Differential levels of speech and manual dysfluency in adults who stutter during simultaneous drawing and speaking tasks

FLP: Factor lattice pattern-based automated detection of Parkinson's disease and specific language impairment using recorded speech

BACKGROUND

Timely detection of neurodevelopmental and neurological conditions is crucial for early intervention. Specific Language Impairment (SLI) in children and Parkinson's disease (PD) manifests in speech disturbances that may be exploited for diagnostic screening using recorded speech signals. We were motivated to develop an accurate yet computationally lightweight model for speech-based detection of SLI and PD, employing novel feature engineering techniques to mimic the adaptable dynamic weight assignment network capability of deep learning architectures.

MATERIALS AND METHODS

In this research, we have introduced an advanced feature engineering model incorporating a novel feature extraction function, the Factor Lattice Pattern (FLP), which is a quantum-inspired method and uses a superposition-like mechanism, making it dynamic in nature. The FLP encompasses eight distinct patterns, from which the most appropriate pattern was discerned based on the data structure. Through the implementation of the FLP, we automatically extracted signal-specific textural features. Additionally, we developed a new feature engineering model to assess the efficacy of the FLP. This model is self-organizing, producing nine potential results and subsequently choosing the optimal one. Our speech classification framework consists of (1) feature extraction using the proposed FLP and a statistical feature extractor; (2) feature selection employing iterative neighborhood component analysis and an intersection-based feature selector; (3) classification via support vector machine and k-nearest neighbors; and (4) outcome determination using combinational majority voting to select the most favorable results.

RESULTS

To validate the classification capabilities of our proposed feature engineering model, designed to automatically detect PD and SLI, we employed three speech datasets of PD and SLI patients. Our presented FLP-centric model achieved classification accuracy of more than 95% and 99.79% for all PD and SLI datasets, respectively.

CONCLUSIONS

Our results indicate that the proposed model is an accurate alternative to deep learning models in classifying neurological conditions using speech signals.

Factors affecting expert performance in bid evaluation: An integrated approach

Experts play a crucial role in underpinning decision-making in most management situations. While recent studies have disclosed the impacts of individuals’ inherent cognition and the external environment on expert performance, these two-dimensional mechanisms remain poorly understood. In this study, we identified 14 factors that influence expert performance in a bid evaluation and applied cross-impact matrix multiplication to examine the interdependence of the factors. The results indicate that the two dimension-related factors affect each other within a person–environment system, and a poor situation perception gives rise to the deviation of expert performance. Expert performance can be improved if external supervision and expertise are strengthened through deliberate practices. The study proposes a new expert performance research tool, elucidates its mechanism in bid evaluation from a cognitive psychology perspective, and provides guidelines for its improvement in workplace contexts.

Adults Who Stutter Show Diminished Word Fluency, Regardless of Mode

PURPOSE

Language abilities have long been thought to be weaker in adults who stutter (AWS) compared to adults who do not stutter (AWNS). However, it is unknown whether modality affects language performance by AWS in time pressure situations. This study aimed to examine lexical access and retrieval abilities of AWS in oral and typed modes.

METHOD

Fifteen AWS and 15 well-matched AWNS completed computer-administered letter fluency tasks. Adults were asked to orally produce words that began with one of two letter targets and type words that began with one of two alternate letters. Conditions were counterbalanced across participants.

RESULTS

Generalized linear mixed-effects models were evaluated to determine the effects of group (AWS/AWNS), mode (oral/typed), and expressive vocabulary on letter fluency performance. Group predicted letter fluency such that AWS generated fewer items on both the oral and typed letter fluency tasks. Mode did not impact letter fluency results. Expressive Vocabulary Test scores predicted letter fluency similarly in both AWS and AWNS.

CONCLUSIONS

AWS were not penalized by oral task demands. AWS generated fewer items on the letter fluency tasks regardless of response mode, suggesting that they have weaker lexical access abilities. Furthermore, better expressive vocabulary skills were associated with better letter fluency performance in both groups.

Practice Mediates Bidirectional Dual-Task Interference When Performing a Novel Sequential Nonword Repetition Task

Introduction The current study examined the extent to which practice amount mediates dual-task interference patterns associated with concurrent performance of a novel speech task and attention-demanding visuomotor task. Method A Sequential Nonword Repetition Task was used to examine the effect of practice on interference associated with concurrent performance of a Visuomotor Pursuit Task. Twenty-five young adult participants were assigned to either an Extended Practice Group or a Limited Practice Group and performed a novel Sequential Nonword Repetition Task in isolation and while performing a concurrent visuomotor pursuit rotor task. Results Participants in the Limited Practice Group who were afforded a limited amount of practice exhibited dual-task interference (i.e., dual-task performance reductions) for both the speech and visuomotor tasks (i.e., bidirectional dual-task interference). Conversely, participants in the Extended Practice Group who were afforded extended practice exhibited little-to-no observable dual-task interference on the nonword repetition task. Conclusion Data from the current investigation suggest that the amount of initial practice mediates the degree of dual-task interference observed when a novel speech production task is performed with an attention-demanding Visuomotor Pursuit Task. Supplemental Material https://doi.org/10.23641/asha.14608071.

