Patterns of respiratory coordination in children who stutter during conversation

Transcription

1 University of Iowa Iowa Research Online Theses and Dissertations Spring 2014 Patterns of respiratory coordination in children who stutter during conversation Danielle Rae Werle University of Iowa Copyright 2014 Danielle Werle This thesis is available at Iowa Research Online: Recommended Citation Werle, Danielle Rae. "Patterns of respiratory coordination in children who stutter during conversation." MA (Master of Arts) thesis, University of Iowa, Follow this and additional works at: Part of the Speech Pathology and Audiology Commons

2 PATTERNS OF RESPIRATORY COORDINATION IN CHILDREN WHO STUTTER DURING CONVERSATION by Danielle Rae Werle A thesis submitted in partial fulfillment of the requirements for the Master of Arts degree in Speech Pathology and Audiology in the Graduate College of The University of Iowa May 2014 Thesis Supervisor: Professor Jerald Moon

3 Graduate College The University of Iowa Iowa City, Iowa CERTIFICATE OF APPROVAL MASTER S THESIS This is to certify that the Master s thesis of Danielle Rae Werle has been approved by the Examining Committee for the thesis requirement for the Master of Arts degree in Speech Pathology and Audiology at the May 2014 graduation Thesis Committee: Jerald Moon, Thesis Supervisor Melissa Duff Patricia Zebrowski

4 ACKNOWLEDGEMENTS Thank you to my advisor, committee, family, and friends who guided this project to completion with the utmost patience. ii

5 TABLE OF CONTENTS LIST OF FIGURES... v CHAPTER I. REVIEW OF THE LITERATURE... 1 CHAPTER II. METHODS CHAPTER Participants Recordings Procedures Condition 1: Reading Condition 2: Monologue Condition 3: Non-verbal conversational turn Condition 4: Fixed conversation Condition 5: Spontaneous conversation Measurements Analysis Inclusion Criteria Respiratory durations Correlation analysis III. RESULTS CHAPTER Rest versus Listening versus Speech Breathing Rest versus Turn versus Speech Breathing Listening Breathing versus Preparatory Breathing Temporal Correspondence Non-verbal conversational turn Scripted conversation Spontaneous conversation Increasing conversational complexity Temporal Correspondence and Fluency IV. DISCUSSION Study Limitations REFERENCES iii

6 LIST OF TABLES 1. Percentage of significant correlations which occurred +/- 2 seconds around a turn change during a Non-verbal Turn for CWS and CWNS Percentage of significant correlations which occurred +/- 3 seconds surrounding a turn change in Scripted Conversation for CWS and CWNS as well as adults (+/- 5 seconds) from McFarland (2001) Percentage of Within -Turn Entrainment for CWS during Scripted Conversation in percentage of Fluent versus Disfluent Turns. Note that Subject D6 had no Disfluent Turns iv

7 LIST OF FIGURES 1. Respitrace waveforms in Windaq from Subject D3 in Condition 1 illustrating the difference in the patterns Rest Breathing and Speech Breathing Respitrace waveforms in Windaq depict Listening, Preparatory, and Turn Breathing in Subject D3 (Condition 3) Respitrace waveforms depicting Subject C1 holding his/her breath throughout his/her partner s turn. Shaded lines denote turn boundaries Average respiratory durations of Rest Breathing (Condition 1) and Speech Breathing (Condition 4) Inhalation durations for Rest Breathing (Condition 1), Listening Breathing (Conditions 3, 4, 5) and Speech Breathing (Conditions 4, 5) Inhalation durations of Rest Breathing (Condition 1), Listening Breathing (Conditions 3, 4), Turn Breathing (Condition 3), and Speech Breathing (Condition 4) to determine if Turn Breathing is a unique respiratory pattern Respiratory durations of Listening Breathing (inhalations and exhalations) compared with Preparatory Breaths (Conditions 3, 4) Inhalation durations of Speech Breathing (Conditions 4, 5) compared with the First Breath of a turn Overall Entrainment compared with Within Turn Entrainment across Conditions 3, 4, and v

8 1 CHAPTER I REVIEW OF THE LITERATURE In everyday conversation, individuals coordinate multiple subsystems to produce speech. The respiratory system must provide sufficient power to support the vocal folds as they vibrate at specific frequencies. The phonatory system must adequately coordinate the abduction and adduction of the vocal folds to provide not only a glottal sound source for speech, but also appropriate prosody and pitch alterations. The articulatory system must produce rapid and precise movements of various structures to form intelligible, connected speech sounds. Through complex integration of these three systems, an acoustic signal perceived by listeners as fluent is produced. Fluent speech may be characterized by temporal control over factors such as rhythm, intonation, stress, rate, and pauses in conjunction with an effortless feel (Guitar, 2006). For people who stutter (PWS), speech is often characterized as disfluent. Vocal productions of PWS may contain repetitions or prolongations of sounds, syllables, or whole words, or involuntary silent blocks. An extremely heterogeneous disorder, researchers have investigated each of the subsystems of speech in an effort to identify underlying behaviors and mechanisms of stuttering. Many studies have especially focused on the isolated movement of articulators (Hutchinson, & Watkin, 1976; McClean, 1996; Zimmermann, 1980), the laryngeal system (Arenas, Zebrowski, & Moon, 2012; Conture, Schwartz, & Brewer, 1985; Smith, Denny, Shaffer, Kelly, & Hirano, 1996), and respiratory system (Baken, MacManus, & Covello, 1983; Denny & Smith, 2000; Johnston, Watkin, & Macklem, 1993) during both fluent and nonfluent utterances. While this has been necessary research in terms of understanding how each system may contribute individually to fluent and disfluent speech, these systems do not function autonomously. Speech requires precise coordination between respiration, phonation, and articulation. More recent research has delved into the interaction of and coordination between these systems in both fluent and non-fluent populations.

