Stuttering: A Unified Approach to a Multifactorial, Dynamic Disorder [1 ed.] 9781410603777

Table of contents :
ch3 Stuttering: A Unified Approach to a Multifactorial, Dynamic Disorder
FIG 3.1
LIMITATIONS OF TRADITIONAL UNITS OF STUTTERING
FIG 3.2
A GLOBAL STRATEGY
FIG 3.3
Beyond Organicity
Beyond Causality
FIG 3.4
REFERENCES

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Stuttering: A Unified Approach to a Multifactorial, Dynamic Disorder Anne Sn1ith Purdue U11iversitr . The goal of this chapter is to propose a global. unified strategy that will aid our attempts to understand and to treat stuttering. r do not suggest that all of us will agree about all aspects of stuttering; \Ve will not. What I propose is that, if we could agree on son1e of the broader issues that drive research and treatment, progress \\"Ollld be n1ore rapid. Furthem1ore, a widely shared, comprehensive approach to stuttering \Vould provide a critically needed foundation for con1municating about the disorder. A shared frame\vork \Vould i1nprove co1n.rnunication among researchers and clinicians, and in tum, communjcation with individuals who stutter, \Vith parents, \vith teachers. and with society at large. The myriad approaches to stuttering research and treatment have created a fragmented and confusing Uterature on the disorder. Papers traditionally were \Vritten as if the "answer" to stuttering could be discovered within whatever clinical or experin1ental approach a particular group believed at a particular time. Those of us who have been in the fie ld for some time have witnessed the recycling of old "ans\vers," for example, the current reemergence of OAF and feedback theories of stuttering (e.g., Harrington, I 988). However, there has been growing agreement among many researchers and clinicians that stuttering is a multifactorial disorder (Conture, 1990; Riley & Riley, 1979; Smith, l 990a; Smith & Kelly, 1997; Stark\veather. Gottwald. & Halfond. 1990; Van Riper, 1982; Wall & Myers, 1995; Zimmennann. 1980; Zimmennann, Sn1ith, & Hanley, 1981 ). The present chapter explores the possible ways in which a multifactorial and dynamic model of stuttering can accelerate and expand progress in our field . A key to progress is the realization that the traditional, static units of distluency counts, for example, part-word repetitions or sound prolongations, are convenient fictions that have misled many of us into rhinking of stuttering as a static entity (Smith & Kelly, 1997). Stuttering is not a series of"stutter events." Stuttering is a dynamic disorder, and the many processes related to stuttering can be observed at 111ultiple levels, within time frames that range from milliseconds to lifespans. and with many different types of tools. We are not alone, however, in being tempted to simplify a complex, dynamic phenomenon \Vithin a static conceptual framework. As an analogy, consider the scientific study of volcanoes. Anyone who has witnessed a film of a volcanic eruption knows that volcanoes are certainly dynamic. Ho,vever, the earliest scientific efforts to study volcanoes did not attempt to account for dynamic aspects of volcanoes. Instead, the focus of volcanologists in the J 9lh century was on counting and classifying volcanoes (Decker & Decker. 1991).

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Classification was based on the shape of the landform (e.g., caldera vs. cone) and the type and shape of eruptive materials (see Figure 3. 1 for variations in landform and gas clouds). Work on counting and classifying continued until the 1960s, and six 1najor types \Vere identified; Fissure, Strombolian, Hawaiian, Vulcanian, Pelean, and Plinian. However, the shortcomings of this classification scheme were readi ly apparent.

FIG 3 I. The science of volcanology was focused tbr n1any years upon counting and classifying volcanoes I lo\vevcr, the licld moved beyond this narrO\V focus \Vith the introduction of a con1prehens1vc theor) of the plate 1ec1onics Like volcnnolog1sts, scientists \vho investigate stuttering 111ust n10\ e beyond classification and counts to a unified thl.!ory of stuttering.

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IAi!..c all generalities, classi Ii cation eruption l) pes and volcanic landronns can be taf...en only so far. Volcanic eruptions are caused by n1any fnctors . ... and the shore or n volcanic mountain ma) be the end

result or a series of eruptions that vary in location, type. size. and sequence... Na1n1ng the l) pe:> of volcanoes, \\hi le helpful. is only a beginning in tr)' ing to un'

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1 IG J.J l·actun; that pla> a rol~ u1 )tunenag mu~t unpl.lCl speech n\titor procc.ses either directly or 1nd1n:ctly I xun1plcs nl potcnt1all} 1mrorlilllt fw.Lo~ arc sho"n l he speech 111t1tor sv~1cn1 produ~ un output that ranges on 1.1 continuum o l stub1ht)' Sp:u.J.crs \Yho \lUllcr prod111:c mot••r outpuls ntorc ollcn nt the ~xcrcml!s of thl!> ~l1nllnuun1

