Ataxia: Inability to coordinate voluntary muscular movements. In common usage, the term describes an unsteady gait. Hereditary ataxias are usually caused by degeneration of the spinal cord, cerebellum, or other parts of the nervous system. The most common is Friedreich ataxia, which begins at ages 3–5, progressing slowly to almost complete incapacity by age 20. There is no specific therapy. Metabolic disorders, brain injuries, and toxins can cause ataxia.
Example: Patient has an ataxic gait.
Etymology: Greek, from a- + tassein to put in order
Aphasia: loss or impairment of the power to use or comprehend words usually resulting from brain damage (as a result of a stroke or head trauma)
Etymology: New Latin, from Greek, from a- + -phasia ,Greek, speech, from phasis utterance, from phanai to speak, say
Abulia: abnormal lack of ability to act or to make decisions that is characteristic of certain psychotic and neurotic conditions
Etymology: New Latin, from 2a- + Greek boulē will