Influence of stuttering variation on talker group classification in preschool children: Preliminary findings
Introduction
Variability is considered to be one hallmark of childhood stuttering (e.g., Ingham & Riley, 1998; Johnson, 1961, Meyers, 1986; Sawyer & Yairi, 2006; Yaruss, 1997). In essence, a child who stutters (CWS) may demonstrate differences in frequency and/or severity of stuttering across various situations, over a given period of time (Guitar, 1998) or as a result of changes in speaking or articulatory rate (see Hall, Amir, & Yairi, 1999, for a review of speaking rate in CWS). Although the exact reason(s) for the variability of childhood stuttering is still unknown, investigators have assessed several variables in attempts to determine those communicative contexts, events, etc. associated with such variability.
Specifically, researchers have investigated how stuttering varies or changes in relation to conversational partner (e.g., Martin, Haroldson, & Kuhl, 1972; Yaruss, 1997), conversational location (e.g., Onslow, Costa, & Rue, 1990; Silverman, 1971, Silverman and Silverman, 1971), as well as conversational context (e.g., Johnson, 1961, Yaruss, 1997). Central to all of these investigations is the notion that stuttering is most apparent when the child is conversing with a conversational partner, a situation that most closely emulates the child's real-life speaking experiences (Ingham & Riley, 1998) and less apparent during a narrative or story-telling task (Yaruss, 1997). Thus, bi-directional communication, between a child who stutters and his or her conversational partner, typically a mother or father, in a naturalistic environment (i.e., home) is considered to be one key prerequisite for childhood stuttering to manifest itself (Martin, Kuhl, & Haroldson, 1972). In contrast, CWS are less likely to exhibit more atypical disfluencies during a monologue-type task (i.e., a narrative or story telling task) (Yaruss, 1997) when compared to dialogue-type tasks (i.e., conversational task).
Although less well studied than conversational discourse, stuttering variability within narrative tasks (i.e., story-retelling and story generation) has also been explored (e.g., Trautman, Healey, Brown, Brown, & Jermano, 1999). Specifically, findings indicated that the percentage of stuttering was significantly higher during a story-retelling task in comparison to a story generation task. It is important to note that empirical studies of narrative abilities (e.g., Scott, Healey, & Norris, 1995; Weiss & Zebrowski, 1994) and stuttering variability (Trautman et al., 1999) in children who stutter have typically involved school-aged children with limited discussion regarding preschool-age children (e.g., Yaruss, 1997). Thus, if stuttering frequency of school-age children varies as a result of narrative task elicitation, one might expect to observe the same with preschool children who stutter. This assumption, however, awaits empirical verification.1
Interestingly, in most of the above studies there is minimal discussion of whether differences or variability of childhood stuttering actually have a significant impact in terms of the child being diagnosed or classified as a stutterer. For example, would a child conversing with the same conversational partner, in the child's home versus a typical clinical setting, exhibit enough variability of stuttering to result in a different diagnosis of stuttering in the home versus clinic? In essence, would variability in stuttering frequency, from one situation or conversational partner to another be sufficient to lead a clinician or researcher to classify a child a stutterer one time but a normally fluent speaker another?
Realistically, not all clinicians have access to other communication partners (i.e., the parent), locations (i.e., home), or contexts (i.e., narrative). This fact would seem to suggest that obtaining multiple sampling of partners, location and context is the ideal or recommended protocol rather than the real protocol that most clinicians must perforce typically employ. It seems reasonable, therefore, to explore whether this relatively common practice – of using less than multiple samples of various communication partners, locations and contexts – significantly impacts a clinician's ability to determine talker group classification.
We hasten to note, however, that none of the above suggests that variability in stuttering frequency does not occur with changes in partners, situations or context. Instead, what it does suggest is that such variability may not make a significant difference when determining whether a child should be classified or diagnosed as someone who stutters. Indeed, we are suggesting that the importance of stuttering variability should be considered in reference to how it may or may not impact a variety of diagnostic, treatment or research decisions like talker group classification. These are, of course, all empirical issues in wait of objective examination.