Adult stuttering and attentional ability: A meta-analytic review

Purpose: The study presents the first review in which the link between attentional ability and developmental stuttering is explored. The review aimed to summarise the published research literature and provide a more conclusive understanding as to the relationship between stuttering and attention.Method: To be included in this review, the studies had to compare the attentional performance of adult people who stutter (PWS) and people who do not stutter (PWNS) over the age of 18 years with a validated psychometric instrument for measuring attentional ability. Articles were searched in four electronic databases where each of the following search terms (attention, vigilance, inhibitory, inhibition, interference, executive and processing) was cross-referenced with each of the following terms (stutter, stammer, speech disfluency and speech dysfluency). A total of 21 studies met the inclusion criteria to be submitted into a meta-analysis.Result: The results of the main meta-analysis, which included all selected studies, demonstrated that PWS had a significantly worse attentional performance as compared to PWNS. Two further meta-analyses on selective attention and dual tasking performance confirmed the latter finding. Importantly, however, the effect was not present in all studies.Conclusion: Our findings should be taken as an indication that stuttering sometimes (but not always) manifests together with poorer attentional ability, such that the identified link does not affect all PWS. These results provide support for the notion that there is a close association between stuttering and attentional ability in a subgroup of PWS, highlighting potential practical implications for stuttering treatment.

Effects of different attention tasks on concurrent speech in adults who stutter and fluent controls

PURPOSE

Motor theories indicate that focusing attention on well-practiced movements interferes with skilled performance; however, specific forms of attention (alerting vs. orienting vs. executive control) associated with this effect are not well understood. The present study explored this question in relation to stuttering, and examined whether dual task conditions that engaged sustained attention or working memory (WM) affected speech fluency in different ways. We also considered whether fluency changes were associated with changes in speech rate and language.

METHODS

Nineteen adults who stutter (AWS) and 20 controls produced spontaneous speech under a baseline condition and two dual task conditions: one involving a sustained attention task, the other involving WM demands.

RESULTS

Both groups produced fewer stutter-like disfluencies under dual task relative to baseline conditions and this reduction did not differ between the two dual tasks (attention vs. WM). Speech rate and language variables, which were potentially influenced by attention conditions, were not affected by dual tasks in the same way as disfluencies, and appeared to be unassociated with fluency results.

CONCLUSIONS

Findings indicate that atypical disfluencies decrease when attention is divided, even when secondary task demands are minimal, as they were in the sustained attention task. For simple secondary tasks, fluency changes do not appear to be a byproduct of slowed rate and are not accompanied by observable changes in language. These results demonstrate that simple manipulations of attention can induce measurable effects on aspects of speech production, and may be a useful tool for facilitating fluency in clinical intervention.

Effects of Concurrent Manual Task Performance on Connected Speech Acoustics in Individuals With Parkinson Disease

Purpose Prior investigations suggest that simultaneous performance of more than 1 motor-oriented task may exacerbate speech motor deficits in individuals with Parkinson disease (PD). The purpose of the current investigation was to examine the extent to which performing a low-demand manual task affected the connected speech in individuals with and without PD. Method Individuals with PD and neurologically healthy controls performed speech tasks (reading and extemporaneous speech tasks) and an oscillatory manual task (a counterclockwise circle-drawing task) in isolation (single-task condition) and concurrently (dual-task condition). Results Relative to speech task performance, no changes in speech acoustics were observed for either group when the low-demand motor task was performed with the concurrent reading tasks. Speakers with PD exhibited a significant decrease in pause duration between the single-task (speech only) and dual-task conditions for the extemporaneous speech task, whereas control participants did not exhibit changes in any speech production variable between the single- and dual-task conditions. Conclusions Overall, there were little to no changes in speech production when a low-demand oscillatory motor task was performed with concurrent reading. For the extemporaneous task, however, individuals with PD exhibited significant changes when the speech and manual tasks were performed concurrently, a pattern that was not observed for control speakers. Supplemental Material https://doi.org/10.23641/asha.8637008.

