A Systematic Investigation of Phonetic Complexity Effects on Articulatory Motor Performance in Progressive Dysarthria

A Systematic Investigation of Phonetic Complexity Effects on Articulatory Motor Performance in Progressive Dysarthria

The goal is to improve the fundamental knowledge about articulatory motor performance in people with Lou Gehrig's disease (also known as ALS) and Parkinson's disease (PD), in order to develop more sensitive assessments for progressive speech loss, which may lead to the improved timing of speech therapies.

The long-term goal is to optimize dysarthria assessment by improving the early detection and tracking of articulatory performance in progressive dysarthrias. The short-term goal of the proposed cross-sectional study is to focus on ALS and PD and quantify articulatory kinematic performance as a function of phonetic complexity, which is experimentally manipulated based on theoretical principles of speech motor development. The research strategy is to use 3D electromagnetic articulography to examine phonetic complexity effects of single word stimuli at the articulatory kinematic level in 15 talkers each with preclinical, mild, and moderate dysarthria, relative to 45 controls. The central hypothesis is that as dysarthria severity increases the discrepancy in articulatory performance, indexed by movement speed, distance, coordination, and variability, between people with dysarthria and typical controls will significantly increase at a lower phonetic complexity level.

Two groups of participants i.e., participants with ALS or PD and healthy controls will be asked to repeat sentences that have target words with varying phonetic complexity.

Conduct a comprehensive kinematic assessment using state-of-the art 3D speech tracking technology on individuals with ALS and PD as well as healthy talkers to identify articulatory motor disturbances as a function of phonetic complexity and dysarthria severity. Phonetic complexity will be experimentally manipulated using the consonant and vowel complexity classification system proposed by Kent (1992) that takes into account the underlying articulatory motor adjustments required to produce various speech sounds.

Use of 3D electromagnetic articulography to examine phonetic complexity effects of single word stimuli at the articulatory kinematic level in talkers each with preclinical, mild, and moderate dysarthria, relative to healthy controls.

Peak speed (millimeters/second) for each articulatory marker is the maximum value of the first-order derivative of each marker's Euclidean distance time-history.

STI is the most widely used metric to capture movement pattern variability during speech. To determine STI, the pattern of articulatory movements and the variability of that pattern over several repetitions of an utterance are examined.

Spatiotemporal coupling relations between articulators will be derived from vertical movements of the articulators using a covariance measure.

Inclusion Criteria: May or may not have a neurological impairment. Age range of 19-90 years. Male or female. Provide written consent before any study specific procedures are performed. Have ability to comply with basic instructions. Monolingual English speaker. Have ability to partake in a 90 minute data collection. Exclusion Criteria: Any speech, language, cognition, or hearing impairment prior to diagnosis of a neurodegenerative disease. Anyone not appropriate for study participation, as deemed by the principal investigator.

The data collected during this study, especially from people with ALS, cannot be easily duplicated so it will be readily shared with other researchers conducting motor speech research. In addition, few investigators have access to tongue tracking technology; therefore, making the tongue kinematic data available will allow other investigators to answer pertinent questions related to speech decline in progressive dysarthrias. Both the raw data and processed data will be made available to interested investigators but will be devoid of identifiers in order to protect the privacy of the participants. Data documentation such as descriptors and units will also be shared to prevent misinterpretation or confusion. Besides the data itself, the PI is willing to share the stimuli as requested by other investigators.