9 2 Phonation for speech requires a coordinated interaction between the respiratory and phonatory (laryngeal) systems. The respiratory system must provide an expiratory airstream of sufficient pressure to drive laryngeal vocal fold vibration. The musculature of the laryngeal system must contract with sufficient magnitude and in the correct timeframe to position the vocal folds appropriately in order to initiate vocal fold vibration. Coordination between the respiratory and phonatory systems, especially during the timeframe just prior to the initiation of vocal fold vibration by normal speakers, has not been extensively studied. The same is true with respect to such coordination in the speech of individuals who stutter. The importance of coordinated activity of the respiratory and phonatory systems has, however, been highlighted by those who have conducted investigations in this area. For example, Adams (1974) suggested that the muscles and forces that promote control, and coordinate subglottic pressure, glottal resistance, and supraglottal pressure are the major determinants of both fluency and stuttering. Adams stated further, that discoordination of these components (i.e. between the respiratory and phonatory systems) would have a deleterious effect on smoothly produced speech. Perkins, Rudas, Johnson, and Bell (1976) discussed discoordination of the subsystems of speech as the event of stuttering, rather than a causal factor. The authors analyzed disfluency as they systematically decreased the coordinative demands of speech. Specifically, they decreased the demands on the phonatory system. Thirty participants who stuttered were asked to read under three speaking conditions: reading aloud, whispering, and articulating without phonation, or mouthing. The progression of conditions was designed to systematically remove an aspect of speech coordination, such as subglottic pressure generation and adductory/abductory vocal fold movement. Of the 30 participants, 27 were less disfluent in the whispering than voiced condition, and all showed a further reduction of disfluency from the whispering to mouthed condition. Furthermore, 17 of the 30 produced no disfluencies at all in the mouthed condition. Given the effect that this progression had over disfluency and the fact that phonatory demands

10 3 were the sole independent variable, a causal relationship between coordinative demands and disfluency is plausible. Though the authors chose to analyze the effect of coordinative demands on the phonatory system, they discussed that a mistiming or discoordination in any subsystem of speech, such as respiration, could result in disfluency. According to Baken, McManus, and Cavallo (1983), phonation normally occurs following an inhalation of sufficient magnitude to meet the demands of the impending speech task. Baken et al. refer to a pre-phonatory posturing as a preparatory act of the respiratory system. This posturing is thought to set the biomechanical properties of the chest wall in such a way so as to optimize the respiratory system for the upcoming phonatory event. Specifically, inward abdominal wall movement accompanied by rib cage expansion is thought to maximize respiratory system efficiency as a pressurized air source for vocal fold vibration (Baken et al., 1979). Baken et al. (1983) analyzed pre-phonatory chest wall posturing in normal speakers and adult speakers who stutter (PWS) to assess potential differences between these groups with respect to pre-phonatory chest wall posturing patterns. As the authors noted, in normal conversation, pre-phonatory movements are likely to occur in the prephonatory inspiratory phase of respiration allowing supported phonation to occur immediately following inhalation. During their study, Baken et al. (1983) asked participants to produce /a/ immediately after being prompted by a tone presented in their left ear. The participants were prompted at varied points during the respiratory cycle. In their analysis of five PWS, the authors noticed the primary difference between the experimental and control groups to be the change in lung volume following stimulus presentation. While the control group s lung volume changed in conformity with the respiratory phase already in progress when the stimulus was presented (for example, lung volume increased during inspiratory phase presentation), the PWS s lung volume almost always decreased immediately before phonating regardless of when the stimulus was presented. Baken et al. attributed this difference to an inability to efficiently prepare the

11 4 larynx, and specifically generate subglottal pressure, rather than a difference in respiratory preparation for speech. The authors suggest that differential lung volumes reflect compensatory rib cage muscle use in an attempt to generate sufficient subglottal pressure. However, this data was not analyzed, as the focus of the study was pre-phonatory chest wall posturing. The authors found no differences in posturing between PWS and the normal controls prior to the fluent production of isolated vowels. Baken et al. (1983) did not, however, assess chest wall posturing prior to disfluent productions. Still, they concluded, stutterers do not suffer a primary disorder that results in disorganization of the posturing of the walls of the ventilatory system for fluent phonation. Others however, have noted differences in the breathing patterns of PWS compared to controls as well as differences between fluent and disfluent productions of the same PWS. Observed differences tend to center on the control of subglottal pressure, reflective of a temporal discoordination between the respiratory and phonatory systems. Zocchi, Estenne, Johnston, del Ferro, Ward, and Macklem (1989) found in their study of ten PWS and five normal controls, that all five controls maintained constant subglottal pressure during conversational speech. The PWS, on the other hand, either spoke at excessively high or excessively low levels of subglottal pressure during disfluent productions of speech. Zocchi et al. discussed the correlation between abnormal subglottal pressure and an incoordination of respiratory muscles, citing that either excessive or reduced contraction of the expiratory muscles and/or the inspiratory rib cage muscles may contribute to abnormal control. Peter and Boves (1988) found similar results in their analysis of fluent productions of ten PWS and seven normal controls. The authors measured voice onset, amplitude and duration, and subglottal pressure for the fluent productions of 80 single word stimuli of varying lengths. The most statistically significant result related to subglottal pressure was that PWS exhibited several deviant types of subglottal pressure buildup compared to the normal controls consistent pressure throughout the experiment. Additionally, the authors pointed out that the criterion selected

