Simple motor and phonemic processing reaction times of stutterers

Simple motor and phonemic processing reaction times were gathered for a group of stutterers and were compared to data obtained from normal speakers. The stutterers' responses were significantly more latent under both conditions. Such findings suggested that at least two neurophysiological factors influence stutterers' reaction-time latencies. These include aberrancies in both motor control and auditory processing capacity.     

The speech production abilities of stutterers: Recent, ongoing, and future research

Recent and ongoing research into the speech production abilities of stutterers has followed four disparate paths. First, there have been objective studies of physiologic, aerodynamic, and acoustic parameters of stutterers' habitual speech patterns and the patterns they display while speaking in the presence of such novel stimuli as DAF or masking. Second, investigators have undertaken the fiberoptic examination of stutterers' larynges during fluent and stuttered utterances. Third, there have been studies of the speed with which stutterers start and terminate voicing independent of the act of speaking. Finally, there have been investigations of possible perceptible differences between the fluency of stutterers and normal speakers. Each of these four types of research is examined. Tentative conclusions are drawn, and directions for future theorizing and experimentation are suggested.     

Speech disruption under delayed auditory feedback in multilingual speakers

The present study investigated the language familiarity hypothesis formulated by Mackay [(1970). How does language familiarity influence stuttering under delayed auditory feedback? Perceptual and Motor Skills, 30, 655-669] that bilinguals speak faster and stutter less under delayed auditory feedback (DAF) when speaking their more familiar language than a less familiar language. Thirty normally fluent native speakers of Dutch (17 males and 13 females, aged between 18;1 and 26;4 years) who were also proficient in French and English read meaningful and nonsense text under DAF in their mother tongue and in the two later acquired languages. The existence of a language familiarity effect was confirmed. The participants required significantly more time and showed significantly more speech disruptions under DAF in the later acquired languages than in the mother tongue, and reading time and number of speech disruptions was significantly higher for the nonsense texts than for the meaningful text for each of the three languages. An additional question addressed was whether or not there were any gender differences in the susceptibility to DAF. Results did not reveal a clear gender difference. EDUCATIONAL OBJECTIVES: The reader will be able to: (1) summarize the importance of language familiarity for the degree of speech disruption experienced by normally fluent multilingual speakers under delayed auditory feedback; and (2) describe gender differences in the susceptibility to delayed auditory feedback.     

Task relevant effects on the assessment of cerebral specialization for facial emotion

Hemispheric specialization for processing different types of rapidly exposed stimuli was examined in a forced choice reaction time task. Four conditions of recognition were included: tacial emotion, neutral faces, emotional words, and neutral words. Only the facial emotion condition produced a significant visual field advantage (in favor of the left visual field), but this condition did not differ significantly from the neutral face condition's left visual field superiority. The verbal conditions produced significantly decreased latencies with RVF presentation, while the LVF presentation was associated with decreased latencies on the facial conditions. These results suggested that facial recognition and affective processing cannot be separated as independent factors generating right hemisphere superiority for facial emotion perception, and that task parameters (verbal vs. nonverbal) are important influences upon effects in studies of cerebral specialization.     

Speakers' knowledge of word meanings: stable and perfect?

This study explored whether the actual state of speakers' knowledge of word meanings is as stable and perfect as Chomsky has claimed. 73 speakers of Japanese (11 men and 62 women, M age=20.6 yr.) each engaged in two tasks, one of defining the meanings of function words and content words and the other of creating a short sentence involving one of these words. Some speakers did a meaning-definition task first and then a sentence-creation task, while others did these tasks in reverse order. Use-dependent definition as an index of insufficient knowledge of word meanings was examined. Findings showed this type of definition occurred more often for the function words than for the content words and that it also occurred more often when the speakers performed the sentence-creation task before the meaning-definition task. The findings suggest that the actual state of speakers' knowledge of word meanings is not as stable nor as perfect as Chomsky has claimed.     

