Rate-dependent articulatory performance changes in talkers with amyotrophic lateral sclerosis

Three studies were conducted to identify articulatory movement constraints during the early stages of ALS when speech intelligibility and speaking rate are minimally affected. A secondary goal was to identify compensatory behaviors in response to these putative physiological constraints. Eight individuals with ALS and eight age and gender matched healthy controls participated in this study. Lower lip and jaw movements were recorded using a 3-dimensional optical motion analysis system. In the first study, the ability to increase lip and jaw speed was tested using a novel fixed-target task. Talkers with ALS showed a limited ability to generate the speeds necessary to reach the fixed target in a timely manner even at the early stages of the disease. Constraints in articulatory movement speed were not detected during an unconstrained speaking task. In the second study, the relative contribution of the jaw was compared between talkers with ALS and controls to identify potential constraints in articulatory movement strategies used to increase speaking rate. The relative contribution of the jaw was greater in talkers with ALS than in healthy controls. In addition, talkers with ALS exhibited minimal rate-related changes in the relative contribution of the jaw during sentence repetitions, which was suggestive of limited coordinative flexibility. In the third study, the spatiotemporal variability of the lower lip was measured during sentence repetitions at various speaking rates and during loud speech to identify a potential limited ability to produce consistent movement patterns. In contrast to this hypothesis, talkers with ALS produced lower lip movements with lower spatiotemporal variability during typical and slower speech rates, but displayed higher movement variability than healthy controls during loud speech. Although the functional significance of these constraints is not fully understood, they may explain some well-know speech phenomena in ALS (i.e., decline in speaking rate and intelligibility). Further, results point to the potential diagnostic and prognostic value of kinematic measures for determining the onset and rate of disease progression of bulbar deterioration due to ALS

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

This study pursued two goals: (1) to establish range of motion (ROM) demand tiers (i.e., low, moderate, high) specific to the jaw (J), lower lip (LL), posterior tongue (PT), and anterior tongue (AT) for multisyllabic words based on the articulatory performance of neurotypical talkers and (2) to identify demand- and disease-specific articulatory performance characteristics in talkers with amyotrophic lateral sclerosis (ALS) and Parkinson’s disease (PD). J, LL, PT, and AT movements of 12 talkers with ALS, 12 talkers with PD, and 12 controls were recorded using electromagnetic articulography. Vertical ROM, average speed, and movement duration were measured. Results showed that in talkers with PD, J and LL ROM were already significantly reduced at the lowest tier whereas PT and AT ROM were only significantly reduced at moderate and high tiers. In talkers with ALS, J ROM was significantly reduced at the moderate tier whereas LL, PT, and AT ROM were only significantly reduced at the highest tier. In both clinical groups, significantly reduced J and LL speeds could already be observed at the lowest tier whereas significantly reduced AT speeds could only be observed at the highest tier. PT speeds were already significantly reduced at the lowest tier in the ALS group but not until the moderate tier in the PD group. Finally, movement duration, but not ROM or speed performance, differentiated between ALS and PD even at the lowest tier. Results suggest that articulatory deficits vary with stimuli-specific motor demands across articulators and clinical groups

LIP MOVEMENT EXAGGERATIONS DURING INFANT DIRECTED SPEECH

Purpose: Although a growing body of literature has indentified the positive effects of visual speech on speech and language learning, oral movements of infant directed speech have rarely been studied. This investigation used 3-dimensional motion capture technology to describe how mothers modify their lip movements when talking to their infants. Method: Lip movements were recorded from twenty-five mothers as they spoke to their infants and other adults. Lip shapes were analyzed for differences across speaking conditions. The maximum fundamental frequency, duration, acoustic intensity, and first and second formant frequency of each vowel were also measured. Results: Lip movements were significantly larger during infant directed speech than during adult directed speech, although the exaggerations were vowel specific. All of the vowels produced during infant directed speech were characterized by an elevated vocal pitch and a slowed speaking rate when compared to vowels produced during adult directed speech. Conclusion: The pattern of lip shape exaggerations did not provide support for the hypothesis that mothers produce exemplar visual models of vowels during infant directed speech. Future work is required to determine if the observed increases in vertical lip aperture engender visual and acoustic enhancements that facilitate the early learning of speech

An Open Dataset of Connected Speech in Aphasia with Consensus Ratings of Auditory-Perceptual Features

Auditory-perceptual rating of connected speech in aphasia (APROCSA) is a system in which trained listeners rate a variety of perceptual features of connected speech samples, representing the disruptions and abnormalities that commonly occur in aphasia. APROCSA has shown promise as an approach for quantifying expressive speech and language function in individuals with aphasia. The aim of this study was to acquire and share a set of audiovisual recordings of connected speech samples from a diverse group of individuals with aphasia, along with consensus ratings of APROCSA features, for future use as training materials to teach others how to use the APROCSA system. Connected speech samples were obtained from six individuals with chronic post-stroke aphasia. The first five minutes of participant speech were excerpted from each sample, and five researchers independently evaluated each sample using APROCSA, rating its 27 features on a five-point scale. The researchers then discussed each feature in turn to obtain consensus ratings. The dataset will provide a useful, freely accessible resource for researchers, clinicians, and students to learn how to evaluate aphasic speech with an auditory-perceptual approach

Dysarthria Subgroups in Talkers with Huntington’s Disease: Comparison of Two Data-Driven Classification Approaches

Although researchers have recognized the need to better account for the heterogeneous perceptual speech characteristics among talkers with the same disease, guidance on how to best establish such dysarthria subgroups is currently lacking. Therefore, we compared subgroup decisions of two data-driven approaches based on a cohort of talkers with Huntington’s disease (HD): (1) a statistical clustering approach (STATCLUSTER) based on perceptual speech characteristic profiles and (2) an auditory free classification approach (FREECLASS) based on listeners’ similarity judgments. We determined the amount of overlap across the two subgrouping decisions and the perceptual speech characteristics driving the subgrouping decisions of each approach. The same speech samples produced by 48 talkers with HD were used for both grouping approaches. The STATCLUSTER approach had been conducted previously. The FREECLASS approach was conducted in the present study. Both approaches yielded four dysarthria subgroups, which overlapped between 50% to 78%. In both grouping approaches, overall bizarreness and speech rate characteristics accounted for the grouping decisions. In addition, voice abnormalities contributed to the grouping decisions in the FREECLASS approach. These findings suggest that apart from overall bizarreness ratings, indexing dysarthria severity, speech rate and voice characteristics may be important features to establish dysarthria subgroups in HD