12 5 to characterize fluent speech was very strict; and though there were definite variations in the types of subglottal pressure generated by the PWS, they all produced fluent productions (Peter & Boves, 1988). The two previous studies have discussed the respiratory differences seen in PWS during disfluent conversational speech, and fluent single word productions. Johnston, Watkin, and Macklem (1993) described the breathing patterns of four PWS during fluent scripted and conversational speech. They analyzed both lung volume changes and control over subglottal pressure during fluent speech. Johnston et al. (1993) found that while the participants maintained relatively good control over subglottal pressure, it was still less controlled than normal speakers. They also found that during fluent speech, PWS spoke at either consistently higher or consistently lower lung volumes than normal speakers. Those who spoke at unusually high lung volumes utilized their diaphragm to provide inspiratory breaking, and those who spoke at low volumes used their abdominal muscles. This is in contrast to normal speakers who utilize their rib cage muscles to provide inspiratory breaking. The authors also asserted however, that there does not appear to be any evidence that stutterers during silence are different in their breathing patterns than normal subjects (Johnston et al., 1993, p. 1). The results of these studies concerning subglottal pressure in PWS outline the similarities and differences seen in the respiratory patterns of PWS compared to both normal controls and across fluent and non-fluent productions. Incoordination of respiratory muscles leads to differences in lung volumes and thus subglottal pressure compared to normal controls. It appears as though those differences in subglottal pressure may be more controlled, though deviant, in fluent speech (Peter & Boves, 1989; Johnston et al. 1993) and significantly aberrant during disfluent speech (Zocchi et al., 1989). However, these studies were performed in a solitary artificial environment. That is, the individuals studied were not engaged in a typical conversational exchange with another person. According to McFarland (2001), during silent breathing in conversation,

13 6 normal speakers exhibit respiratory entrainment with their communication partner just before their turn. In other words, during pre-phonatory breathing in conversation, normal speakers tend to synchronize their chest wall movements with the person with whom they are talking. In this study, ten conversation dyads respiratory movements were measured during quiet breathing, reading aloud, spontaneous monologue, scripted dialog, and spontaneous conversation. Specifically, movements of the rib cage and abdomen were used to analyze the breathing patterns of each participant. McFarland found inspiratory breathing to be the most sensitive determining characteristic of speech breathing versus rest breathing. While there was variability amongst the respiratory patterns of each participant, speech breathing was characterized by shortened inspiratory durations across participants. Inspiratory durations were observed to decrease while listening in conversation compared to quiet breathing, more closely approximating values seen during speech production. Further, expiratory durations were observed to increase before the onset of a turn taking, suggested by McFarland to reflect the establishment of a preparatory set for speech production. McFarland described how this synchronization, or entrainment, also indicates that, speech production processes must be closely linked at these key moments to facilitate the dynamic interchanges between listeners and speakers (McFarland, 2001, p ). In other words, respiratory entrainment amongst conversation partners may in fact facilitate conversational, or communicative, success. Entrainment and its consequences have also been described in both sociolinguistic and physiologic domains of conversation. Often, it is discussed in the context of the communication accommodation theory (CAT; Giles, Mulac, Bradac, & Johnson, 1987). This theory proposes that individuals change a number of nonverbal and nonlinguistic behaviors to converge and accommodate to their conversation partner and reflects a societal need for integration and identification (Giles, Coupland, & Coupland, 1991). Convergence and accommodation are defined, respectively, as a strategy whereby individuals adapt to each other s communicative behaviors in terms of a wide range of

14 7 linguistic/prosodic/non-verbal features (Giles & Coupland, 1991, p. 63) and the general sense of adjusting our communication actions relative to those of our conversation partners (p.60). These definitions parallel McFarland s (2001) observations of synchronous, entrained chest wall movements amongst conversation partners and will thus be discussed synonymously with the terms entrainment and synchronization. Evidence of convergence and accommodation has been documented in several aspects of conversation such as language (Giles, Taylor, & Bourhis, 1973), speech rates (Webb, 1970), and pause and utterance duration (Jaffe & Feldstein, 1970; Matarazzo, 1973). Additionally, some conversational elements have been attributed to less linguistic and more social attributes such as attractiveness (Berry, 1990, 1992; Natale, 1975a, 1975b; Zuckerman & Driver, 1989; Zuckerman, Hodgins, & Miyake, 1990; Zuckerman & Miyake, 1993), and emotions (Burns & Beier, 1973; Helfrich & Wallbott, 1986; Trimboli & Walker, 1987). There is some evidence that communicative accommodation also occurs at the physiologic level. Aside from McFarland s observation of entrainment at the level of chest wall movement, research has shown that conversation partners exhibit accommodation at the level of the larynx by matching fundamental frequency of their voices during conversation (Gregory & Webster, 1996). Gregory et al. (1997) aimed to find the functional, or social, implications of such accommodation. In their two part study, the authors set out to show first the active accommodation to fundamental frequency by conversation partners, and second the negative social perception of conversations which lack the accommodation. In their evaluation of filtered and unfiltered conversations between 30 conversation dyads, the authors found that during filtered conversations, in which the fundamental frequency was removed before it was presented to each listener, participants showed much less spectral accommodation. Likewise, partners actively accommodated to their partner s fundamental frequency when presented with unfiltered, or full spectrum, conversation. The authors then played the conversation recordings to

