Dysarthria encompasses a range of neurogenic speech disorders characterized by abnormalities in the coordination, strength, speed, range, steadiness, tone, or accuracy of movements needed for various aspects of speech production (Duffy, 2020).

These abnormalities arise from sensorimotor issues such as weakness, paralysis, lack of coordination, involuntary movements, or changes in muscle tone. They can impair the clarity and naturalness of speech and may coexist with other neurogenic conditions affecting language, cognition, and swallowing.

The main approach to diagnosing dysarthria relies on perceptual classification, primarily through auditory analysis of speech characteristics indicative of underlying pathophysiology (Darley et al., 1969a, 1969b, 1975). These perceptual attributes, combined with knowledge of the underlying neurological condition, help in identifying specific types of dysarthria.

The primary types of dysarthria, categorized by perceptual attributes and associated pathophysiological localization, include:

• Flaccid dysarthria: weakness or paralysis of the muscles involved in speech production. Characteristics include imprecise articulation, breathy voice quality, hypernasality, and reduced loudness.

• Spastic dysarthria: abnormal muscle tone and stiffness. Characterized by imprecise articulation, strained or effortful speech, harsh or strained voice quality, slow or labored speech rate.

• Ataxic dysarthria: difficulties in coordinating the muscle movements necessary for speech production. Characteristics include irregular articulatory breakdowns, excessive or irregular speech rate, irregular prosody, and hypotonia.

• Hypokinetic dysarthria: reduced movement and muscle rigidity. Often characterized by monotonous or reduced speech volume, hypophonia, and variable speech rate.

• Hyperkinetic dysarthria: involuntary movements affecting speech production. Characteristics include irregular speech rhythm, excessive or involuntary movements, and variable speech rate.

• Unilateral upper motor neuron dysarthria: neurogenic speech disorder characterized by impaired speech production. Characterized by weakness or paralysis of one side of the face, reduced range of motion, and asymmetrical facial expressions.

• Mixed dysarthria: combining various dysarthria types, such as spastic-ataxic or flaccid-spastic.