Cara Stepp

Cara Stepp
Boston University | BU · Department of Speech, Language and Hearing Sciences

Ph.D.

About

155
Publications
26,177
Reads
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2,102
Citations
Citations since 2016
87 Research Items
1666 Citations
20162017201820192020202120220100200300400
20162017201820192020202120220100200300400
20162017201820192020202120220100200300400
20162017201820192020202120220100200300400
Additional affiliations
July 2011 - present
September 2009 - August 2011
September 2004 - August 2009
Massachusetts Institute of Technology
Education
September 2004 - August 2009
Harvard-MIT Division of Health Sciences and Technology
Field of study
  • Biomedical Engineering
September 2004 - August 2008
Massachusetts Institute of Technology
Field of study
  • Electrical Engineering and Computer Science
September 2000 - May 2004
Smith College
Field of study
  • Engineering Science

Publications

Publications (155)
Article
Full-text available
Fundamental frequency patterns during phonation onset have received renewed interest due to their promising application in objective classification of normal and pathological voices. However, the associated underlying mechanisms producing the wide array of patterns observed in different phonetic contexts are not yet fully understood. Herein, we emp...
Article
Objectives Relative fundamental frequency (RFF) is an acoustic measure of changes in fundamental frequency during voicing transitions. The physiological mechanisms underlying RFF remain unclear. Recent modeling suggests that changes in RFF during voicing offset are due to decreases in overall system stiffness as a direct result of the cessation of...
Article
Objectives Differential diagnosis for adductor laryngeal dystonia (AdLD) is often carried out by comparing symptom expression during sentences with either all voiced or voiced and voiceless consonants. However, empirical research examining the effects of phonetic context on symptoms is sparse. The purpose of this study was to examine whether sympto...
Article
Objective Currently, no clinically feasible objective measures exist that are specific to the signs of adductor laryngeal dystonia (LD), deterring effective diagnosis and treatment. This project sought to establish concurrent validity of a new automated acoustic outcome measure, designed to be specific to adductor laryngeal dystonia (AdLD): the spe...
Article
Purpose This exploratory study aims to investigate variations in voice production in the presence of background noise (Lombard effect) in individuals with nonphonotraumatic vocal hyperfunction (NPVH) and individuals with typical voices using acoustic, aerodynamic, and vocal fold vibratory measures of phonatory function. Method Nineteen participant...
Article
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Purpose Speech production is a complex motor task involving multiple subsystems. The relationships between these subsystems need to be comprehensively investigated to understand the underlying mechanisms of speech production. The goal of this paper is to examine the differential contributions of 1) auditory and somatosensory feedback control mechan...
Article
Purpose The goal of this study was to use speech resynthesis to investigate the effects of changes to individual acoustic features on speech-based gender perception of transmasculine voice samples following the onset of hormone replacement therapy (HRT) with exogenous testosterone. We hypothesized that mean fundamental frequency ( f o ) would have...
Article
Full-text available
Many voice disorders are the result of intricate neural and/or biomechanical impairments that are poorly understood. The limited knowledge of their etiological and pathophysiological mechanisms hampers effective clinical management. Behavioral studies have been used concurrently with computational models to better understand typical and pathologica...
Article
Purpose The purpose of this study was to measure the short-term effects of circumlaryngeal massage and laryngeal reposturing on acoustic and perceptual characteristics of voice in transmasculine individuals. Method Fifteen transmasculine individuals underwent one session of sequential circumlaryngeal massage and laryngeal reposturing with a speech...
Article
Purpose This study reports on two experiments to examine vocal fold abduction and its relationship with relative fundamental frequency (RFF), considering two attributes that have been shown to elicit group differences in RFF: age (Experiment 1) and Parkinson's disease (PD; Experiment 2). Methods For both experiments, simultaneous acoustic and nase...
Article
Purpose The goal of this review article is to provide a summary of the progression of altered auditory feedback (AAF) as a method to understand the pathophysiology of voice disorders. This review article focuses on populations with voice disorders that have thus far been studied using AAF, including individuals with Parkinson's disease, cerebellar...
Article
Purpose This study examined the discriminative ability of acoustic indices of vocal hyperfunction combining smoothed cepstral peak prominence (CPPS) and relative fundamental frequency (RFF). Method Demographic, CPPS, and RFF parameters were entered into logistic regression models trained on two 1:1 case–control groups: individuals with and without...