An acoustical analysis of stutterer''s speech prior to and at the termination of speech therapy

The speech of nine adult stutterers was analyzed acoustically prior to and at the termination of a modified Van Riperian procedure to determine if therapy produced discernable changes in their post-therapy fluent speech. The findings indicate that stuttering frequency decreased significantly and reading rate decreased by a statistically insignificant amount during the course of therapy. Vowel duration and the occurrence of voicing during the stop consonant production increased significantly. These findings support the hypothesis that stuttering therapy can affect more than the fluency and rate characteristics of the stutterer's posttherapy speech.     

Neural mechanisms underlying stuttering: Evidence from bimanual handwriting performance

Left- and right-handed male and female stutterers were compared with fluent speakers on a bimanual handwriting task. On each trial four words were read to the subject. After repeating the words, subjects had to write the initial letters as quickly as possible using the two hands simultaneously and without visual guidance. As a group, stutterers were slower, made more mirror-reversed letters, and formed letters of poorer quality than fluent speakers. The effects were the same for males and females, and the data for left- and right-handers were mirror-symmetric with respect to left and right hands. Evidence was found for two subgroups of stutterers with respect to scores on the dependent variables. It was suggested that the overall pattern of results implicates the supplementary motor area in the mediation of stuttering, possibly through relatively ungated callosal pathways.     

A novel radiant heat test for assessing pain threshold in human subjects: Measurement stability

New methodologies to assess analgesic response in humans are needed to better integrate preclinical and clinical data. In the present study we examined the test-retest stability of an innovative radiant heat methodology compared with an electrical stimulation methodology. For the radiant heat task, a modified rodent tail flick apparatus was used. The latency for finger withdrawal was recorded. For the electrical stimulation tasks, subjects placed two fingers on two electrodes from which they received a brief series of increasingly intense electrical stimulations. Maximum stimulus intensity (in milliamps) delivered was recorded. On each of 4 test days, the subjects received five test trials with a 10-min interval between trials. All the subjects were tested twice on each apparatus in a counterbalanced design. Finger withdrawal latencies for the radiant heat task did not differ significantly across test trials or test days. Finger withdrawal scores for electrical stimulation increased significantly across test trials as well as test days. These data show that the radiant heat method generates consistent latencies across trials and days, whereas shock produces trends over time. The radiant heat task, which is convenient to operate and inexpensive to build, appears promising as a reliable test of pain threshold in humans.     

Formant transitions in the fluent speech of Farsi-speaking people who stutter

PurposeSecond formant (F2) transitions can be used to infer attributes of articulatory transitions. This study compared formant transitions during fluent speech segments of Farsi (Persian) speaking people who stutter and normally fluent Farsi speakers.MethodsTen Iranian males who stutter and 10 normally fluent Iranian males participated. Sixteen different “CVt” tokens were embedded within the phrase “Begu CVt an”. Measures included overall F2 transition frequency extents, durations, and derived overall slopes, initial F2 transition slopes at 30 ms and 60 ms, and speaking rate.Results(1) Mean overall formant frequency extent was significantly greater in 14 of the 16 CVt tokens for the group of stuttering speakers. (2) Stuttering speakers exhibited significantly longer overall F2 transitions for all 16 tokens compared to the nonstuttering speakers. (3) The overall F2 slopes were similar between the two groups. (4) The stuttering speakers exhibited significantly greater initial F2 transition slopes (positive or negative) for five of the 16 tokens at 30 ms and six of the 16 tokens at 60 ms. (5) The stuttering group produced a slower syllable rate than the non-stuttering group.ConclusionsDuring perceptually fluent utterances, the stuttering speakers had greater F2 frequency extents during transitions, took longer to reach vowel steady state, exhibited some evidence of steeper slopes at the beginning of transitions, had overall similar F2 formant slopes, and had slower speaking rates compared to nonstuttering speakers. Findings support the notion of different speech motor timing strategies in stuttering speakers. Findings are likely to be independent of the language spoken.Educational objectives This study compares aspects of F2 formant transitions between 10 stuttering and 10 nonstuttering speakers. Readers will be able to describe: (a) characteristics of formant frequency as a specific acoustic feature used to infer speech movements in stuttering and nonstuttering speakers, (b) two methods of measuring second formant (F2) transitions: the visual criteria method and fixed time criteria method, (c) characteristics of F2 transitions in the fluent speech of stuttering speakers and how those characteristics appear to differ from normally fluent speakers, and (d) possible cross-linguistic effects on acoustic analyses of stuttering.     