Estimates of functional cerebral hemispheric differences in monolingual and bilingual people who stutter: Dual-task paradigm

The inter-relationship of stuttering and bilingualism to functional cerebral hemispheric processing was examined on a dual-task paradigm. Eighty native German (L1) speakers, half of whom were sequential bilinguals (L2 = English), were recruited. The participants (mean age = 38.9 years) were organised into four different groups according to speech status and language ability: 20 bilinguals who stutter (BWS), 20 monolinguals who stutter (MWS), 20 bilinguals who do not stutter (BWNS), and 20 monolinguals who do not stutter (MWNS). All participants completed a dual-task paradigm involving simultaneous speaking and finger tapping. No performance differences between BWS and BWNS were found. In contrast, MWS showed greater dual-task interference compared to BWS and MWNS, as well as greater right- than left-hand disruption. A prevailing finding was that bilingualism seems to offset deficits in executive functioning associated with stuttering. Cognitive reserve may have been reflected in the present study, resulting in a bilingual advantage.

Does Working Memory Enhance or Interfere With Speech Fluency in Adults Who Do and Do Not Stutter? Evidence From a Dual-Task Paradigm

PURPOSE

The present study examined whether engaging working memory in a secondary task benefits speech fluency. Effects of dual-task conditions on speech fluency, rate, and errors were examined with respect to predictions derived from three related theoretical accounts of disfluencies.

METHOD

Nineteen adults who stutter and twenty adults who do not stutter participated in the study. All participants completed 2 baseline tasks: a continuous-speaking task and a working-memory (WM) task involving manipulations of domain, load, and interstimulus interval. In the dual-task portion of the experiment, participants simultaneously performed the speaking task with each unique combination of WM conditions.

RESULTS

All speakers showed similar fluency benefits and decrements in WM accuracy as a result of dual-task conditions. Fluency effects were specific to atypical forms of disfluency and were comparable across WM-task manipulations. Changes in fluency were accompanied by reductions in speaking rate but not by corresponding changes in overt errors.

CONCLUSIONS

Findings suggest that WM contributes to disfluencies regardless of stuttering status and that engaging WM resources while speaking enhances fluency. Further research is needed to verify the cognitive mechanism involved in this effect and to determine how these findings can best inform clinical intervention.

Attention demands of language production in adults who stutter

OBJECTIVE

We investigated whether language production is atypically resource-demanding in adults who stutter (AWS) versus typically-fluent adults (TFA).

METHODS

Fifteen TFA and 15 AWS named pictures overlaid with printed Semantic, Phonological or Unrelated Distractor words while monitoring frequent low tones versus rare high tones. Tones were presented at a short or long Stimulus Onset Asynchrony (SOA) relative to picture onset. Group, Tone Type, Tone SOA and Distractor Type effects on P3 amplitudes were the main focus. P3 amplitude was also investigated separately in a simple tone oddball task.

RESULTS

P3 morphology was similar between groups in the simple task. In the dual task, a P3 effect was detected in TFA in all three distractor conditions at each Tone SOA. In AWS, a P3 effect was attenuated or undetectable at the Short Tone SOA depending on Distractor Type.

CONCLUSIONS

In TFA, attentional resources were available for P3-indexed processes in tone perception and categorization in all distractor conditions at both Tone SOAs. For AWS, availability of attentional resources for secondary task processing was reduced as competition in word retrieval was resolved.

SIGNIFICANCE

Results suggest that language production can be atypically resource-demanding in AWS. Theoretical and clinical implications of the findings are discussed.

Behavioral and multimodal neuroimaging evidence for a deficit in brain timing networks in stuttering: a hypothesis and theory

The fluent production of speech requires accurately timed movements. In this article, we propose that a deficit in brain timing networks is one of the core neurophysiological deficits in stuttering. We first discuss the experimental evidence supporting the involvement of the basal ganglia and supplementary motor area (SMA) in stuttering and the involvement of the cerebellum as a possible mechanism for compensating for the neural deficits that underlie stuttering. Next, we outline the involvement of the right inferior frontal gyrus (IFG) as another putative compensatory locus in stuttering and suggest a role for this structure in an expanded core timing-network. Subsequently, we review behavioral studies of timing in people who stutter and examine their behavioral performance as compared to people who do not stutter. Finally, we highlight challenges to existing research and provide avenues for future research with specific hypotheses.