15 8 separate participants who served as judges on social aspects of the recordings. Gregory et al. found the outside judges consistently rated the unfiltered conversations, which exhibited spectral accommodation, higher in terms of positivity of the conversation (e.g. more happy, friendly, sociable, pleasant, etc.). These results indicate that individuals accommodate to one another during conversation at least on one physiological level, fundamental frequency. As discussed, conversational accommodation and entrainment occur at several linguistic and nonlinguistic levels. As evidenced by Gregory et al. (1997) and McFarland (2001), entrainment also manifests in some physiologic aspects of conversation. These studies have all addressed entrainment in normal populations. In other words, populations that may be susceptible to conversational breakdowns, such as PWS, have not been analyzed for their level of conversational accommodation. As fluent conversation requires the temporal coordination of several subsystems, and PWS exhibit differences and or difficulties in both respiratory movement and coordination for speech (Perkins et al., 1976; Baken et al., 1983; Zocchi et al., 1989; Johnston et al., 1993; Peter & Boves, 1988), a logical next step is to analyze the presence of respiratory entrainment in PWS and its possible effect on fluency. Furthermore, the current literature on respiratory patterns has largely assessed adults. As the pragmatic skill of conversation is often developed with age and maturity, it is natural to investigate whether respiratory patterns in conversation are affected by speaker age, that is, whether the same preparatory respiratory patterns and entrainment are evident in children. The present study has multiple aims. First, the two respiratory patterns reviewed, preparatory postures and entrainment, will be described in children who do not stutter (CWNS) as well as children who stutter (CWS). Respiratory patterns of CWS will be compared to both CWNS and to the existing literature on patterns of normally developed adults during conversation. Much of the literature on PWS has been conducted in solitary contexts. For individuals and therapists who work with PWS or CWS, more research is

16 9 needed in functional contexts, such as spontaneous conversation. The presence or absence of respiratory entrainment in PWS may suggest a different manifestation of respiratory and phonatory discoordination that may be targeted by therapists such as speech-language pathologists. Given that a normal component of speech initiation in the context of a verbal exchange with a conversational partner appears to involve temporally sensitive adjustments of the respiratory system that involve entrainment of a listener s respiratory patterns to that of his/her conversational partner in preparation for speech initiation at a turn taking moment, one might ask whether PWS differ in this ability compared to normal speakers. The presence or absence of respiratory entrainment in PWS may suggest a new level of breakdown that may be targeted by therapists such as speech-language pathologists. Next, the effect of conversational complexity will be assessed. As Perkins, Rudas, Johnson, and Bell (1976) discussed, PWS are particularly vulnerable to discoordination of speech subsystems. However, Perkins et al. only assessed the effect of increased phonatory demands. The present study will aim to describe the effect of conversational complexity on preparatory respiratory patterns, entrainment, and fluency of CWS. One might also ask whether a relationship exists between this entrainment and the production of fluent versus disfluent speech by PWS. The final aim of this study is to assess this relationship. As previously described, PWS exhibit differences in respiratory physiology; namely the utilization of different respiratory muscles. Additionally, changes in the level of coordinative demands amongst subsystems have shown deleterious effects on fluency in PWS (Perkins et al., 1976). It is logical to question whether if, during an increase in social and respiratory demands, a combination of respiratory differences and difficulties with timing and coordination will result in respiratory discoordination followed by disfluency for PWS; and, similarly, if productions of fluent speech will be preceded by respiratory entrainment.

17 10 CHAPTER II METHODS Participants Participants in the experimental group consisted of one girl and five boys between the ages of 8-13 years (mean age = 10;2) participating in the University of Iowa Summer Program to Educate Adults and Kids who Stutter (UI SPEAKS). Each of the participants was a child who stutters (CWS) and completed the study with a parent as the conversational partner, with the exception of one subject who participated with a familiar adult. All but one of the conversational partners were female. This made for twelve participants and six conversation dyads in the experimental group. The control group of children with no history of speech and/or language deficits (CWNS) consisted of twelve conversation dyads. Seven girls and five boys between the ages of 8 and 13 years (mean age = 9;10) participated with a parent as their conversational partner. Three sets of siblings participated in the study. Instead of having a separate parent participate for each sibling, the same mother/father participated twice with each child individually. Two males and seven females made up the control conversational partner group. Recordings After providing informed consent to participate in this IRB approved study, and prior to completing the experimental tasks, the participants and their partners were connected to separate Respitrace inductive plethysmograph systems (Ambulatory Monitoring, Inc., Ardsley, NY). Chest and abdominal wall movements were transduced using Respitrace bands placed around the thorax just under the axilla and around the abdomen just below the lower rib and above the umbilicus. Conversation pairs were seated in chairs facing one another from a distance of roughly 40 inches, and were instructed to maintain a stable upright posture throughout the experimental session. A Sennheiser (model EW100; Sennheiser Electronic Corp., Old Lym, CT) wireless microphone was placed between the two participants to record both voices. The rib cage,

