Short answer

When designing for individuals with speech differences, account for increased variability and deterministic patterns in articulation, particularly under stressful conditions, and explore how technology can support motor flexibility.

Field: Human Factors
Source: CUNY Academic Works (City University of New York) (2015)
Method: Experimental research employing both linear and nonlinear analysis techniques on speech kinematics and acoustics.
Sample: 31 participants (20 who stutter, 21 who do not stutter) in the primary experiment.
Evidence: Strong effect

Adults who stutter exhibit greater variability in speech articulation, particularly under conditions of increased linguistic complexity, and their lip movements show more predictable, deterministic patterns, especially when under the stress of an audience. This human factors research insight is drawn from a 2015 study published in CUNY Academic Works (City University of New York). Using Experimental research employing both linear and nonlinear analysis techniques on speech kinematics and acoustics. with 31 participants (20 who stutter, 21 who do not stutter) in the primary experiment., researchers explored how this design variable affects real-world outcomes. The key design takeaway: When designing for individuals with speech differences, account for increased variability and deterministic patterns in articulation, particularly under stressful conditions, and explore how technology can support motor flexibility.

Study

Human FactorsHigh ImpactStrong effect

Increased speech variability in stuttering adults linked to deterministic lip dynamics under cognitive-emotional stress

CUNY Academic Works (City University of New York) · 2015

Key Findings

01Adults who stutter exhibit greater effector variability than adults who do not stutter when target utterances are embedded in sentences of increased linguistic complexity.
02Linear acoustic measures are as effective as linear kinematic measures for quantifying speech variability.
03Adults who stutter exhibit more deterministic structure in lip aperture dynamics.
04The presence of an audience (cognitive-emotional stress) resulted in decreased surface variability and increased deterministic structure in speech.

Application

Design takeaway

How to apply

In designing communication interfaces or therapeutic tools for individuals with speech disorders, consider incorporating adaptive features that can adjust to varying levels of speech variability and stress.

Project actions

01When studying human movement, consider both simple (linear) and complex (nonlinear) ways to measure variability.
02Investigate how environmental factors like audience presence can affect performance in your design project.

Method & Evidence

AimTo investigate the differences in speech variability, stability, and flexibility between adults who stutter and those who do not, examining the influence of linguistic complexity and audience presence on lip kinematics and acoustics.

MethodExperimental research employing both linear and nonlinear analysis techniques on speech kinematics and acoustics.

ProcedureThe study involved two experiments. The first was a pilot study to select fluent utterances. The primary experiment measured lip aperture kinematics and acoustics from adults who stutter and adults who do not stutter under conditions of varying audience presence and increasing linguistic complexity.

Sample31 participants (20 who stutter, 21 who do not stutter) in the primary experiment.

ContextSpeech production and communication disorders.

Variables

IV["Stuttering status (stutterer vs. non-stutterer)","Linguistic complexity (low vs. high)","Audience presence (present vs. absent)"]

DV["Speech variability (linear and nonlinear measures)","Lip aperture kinematics","Acoustic measures","Deterministic structure of lip dynamics"]

CV["Utterance content","Recording environment","Participant age range"]

Strengths & Limitations

Strengths

+Utilized both linear and nonlinear analysis techniques for a more comprehensive understanding of variability.
+Investigated the impact of multiple contextual factors (linguistic complexity, audience).

Limitations

It can be challenging to accurately simulate 'cognitive-emotional stress' in a controlled design project setting without impacting participant comfort.

Reliability & validity

Reliability would be assessed by the consistency of measurements across repeated trials for the same participant. Validity is supported by the use of established kinematic and acoustic analysis techniques and corroboration with prior research using linear methods.

Think critically

How might the 'deterministic structure' observed in lip movements of individuals who stutter relate to potential control strategies or compensatory mechanisms, and how could a design project leverage or mitigate these?

Design Principles

"Speech production variability is influenced by cognitive-emotional load and linguistic complexity, with individuals who stutter exhibiting distinct kinematic and acoustic patterns."

Understanding the subtle kinematic and acoustic differences in speech production, even in perceived fluent speech, is crucial for developing more effective communication aids and therapeutic interventions. This research highlights how cognitive-emotional factors can significantly influence speech motor control, impacting variability and predictability.

What This Means for Your Design

This study found that people who stutter have more inconsistent speech movements, especially when talking about complex things or when people are watching them. Their lip movements are also more predictable. Stress makes their speech less varied on the surface but more rigid.

How to use in your project

1.This research can inform the design of user interfaces that are sensitive to user stress or cognitive load, particularly in assistive technology projects.

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Quick Cite

Paragraph starter

This research indicates that individuals with speech differences, such as stuttering, exhibit heightened speech variability and deterministic motor patterns, particularly under conditions of increased linguistic complexity and cognitive-emotional stress. These findings suggest that design interventions aimed at supporting communication should account for these dynamic variations in motor control and the potential impact of user stress.

Source

CUNY Academic Works (City University of New York)

Variability, Stability, and Flexibility in the Speech Kinematics and Acoustics of Adults Who Do and Do Not Stutter

journal · 2015

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Questions About This Research

What does the research say about increased speech variability in stuttering adults linked to deterministic lip dynamics under cognitive-emotional stress?: When designing for individuals with speech differences, account for increased variability and deterministic patterns in articulation, particularly under stressful conditions, and explore how technology can support motor flexibility. Evidence: CUNY Academic Works (City University of New York) (2015).
Why does "Increased speech variability in stuttering adults linked to deterministic lip dynamics under cognitive-emotional stress" matter for design?: Understanding the subtle kinematic and acoustic differences in speech production, even in perceived fluent speech, is crucial for developing more effective communication aids and therapeutic interventions. This research highlights how cognitive-emotional factors can significantly influence speech motor control, impacting variability and predictability.
How can designers apply this research?: When designing for individuals with speech differences, account for increased variability and deterministic patterns in articulation, particularly under stressful conditions, and explore how technology can support motor flexibility.
What were the main findings?: Adults who stutter exhibit greater effector variability than adults who do not stutter when target utterances are embedded in sentences of increased linguistic complexity.. Linear acoustic measures are as effective as linear kinematic measures for quantifying speech variability.. Adults who stutter exhibit more deterministic structure in lip aperture dynamics.. The presence of an audience (cognitive-emotional stress) resulted in decreased surface variability and increased deterministic structure in speech.
What research method was used?: Experimental research employing both linear and nonlinear analysis techniques on speech kinematics and acoustics. with 31 participants (20 who stutter, 21 who do not stutter) in the primary experiment..
How strong is the evidence?: Evidence strength is rated Strong effect, based on a 2015 journal from CUNY Academic Works (City University of New York).
What should I do differently in my next project?: In designing communication interfaces or therapeutic tools for individuals with speech disorders, consider incorporating adaptive features that can adjust to varying levels of speech variability and stress.
What are the limitations?: The study focused on specific kinematic measures (lip aperture) and may not generalize to all aspects of speech production. The 'audience' manipulation was a proxy for cognitive-emotional stress and may not fully replicate real-world social anxieties.