Dysarthria, on the other hand, is simply a
collective name for a group of speech disorders resulting from disturbances of
muscular control of speech production. In dysarthric patients, the actual
language (grammar, word choice, understanding) is normal. Dysarthria may result
from many etiologies, both locally and in the central and peripheral nervous
systems. For instance, dysarthria can be seen in:
• Local disorders
(e.g., disorders of the tongue, palate and larynx)
• Myopathies
(e.g., oculopharyngeal muscular dystrophy, FSH
muscular dystrophy)
• NMJ Disorders
(e.g., myasthenia gravis)
• Disorders of Cranial Nerves 5, 7, 9, 10, or 12
(e.g., skull based tumors)
• Diffuse Peripheral Neuropathies
(e.g., Guillain-Barré Syndrome)
• Brainstem disorders
(e.g., stroke, tumor)
• Cerebellar disorders
(e.g., scanning speech in paraneoplastic
degeneration, multiple sclerosis, etc.)
• Basal ganglionic disorders
(e.g., hypophonic speech in Parkinson’s)
• Subcortical disorders
(e.g., slurred speech in lacunar strokes)
• Cortical disorders
(e.g., slurred speech in a MCA stroke)
• Mixed Upper and Lower Motor Neuron Disorders
(e.g., mixed flaccid and spastic speech in ALS) |
Although dysarthria often implicates a neurologic disorder, dysarthria is
often not localizing in isolation. Aphasia, on the other hand, always implicates
a central nervous system disorder, usually cortical, affecting the dominant
hemisphere in the peri-sylvian area. Patients can have both dysarthria and
aphasia (e.g., stroke in the left frontal lobe). |