Articulatory Performance in Dysarthria: Using a Data-Driven Approach to Estimate Articulatory Demands and Deficits

Area of Science:

• Speech motor control
• Neurology
• Linguistics

Background:

• Speech production relies on precise articulatory movements.
• Neurological conditions like Parkinson's disease (PD) and amyotrophic lateral sclerosis (ALS) impair motor control, affecting speech.
• Understanding articulatory demand tiers is crucial for diagnosing and managing speech deficits.

Purpose of the Study:

• To establish range of motion (ROM) demand tiers for jaw (J), lower lip (LL), posterior tongue (PT), and anterior tongue (AT) in multisyllabic words.
• To identify disease-specific articulatory performance characteristics in talkers with ALS and PD.
• To compare articulatory deficits across different motor demand levels and patient groups.

Main Methods:

• Electromagnetic articulography (EMA) recorded J, LL, PT, and AT movements in 12 talkers with ALS, 12 with PD, and 12 controls.
• Measured vertical ROM, average speed, and movement duration for speech tasks.
• Analyzed performance across established low, moderate, and high ROM demand tiers.

Main Results:

• PD group: Reduced J and LL ROM at low tiers; PT and AT ROM reduced at moderate/high tiers.
• ALS group: Reduced J ROM at moderate tier; LL, PT, AT ROM reduced at highest tier.
• Both groups: Reduced J and LL speeds at low tiers; AT speeds reduced at highest tier. Movement duration differentiated ALS and PD at the lowest tier.

Conclusions:

• Articulatory deficits in ALS and PD are specific to the articulator and the motor demand of the speech task.
• Speech speed deficits are apparent earlier than ROM deficits in both conditions.
• Movement duration is a key differentiator between ALS and PD speech characteristics, even at low demand levels.