Apraxia is a neurological disorder that affects the ability to perform purposeful, learned movements, even though there is no underlying muscle weakness or paralysis. The core problem lies in the brain’s inability to correctly plan and sequence the motor commands necessary for an action. Individuals with apraxia know what they want to do and have the physical capacity for movement, but the message from the brain to the muscles becomes corrupted during the planning stage. This disconnect results in visible difficulties when attempting tasks that require coordination and memory of how to move.
How Apraxia Affects Limb and Body Movements
Ideomotor apraxia is the most common form affecting the limbs, and it is characterized by a visible inability to perform common motor tasks or gestures on command. A person might struggle to imitate an action like waving goodbye or saluting, even though they understand the request and have the physical strength to move their arm. This deficit in the motor plan often results in movements that appear awkward, clumsy, or imprecise, featuring abnormal trajectories of the fingers, hands, or arms.
Difficulty is most obvious when the action is requested out of context, such as pantomiming using a tool (e.g., showing how to use a hammer). They may successfully use the tool spontaneously later, suggesting the stored memory is intact, but voluntary retrieval and execution are impaired.
Ideational apraxia involves a failure to conceptualize the entire sequence of a complex, multi-step task. This makes it difficult to organize and execute steps for daily activities, such as getting dressed or preparing a meal. A person may perform individual movements correctly but arrange them in the wrong order, such as putting on shoes before socks. The observable sign is a profound disorganization or misuse of objects, like trying to write with a screwdriver instead of a pen.
How Apraxia Affects Facial and Oral Control
Apraxia can also affect the face, mouth, tongue, and larynx, a condition known as buccofacial or oral apraxia. This form focuses specifically on the inability to carry out non-speech movements of the oral structures upon request. The person understands the instruction but cannot voluntarily initiate the motor plan for the movement, despite the muscles themselves being functional.
Observable signs include struggling to perform an action like licking one’s lips, winking, or sticking out the tongue on command. A person may also have difficulty with sequenced oral actions such as whistling, blowing out a candle, or making a kiss face when asked. They may perform these movements spontaneously, such as clearing their throat naturally, but cannot do the same when explicitly directed.
How Apraxia Affects Speech Production
Childhood Apraxia of Speech (CAS) is a specific type of apraxia where the brain has difficulty planning and coordinating the precise movements of the jaw, lips, and tongue needed to produce clear speech. The child knows the words they want to say, but the neural pathways that send the message to the mouth muscles are disrupted. This results in a highly observable and inconsistent pattern of speech errors that is distinct from other speech disorders.
One of the defining features is the inconsistency of errors; a child may say a sound or word correctly one time and then say it incorrectly the next time or even within the same sentence. This fluctuation means their speech errors do not follow the typical, predictable patterns seen in children with articulation disorders. Another visible sign is a characteristic groping or searching movement of the mouth and jaw as the child attempts to find the correct position before producing a sound.
The disorder also affects the rhythm, stress, and flow of speech, leading to distorted prosody. Speech may sound choppy, flat, or monotone, with unusual pauses placed between sounds or syllables within words. The child often struggles significantly with longer words or phrases, which require more complex and rapid sequencing of sounds.
Children with CAS often have a limited variety of consonant and vowel sounds in their repertoire, and they may find it difficult to imitate speech sounds when asked. The visible effort and struggle to speak can make the child hard to understand, especially for people who are unfamiliar with their speech patterns. The discrepancy between the child’s good comprehension of language and their difficulty with verbal expression highlights the motor planning nature of the disorder.
Next Steps After Identifying Symptoms
If these observable difficulties are noted, particularly if they persist and do not align with typical development, seeking professional evaluation is the next step. Self-diagnosis is insufficient for a condition that requires specialized assessment to differentiate it from other neurological or motor disorders.
For concerns related to speech, oral, and facial movements, consultation with a certified Speech-Language Pathologist (SLP) is appropriate. If the symptoms primarily involve limb and body movements, a Neurologist or an Occupational Therapist (OT) should be consulted. These specialists can conduct a comprehensive evaluation to correctly diagnose the specific type of apraxia and determine the appropriate path forward.