'''OL1lu not clt111n tha1 eruptions 'cause'' volcanoes. The lask lhen becomes to

deline the essen11al characteristic of an en1ption Is Java flo\v a necessary condition? ls sn1oke or a gas cloLad a necessary condition? lf a fissure in the earth produces sn1oke but uoes not have a cone shnpe or lava no,v, as tha1 an en1ption, and should the fissure be clnssilied ns a' olcano? It seems obvious that these rypes of questions l ou lu occup) volcanologrsts for n1any years, but that these are the wrong questions. J'he preferred strategy 1s to develop and disscminare a mul1ifactorial n1odel and to assess \vh1ch v. systems that produce language and speech I-to'' can '' c 11111"-e progress to\vard the goal of reJin1ng and expanding a n1 ultifactorial, d) nan11c 1heo~' of c;tutter1ng'? Thelen ttnd Smith ( 1994) offered a useful introduction lo de\.~loprnental dyna1n1cs, and they den1ons1rated how pr1nc1ples from this ne'' science could be used 10 study the development of cognition and act ton The) asket! questions such as .. \vhy does change occur" and "\\ h)' do or!!.tlnisms move from one state to another?" They borro\ved heavil} from physicnl theorres of nonlinear dyna1n1cs to illuscrate hO\\' \'e/f-organi:i11g 'iJ'Sft:n1.'i produce pattcn1ed output. fhat 1s. sy-.ten1s \\ ith n1any interacting con1poncnts can suddenly produce patte111!> ln space and time. and can display nonlinear behavior, that is a shifting from one pattern of output to another very rapidly We discussed 1n an earlier paper CSm11h & Kell:. f 997) ho"" this feature ofnonlinearit)' is exlrernely rele\ ant to the understanding of stuttering: The onset of stuttering m childhood can be sv.1ft and severe (YairL 1997); an adu lt speaker \Vho stutters rnay shift very sudden!\- fron1 fluent to hit?hlv .... - disfluent modes To understand and model these nonlinear shifts in the output behavior of con1plex systems. dynan1ic theorists define a/tractor states. "\vhen systems selforganize .. . they 'settle into' one or a fe\\' modes of behavior (which then1 selves ma) be quite co1np l~\ ) that the sy!>tem prefers over all the possible modes" (TI1elcn & Sn11th p. 56) /\s shown 1n fig. 3.4, these attractors are often represented as "alle) s \\.Ith a ball at the bonon1 The n1ore stable an attractor state. the deeper the vallc). and rnore cnerg) is required to move out of that mode or state. During development. the number and depth of attractors change. and Thelen and her colleagues have used such illustrations to depict the ontogenetic .. landscape" for locomot1on (see Fig. -t 17 of Thelen and Smith. 1994). As suggested 1n Fig. 3.4, a si111ilar approach could be ernployed 10 describe an on1ogenetLc landscape for the development of speech. As a brief illustration for 1he present purpose, suppose that. as speech mo1or skills are cn1crg1ng, in a typically developing child u1 the 2- 5 year period, attractors are shallo\\', and production is unstable (top trace. Fig. 3.4 ). During periods of normal nonfluenc) 1n ch1ldhood. some of these actractors or n1odes result in nonnucnt speech (second trace, Fig. 3.4). \\' ith maturation, these n1ult1ple speech al tractors or modes eventually disappear and a deep, stable anractor for Ouent speech emerges. It takes consuJerable noi~e or energy (e.g., extreme fatigue, a large audience) to n1ovc anom1aJ ndull speaker ou1 of th ts normally fluent mode {third trace). On 1he other hand, \Ve hypothesize that some children. as they move through the ontogenet1c landscape for speech, continue to ha\'.e unstable 1

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Young cluld. millly 32) Ne\\ York The Ne\\' Yor" Acadern) of Sciences. t-1adore. B F. & Freedman. \I./ L ( 1987). Seff-{)rganizing structures. A1nerican Scientist, 75, 252-259. McGuire. B , Kilburn. C., & ~1urray, J. (Eds). ( 1995). Afon1tor111g active volcanoes. Strategies. procedures and tecl1111q11es. London . UCL Press Limited. Perkins. W. 11. ( J fallon, J. Lacasse, L., Chin, S., Klein, C.. Tang, t . C.'adv•ell, S. & I oucnhcrg. S ( 199'i) A positron e1nission tomography ( 181) deoxyglucose stud} of de\ clopn1ental stu1terang ,\'euroreport 6. 50 1- 505 \crra C , ~lcm , J !\1 & f\.1er1cnic.h. f\.1 M ( 1994) Alterations ol the cortical representation ul 1hc rat \en1run1 induced b> nursing behavior Journal of "reurosc1ence / ./(J) 1710172 1 \ :11n. [ ( 1997) [)1slluenc) characteristics of childhood stuttering. In R F Curlee & G M Siegel (Lds ). \uturc and 1rea1111e111 o,( stullerrng f..e11• d1rec11ons (2nd ed , pp 49-78) Necdharn I lc1ghts, ~10 All) n & Bacon. /1111n1ermann ( , N (1980) Stut1cring A disorder of movement Journal o.f Speech and llear111K Research 23. 122· 136 Limmermann. (, N . Sm ith. A . & Hanle) . J M. ( 1981) Stuttering In need of a unifying conceptual fran1c,11or~ Jo111 11ul of Speech and Hearing Research 2./. 25- 3 I \\ 11

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