and the internal communication between them. All thoughts, beliefs, memories, behaviors, and moods... read more : The brain stem controls the muscles that are used in breathing and those used to help make sounds.
The nerve fibers that connect the outer layer of the cerebrum (cerebral cortex) to the brain stem: These nerve fibers relay information needed to control and coordinate the muscles used to produce speech, including muscles of the lips, tongue, palate, and vocal cords.
Neuromuscular junction Overview of Neuromuscular Junction Disorders Nerves connect with muscles at the neuromuscular junction. There, the ends of nerve fibers connect to special sites on the muscle’s membrane called motor end plates. These plates contain receptors... read more : Nerves connect with muscles at the neuromuscular junction.
These structures can be damaged by degenerative disorders (such as amyotrophic lateral sclerosis Amyotrophic Lateral Sclerosis (ALS) and Other Motor Neuron Diseases (MNDs) Motor neuron diseases are characterized by progressive deterioration of the nerve cells that initiate muscle movement. As a result, the muscles stimulated by these nerves deteriorate, become... read more , Parkinson disease Parkinson Disease (PD) Parkinson disease is a slowly progressive degenerative disorder of specific areas of the brain. It is characterized by tremor when muscles are at rest (resting tremor), increased muscle tone... read more , and Huntington disease Huntington Disease Huntington disease is a hereditary disease that begins with occasional involuntary jerking or spasms, then progresses to more pronounced involuntary movements (chorea and athetosis), mental... read more ), multiple sclerosis Introduction to Meningitis Meningitis is inflammation of the layers of tissue that cover the brain and spinal cord (meninges) and of the fluid-filled space between the meninges (subarachnoid space). Meningitis can be... read more , head injuries Overview of Head Injuries Head injuries that involve the brain are particularly concerning. Common causes of head injuries include falls, motor vehicle crashes, assaults, and mishaps during sports and recreational activities... read more , brain tumors Overview of Brain Tumors A brain tumor can be a noncancerous (benign) or cancerous (malignant) growth in the brain. It may originate in the brain or have spread (metastasized) to the brain from another part of the body... read more , strokes Overview of Stroke A stroke occurs when an artery to the brain becomes blocked or ruptures, resulting in death of an area of brain tissue due to loss of its blood supply (cerebral infarction) and symptoms that... read more , or infections such as Lyme disease Lyme Disease Lyme disease is a tick-transmitted infection caused by Borrelia species, primarily by Borrelia burgdorferi and sometimes by Borrelia mayonii in the United States. These spiral-shaped bacteria... read more .
People who have dysarthria produce sounds that approximate what they mean and that are in the correct order. However, speech may be jerky, staccato, breathy, irregular, imprecise, or monotonous, depending on where the damage is.
Because the ability to understand and use language is not usually affected, most people with dysarthria can read and write normally.
The disorder that causes dysarthria can also cause difficulty chewing and swallowing.
To diagnose dysarthria, a doctor asks the person about symptoms and does a physical examination. A speech therapist often helps in the evaluation. The practitioner may also do the following:
Ask the person to do some simple tasks, such as blowing out a candle, biting the lower lip, and sticking out the tongue: Observing the person doing these tasks helps the practitioner evaluate the strength and movement of the muscles involved in speech.
Ask the person to repeat words and sentences, sing, and count: Observing the person producing sounds helps the practitioner detect problems with speaking, such as breathiness and jerky speech.
Standardized tests of brain function (neuropsychologic testing Agnosia is loss of the ability to identify objects using one or more of the senses. Symptoms vary depending on where the brain is damaged. Doctors determine whether people have agnosia by asking... read more ) may be given by a neuropsychologist or speech therapist. These tests also help practitioners plan treatment and determine how likely recovery is.
Imaging tests, such as computed tomography (CT) or magnetic resonance imaging (MRI), are done to help identify the cause.
Other tests may be done, depending on the suspected cause. These tests may include blood and urine tests, a spinal tap Spinal Tap Diagnostic procedures may be needed to confirm a diagnosis suggested by the medical history and neurologic examination. Electroencephalography (EEG) is a simple, painless procedure in which... read more (lumbar puncture), electroencephalography Electroencephalography Diagnostic procedures may be needed to confirm a diagnosis suggested by the medical history and neurologic examination. Electroencephalography (EEG) is a simple, painless procedure in which... read more (EEG), and electromyography and nerve conduction studies Electromyography and Nerve Conduction Studies Diagnostic procedures may be needed to confirm a diagnosis suggested by the medical history and neurologic examination. Electroencephalography (EEG) is a simple, painless procedure in which... read more .
Speech therapy Rehabilitation services are needed by people who have lost the ability to speak normally, often because of an injury, a stroke, an infection, a tumor, surgery, or a progressive disorder. Aphasia... read more helps some people with dysarthria. Speech therapy may involve breathing and muscle exercises and repetition of words or sentences.
If dysarthria is severe, therapists may recommend using a letter or picture board or a computer-based device with a keyboard and message display.