Which are the major types of the motor speech disorder dysarthria?
Dysarthria is a motor speech disorder which can be classified according to the underlying neuropathology and is associated with disturbances of respiration, laryngeal function, airflow direction, and articulation resulting in difficulties of speech quality and intelligibility. There are six major types of dysarthria: "flaccid dysarthria" associated with lower motor neuron impairment, "spastic dysarthria" associated with damaged upper motor neurons linked to the motor areas of the cerebral cortex, "ataxic dysarthria" primarily caused by cerebellar dysfunction, and "hyperkinetic dysarthria" and "hypokinetic dysarthria", which are related to a disorder of the extrapyramidal system. The sixth is generally termed a "mixed dysarthria" and is associated with damage in more than one area, resulting in speech characteristics of at least two groups.