18 11 abdomen, summed rib cage and abdomen Respitrace signals and microphone signal were digitized using WinDaq data acquisition software (Dataq Instruments, Inc., Akron, OH) using a sampling rate of 5KHz per channel and stored on a PC laboratory computer for later analysis. Procedures Five different conditions were completed during the experimental session. These conditions were designed to elicit four different respiratory patterns: Rest Breathing, Listening Breathing, Turn Breathing, and Speech Breathing. They were also designed to systematically increase in complexity. Prior to the initiation of Condition 1, the subjects were instructed to remain as still as possible and to maintain an upright seated posture throughout the experiment. The output of the Respitrace bands was checked during silent breathing and the subjects were asked to count to five (individually) to check microphone gain level. Condition 1: Reading The first condition was designed to elicit Rest Breathing as well as a baseline measure of Speech Breathing during an individual structured activity. Rest Breathing was defined as inhalations and exhalations produced by the participant during silence, and Speech Breathing was defined as the participant s breathing patterns while speaking. During Condition 1, each child was asked to relax and breathe while silently reading a paragraph of the passage Roly-Poly Pill Bugs by Cynthia Sherwood to elicit Rest Breathing. They were then asked to read another paragraph of the passage aloud to obtain a baseline measure of inhalation and exhalation patterns of Speech Breathing. An exception to this occurred for one participant in the experimental group for whom the reading level was too high. This participant read from a passage he was working on with his clinician during UI SPEAKS. The purpose of Condition 1 was not only to provide baseline Rest Breathing and Speech Breathing measurements, but also to assess whether

19 12 there were significant differences in the production of these patterns between CWS and CWNS. Condition 2: Monologue To obtain Speech Breathing patterns for a semi-structured activity, the child was asked to respond to the question, What would you do with a million dollars? into the microphone. Participants were encouraged to describe at least ten things they would do or buy with the money. Condition 3: Non-verbal conversational turn Condition 3 was designed to elicit Listening Breathing and Turn Breathing. Listening Breathing was defined by inhalations and exhalations produced by a participant during his/her partner s turn. Turn Breathing was defined as a participant s breathing patterns during a non-verbal conversational turn. During Condition 3, the child s conversation partner was asked to read to the child a series of yes or no questions (e.g. I always get a cake on my birthday. Have you ever baked a cake? ). The child was instructed to respond to these questions either with a slight head nod for yes or slight head shake for no. No verbal response was allowed for this condition. Each question was preceded with and introduction or carrier phrase to allow for sufficient data collection of breathing patterns while the participant listened to the partner, as well as during his or her silent conversational turn (head nod/shake). The goal of Condition 3 was to compare Listening Breathing as well as Turn Breathing to Rest and Speech Breathing to assess whether they were distinguished as unique respiratory patterns by CWS and CWNS. Additionally, this condition, as well as Condition 4, provided the opportunity for measurement of breathing patterns as individuals approached conversational turns. This allowed for assessment of whether Listening Breathing more closely resembles Speech Breathing as an individual prepares for a conversational turn.

20 13 Condition 4: Fixed conversation To facilitate a structured conversation with fixed conversational turns, the conversation dyad was assigned roles from the play David the Copperbottom Magician (Snickelfoose, 2008) to read aloud. Measured from this condition were the participants productions of Listening and Speech Breathing. The conversation dyads were instructed not to be concerned with the length of the task or their reading abilities. They were also instructed to look at and listen to their conversation partner when it was not their turn instead of attending to the text. This allowed participants to more actively engage in the conversation, instead of reading ahead to prepare for his or her turn and avoided preemptive preparatory postures or breathing patterns. There was one exception for this condition for the same participant in the experimental group mentioned above in Condition 1. Instead, this participant and conversation partner read from a play created by the participant during UI SPEAKS. The goals of Condition 4 were identical to Condition 3. Additionally, the conversational complexity of Condition 4 was increased from Condition 3 by the addition of a verbal conversational turn (reading aloud). This allowed for analysis of preparatory respiratory patterns and entrainment as social and respiratory demands increased. Condition 5: Spontaneous conversation The dyads were instructed to discuss one of two prompts amongst themselves; You have a week-long vacation to go wherever you would like. Between the two of you, decide where you would go, what activities you would do, and what or who you would bring during that week or You are stranded on a remote island. Together, discuss how you would survive and what or who you would need to do so. This task allowed for data collection of Listening and Speech Breathing, which allowed for analysis similar to Condition 3 and 4, but with the increased social and respiratory demands. With the completion of this task, respiratory entrainment and fluency of CWS could be compared across conditions systematically increasing in coordinative demands

21 14 Measurements All signals were first smoothed (30 Hz low pass) in WinDaq. Inhalatory and exhalatory onsets were then identified and marked and used to calculate inhalation and exhalation durations. Durations were measured primarily using the rib cage signal. However, if the abdominal signal for a participant was clearly dominant, meaning the participant primarily utilized his/her abdomen during respiration, the abdominal signal was measured. In cases of conflict between rib cage and abdominal signals, the more dominant signal was measured. Inhalation and exhalation durations were measured for respiratory cycles during Rest Breathing, Listening Breathing, Speech Breathing, and silent conversational turns (Turn Breathing) A turn was defined as the termination of the acoustic signal of the adult conversational partner. Rest Breathing, breathing during silence, was measured during silent reading in Condition 1 as well as during extended periods of silence in Condition 5 (conversation). Speech Breathing, breathing while a participant was speaking, was measured during conversational turns in Conditions 4 and 5. Rest and Speech Breathing served as baseline respiratory patterns for comparison to Listening and Turn Breathing (Figure 1). Turn Breathing was defined as a participant s inhalations and exhalations during a non-verbal conversational turn. At least one cycle of Turn Breathing and Speech Breathing (one inhalation and one exhalation) was measured for each included turn; more cycles were measured if available. Listening Breathing, breathing measured during a partner s conversational turn, was measured in Conditions 3, 4, and 5. A respiratory cycle was categorized as Listening Breathing if the entire inhalation occurred prior to the turn change. If part or all of an inhalation occurred following the turn change, it was categorized as a Turn or Speech Breath. Respiratory cycles were measured during turns in which the carrier phrase was long enough to allow for at least one respiratory cycle by the child before the end of the turn. This allowed for analysis of a preparatory respiratory

