What are Speech Sound Disorders?

Intervention for speech sound disorders consists of the assessment and treatment of disorders including apraxia, dysarthria, articulation, phonology, stuttering, and voice. Speech disorders impact a person’s articulation, or ability to produce sounds that are needed to create words. They may also affect fluency or voice.

Types of Speech Sound Disorders

Apraxia of Speech

Apraxia of speech is caused by a disruption the brain telling the mouth muscles how to move to produce on-command speech. Apraxia of speech can occur in children or adults and is characterized by inconsistent articulation errors. Childhood apraxia of speech can be caused by strokes, brain injuries, or genetic disorders/syndromes, though it is often present due to an unknown cause. Adults typically acquire apraxia of speech as a result of damage to the brain from strokes, traumatic brain injury, dementia, brain tumors, or neurological conditions.

Dysarthria

Dysarthria is a neurological motor speech impairment that is characterized by weakness of the muscles used to produce speech. Dysarthria can occur in children or adults and can be developmental (cerebral palsy, muscular dystrophy, etc.) or acquired (stroke, trauma, Parkinson’s disease, etc.).

Articulation disorder

An articulation disorder is present when specific sounds in words are distorted, added, omitted, or substituted by another sound due to incoordination or weakness of muscles needed to produce the sounds.  Although an articulation disorder is often due to developmental delay of unknown origin, it can also be caused by craniofacial anomalies, hearing loss, brain injury, or disorders affecting the physical, sensory-motor, and cognitive domains such as cerebral palsy, autism spectrum disorder, and down syndrome.

Phonological disorder

A phonological disorder is not based on oral motor movements like an articulation disorder, rather it involves organizing the patterns of sounds in the brain. Those with a phonological disorder produce multiple speech errors in predictable patterns. These patterns are often common in development, but at a certain age are expected to disappear. Although a phonological disorder is often due to developmental delay of unknown origin, it can also be caused by craniofacial anomalies, hearing loss, brain injury, or disorders affecting the physical, sensory-motor, and cognitive domains such as cerebral palsy, autism spectrum disorder, and down syndrome.

Stuttering

Stuttering or child-onset fluency disorder is when atypical disfluencies disrupt the smooth flow of speech. Stuttering often involves secondary characteristics such as facial and body movements, which are used as behaviors to stop or keep from stuttering. According to The Stuttering Foundation, there are four factors that most likely contribute to development of stuttering. They include genetics, coexisting developmental delays including speech and language problems, neurophysiology, and family dynamics.

Voice

A voice disorder occurs when a person’s voice is not perceived to sound appropriate by either themselves or by their communication partners. Altered vocal quality, pitch, loudness, or vocal effect are impacted by voice disorders. Voice disorders can be caused by organic pathologies such as structural changes or neurological disorders; functional causes such as vocal fatigue or muscle tension; or psychogenic causes such as anxiety. Common types of voice disorders include laryngitis, lesions such as nodules or polyps, or muscle tension dysphonia.