Stuttering amelioration at various auditory feedback delays and speech rates

Abstract

The primary purpose of this study was to determine i f the finding of Kalinowski et al. (1993) of dramatic reductions in stuttering under delayed auditory feedback (DAF) at normal and fast speech rates could be replicated. The second purpose was to determine if stuttering frequency is differentially affected by various delays in an attempt to identify the optimal delay for fluency enhancement for both normal and fast speech rates. Fourteen adult stutterers read eight different passages at either a normal or fast speech rate under non-altered auditory feedback (NAF) and D A F with delays of 25, 50 and 75 ms. Results showed that significant fluency enhancement occurred under DAF at both normal and fast speech rates at all D A F settings (p<0.05). This finding corroborates the notion that a slowed rate of speech is not a necessary antecedent for fluency improvement under conditions of altered auditory feedback. In addition, the results indicated that 50 ms appears to be the shortest delay producing the maximum reduction in stuttering frequency.Le but principal de cette ktude est de dkterminer s'il est possible de reproduire les rksultats spectaculaires de Kalinowski et al. (1993) en matiire de rkduction du bkgaiement quand le feedback acoustique est retard6 (DAF) lors de vitesses d'klocution normale et accklkrte. L'autre but est de dkterminer si la frkquence de bkgaiement est affectke diversement selon les retards de feedback, afin de trouver le retard qui amkliore le mieux la fluidite' d' klocution 6 des vitesses normale et accklkrke. Quatorze adultes bigues ont lu huit passages diffkrents d vitesses normale ou accklkrke,sous feedback acoustique non modifik (NAF) ou sous DAF avec des retards de 25, 50 et 75 ms. Les rtsultats ont montrk qu'a vitesses normale et acctlkrke, et quel que soit le rtglage du retard, une amdioration significative se produisait sous DAF (p < 0,OS). Ces rksultats confirment la notion qu'il n'est pas nkcessaire d'utiliser une vitesse plus faible pour amkliorer la fluiditk d'klocution quand on se sert de feedback acoustique modifik. De plus, il semble qu'il faut un retard d'au moins 50 ms pour rkduire au maximum la frkquence des bkgaiements. Das primare Ziel dieser Studie war es, festzustellen, ob der Befund von Kalinowski et al. (1993), dalj sich das Stottern unter verzogerter auditiver Riickkopplung (DAF = Delayed Auditory Feedback) bei normalem und schnellem Sprechtempo dramatisch reduziert, zu replizieren sei. Der z weite Zweck war es, festzustellen, ob die Haufigkeit des Stotterns durch die Verzogerungsdauer unterschiedlich beeinfluljt wird, um eine optimale Verzogerungsdauer fiir die Verbesserung des Sprechflusses sowohl fiir normales als auch fiir schnelles Sprechtempo zu identifizieren. Viertehn erwachsene Stotterer lasen acht verschiedene Texte entweder rnit normalem oder rnit schnellem Sprechtempo bei unveranderter auditiver Riickkopplung oder bei DAF-Werten von 25, 50 und 75 ms. Ein signifikant verbesserter Sprechflulj wurde bei allem DAF-Werten f u r normales und schnelles Sprechen...

Effects of altered auditory feedback (AAF) on stuttering frequency during monologue speech production

“…For DAF speakers hear their own speech with a short time delay. Delays are typically less than a quarter of a second (50-250 ms) (Burke, 1975;Kalinowski, Stuart, Sark, & Armson, 1996;Van Borsel, Reunes, & Van den Bergh, 2003). FAF is a form of AAF whereby the frequency range of the speaker's speech is shifted up or down leading to changes in pitch.…”

“…Long delays lead to reduced speech rate and prolongation of vowels, producing unnatural sounding speech (Goldiamond, 1965;Martin, Haroldson, & Triden, 1984;Perkins, Bell, Johnson, & Stochs, 1979). It has been suggested that reduced speech rate, rather than interference with an auditory feedback mechanism, causes the reduction in stuttering (Bloodstein, 1995;Costello-Ingham, 1993;Kalinowski et al, 1996;Wingate, 1970). Reduction in speech rate is known to improve fluency (Adams, Lewis, & Besozzi, 1973;Perkins et al, 1979).…”

“…Early AAF investigations highlighted a number of limitations of the technique, including the size of the devices, individual variability, lack of sustained improvements, and unnatural speech associated with long delays (Bloodstein, 1995;Costello-Ingham, 1993;Goldiamond, 1965;MacKay, 1968;Martin et al, 1984;Perkins et al, 1979). As a result, the effect of AAF on stuttering was discounted until a series of more recent experiments were published (Howell et al, 1987;Kalinowski et al, 1993;Kalinowski et al, 1996;Stuart, Kalinowski, Rastatter, & Lynch, 2002). In contrast to the earlier studies, short delay intervals of 25, 50, 75 ms were used.…”

Inducement of fluent speech in persons who stutter via visual choral speech

“…A substantial number of phenomena have been recognized that immediately eliminate or nearly eliminate stuttering and induce relatively fluent speech (i.e., 90 to 100% reduction in stuttering frequency) in those that stutter [1,2,7,8,18,19]. A wealth of replicated empirical reports and the near total absence of opposing reports substantiate these phenomena.…”

Speech disruption during delayed auditory feedback with simultaneous visual feedback

“…For example, Lee (1950) was among the first to note the similarity of DAF effects to stuttering and since then a number of researchers have hypothesized the irregular use of auditory feedback as a cause of stuttering (Fairbanks, 1954;1955;Max et al, 2004). This view was paradoxically bolstered by reports that dysfluency could be reduced by providing people who stutter with DAF (Kalinowski et al, 1993;1996;Van Borsel et al, 2003;Alm, 2006). How altered auditory feedback reduces stuttering is the subject of intense debate.…”