Dysarthria encompasses a cluster of neurogenic speech disorders marked by ‘irregularities in the strength, speed, range, steadiness, tone, or precision of movements needed for breathing, phonation, resonance, articulation, or prosody in speech production.’
These alterations stem from one or more sensorimotor issues, including muscular weakness or paralysis, lack of coordination, involuntary movements, or fluctuations in muscle tone—whether excessive, diminished, or inconsistent. Dysarthria can significantly impact speech intelligibility and the naturalness of speech production. Furthermore, it may co-occur with other neurogenic disorders related to language, cognition, and swallowing.
The primary approach for distinguishing between various forms of dysarthria relies on a perceptual classification method. This method predominantly relies on auditory perception of speech attributes that provide insights into the underlying pathophysiology. These perceptual attributes aid in characterizing dysarthria and, when coupled with pathophysiological information, can assist in identifying the root neurological condition.
The key types of dysarthria, differentiated by perceptual attributes and the corresponding localization of pathophysiological factors, are as follows:
- Flaccid Dysarthria: Linked to disorders affecting the lower motor neuron pathways and motor units.
- Spastic Dysarthria: Associated with bilateral disorders of the upper motor neuron system.
- Ataxic Dysarthria: Tied to disorders impacting the cerebellar control circuit.
- Hypokinetic Dysarthria: Linked to disorders affecting the basal ganglia control circuit.
- Hyperkinetic Dysarthria: Also associated with disorders of the basal ganglia control circuit.
- Unilateral Upper Motor Neuron Dysarthria: Connected to unilateral disorders of the upper motor neuron system.
- Mixed Dysarthria: Combining various dysarthria types, such as spastic-ataxic or flaccid-spastic.
For those seeking treatment techniques for dysarthria or treatment for dysarthria in adults, comprehensive approaches exist for managing this condition. Treatment and management of dysarthria aim to improve speech function and communication skills, ensuring individuals receive the support and care needed to enhance their quality of life.