A dysarthria caused by lower motor neuron (LMN) damage (e.g., cranial nerve injury or brainstem lesion), leading to weak, hypotonic speech muscles. Hallmark features include breathy, nasal voice quality with prominent hypernasality and nasal emission, imprecise consonants, and slow, labored articulation due to muscle weakness or paralysis. Atrophy or fasciculations of the tongue or face may be observed clinically. This contrasts with spastic dysarthria, which has increased tone (strained voice) rather than the flaccid tone and breathiness seen here.
Biller, José, ed. Practical Neurology. 4th ed. Philadelphia: Wolters Kluwer, (2016).