22 15 cycle that could be compared to Rest Breathing. Additional respiratory cycles were measured if available to compare general Listening Breathing to the preparatory respiratory cycle, or Preparatory Breath (Figure 2). Excluded from analysis were turns containing laughter, simultaneous speech, and verbal answers from the child in Condition 3. Breath holding was a frequent occurrence. The individuals who held their breath did it in one of two fashions. Some individuals consistently held their breath (i.e. at the end of every exhalation). More common, however, was the presence of breath holding through a partner s turn (Figure 3). This was observed in every condition and by both children and adults. Analysis of respiratory cycles for this study primarily focused on inspiratory times due to breath holding as well as the great variability in exhalations based upon speaking context. Exhalations were included as able to assess how breathing patterns changed during Listening Breathing as a participant approached a conversational turn. Analysis Inclusion Criteria Participants were included in analysis based upon level of participation and signal quality. Not every participant actively engaged in each condition, disallowing data collection. Additionally, some participants were excluded due to extraneous movements reducing the quality of the signal so that respiratory patterns could not be accurately measured. All six CWS were included in analysis for each condition except Condition 5, which included five. Eleven CWNS were included for Condition 1, ten in Condition 3 for respiratory durations and nine for temporal correspondence, and seven in Conditions 4 and 5. Condition 2 was not utilized for analysis as Speech Breathing from Condition 4 provided more consistent tokens of Speech Breathing. Turn inclusion for analysis was primarily based upon turn length in order to ensure enough respiratory cycles for accurate analysis. For Condition 3, fourteen turns were chosen for analysis based on length of parent turn. This was done in order to collect

23 16 enough cycles to compare Listening Breathing overall with the Preparatory Breath, or last respiratory cycle, prior to the conversational turn. In Condition 4, twelve turns were chosen for analysis based on length of both parent turns and child turns so that at least two cycles of Listening Breathing and one cycle of Speech Breathing could be measured. All twelve turns were utilized for analysis of temporal correspondence, and all respiratory cycles were included as able for analysis of respiratory durations (i.e., Not every turn included a Preparatory Breath due to temporal pause between speakers). In Condition 5, five to ten conversational turns were chosen for analysis based on length of parent turn. Respiratory durations For each child, averages and standard deviations for inhalation and exhalation durations were calculated as a function of breath type (Rest, Listening, Turn, Speech) and condition. Additionally, means and standard deviations were calculated for preparatory respiratory cycles, defined as the last listening respiratory cycle prior to a turn, and the first respiratory cycle in a verbal or nonverbal conversational turn. This variable was calculated for each individual participant as well as by group to analyze individual variability, variability within groups, and for group comparisons within each condition. This also allowed for analysis of individual and group variability across conditions as conversational demands increased. For statistical analysis, a linear mixed model analysis was utilized using three different models to test for differences in respiratory durations as a function of breath type and condition for each of the two subject groups. The first model compared durations of Rest, Listening, Turn, and Speech inhalations and exhalations. The second model compared Listening Breathing with Preparatory Breathing. The third model compared Speech Breathing with the first cycle of Speech Breathing in a turn. The fixed effects of the model included group (CWNS/CWS), breathing state (inhalation/exhalation), condition, and breath type. Models 2 and 3 included all 2, 3, and 4 factor interactions. For the first model, all breath types were delineated by type and condition, resulting in 7 total

24 17 effects. Means of specific effects were then selected for pairwise comparisons. Based on the number of comparisons conducted in Model 1, the Bonferroni corrected statistical significance level for these comparisons was set to Correlation analysis The second analysis was conducted to describe the entrainment of respiratory waveforms between conversational partners. This was done using a continuous crosscorrelational analysis similar to that employed by McFarland (2001) to describe the temporal correspondence between respiratory waveforms of each conversational partner (p. 131). Using algorithms written in Matlab, Rib cage and abdominal waveforms were digitally low-passed filtered (15 Hz). Conversational partners rib cage and abdomen waveforms were then subjected to the cross-correlation analysis, respectively, to assess temporal correspondence. A three second analysis window was employed, representing the approximate duration of a single respiratory cycle observed in this study. The analysis window was advanced in.5 second increments, resulting in the generation of a series of 3 second long correlations for each conversation trial in Conditions 3, 4, and 5.These correlations were then plotted against the conversational dyad Respitrace. This allowed for a visual representation of any respiratory pattern entrainment and was used to determine and qualitatively describe patterns of significant positive or negative correlation values in relation to respiratory behaviors or temporal cues. Because random highly positive and/or negatively correlated but unrelated synchronizations of child/partner respiratory patterns could be expected, it was necessary to establish significance thresholds. To do so, cross-correlations were calculated for 10 random pairings of waveforms within each condition (e.g. Normal child 1 with adult partner of CWS subject 4, etc). From this dataset of cross correlations, 90% confidence intervals were calculated for each condition. Correlations falling outside this interval (positively or negatively) were then considered to be significant if it fell outside of

