Stuttering and the valsalva mechanism: A hypothesis in need of investigation

This note presents the hypothesis than the excessively forceful closure of the mouth of larynx associated with certain types of stuttering may involve a neurological confusion between speech and the human body's Valsalva mechanism, which is designed to increase pulmonary pressure by forceful closure of the upper airway to assist in many types of physical effort. It is suggested that such behavior may result from excessive neuromotor tuning of the Valsalva mechanism prior to speech, especially in situations where the stutterer anticipates the need to “try hard” to speak properly. Such tuning may both interfere with phonation and render the Valsalva mechanism overexcitable to triggering stimuli, such as the increase in subglottal pressure that accompanies the start of articulation.     

Clinician attitudes toward stuttering: A decade of change (1973–1983)

The attitudes of 674 speech-language pathologists toward stuttering, stutterers, stuttering therapy, parents of stutterers, and related issues were studied during the years 1973–1983. During that period, clinician attitudes were found to shift away from support of the John-sonian concepts, which suggest parental causality and dangers in early intervention. In addition, clinicians became less likely to perceive stutterers as possessing psychologic disorders and misperceptions of their problem and of their interpersonal relationships. However, a significant number of clinician's were found to continue to hold unsubstantiated beliefs regarding the personality of stutterers, their parents, and the efficacy of early intervention with very young stutterers. The results of the study were interpreted as suggesting the need to educate fluency specialists.     

Clustering of disfluency in nonstuttering childrens' early utterances

The clustering of disfluency within early utterances in the speech of four nonstuttering children was examined. During the developmental period their mean length of utterance was between 2.25 and 3.0 morphemes. The frequency and characteristics of the clustered disfluencies are described and compared with single disfluent moments. Clusters of two disfluencies were analyzed for interactive effects of positional preference and type. Results were similar to those found in older preschool nonstuttering speakers, demonstrating the normal developmental nature of clustering in early sentences. Implications for using this temporal measure to differentially diagnose normal from abnormal disfluency are discussed.     

Different methods of lexical access for words presented in the left and right visual hemifields

Right-handed adults were asked to identify by name bilaterally presented words and pronounceable nonwords. For words in the normal horizontal format, word length (number of letters) affected left visual hemifield (LVF) but not right visual hemifield (RVF) performance in Experiments 1, 2, 3, 5, and 6. This finding was made for words of high and low frequency (Experiment 6) and imageability (Experiment 5). It also held across markedly different levels of overall performance (Experiments 1 and 2), and across different relative positionings of short and long words in the LVF and RVF (Experiment 3). Experiment 4 demonstrated that the variable affecting LVF performance is the number of letters in a word, not its phonological length. For pronounceable nonwords (Experiment 7) and words in unusual formats (Experiment 8), however, length affected both LVF and RVF performance. The characteristics identified for RVF performance in these experiments also hold for the normal reading system. In this (normal) system the absence of length effects for horizontally formatted words is generally taken to reflect the processes involved in lexical access. Length effects in the normal reading system are thought to arise when lexical access for unusually formatted words and for the pronunciation of nonwords requires the short-term storage of information at a graphemic level of analysis. The characteristics of LVF performance indicate that horizontally formatted words presented to the right cerebral hemisphere can only achieve lexical access by a method that requires the short-term storage of graphemic information. This qualitative difference in methods of lexical access applies regardless of whether the right hemisphere is seen as accessing words in the left hemisphere's lexicon or words in a lexicon of its own.     

Vowel duration in stutterers participating in precision fluency shaping

The purpose of this study was to determine the extent to which stutters manipulate vowel duration to achieve fluency after participating in Precision Fluency Shaping. Nine stutterers who read an all-voiced sentence fluently before and after therapy were selected for study. Wide-band spectrograms were made of the initial phrase of the sentences, and vowel durations were computed. Results indicated that extended vowel durations were characteristic of the fluency of stutterers posttherapy. The subject that had the highest rate of disfluency after therapy also had the shortest vowel durations. Clinical implications concerning the importance of speech rate during carryover practice are made.     

Group differences in intelligence and speed of information-processing

Three samples of different levels of mental ability, but each of average or above- average intelligence, were administered a battery of reaction time test which measure the speed with which persons can execute various elementary cognitive processes. Discriminant analyses revealed significant differences between the groups in reaction times and intraindividual standard deviations, and univariate analyses indicated that higher ability groups tended to obtain significantly faster mean reaction times and to show significantly less intraindividual variability than lower ability groups. Groups which differed the most in mental ability differed to the greatest extent on the more complex reaction time tests but this pattern was reversed for groups which were relatively close in mean IQ. Generally, the results support the hypothesis that speed- of-processing is an important factor unferlying intelligence, but a number of puzzling findings indicate the need for continued research in this area.     

CORRESPONDENCE TRAINING: AN EXAMPLE OF RULE-GOVERNED BEHAVIOR?

Two groups of six mentally retarded adults were exposed to either a “say/do” correspondence training program or a “do only” reinforcement procedure to evaluate the suggestion of Rogers-Warren and Baer (1976) that reinforcement of the nonverbal target behavior in the absence of the relevant verbal behavior may account for the behavior changes seen in correspondence training. The participants worked in an experimental setting on a variety of manipulatory responses leading to various auditory and visual consequences. Analysis of individual patterns of responding indicated no apparent differences between the groups during training; four individuals in each group appeared to develop generalized correspondence skills. We conclude that the outcome of correspondence training may not necessarily be verbal regulation of behavior as is assumed. Rather, we suggest that the notion of rule-governed behavior can best account for the type of behavior changes seen in correspondence studies.     

Saying and doing: A contingency-space analysis

Correspondences between verbal responding (saying) and nonverbal responding (doing) may be organized in terms of the classes of verbal/nonverbal relations into which particular instances of verbal/nonverbal response sequences can enter. Contingency spaces, which display relations among events in terms of the probability of one event given or not given another, have been useful in analyses of nonverbal behavior. We derive a taxonomy of verbal/nonverbal behavior relations from a contingency space that takes into account two conditional probabilities: the probability of a nonverbal response given a verbal response and that probability given the absence of the verbal response. For example, positive correspondence may be said to exist as a response class when the probability of doing is high given saying but is otherwise low. Criteria for other generalized classes, including negative correspondence, follow from this analysis.