Michael Blomgren

Acoustic, aerodynamic, physiologic, and perceptual properties of modal and vocal fry registers

The purpose of the study was to examine the acoustic, aerodynamic, physiologic, and perceptual characteristics of modal and vocal fry production. Twenty normal speakers (10 males, 10 females) participated in the study. Speech material included four sustained vowels (/i/, /a/, /ae/, /u/), and syllable strings of /pi/ repetitions produced in both modal and vocal fry registers. Acoustic data (fundamental frequency, jitter, shimmer, and signal-to-noise ratio), aerodynamic data (airflow and air pressure), and electroglottographic (EGG) data were obtained simultaneously. Results demonstrated considerable differences across voice parameters for the modal and vocal fry registers. Fundamental frequency was significantly lower in vocal fry than in modal register for both males and females, however, significant gender differences existed only in modal register. For both males and females, measurements of jitter and shimmer were significantly higher and signal to noise ratio was significantly lower in vocal fry. In addition, airflow rate in modal register was almost three times as high as the airflow rate in vocal fry register during sustained vowel production. During syllable string production, subglottal air pressure values in modal register were approximately 1.5 times higher than that in the vocal fry register. In general, these data emphasize that the aeromechanical mechanisms of vocal fold vibratory behavior are substantially different between modal and vocal fry registers. A model of vocal fry phonation is presented to account for the present results.

An Evaluation of the Effects of Three Laryngeal Lubricants on Phonation Threshold Pressure (PTP)

Clinicians frequently offer advice to performers and voice-disordered patients aimed ostensibly to manipulate the water content and/or viscosity of the mucus blanket covering the vocal folds. To evaluate the relative effects of three potential laryngeal lubricants on phonatory function (ie, water, Mannitol--an osmotic agent, and Entertainers Secret Throat Relief (Kli Corp., Carmel, IN)--a glycerin-based product), phonation threshold pressure (PTP) was measured in 18 healthy, vocally normal female participants twice before (baseline) and then four times after 2 ml of each substance were nebulized. PTP is the minimum subglottal pressure required to initiate vocal fold oscillation, and the lowering of PTP is assumed to correspond to physiologically more efficient phonation and reduced phonatory effort. Over a 3-week period, participants were tested on three separate occasions (at 1-week intervals). On each occasion, a different nebulized treatment was administered. PTP for both comfortable and high fundamental frequency productions was measured using an oral pressure-flow system (Perci-Sars, MicroTronics Corp., Chapel Hill, NC). Analysis of the results revealed that Mannitol, an agent that encourages osmotic water flux to the luminal airway surface, lowered PTP immediately after its administration (ie, p = 0.071, for high-pitched productions only). However, the duration of its PTP lowering effect was less than 20 minutes. The other two substances did not demonstrate any significant postadministration effect on PTP.

Parkinsonian speech disfluencies: effects of L-dopa-related fluctuations

UNLABELLED The excess dopamine theory of stuttering (Wu et al., 1997) contends that stuttering may be related to excess levels of the neurotransmitter dopamine in the brain. As Parkinsons disease (PD) patients commonly exhibit changes in dopamine levels accompanied by changes in motor performance, the present study examined disfluency in PD patients to gain information on the role of dopamine in speech disfluencies. Nine PD patients with no history of developmental stuttering were recorded once before and twice after taking their morning medication (on separate days). They read a passage and produced a monologue. Within-word and overall speech disfluencies were calculated at each recording. Through motor testing, it was inferred that participants had relatively low dopamine levels before taking medication, and relatively high dopamine levels after taking medication. There were no group changes in disfluency levels when the low-dopamine and high-dopamine states were compared. There were, however, significant differences in percent disfluencies between the PD participants and age-matched controls. The results of this study do not strongly support the excess dopamine theory of stuttering. Rather, the disfluency changes exhibited by individual participants support a hypothesis that speech disfluencies may be related to increases or decreases in dopamine levels in the brain. EDUCATIONAL OBJECTIVES The reader will learn about: (1). the characteristics of disfluent speech exhibited by speakers with Parkinsons disease. (2). The effect of L-dopa based medications on disfluencies of Parkinsonian speakers. (3). The complex role brain dopamine levels may play in disfluent speaking behavior.

Exploratory randomized clinical study of pagoclone in persistent developmental stuttering: the EXamining Pagoclone for peRsistent dEvelopmental Stuttering Study.

Introduction: Stuttering is a speech disorder in which the flow of speech is disrupted by repetitions, prolongation, and blocks of sounds, syllables, or words. No pharmacological treatments are approved for use in stuttering, and the most common form of treatment is speech therapy. This study was designed to assess the safety, tolerability, and effectiveness of pagoclone during 8 weeks of double-blind treatment followed by a 1-year open-label extension in patients who stutter. Methods: An 8-week, multicenter, parallel-group, 2-arm, randomized (ratio 2:1 pagoclone-placebo), double-blind study with a 1-year open-label extension conducted at 16 US centers, including men and women aged 18 to 65 years who developed stuttering before 8 years of age. Twice-daily dosing with pagoclone (n = 88 patients) or matching placebo (n = 44 patients), with primary and secondary efficacy variables defined a priori, including Stuttering Severity Instrument Version 3 outcomes, clinician global impressions of improvement, and the change in the percentage of syllables stuttered. Results: Pagoclone produced an average 19.4% reduction in percentage of syllables stuttered compared with 5.1% reduction for placebo. During open-label treatment, a 40% reduction in the percent syllables stuttered was observed after 1 year of treatment with pagoclone. The most commonly reported adverse event during double-blind treatment was headache (12.5% pagoclone patients, 6.8% placebo patients). Discussion: Pagoclone was effective in reducing symptoms of stuttering and was well tolerated. In light of its favorable tolerability profile, as well as consistency of effects across multiple efficacy variables, pagoclone may have potential as a pharmacological treatment of stuttering. Limitations: The main limitation of this study was the adequacy of the number of subjects who participated because this study was conducted as a pilot investigation. Furthermore, as this condition waxes and wanes, the assessment of stuttering within the clinic setting may not be an adequate reflection of the stuttering of the patients within the community.

