A Neuromotor to Acoustical Jaw-Tongue Projection Model With Application in Parkinson’s Disease Hypokinetic Dysarthria

Abstract

AimThe present work proposes the study of the neuromotor activity of the masseter-jaw-tongue articulation during diadochokinetic exercising to establish functional statistical relationships between surface Electromyography (sEMG), 3D Accelerometry (3DAcc), and acoustic features extracted from the speech signal, with the aim of characterizing Hypokinetic Dysarthria (HD). A database of multi-trait signals of recordings from an age-matched control and PD participants are used in the experimental study.Hypothesis:The main assumption is that information between sEMG and 3D acceleration, and acoustic features may be quantified using linear regression methods.MethodsRecordings from a cohort of eight age-matched control participants (4 males, 4 females) and eight PD participants (4 males, 4 females) were collected during the utterance of a diadochokinetic exercise (the fast repetition of diphthong [aI]). The dynamic and acoustic absolute kinematic velocities produced during the exercises were estimated by acoustic filter inversion and numerical integration and differentiation of the speech signal. The amplitude distributions of the absolute kinematic and acoustic velocities (AKV and AFV) are estimated to allow comparisons in terms of Mutual Information.ResultsThe regression results show the relationships between sEMG and dynamic and acoustic estimates. The projection methodology may help in understanding the basic neuromotor muscle activity regarding neurodegenerative speech in remote monitoring neuromotor and neurocognitive diseases using speech as the vehicular tool, and in the study of other speech-related disorders. The study also showed strong and significant cross-correlations between articulation kinematics, both for the control and the PD cohorts. The absolute kinematic variables presents an observable difference for the PD participants compared to the control group.ConclusionKinematic distributions derived from acoustic analysis may be useful biomarkers toward characterizing HD in neuromotor disorders providing new insights into PD.

Acoustic to kinematic projection in Parkinson’s disease dysarthria

“…The present study is based on a simplified jaw-tongue articulation model [16] which is known to be representative of PD dysarthria [18]. It allows to create a relationship between acoustic and kinematic variables relating the first two formants F={F1, F2} to the horizontal and vertical coordinates S={xr, yr} of the joint Jaw-Tongue Reference Point (PrJT) in the sagittal plane This point represents the center of moments of the biomechanical system integrated by the maxillary bone, tongue and facial tissues associated [17] (see Figure 1).…”

“…where ΔS = {Δs1, Δs2} is the vector of the horizontal and vertical displacements of PrJT in the time domain, which may be obtained from the rotation and integration of the tangential and normal acceleration components {xa, ya} on the participant's chin, W in (1) is a 2x2 matrix expressing the LTI projection model, which will be referred to as the acoustic-to-kinematic projection, and ΔF is the relative displacement in frequency of the first two formants with respect to their means in the time domain, as the first two formants are strongly associated with articulation kinematics [17], defined as…”

“…This led to further exploratory work, were the relationships between sEMG, accelerometry and Speech were investigated [15]. After an in-depth study of the affectations of PD on these biometric signals [16], the conclusions were applied to the characterization of PD hypokinetic dysarthria [17], [18].…”