25 18 the interval. For Condition 3, a correlation was significant if it was greater than +.69 or less than For Condition 4, these thresholds were +.72 and -.72 and for Condition 5, +.78 and Significant correlations for these conditions were then plotted against dyads Respitrace waveforms. Percentages were then calculated to represent the number of significant correlations associated with a conversational turn compared to the total number of significant correlations identified within the entire trial. For Conditions 4 and 5, these percentages were calculated for three seconds centered on a turn change, as well as three seconds prior to and three seconds following a turn change. For Condition 3, percentages were calculated for three seconds centered on a turn and two seconds prior to and two seconds follow a turn change. The two second interval for this condition was selected due to the short duration of turns in Condition 3, and to avoid overlapping of analysis windows that would result in significant correlations being counted for more than one turn. Percentages were also calculated for the number of significant correlations in a turn window compared to the total number of correlations in a turn window. This variable was chosen as an alternate comparison for Condition 5, for which only 5-10 turns of conversations were available for analysis based on the inclusion criteria mentioned previously. These percentages were calculated for a three second window centered on the turn for Conditions 3, 4, and 5, a three second pre plus three second post-turn window for Conditions 4 and 5, and a two second pre plus 2 second post-turn window for Condition 3. Means and standard deviations of both of these percentage analyses were calculated by group for each condition. Finally, correlation data was to evaluate the relationship between significant correlations and fluency ratings for the experimental group. All turns of CWS included for analysis in Conditions 4 and 5 were rated as fluent or disfluent. Each turn was then analyzed for the percent of significant correlations around the turn to determine whether a

26 19 relationship existed between disfluent conversational turns and percentage of entrainment within a turn.

27 Figure 1. Respitrace waveforms in Windaq from Subject D3 in Condition 1 illustrating the difference in the patterns Rest Breathing and Speech Breathing. 20

28 Figure 2. Respitrace waveforms in Windaq depict Listening, Preparatory, and Turn Breathing in Subject D3 (Condition 3). 21

29 Figure 3. Respitrace waveforms depicting Subject C1 holding his/her breath throughout his/her partner s turn. Shaded lines denote turn boundaries. 22

30 23 CHAPTER III RESULTS Rest versus Speech Breathing The initial analysis compared Rest and Speech Breathing patterns amongst CWS and CWNS. To do so, comparisons were made between Rest Breathing inhalation and exhalation durations (Condition 1), Speech Breathing inhalation and exhalation durations (Condition 4), Rest Breathing inhalation durations (Condition 1) and Speech Breathing inhalation durations (Condition 4), and Rest Breathing exhalation durations (Condition 1) and Speech Breathing exhalation durations (Condition 4). For Rest Breathing, CWS did not exhibit a significant difference between inhalation and exhalation durations. However, CWNS were found to have significantly longer Rest Breathing exhalations (p =.002). Despite this difference, no significant difference was observed in respiratory durations between groups. Both subject groups displayed patterns of Speech Breathing in which inhalation durations were significantly shorter than exhalations (p <.0001). Comparing Rest Breathing to Speech Breathing, both groups had Rest Breathing inhalations that were significantly (p <.0001) longer than Speech Breathing inhalations and Rest Breathing exhalations that were significantly (p <.0001) shorter than Speech Breathing exhalations (Figures 1, 4). Rest versus Listening versus Speech Breathing To assess whether CWNS and CWS distinguish Listening Breathing as a unique respiratory pattern, inhalation durations of Listening Breathing (Conditions 3, 4, and 5) were compared to Speech Breathing inhalation durations (Conditions 4 and 5) as well as Rest Breathing inhalation durations (Condition 1). The results of this analysis revealed that both CWS and CWNS exhibited significantly longer inspiratory durations during Listening Breathing than during Speech Breathing (p <.0001) (Figure 5). However, CWS showed little durational difference in inhalation between Rest Breathing and Listening Breathing. CWNS, by comparison, showed Listening Breathing inhalations that were

31 24 significantly shorter in duration than Rest Breathing (p =.002). The group difference in this parameter approached statistical significance (p =.081). Rest versus Turn versus Speech Breathing Condition 3 required participants to take non-verbal conversational turns to assess whether CWS and CWNS distinguish non-verbal conversational turns, Turn Breathing, as a unique respiratory pattern. Therefore, the respiratory patterns of non-verbal conversational turns, or cycles of Turn Breathing, were compared to patterns observed during Rest, Listening, and Speech Breathing. Specifically, this was done by comparing Turn Breathing inhalations (Condition 3) to Rest Breathing inhalations (Condition 1) as well as Speech Breathing Inhalations (Condition 4) (Figure 6). For both CWNS and CWS, though Turn Breathing inhalations were significantly longer in duration than Speech Breathing (p <.0001, p =.0001), neither group exhibited significantly different inhalation durations from Rest Breathing. Though there were slight differences between the groups, Turn Breathing was not distinguished as a separate respiratory pattern for either group. Listening Breathing versus Preparatory Breathing The next analysis was to describe respiratory patterns associated with a conversational turn (Figure 2). To assess this, Listening Breathing inhalations and exhalations (Conditions 3 and 4) were compared with the durations of the last respiratory cycle in a turn, or the Preparatory Breath, also derived from Conditions 3 and 4 (Figure 7). During Condition 3, Preparatory Breath exhalations for both CWS and CWNS did not differ significantly from Listening Breath exhalations. In Condition 4, with verbal turn demands present, Preparatory Breath exhalations tended to be shorter in duration than Listening Breath exhalations, the difference approaching significance for both CWNS (p =.058) and CWS (p =.076). Preparatory Breath inhalations, for both CWS and CWNS in both Conditions 3 and 4, were not significantly different in duration from the rest of the Listening Breathing. Preparatory Breath inhalations of Conditions 5 could not be