Article
Purpose Auditory feedback is thought to contribute to the online control of speech production. Yet, the standard method of estimating auditory feedback control (i.e., reflexive responses to auditory–motor perturbations), although sound, requires specialized instrumentation, meticulous calibration, unnatural tasks, and specific acoustic environments...
Article
Full-text available
Purpose: The goal of this study was to examine the effects of increases in vocal effort, without changing speech intensity, on respiratory and articulatory kinematics in young adults with typical voices. Method: A total of 10 participants completed a reading task under three speaking conditions: baseline, mild vocal effort, and maximum vocal effort...
Article
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Purpose Unexpected and sustained manipulations of auditory feedback during speech production result in “reflexive” and “adaptive” responses, which can shed light on feedback and feedforward auditory-motor control processes, respectively. Persons with Parkinson's disease (PwPD) have shown aberrant reflexive and adaptive responses, but responses appe...
Article
Objective Relative fundamental frequency (RFF) has been investigated as an acoustic measure to assess for changes in laryngeal tension. This study aimed to assess RFF in individuals with globus syndrome, individuals with muscle tension dysphagia (MTDg), and individuals with typical voices. Methods RFF values were calculated from the speech acousti...
Article
Purpose This study assessed the reliability and accuracy of auditory-perceptual voice evaluations by experienced clinicians via telepractice platforms. Method Voice samples from 20 individuals were recorded after transmission via telepractice platforms. Twenty experienced clinicians (10 speech-language pathologists, 10 laryngologists) evaluated th...
Article
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Hyperfunctional voice disorders (HVDs) are the most common class of voice disorders, consisting of diagnoses such as vocal fold nodules and muscle tension dysphonia. These speech production disorders result in effort, fatigue, pain, and even complete loss of voice. The mechanisms underlying HVDs are largely unknown. Here, the auditory-motor control...
Article
Full-text available
Purpose Telepractice improves patient access to clinical care for voice disorders. Acoustic assessment has the potential to provide critical, objective information during telepractice, yet its validity via telepractice is currently unknown. The current study investigated the accuracy of acoustic measures of voice in a variety of telepractice platfo...
Article
Relative fundamental frequency (RFF) is a promising assessment technique for vocal pathologies. Herein, we explore the underlying laryngeal factors dictating RFF behaviours during phonation offset. To gain physical insights, we analyze a simple impact oscillator model and follow that with a numerical study using the well-established body-cover mode...
Article
Purpose Society has become increasingly dependent on telecommunication, which has been shown to negatively impact vocal function. This study explores the use of sidetone regulation during audio-visual communication as one potential technique to alleviate the effects of telecommunication on the voice. Method The speech acoustics of 18 participants...
Article
Purpose The reliability of auditory-perceptual judgments between listeners is a long-standing problem in the assessment of voice disorders. The purpose of this study was to determine whether a relatively novel experimental scaling method, called visual sort and rate (VSR), yielded stronger reliability than the more frequently used method of visual...
Article
Methods for automating relative fundamental frequency (RFF)-an acoustic estimate of laryngeal tension-rely on manual identification of voiced/unvoiced boundaries from acoustic signals. This study determined the effect of incorporating features derived from vocal fold vibratory transitions for acoustic boundary detection. Simultaneous microphone and...
Article
Purpose Prior work suggests that voice onset time (VOT) may be impacted by laryngeal tension: VOT means decrease when individuals with typical voices increase their fundamental frequency ( f o ) and VOT variability is increased in individuals with vocal hyperfunction, a voice disorder characterized by increased laryngeal tension. This study further...
Article
The acoustic measure, relative fundamental frequency (RFF), has been proposed as an objective metric for assessing vocal hyperfunction; however, its underlying physiological mechanisms have not yet been fully characterized. This study aimed to characterize the relationship between RFF and vocal fold kinematics. Simultaneous acoustic and high-speed...
Article
Full-text available
Purpose The purpose of this study was to determine the effect of cognitive load on relative fundamental frequency (RFF) in individuals with healthy voices. Method Twenty adults with healthy voices read sentences under different cognitive load conditions. Each sentence contained color terms printed in colored ink, creating an embedded Stroop task....
Article
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Voice is one of the most noticeably dimorphic traits in humans and plays a central role in gender presentation. Transgender males seeking to align internal identity and external gender expression frequently undergo testosterone (T) therapy to masculinize their voices and other traits. We aimed to determine the importance of changes in vocal masculi...