It is apparent, upon reflection, that the number of permutations of different conversations, conversational partners and conversational situations is beyond the scope of any one empirical study. Nevertheless, some reasonable beginning can and should be initiated in attempts to determine whether variation, at both groups as well as individual levels, is sufficient to impact diagnostic decisions. It would seem that if such variability was of sufficient magnitude, most preschool-age CWS would frequently be diagnosed as a person who stutters in one situation but not in another. Although not an unreasonable conjecture, such possibilities do not appear to be supported, one way or the other, based on clinical experience as well as empirical data.
Again, the present writers are not questioning whether variability exists among CWS. Variability in stuttering frequency is apparent to anyone who treats and studies childhood stuttering. Indeed, variability in stuttering is one of the main reasons prudent clinicians attempt to characterize the degree (as well as possible sources) of variability of stuttering for the child they are treating (Ingham & Riley, 1998). This window of variability serves as a referent or benchmark against which to assess whether the child's therapeutic intervention is more or less effective. Those are sound practices that we do not question. What we do question, however, is whether variability of stuttering frequency is sufficient to “cross” diagnostic boundaries for most children who stutter.
We speculate that for children who stutter as a group – averaging across those who are mild, moderate and severe in nature – variations in stuttering make little differences diagnostically. We further speculate that this is particularly true for those who are moderate to severe. Conversely, we believe this is less the case for children whose stuttering is very mild and closer to the boundary between being a child who does or does not stutter (CWNS). For these children whose stuttering is relatively mild, we speculate that some may appear not to stutter in one situation but stutter in another. If the above speculation is supported after manipulation of some of the more typical aspects of bi-directional communication (e.g., changes in conversational partner, location and conversational context), we will need more systematic empirical assessment of the oft-suggested notion that CWS should be examined in various situations, with various partners, etc.
Diagnostically and empirically, the frequency of stuttering-like (SLD) and nonstuttering-like disfluencies (nSLD) is commonly used to help determine the presence or absence of stuttering (e.g., Cordes & Ingham, 1994; Pellowski & Conture, 2002; Yairi & Ambrose, 2005; Yaruss, 1998). Typically, presence or frequency of stuttering is based on two fundamental measurements: (1) number of total disfluencies (SLD + nSLD) per total number of spoken words [%TD] and (2) number of SLDs per total number of spoken words [%SLD] (Yaruss, 1998). Empirical evidence suggests that for CWS, the %TD and %SLD are typically greater than 10% and 3%, respectively (see Conture, 2001; Cordes & Ingham, 1994; Sawyer & Yairi, 2006).
The ratio of SLD to TD (%SLD/TD) is another diagnostic index that has been used empirically to reliably distinguish between CWS and CWNS. On average, the %SLD/TD for CWS has been found to be approximately 65% or greater whereas the %SLD/TD for CWNS has been reported at 40% or lower (Ambrose & Yairi, 1999; Pellowski & Conture, 2002; Yairi, 1997). However, the question that remains unanswered is whether known variability in childhood stuttering significantly affects the diagnostic categories driven by the %SLD/TD.
Thus, the purpose of the present study was to determine whether variations in disfluencies of young CWS and young CWNS significantly influence their diagnosis from stutterer to nonstutterer, and vice versa. Specifically, we wanted to assess whether changes in diagnostic categories would occur as a result of changes in conversational partner (parent–clinician), location (home–clinic setting) and context (conversation–narrative).
If, for most children, the diagnostic category (CWS or CWNS) does change in association with changes in conversational partner, location and context, this would imply that basing the diagnosis of stuttering on a limited number and type of samples is contraindicated, even if the clinician has limited access to obtaining additional samples (i.e., in the home or with the parent). If, however, the diagnostic category does not change substantially, this would imply that clinicians should be able to diagnosis stuttering (or nonstuttering) in preschool-age children with some level of confidence for most children based on a limited number and type of speech samples. This latter implication would seem to provide support for those clinicians who have limited to no access to other conversational partners (i.e., the parent), other locations (i.e., home), or contexts (i.e., narrative).
Given the above, we developed two hypotheses. First, we hypothesized, for both preschool CWS and CWNS, that their respective diagnostic categories would not significantly change as a result of changes in conversational partner, context or location. Secondly, it was hypothesized that changes in these variables (i.e., conversational partner, context, and location), would have their greatest impact on children on or around the borderline for each talker group classification (CWS or CWNS).