Gender and speech rate in the perception of competence and social attractiveness

The authors' hypotheses were that (a) listeners regard speakers whose global speech rates they judge to be similar to their own as more competent and more socially attractive than speakers whose rates are different from their own and (b) gender influences those perceptions. Participants were 17 male and 28 female listeners; they judged each of 3 male and 3 female speakers in terms of 10 unipolar adjective scales. The authors used 8 of the scales to derive 2 scores describing the extent to which the listener viewed a speaker as competent and socially attractive. The 2 scores were related by trend analyses (a) to the listeners' perceptions of the speakers' speech rates as compared with their own and (b) to comparisons of the actual speech rates of the speakers and listeners. The authors examined trend components of the data by split-plot multiple regression analyses. In general, the results supported both hypotheses. The participants judged speakers with speech rates similar to their own as more competent and socially attractive than speakers with speech rates slower or faster than their own. However, the ratings of competence were significantly influenced by the gender of the listeners, and those of social attractiveness were influenced by the gender of the listeners and the speakers.     

汉语图片命名中获得年龄的作用

不同语种的研究都发现获得年龄是影响图片命名和词汇命名的重要因素。该研究对汉语图片命名中获得年龄的作用进行了初步探讨。研究分为两部分,第一部分让20名大学生对187幅选自Snodgrass和Vanderwart图片集的线条画的名称的获得年龄进行了评定;第二部分以该187幅图片为刺激,30名大学生被试对图片进行命名反应。以命名反应时为因变量,采用多重回归分析,发现除了名称一致性和概念熟悉性,获得年龄是图片命名反应时的主要预测指标,并没有发现词频的效应。文章对此结果进行了讨论。     

Accent trumps race in guiding children's social preferences

A series of experiments investigated the effect of speakers' language, accent, and race on children's social preferences. When presented with photographs and voice recordings of novel children, 5-year-old children chose to be friends with native speakers of their native language rather than foreign-language or foreign-accented speakers. These preferences were not exclusively due to the intelligibility of the speech, as children found the accented speech to be comprehensible, and did not make social distinctions between foreign-accented and foreign-language speakers. Finally, children chose same-race children as friends when the target children were silent, but they chose other-race children with a native accent when accent was pitted against race. A control experiment provided evidence that children's privileging of accent over race was not due to the relative familiarity of each dimension. The results, discussed in an evolutionary framework, suggest that children preferentially evaluate others along dimensions that distinguished social groups in prehistoric human societies.     

Perceptual comparisons of adolescent stutterers' and nonstutterers' fluent speech

Numerous investigators have reported that listeners are able to perceptually differentiate adult stutterers' and nonstutterers' fluent speech productions. However, findings from similar studies with children ranging in age from 3 to 9 yr have indicated that perceptual discrimination of child stutterers is difficult. A logical extension of this line of investigation would be to determine when during maturation from childhood to adulthood stutterers' fluent speech becomes perceptibly different than nonstutterers'. Therefore, in this study similar fluent speech samples from seven 12–16-yr-old adolescent male stutterers and seven matched nonstutterers were analyzed perceptually in a paired stimulus paradigm by 15 sophisticated listeners. Individual subject analyses using signal detection theory revealed that five of the seven stutterers were discriminated. When averaged for subject group comparison, these findings indicated that listeners successfully discriminated between the fluent speech of the two groups. Therefore, the perceptual difference in fluent speech production reported previously for adults appears to be present by adolescence.     