Article
Speech nasalization is achieved primarily through the opening and closing of the velopharyngeal port. However, the resultant acoustic features can also be influenced by tongue configuration. Although vowel nasalization is not contrastive in English, two previous studies have found possible differences in the oral articulation of nasal and oral vowe...
Article
Objectives/Hypothesis The purpose of this study was to determine the relationships among cognitive loading, autonomic arousal, and acoustic measures of voice in healthy older adults. Study Design Prospective and observational. Methods Twelve healthy older adults (six females) produced a sentence containing an embedded Stroop task in each of two c...
Article
Purpose Assessment of strained voice quality is difficult due to the weak reliability of auditory-perceptual evaluation and lack of strong acoustic correlates. This study evaluated the contributions of relative fundamental frequency (RFF) and mid-to-high frequency noise to the perception of strain. Method Stimuli were created using recordings of s...
Article
Full-text available
Purpose The purpose of this study was to explore the relationship between feedback and feedforward control of articulation and voice by measuring reflexive and adaptive responses to first formant ( F 1 ) and fundamental frequency ( f o ) perturbations. In addition, perception of F 1 and f o perturbation was estimated using passive (listening) and a...
Article
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Purpose The purpose of this viewpoint article is to facilitate research on vocal hyperfunction (VH). VH is implicated in the most commonly occurring types of voice disorders, but there remains a pressing need to increase our understanding of the etiological and pathophysiological mechanisms associated with VH to improve the prevention, diagnosis, a...
Article
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Objectives/hypothesis: Interaction with voice recognition systems, such as Siri™ and Alexa™, is an increasingly important part of everyday life. Patients with voice disorders may have difficulty with this technology, leading to frustration and reduction in quality of life. This study evaluates the ability of common voice recognition systems to tra...
Article
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Purpose Given the role of auditory perception in voice production, studies have investigated whether impairments in auditory perception may underlie the noted disruptions in speech in Parkinson's disease (PD). Studies of loudness perception in PD show impairments in the perception of self-generated speech, but not external tones. Studies of pitch p...
Article
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Purpose Communicating remotely using audio and audiovisual technology is ubiquitous in modern work and social environments. Remote communication is increasing in medicine and in voice therapy delivery, and this evolution may have an impact on speakers' voices. This study sought to determine whether these communication modalities impact the voice pr...
Article
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Purpose Gradual and sudden perturbations of vocal fundamental frequency (fo), also known as adaptive and reflexive fo perturbations, are techniques to study the influence of auditory feedback on voice fo control mechanisms. Previous vocal fo perturbations have incorporated varied setup-specific feedback delays and amplifications. Here, we investi...
Article
Full-text available
Purpose This study is a secondary analysis of existing data. The goal of the study was to construct an acoustic model of perceived overall severity of dysphonia in adductory laryngeal dystonia (AdLD). We predicted that acoustic measures (a) related to voice and pitch breaks and (b) related to vocal effort would form the primary elements of a model...
Article
Full-text available
Objective Relative fundamental frequency (RFF) has been suggested as a potential acoustic measure of vocal effort. However, current clinical standards for RFF measures require time-consuming manual markings. Previous semi-automated algorithms have been developed to calculate RFF from microphone signals. The current study aimed to develop fully auto...
Article
Purpose To better define the contributions of somatosensory and auditory feedback in vocal motor control, a laryngeal perturbation experiment was conducted with and without masking of auditory feedback. Method Eighteen native speakers of English produced a sustained vowel while their larynx was physically and externally displaced on a subset of tr...
Article
Full-text available
The purpose of this study is to investigate the effects of different cursor click modalities in an alternative computer access device using accelerometry from head tilt to control cursor movement. Eighteen healthy adults performed a target acquisition task using the device with five different cursor click modalities, while maintaining cursor moveme...
Article
Purpose The goal of this study was to explore the relationships among vocal effort, extrinsic laryngeal muscle activity, and vocal tract length (VTL) within healthy speakers. We hypothesized that increased vocal effort would result in increased suprahyoid muscle activation and decreased VTL, as previously observed in individuals with vocal hyperfun...
Article
Full-text available
This study evaluated the performance of two alternate computer access methods that could be used for two-dimensional cursor control. The first method, ACC/sEMG, integrates head acceleration and facial surface electromyography. The second method, Camera Mouse, is a free-to-use, computer vision-based access method. Twenty-four healthy adults performe...
