Dysarthria is a motor speech abnormality that commonly results from stroke and is related to focal muscular deficits in the face.
One of the most challenging aspects of recognizing dysarthria relates to distinguishing it from apraxia.
Apraxia has nothing to do with a focal motor deficit, but rather a cortical deficit which results in an inability to optimally execute the function of the facial musculature.
Isolated dysarthria without other neurologic deficit, termed pure dysarthria, is rare and thought to result from multiple lacunar infarcts causing hypoperfusion of the frontal cortex.
References
Okuda, et al. "Cerebral Blood Flow in Pure Dysarthria: Role of Frontal Cortical Hypoperfusion." Stroke 30: 109-13. 1999.