Speech production requires motor coordination of structures of the respiratory system, larynx, pharynx and mouth, but motor speech disorders interrupt the complex interplay required for speech. The two most common motor speech disorders are dysarthria (disturbance in controlling speech muscles themselves) and apraxia (inability to connect what you want to say to the motor control needed to say it). People with motor speech disorders usually have intact cognitive abilities and understand written and spoken language.

Dysarthria involves weakness or difficulty controlling or coordinating the muscles used for speaking. Speech may be slow or slurred and difficult to understand.

Dysarthria can result from one of several serious underlying conditions:

Diagnosis of Dysarthria
At Houston Methodist, speech-language pathologists diagnose the type of dysarthria you may have and work in concert with neurologists to determine the underlying cause of your condition. Each patient will have a complete a physical examination along with a review of medical history. Several tests may be recommend to help identify the cause of your condition, including imaging tests to create detailed images of the brain, head and neck; brain and nerve studies to pinpoint the source of symptoms (electroencephalography, electromyography, nerve-conduction tests); blood and urine tests to help determine if infection or inflammation may be a factor; a lumbar puncture (spinal tap) may be needed; brain biopsy; and neuropsychological tests to assess cognitive skills.

Treatment Options for Dysarthria
Our goal at Houston Methodist is to help you regain the ability to communicate. Your treatment depends on the cause and severity of symptoms and the type of dysarthria you may have. We may recommend speech and language therapy to help you improve communication and regain normal speech.

Apraxia is a neurological disorder that affects areas of the brain involved in motor planning to perform movements or tasks that one is willing and able to do. Speech apraxia affects the brain’s ability to create a plan to make the muscles of speech work.

The two forms of speech apraxia are acquired apraxia (typically occurring in adults) and developmental apraxia (typically occurring in children). Acquired apraxia results in the loss of speech-making ability and can be caused by trauma, stroke or a brain tumor. Developmental apraxia is present from birth and rarely occurs without other language or cognitive defects; children with speech apraxia often understand speech much more than their ability to speak. The causes of developmental apraxia are not well understood.

The symptoms of apraxia include difficulty stringing syllables together in the appropriate order to make words, difficulty saying long or complex words, repeated attempts to pronounce words, inability to use correct inflections and stresses, omission of consonants at the beginning and ending of words and inconsistency in speech abilities. Children and infants may make excessive use of nonverbal forms of communication and engage in very little babbling.

Diagnosis of Apraxia
The diagnosis of apraxia may involve looking for symptoms to rule it out. For example, difficulties understanding language may indicate a condition other than motor planning for speech. When diagnosing acquired apraxia, brain imaging, such as with magnetic resonance imaging (MRI), may help to identify damaged areas. For developmental apraxia, tests are generally performed after two years of age, when a child is old enough to understand directions for the tests.

Treatment Options for Apraxia
Our team at Houston Methodist works to determine and treat the underlying causes of apraxia. In many cases, acquired apraxia resolves spontaneously. However, developmental apraxia requires highly individualized treatment. We tailor exercises to help our patients develop or regain the power of communication.


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