Article
Full-text available
The purpose of this study was to examine the relationships between vocal pitch discrimination abilities and vocal responses to auditory pitch-shifts. Twenty children (6.6–11.7 years) and twenty adults (18–28 years) completed a listening task to determine auditory discrimination abilities to vocal fundamental frequency (fo) as well as two vocalizati...
Article
Full-text available
Objective An important clinical outcome of voice masculinization treatments in transmasculine speakers is voice-based perception of gender. Rigorous assessments of voice treatment that utilize ratings of perception of gender typically do not control for demographic characteristics of the listeners. The objective of the present study was to determin...
Article
Full-text available
Purpose Relative fundamental frequency (RFF) is an acoustic measure that is sensitive to functional voice differences in adults. The aim of the current study was to evaluate RFF in children, as there are known structural and functional differences between the pediatric and adult vocal mechanisms. Method RFF was analyzed in 28 children with vocal f...
Article
Full-text available
Purpose This study examined vocal hyperfunction (VH) using voice onset time (VOT). We hypothesized that speakers with VH would produce shorter VOTs, indicating increased laryngeal tension, and more variable VOTs, indicating disordered vocal motor control. Method We enrolled 32 adult women with VH (aged 20–74 years) and 32 age- and sex-matched cont...
Article
Relative fundamental frequency (RFF) is a promising acoustic measure for evaluating voice disorders. Yet, the accuracy of the current RFF algorithm varies across a broad range of vocal signals. The authors investigated how fundamental frequency (f o) estimation and sample characteristics impact the relationship between manual and semi-automated RFF...
Article
Full-text available
Purpose Individuals with Parkinson disease (PD) present with complex and variable symptoms, with recent findings suggesting that the etiology of PD extends beyond the involvement of just the basal ganglia. These symptoms include significant impairments in the speech and swallowing domains, which can greatly affect quality of life and therefore requ...
Article
Full-text available
Purpose Previous studies of speech articulation have shown that individuals who can perceive smaller differences between similar-sounding phonemes showed larger contrasts in their productions of those phonemes. Here, a similar relationship was examined between the perception and production of breathy voice quality. Method Twenty females with healt...
Article
Full-text available
Vocal pitch discrimination abilities were compared in sixteen children with vocal fold nodules (CwVN) and sixteen matched controls with typical voices (CwTV). Vocal pitch discrimination was also evaluated in thirty-five vocally healthy children and twenty adults to examine potential changes as a function of maturation. CwTV were categorized as eith...
Article
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Purpose We empirically assessed the results of computational optimization and prediction in communication interfaces that were designed to allow individuals with severe motor speech disorders to select phonemes and generate speech output. Method Interface layouts were either random or optimized, in which phoneme targets that were likely to be sele...
Article
Purpose This study investigated how modulating fundamental frequency (f0) and speech rate differentially impact the naturalness, intelligibility, and communication efficiency of synthetic speech. Method Sixteen sentences of varying prosodic content were developed via a speech synthesizer. The f0 contour and speech rate of these sentences were alte...
Article
Full-text available
Purpose While orthographic transcription (OT) is the gold standard for measures of intelligibility, it is relatively inaccessible to clinicians. This study investigates the relationship between visual analog scale (VAS) ratings and OT measures of intelligibility for speakers with Parkinson's disease (PD), with the eventual goal of developing more c...
Article
Purpose This study details the intended and unintended consequences of pitch shifting with the commercially available Eventide Eclipse. Method Ten vocally healthy participants ( M = 22.0 years; 6 cisgender females, 4 cisgender males) produced a sustained /ɑ/, creating an input signal. This input signal was processed in near real time by the Eventi...
Article
Objective Prephonatory vocal fold angle trajectories may supply useful information about the laryngeal system but were examined in previous studies using sigmoidal curves fit to data collected at 30 frames per second (fps). Here, high-speed videoendoscopy (HSV) was used to investigate the impacts of video frame rate and sigmoidal fitting strategy o...
Article
Full-text available
Purpose Recent studies have shown that an acoustic measure, relative fundamental frequency (RFF), has potential for the assessment of excessive laryngeal tension and vocal effort associated with functional and neurological voice disorders. This study presents an analysis of the test–retest reliability of RFF in individuals with healthy voices and a...
Article
Full-text available
This case study measured the effects of manual laryngeal therapy on the fundamental frequency (fo), formant frequencies, estimated vocal tract length, and listener perception of masculinity of a 32-year-old transmasculine individual. The participant began testosterone therapy 1.5 years prior to the study. Two therapy approaches were administered se...