Retention of verbal information by rehearsal in relation to the fluency of verbal output in aphasia

The purpose of the present study was to determine if aphasic subject groups differentiated by the fluency of their verbal output employed rehearsal as a strategy for maintaining verbally coded information in primary memory. A task based upon the Brown-Peterson paradigm was administered to 10 fluent aphasic patients, 10 nonfluent aphasic patients, 10 right-brain-damaged patients, and 10 nonneurological patients. The findings indicate that the nonfluent aphasic patients did not rehearse the verbal information while the fluent aphasic, right-brain-damaged, and nonneurological patients did rehearse. In addition, both fluent and nonfluent aphasic patients encoded significantly less information into the memory system initially and performed worse on the task overall than right-brain-damaged and nonneurological patients.     

Voice onset time characteristics in apraxia of speech

In order to examine the timing control of laryngeal and supralaryngeal articulatory adjustments in apraxia of speech, voice onset time (VOT) data for stop consonants in monosyllables /de/, /te/, /ge/ and /ke/ were obtained from four apraxic subjects and compared with those of fluent aphasic and normal (both young and aged) speakers (Experiment 1). The results indicated that the VOT distribution patterns of the apraxic patients differed markedly from those of the other speakers. A second experiment was conducted to determine whether the VOT distribution patterns of these four apraxic patients and of two normal controls would change with a lapse of time (Experiment 2). The results of the second experiment demonstrated marked changes in the VOT distribution patterns over time in half of the apraxic patients examined, but essentially no change in the normal controls.     

A perceptual comparison between paired stimulus and single stimulus methods of presentation of the fluent utterances of stutterers

This investigation compared tape recordings containing the fluent utterances of treated stutterers with those of normal speakers as paired stimuli and single stimuli as presented to 20 sophisticated judges. Fluent utterances were obtained from stutterers successfully treated in one of the following programs: (1) Van Riperian, (2) metronome-conditioning speech retraining, (3) delayed auditory feedback, (4) operant conditioning, (5) precision fluency shaping program, and (6) holistic therapy. In addition, a group of partially treated stutterers were included. The original tape recordings containing matched samples of the fluent utterances of a stutterer and normal speaker were presented as paired stimuli. These paired samples were then separated, randomized, and assembled individually on another tape recording and presented as single stimuli to the same judges. The results of the statistical analysis indicated that the fluent utterances of treated stutterers was perceptibly different from the fluent utterances of nonstutterers, regardless of the method of stimulus presentation.     

Individual differences in electrodermal activity as a function of subjects' anxiety

The present study examines the relationships between electrodermal activity (EDA) and anxiety in an attention demanding task, by looking at the neuropsychology of individual differences. 261 normal volunteer female students completed the Cattell anxiety form, and only subjects with extreme anxiety scores (deciles 0, 1 and 2 on the one hand, N = 22; deciles 9 and 10 on the other hand, N = 24) were retained. Subjects were presented a set of 16 stimuli (8 neutral and 8 emotional slides) in a randomized order (different for each subject), of 35 msec and 1 sec duration and a randomized inter-stimuli time of average 45 sec. Skin conductance levels (SCLs), interstimuli spontaneous fluctuations (SSCRs), skin conductance response (SCR) amplitudes and electrodermal latencies were recorded, as well as skin temperature (ST). Highly anxious subjects showed significantly lower SCLs, lower SCR amplitudes, fewer interstimuli SSCRs and longer latencies than subjects with low anxiety, whereas ST did not differ between groups. These results, showing that in normal subjects there are individual electrodermal differences as a function of trait-anxiety scores, are discussed both in terms of individual differences in self-regulatory neural processes and in reference to Gray's anxiety theory.