Analysis of F2 transitions in the speech of stutterers and nonstutterers

Lingual coarticulation was acoustically examined in the fluent speech of stutterers and nonstutterers. Coarticulation was evaluated by determining the slope of second formant (F2) transitions following consonant release. In general, stutterers were found to display larger slope coefficients in comparison to the nonstutterers. The large coefficients were interpreted to reflect greater or quicker dimensional changes in vocal-tract behavior compared to those of nonstutterers. Discussion focuses on the speech motor skills characterizing fluent speech production.

Characteristics of speech disfluency in Parkinson disease

The purpose of this study was to describe speech disfluency characteristics in a group of 32 individuals with Parkinson disease (PD). Individuals with PD read a standard passage, and percentages of within-word and between-word disfluencies were calculated. The disfluency percentages exhibited by the individuals with PD were significantly greater than age-matched control speakers. Similarity was found between PD-related disfluencies and disfluencies seen in developmental stuttering, as the PD participants produced primarily motoric-based within-word disfluencies, including both repeated movements and fixed postures. A relationship was also found between self-ratings of medication effectiveness and disfluency levels, and this relationship is interpreted relative to the dopamine hypothesis of stuttering. Finally, significant reductions in within-word disfluencies were seen during a clear-speech task, along with an increase in disfluency levels during a monologue compared to a reading task.

Behavioral treatments for children and adults who stutter: a review.

This paper provides a brief overview of stuttering followed by a synopsis of current approaches to treat stuttering in children and adults. Treatment is discussed in terms of multifactorial, operant, speech restructuring, and anxiolytic approaches. Multifactorial and operant treatments are designed for young children who stutter. Both of these approaches involve parent training and differ primarily in their focus on reducing demands on the child (multifactorial) or in their use of response contingent stimulation (operant conditioning). Speech restructuring and anxiolytic approaches are used with adults who stutter. Speech restructuring approaches focus on the mechanics of speech production, and anxiolytic treatments tend to focus on the symptoms and social and vocational challenges of stuttering. The evidence base for these different approaches is outlined. Response contingent therapy (for children) and speech restructuring therapy (for adults) have the most robust empirical evidence base. Multifactorial treatments for children and stuttering management approaches for adults are popular but are based on theoretical models of stuttering; the evidence base is not robust and tends to be inferred from work in areas such as cognitive behavior therapy and desensitization. Comprehensive, or holistic, approaches to treating stuttering are also discussed. Comprehensive approaches for treating stuttering in adults address both improved speech fluency and stuttering management.

Stuttering treatment for adults: an update on contemporary approaches.

This article provides a brief overview of historical and current approaches to stuttering treatment for adults. Treatment is discussed in terms of stuttering management approaches, fluency-shaping approaches, and combined approaches. The evidence base for these various approaches is outlined. Fluency-shaping approaches have the most robust outcome evidence. Stuttering management approaches are based more on theoretical models of stuttering, and the evidence base tends to be inferred from work using the approaches of cognitive behavior therapy and desensitization with other disorders such as anxiety. Finally, comprehensive approaches to treating stuttering are discussed, and several clinical methods are outlined. Comprehensive approaches target both improved speech fluency and stuttering management. Although it is presented that a comprehensive approach to stuttering treatment will provide the best results, no single approach to stuttering treatment can claim universal success with all adults who stutter.

The frequency of simultaneous disfluency and phonological errors in children: A preliminary investigation

The frequency of simultaneous disfluency and phonological errors was examined in seven young English-speaking children exhibiting coexisting stuttering and phonological disorders. Data were gathered during 30 minutes of mother-child conversation and analyzed in three parts: (1) stuttering, (2) phonological errors, and (3) stuttering and phonological error co-occurrence. Results indicated that stuttering did not occur more frequently on syllables with phonological errors than on syllables without phonological errors. However, the frequency of disfluency on word-initial consonant clusters with phonological errors was significantly higher than on word-initial consonant clusters without phonological errors. Theoretical and clinical implications are discussed.

Formant frequency fluctuation in stuttering and nonstuttering adults

Abstract Inferences were made regarding the vocal tract stability of stutterers’ and nonstutterers’ fluent speech through the examination of formant frequency fluctuation (FFF). Fifteen adult males served as subjects comprising separate groups of untreated stutterers, stutterers enrolled in a fluency-shaping treatment program, and nonstuttering controls. The steady-state portion of formant 2 (F2) was examined in the production of various CVC tokens and evaluated by examining the absolute Hz difference in F2 across consecutive glottal periods. Results of the acoustic analysis indicated a trend in FFF across the three groups. The untreated stutterers displayed the greatest FFF, followed by the control group, with the treated stutterers displaying the most F2 stability. Discussion focuses on the vocal tract stability displayed by each group, as well as the influence of a fluency-shaping treatment program to achieve perceptually fluent speech.