Article
Purpose This study aimed to examine the relationship between a large set of hypothesized physiological measures of vocal effort and self-ratings of vocal effort. Method Twenty-six healthy adults modulated speech rate and vocal effort during repetitions of the utterance /ifi/, followed by self-perceptual ratings of vocal effort on a visual analog s...
Article
The purpose of this study was to comprehensively evaluate voice and speech changes in one healthy 30-year-old transgender male undergoing testosterone therapy for transition. Testing occurred at three timepoints before cross-sex hormone therapy and every 2 weeks thereafter for 1 year. Data collected included measures of acoustics, aerodynamics, and...
Presentation
Full-text available
As part of a program of research investigating the sensitivity, reliability and efficacy of rating perceived listening effort (PLE) for different and disordered speech, this study compares PLE ratings obtained using visual analog scales (VAS) and equal-appearing interval (EAI) scales. This is the first study to our knowledge to directly compare any...
Article
Excessive vocal effort is a common clinical voice symptom, yet the acoustical manifestation of vocal effort and how that is perceived by speakers and listeners has not been fully elucidated. Here, 26 vocally healthy adults increased vocal effort during the production of the utterance /ifi/, followed by self-ratings of effort on a 100 mm visual anal...
Article
Full-text available
Objective: Relative fundamental frequency (RFF) has been investigated as a possible acoustic measure to assess laryngeal tension. This study aimed to identify possible factors in RFF stimuli (stress type, vowel identity, baseline f0, and loudness) that might also affect RFF values. Methods: Fifteen speakers with healthy voices produced short RFF...
Article
Full-text available
Purpose: Reduced intensity is a hallmark of speech production in Parkinson's disease (PD). Previous work has examined the perception of intensity in PD to explain these speech deficits. This study reports loudness ratings of pure tones by individuals with PD and controls, all with normal thesholds for older adults. Method: Twenty individuals wit...
Article
Full-text available
The laryngeal adductor reflex (LAR) is an airway protective reflex that manifests as a brief vocal fold closure in response to laryngeal stimulation. This study examined if the absence of the LAR in response to touch delivered by a laryngoscope is associated with penetration/aspiration or pneumonia in patients with dysphagia. Inpatients at a teachi...
Article
Full-text available
Objective This study examined adaptive responses to auditory perturbation of fundamental frequency (fo) in speakers with Parkinson’s disease (PD) and control speakers. Method Sixteen speakers with PD and nineteen control speakers produced sustained vowels while they received perturbed auditory feedback (i.e., fo shifted upward or downward). Speake...
Data
Individual speaker data. Individual speaker data by group including sex, age, PD severity, average fundamental frequency, pitch acuity scores, intelligibility scores, compensation magnitudes in cents, baseline variability in cents, and individual trial data for all adaptation conditions. (XLSX)
Article
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Purpose: This study examined the relationship between the magnitude of neck-surface vibration (NSVMag; transduced with an accelerometer) and intraoral estimates of subglottal pressure (P'sg) during variations in vocal effort at 3 intensity levels. Method: Twelve vocally healthy adults produced strings of /pɑ/ syllables in 3 vocal intensity condi...
Conference Paper
Full-text available
In this paper, optimized communication interfaces in which users select phonemes (sounds) instead of letters or whole words are presented and evaluated. Optimization is based on phoneme transition likelihoods (i.e., the probability of transitioning from one phoneme to another in a particular communication corpus), similar to letter-to-letter transi...
Article
Objective: The purpose of this study was to examine whether changes in respiratory patterns occurred in response to volitional changes in glottal configuration. Methods: Twelve vocally healthy participants read a passage while wearing the Inductotrace respiratory inductive plethysmograph, which measures the excursions of the rib cage and abdomen...
Article
Full-text available
Objectives: Relative fundamental frequency (RFF) has shown promise as an acoustic measure of voice, but the subjective and time-consuming nature of its manual estimation has made clinical translation infeasible. Here, a faster, more objective algorithm for RFF estimation is evaluated in a large and diverse sample of individuals with and without vo...
Article
Purpose: Clinicians often test laryngeal sensation by touching the laryngeal mucosa with the tip of a flexible laryngoscope. However, the pressure applied to the larynx by using this touch method is unknown, and the expected responses elicited by this method are uncertain. The variability in pressure delivered by clinicians using the touch method...