32 25 accurately analyzed due to the low number of qualifying respiratory cycles available for measurement. The third analysis assessed whether Speech Breathing patterns changed throughout the course of a conversational turn. CWS and CWNS both displayed significantly longer inspiratory durations for the first respiratory cycle in a turn in Condition 4 compared to the rest of the Speech Breathing cycles (p =.0001). Neither group showed significant differences during Condition 5, although the difference (greater first respiratory cycle duration) for CWNS approached significance (p =.085) (Figure 8). Temporal Correspondence A second aim of the current study was to evaluate temporal correspondence (entrainment) between CWNS and CWS and their conversational partners. Non-verbal conversational turn Temporal correspondence was first examined during non-verbal conversational turns. The window centered on this turn was reduced to +/- 2 seconds due to the reduced length of turns observed during Condition 3. This window length allowed for the largest temporal window surrounding a turn without window overlap. Seven of the nine CWNS participants had greater than 50% of significant cross-correlations centered around turns (Mean = 57.31%, SD = 10.14%) (Table 1). All six of the CWS participants had greater than 50% of significant correlations centered on turns (Mean = 62.08%, SD = 9.85%). Scripted conversation For all seven CWNS included in Condition 4, greater than 50% of the significant cross-correlations occurred within +/- 3 seconds of a turn change (Mean = 60.56%, SD = 3.80%)(Table 2). Of the six CWS, greater than 50% of significant cross-correlations occurred within +/- 3 seconds of a turn change for only three. Additionally, the overall mean for the group was 48.87%, compared to 60.56% for CWNS. Further, CWS had a larger standard deviation (12% versus 3.8%) reflecting a higher degree of variability among the CWS participants. Finally, CWNS exhibited entrainment levels comparable to

33 26 that of adults during Scripted Conversation, who, as a group, had 57% of their significant correlations occur surrounding turn changes (McFarland, 2001). Spontaneous conversation Due to the few number of tokens available for Condition 5, there was limited data available to accurately determine the overall temporal correspondence of participants and their conversational partners during Spontaneous Conversation. In an attempt to gain some insights despite the limited amount of data for Condition 5, and to allow for a comparison across conditions (to be discussed in next section), entrainment was also assessed in all conditions in terms of individual turns, instead of the overall sample. That is, percentages were calculated of the number of significant correlations present in a turn compared to all correlations present in that turn. This is different from the number of significant correlations surrounding turns compared to the number of significant correlations in the entire sample. Of the turns available for analysis in Condition 5, CWS exhibited slightly less entrainment (using within-turn calculation) compared with CWNS during Spontaneous Conversation (Figure 9). Increasing conversational complexity The current study was designed to systematically increase the complexity of the conversational tasks in order to assess the effects of increasing social and respiratory demands on respiratory entrainment and fluency in CWS. The CWS subjects showed an obvious decrease in overall entrainment with their conversational partner in association with this increase in task complexity, as evidenced by the reduction in significant correlations surrounding turn changes from Condition 3 to Condition 4 (Figure 9). In contrast, for the CWNS subjects a slight increase in overall correspondence was observed from Condition 3 to Condition 4. Considering overall entrainment values, both CWS and CWNS exhibited a substantial reduction in degree of entrainment surrounding turn changes in the spontaneous conversation condition (Condition 5) compared to the nonverbal (Condition 3) and scripted dialogue (Condition 4) conditions. Again however,

34 27 Condition 5 values are likely affected by the limited number of turns included for analysis. As mentioned above, within turn entrainment was calculated in an attempt to accommodate this data limitation. When considering the alternate within-turn entrainment calculation, a similar trend was observed, with CWS showing a consistent reduction from Condition 3, to Condition 4, and furthest to Condition 5. CWNS showed an increase in entrainment from Condition 3 to 4, with reduced levels in Condition 5. Temporal Correspondence and Fluency The final aim of this study was to investigate the possible relationship between respiratory entrainment and fluency in CWS. This analysis was performed at the level of individual turns to assess the level of entrainment preceding fluent versus disfluent turns. A major (unanticipated) obstacle of this analysis was the low number of turns followed by disfluent speech available for analysis. Additionally, there was a high amount of variability in number of disfluent turns amongst the participants. However, based on the samples available for analysis, no discernable relationship between degree of entrainment and speech fluency was observed during Conditions 4 and 5 (Table 3).

35 Figure 4. Average respiratory durations of Rest Breathing (Condition 1) and Speech Breathing (Condition 4). 28

36 Figure 5. Inhalation durations for Rest Breathing (Condition 1), Listening Breathing (Conditions 3, 4, 5) and Speech Breathing (Conditions 4, 5). 29

37 Figure 6. Inhalation durations of Rest Breathing (Condition 1), Listening Breathing (Conditions 3, 4), Turn Breathing (Condition 3), and Speech Breathing (Condition 4) to determine if Turn Breathing is a unique respiratory pattern. 30

38 Figure 7. Respiratory durations of Listening Breathing (inhalations and exhalations) compared with Preparatory Breaths (Conditions 3, 4). 31

39 Figure 8. Inhalation durations of Speech Breathing (Conditions 4, 5) compared with the First Breath of a turn. 32

40 33 Table 1. Percentage of significant correlations which occurred +/- 2 seconds around a turn change during a Non-verbal Turn for CWS and CWNS. CWS Mean CWNS Mean Average: SD:

41 34 Table 2. Percentage of significant correlations which occurred +/- 3 seconds surrounding a turn change in Scripted Conversation for CWS and CWNS as well as adults (+/- 5 seconds) from McFarland (2001). CWS Mean CWNS Mean Adult Mean Dyad Average: SD:

42 Figure 9. Overall Entrainment compared with Within Turn Entrainment across Conditions 3, 4, and 5. 35