Generalized motor programme and parameterization accuracy in apraxia of speech and conduction aphasia

The present study examined three aspects of motor programming (generalized motor programme (GMP) accuracy, temporal parameterization accuracy, and amplitude parameterization accuracy) in subjects with apraxia of speech (AOS) or conduction aphasia (CA) and normal speaking participants. Subjects were presented with a movement pattern on a monitor that they were required to produce with the jaw, after the target pattern had been removed from view. Analyses examined differences in relative (parameterization) and absolute (GMP) timing and amplitude between the target and actual movement. Examination of individual subject performance revealed inter-subject variability within the AOS group, with two of the four subjects demonstrating unimpaired GMP accuracy but poor parameterization accuracy, while the other two subjects exhibited the opposite pattern, impaired GMP accuracy but normal parameterization. No clear pattern of deficit was noted for the subjects with CA. Results are discussed with respect to motor control theories of AOS and CA.