Neurogenic dysphonia.

Disorders of phonation and resonation subsequent to damage to the central or peripheral nervous system (neurogenic dysphonia) typically occur with alterations in other aspects of motor speech: articulation, prosody, and respiration. Deficits in voice initiation or coordination of resonation with speech that occur without significant neuromuscular impairment following a lesion to Broca's area are compatible with a motor speech programming disorder, or apraxia of speech. Conversely, damage to upper or lower motor neurons subserving motor speech results in a group of neuromuscular speech disorders, the dysarthrias, which have signs including aberrations of phonation and resonation which can be differentiated. The neuropathologic and perceptual characteristics of neurogenic dysphonia are elucidated, and suggestions are provided for their identification and differentiation.