Speech Disorders

Conditions that affect the ability of structures of the MOUTH and THROAT to form the sounds necessary for speech. Health-care providers often refer to these conditions as disorders of articulation to distinguish them from LEARNING DISORDERS that may affect speech. Learning disabilities typically involve BRAIN function, whereas speech or articulation disorders involve the mechanics of speech.

Many speech disorders arise from structural anomalies that become apparent during early childhood, such as CLEFT PALATE/CLEFT PALATE AND LIP, incorrect placement of the TEETH as they erupt, or deviations in the size and shape of the oral cavity. Functional difficulties, such as tongue control and lip placement during articulation, may also cause or contribute to speech disorders. HEARING LOSS, neurologic conditions that affect control of the muscles of the face and throat, and brain injury are additional factors that influence the ability to speak, particularly in adults. STROKE is a leading cause of speech disability in adults.

Symptoms of speech disorders range from the obvious to the subtle and may include

• omitted sounds, in which certain consistent sounds do not appear in speech, for example, leaving the starting or ending consonants off words
• substituted sounds, in which one sound substitutes for another, such as w for r (wabbit)
• distorted sounds, in which extra noises such as whistling or whooshing accompany certain words or letters
• slurred, slow sounds, called dysarthria, which represent an inability to coordinate the neurologic and muscular functions necessary for speech

Speech disorders may indicate disorders of brain function; a comprehensive NEUROLOGIC EXAMINATION helps make this determination. Speech difficulties that suddenly arise suggest a physical basis, such as injury to the brain (stroke) or damage to the NERVE pathways between the brain and the face. Speech disorders may also appear as a component of learning disabilities and other developmental factors. In children, the reasons for speech disorders sometimes remain unclear, though speech therapy often can eliminate the symptoms.

The first goal of treatment is to remedy any apparent physical causes such as cleft palate or misaligned teeth. Other treatment targets strengthening the muscles of the tongue and face in conjunction with learning proper placement of the tongue and lips during speech. This is the venue of speech therapy, which provides instruction to help with forming the mouth positions and movements necessary for articulation. The speech therapist, also called speech-language pathologist, may use video and audio recordings in combination with physical findings to assess the extent and possible causes of speech disorders and to develop methods to overcome the difficulties. With appropriate treatment, most people experience improvement, and many people experience complete restoration, of speech. Children may need ongoing speech therapy as their facial features continue to grow and change.