Section snippets
Participants
Participants consisted of 17 preschool CWS and 9 preschool CWNS, all of whom were native speakers of American English. All children participated in a series of studies through the Vanderbilt University Developmental Stuttering Research Project.
Participants were between the ages of 3; 0 and 5; 2 (CWS: M = 45.53, S.D. = 8.32; CWNS: M = 47.67, S.D. = 6.69) with no statistically significant between-group difference (t [24] = −.664, p = .51) in chronological age. The CWS group consisted of 12 boys and 5 girls
Stuttering/speech disfluencies
Descriptive statistics for %SLD, %nonSLD, and SLD/TD, for CWS (n = 17) and CWNS (n = 9), are presented in Table 2.
Based on the typical clinical condition only (i.e., clinician–child conversation in clinical setting), there was a statistically significant difference, t [24] = 3.38, p < .01, in frequency of stuttering-like disfluencies (see Fig. 1) between CWS (M = 8.58, S.D. = 7.04) and CWNS (M = .57, S.D. = .52) as well as a significant difference, t [24] = 6.21, p < .001, in the ratio of SLD/TD (see Fig. 2)
Discussion
The results of the present study lead to three main findings. The first main finding was that, changes in conversational partner, location, and context were not significantly related to changes in the %SLD, %nonSLD and the SLD/TD, with the exception of SLD/TD which differed in CWS (but not CWNS) between conversation and narrative. The second main finding was that these variations, although theoretically and empirically meaningful, were not found to significantly influence the diagnosis of CWS
Acknowledgements
The authors would like to sincerely thank the following for aiding with the data collection process: Drs. Hayley S. Arnold and Corrin Richels, as well as Geoff Coalson, Katerina Ntouro and Krista Schwenk Garner. Last, but not least, the authors extend their appreciation to the many children and their families who participated in this study. This research was funded in part by grants from NIH/NICHD (5T32HD007226-29), NIH/NIDCD (3R01DC000523-13; 1R01EC006477-01A2) and a Discovery Grant from
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2020, Journal of Fluency DisordersCitation Excerpt :For all children examined in this study, there was no history of speech or language disorders other than stuttering. All CWS across studies met a criterion of at least 3 % stutter-like disfluencies in their spontaneous language samples and ranged from very mild to very severe, as calculated by percent stuttered syllables (Choo et al., 2016; Silverman & Bernstein Ratner, 2002), parent and speech-language pathologist report (Leech, Bernstein Ratner, Brown, & Weber, 2017; Leech, Bernstein Ratner, Brown, & Weber, 2019), or SSI-3 (Hakim & Bernstein Ratner, 2004; Johnson et al., 2009; Wagovich & Hall, 2018; Wagovich et al., 2009). Some of these studies originally only examined lexical diversity in spontaneous language, others only examined lexical skills on standardized vocabulary tests, and others examined both.
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2017, Journal of Communication DisordersCitation Excerpt :However, caution is needed when interpreting these results because the proportion of SLD in TD of children with ADHD symptoms was approximately 35%, which is lower than that typically reported in CWS. According to Johnson et al. (2009), the average proportion of SLD in TD among CWS has been found to be approximately 65% or greater whereas the proportion of SLD in TD for CWNS has been reported at 40% or lower (Conture, 2001), and this proportion has been used as a diagnostic index to distinguish between CWS and CWNS. Additionally, findings indicated that children with ADHD symptoms exhibited more disrhythmic phonations per TD, whereas the control group exhibited more revision/abandoned utterances per TD.
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2016, Journal of Communication DisordersCitation Excerpt :Clinicians are also affected by variability because they do not know if their measurements of a speaker’s stuttering behaviors are representative of the speaker’s overall experience with the disorder. The stuttering behaviors observed in the clinic are not representative of the client’s fluency in general (Ingham, 1975, 1980; Ingham & Lewis, 1978; Johnson, Karrass, Conture, & Walden, 2009). Moreover, when treating a person who stutters, clinicians cannot be certain whether any observed change in stuttering frequency is due to their treatment or to the variability of the speaker’s stuttering (Bloodstein & Bernstein Ratner, 2008).
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