A comparative study on diadochokinetic skill of dyslexic, stuttering, and normal children

Objective. Previous studies have shown some motor deficits among stuttering and dyslexic children. While motor deficits in speech articulation of the stuttering children are among the controversial topics, no study on motor deficits of dyslexic children has been documented to date. Methods. 120 children (40 stuttering, 40 dyslexia, and 40 normal) 6–11 years old were matched and compared in terms of diadochokinetic skill. Dyslexia symptoms checklist, reading test, and diadochokinetic task were used as measurement instruments. Results. The data analysis showed that there are significant differences (P < 0.001) in reaction time and the number of syllables in accomplishing diadochokinetic tasks among stuttering children, dyslexics, and the control group. This indicates that stuttering children and dyslexics have poor performance in reaction time and in the number of monosyllable articulation and long syllable articulation. Furthermore, there are significant differences (P < 0.001) in these indices between stuttering children and dyslexics, so that the latter group have better performance than the former one. Conclusion. The findings indicate that stuttering children and dyslexics have deficits in diadochokinetic skill which suggests their low performance in the motor control of speech production and articulation. Such deficits might be due to the role of the tongue in the development of stuttering and dyslexia.

A kinematic analysis of manual aiming control on euthymic bipolar disorder

Motor deficits in tasks that require force steadiness or scaling of movement velocity have been found in bipolar disorder (BD). A potential explanation for these results is the abnormal functioning of the frontostriatal circuitry. We designed this study to investigate the possible impairments in a manual aiming task. Participants comprised 15 euthymic BD patients and 15 healthy controls, who performed 100 trials of a goal-directed manual movement with a non-inking pen on a digitizing tablet. Four different conditions of execution were required. The control condition appeared on the computer screen in 70% of the trials, and the other three conditions, (a) distractor, (b) inhibition of response and (c) higher index of difficulty, each appeared in 10% of the trials. Compared to the controls, the BD patients were less fluent in their movements, relied more heavily on visual feedback to control their manual movements and presented a lower spatial accuracy. We found that motor deficits in euthymic BD were observed in the kinematic analysis of manual aiming. Our findings are consistent with the hypothesis of abnormal functioning of the frontostriatal circuitry in euthymic BD.

Curved motions in horizontal and vertical orientations

A consideration of handwriting demonstrates that motions can be remarkably constant, even when performed with different effectors. Nevertheless, the transposition of writing from horizontal to vertical orientations, as occurs when writing on blackboards, poses additional problems for the constraint of movement. Motions in horizontal and vertical planes potentially challenge the mechanisms responsible for motor constancy. Gravitational fields impose different accelerative forces on vertical (up/down) compared with horizontal (left/right) motions. A 1/3 power law linking tangential velocity and radius of curvature is sometimes invoked to explain how equivalent motions can be performed by different effectors. To evaluate the operation of the power law when movements are performed in different orientations, 12 participants drew ellipses in horizontal and vertical planes at about 1 or 2 Hz. Mean tangential velocity, radius of curvature and the strength of the 1/3 power law were analyzed. The power law was strongest for curved motions at faster speeds. The power law was weakest at slower speeds in the vertical orientation. As participants controlled their movement periodicity, this placed tighter constraints upon curvature in the vertical orientations than the horizontal orientations. Speed of motion had a greater effect upon curvatures in the horizontal than the vertical orientation. The data offer insights into variations in the strength of the power law under different orientations, and indicate a limited role for the 1/3 power law in motor constancy.

Right-shift for non-speech motor processing in adults who stutter

INTRODUCTION

In adults who do not stutter (AWNS), the control of hand movement timing is assumed to be lateralized to the left dorsolateral premotor cortex (PMd). In adults who stutter (AWS), the network of speech motor control is abnormally shifted to the right hemisphere. Motor impairments in AWS are not restricted to speech, but extend to non-speech orofacial and finger movements. We here investigated the lateralization of finger movement timing control in AWS.

METHODS

We explored PMd function in 14 right-handed AWS and 15 age matched AWNS. In separate sessions, they received subthreshold repetitive transcranial magnetic stimulation (rTMS) for 20 min at 1Hz over the left or right PMd, respectively. Pre- and post-stimulation participants were instructed to synchronize their index finger taps of either hand with an isochronous sequence of clicks presented binaurally via earphones. Synchronization accuracy was measured to quantify the effect of the PMd stimulation.

RESULTS

In AWNS inhibition of left PMd affected synchronization accuracy of the left hand. Conversely, in AWS TMS over the right PMd increased the asynchrony of the left hand.

CONCLUSIONS

The present data indicate an altered functional connectivity in AWS in which the right PMd seems to be important for the control of timed non-speech movements. Moreover, the laterality-shift suggests a compensatory role of the right PMd to successfully perform paced finger tapping.