Introduction to Apraxia of Speech (AOS)
Apraxia of Speech (AOS) is a complex motor speech disorder characterized by difficulties in planning and programming the movements necessary for speech production. This condition often results in distorted phonemes, prolonged segment durations, and inconsistent speech errors. AOS is commonly associated with damage to Broca's area and adjacent regions in the brain, often due to stroke.
Research Insights: Behavioral, Computational, and Neuroimaging Studies
Recent research, such as the study by Ballard, Tourville, and Robin, has employed a multifaceted approach to understand AOS. This includes behavioral studies, neuroimaging, and computational modeling to explore the speech motor network's components associated with both normal and disordered speech motor programming.
Behavioral Studies: Understanding Feedback and Feedforward Control
Behavioral paradigms have been instrumental in distinguishing between feedback and feedforward control systems in individuals with AOS. Studies using visuomotor tracking and sensorimotor perturbation have revealed that individuals with AOS may rely more heavily on feedback due to impaired feedforward control, impacting their speech accuracy and fluency.
Neuroimaging: Mapping the Brain's Speech Network
Neuroimaging studies have identified critical areas involved in AOS, such as the inferior frontal gyrus and lateral premotor cortex. These regions are crucial for articulatory preparation and motor programming, providing insights into the anatomical substrates of AOS.
Computational Modeling: The DIVA Model
The DIVA model offers a comprehensive framework for understanding speech production, integrating feedforward and feedback control systems. By simulating speech tasks, researchers can compare model predictions with empirical data, enhancing our understanding of the neural mechanisms underlying AOS.
Implications for Practitioners
Practitioners can leverage these research findings to improve therapeutic outcomes for children with AOS. By understanding the underlying neural mechanisms and control systems, speech-language pathologists can develop targeted interventions that address specific deficits in feedforward and feedback control.
Encouraging Further Research
While significant progress has been made, further research is needed to fully elucidate the complex interactions within the speech motor network in AOS. Practitioners are encouraged to stay informed about ongoing research and consider participating in studies that advance our understanding of this disorder.
To read the original research paper, please follow this link: Behavioral, computational, and neuroimaging studies of acquired apraxia of speech.
