Differential diagnosis of cluttering and stuttering in Bulgaria

Fifteen stutterers, primarily children, who visited the Medical Pedagogical Department at the University of Blagoevgrad were evaluated for a variety of criteria used in Bulgaria to differentiate cluttering, stuttering, and mixed cluttering and stuttering. The same battery of tests was administered to all subjects. Based on these criteria, five subjects were diagnosed as clutterers, six as stutterers, and four as mixed. Daly's (1992–1993) Checklist for Possible Cluttering, Experimental Edition was also utilized to classify the subjects. Differences between the differential diagnostic criteria used by Bulgarian logopedists and other authors are discussed.     

Disfluencies in cluttered speech

The purpose of this study was to examine the nature and frequency of occurrence of disfluencies, as they occur in singletons and in clusters, in the conversational speech of individuals who clutter compared to typical speakers. Except for two disfluency types (revisions in clusters, and word repetitions in clusters) nearly all disfluency types were virtually indistinguishable in frequency of occurrence between the two groups. These findings shed light on cluttering in several respects, foremost of which is that it provides documentation on the nature of disfluencies in cluttering. Findings also have implications for our understanding of the relationship between cluttering and typical speech, cluttering and stuttering, the Cluttering Spectrum Hypothesis, as well as the Lowest Common Denominator definition of cluttering. EDUCATIONAL OBJECTIVES: At the end of this activity the reader will be able to: (a) identify types of disfluency associated with cluttered speech; (b) contrast disfluencies in cluttered speech with those associated with stuttering; (c) compare the disfluencies of typical speakers with those of cluttering; (d) explain the perceptual nature of cluttering.     

Subgroups of stuttering children: Speech and voice reaction times,segmental durations,and naming latencies

Speech and voice reaction times, speech segment durations, and object-naming latencies were obtained from a group of nonstuttering children and two subgroups of stuttering children: one subgroup (“stuttering-plus”) consisting of those who needed special education services for problems in addition to stuttering, and the other subgroup (“stuttering-only”) whose only apparent problem was stuttering. The stuttering-plus children had significantly longer speech and voice reaction times and naming latencies than did the stuttering-only and nonstuttering children. The stuttering-only children differed from the nonstuttering children only in voice termination times. The three groups did not differ in speech segment durations or in the variability of such measures. The need for identifying and studying subgroups of stutterers is discussed.     

Perceptual study of the speech of “successfully therapeutized” stutterers

The purpose of this investigation was to determine if the fluent speech of “successfully therapeutized” stutterers and a group of partially treated stutterers was perceptually different from the fluent speech of normal speaking subjects. Tape recorded speech samples of treated stutterers were obtained from leading exponents of (1) Van Riperian, (2) metronome-conditioned speech retraining, (3) delayed auditory feedback, (4) operant conditioning, (5) precision fluency shaping, and (6) “holistic” therapy programs. All forms of disfluency were edited out of these tapes. The remaining samples were then paired with matched fluent samples of normal talkers and presented to a group of 20 sophisticated judges. The judges were instructed to select from each paired speech sample presented to them the one produced by the stuttering subject. The results of the analyses of variance for correct identification of the stutterers showed that the partially treated stutterers, as well as each group of therapeutized stutterers, were identified at levels significantly above chance. This meant that the fluent speech of the partially and successfully treated stutterers was perceptibly different from the utterances of the normal speakers sampled. In addition, the analyses of variance also revealed that all stuttering groups had a significant severity factor. This finding indicated there was a significant difference between the severity subgroup in all the samples investigated. These results were discussed in terms of their clinical implications.     

Perceptual evaluation of the speech before and after fluency shaping stuttering therapy

An often-cited criterion for assessing the effect of a stuttering therapy is the ability of the stutterers to produce normally fluent speech. Many modern stuttering therapies use special techniques that may produce stutter-free speech that does not sound completely normal. The present study investigates this problem in the framework of the Dutch adaptation of the Precision Fluency Shaping Program.

Pre-, post-, and -year follow-up therapy speech samples of 32 severe stutterers who were treated in a four-week intensive therapy are compared with comparable samples of 20 nonstutterers. For that aim the samples were rated on 14 bipolar scales by groups of about 20 listeners. The results show that the speech of the stutterers in all three conditions differs significantly from the speech of the nonstutterers. The pretherapy speech takes an extreme position on a Distorted Speech dimension, due to the large proportion of disfluencies. The posttherapy speech has extremely low scores on a Dynamics/Prosody dimension, a‘1 while the follow-up therapy speech differs from the normal speech on both dimensions, but now the distances are smaller. These results are discussed in relation to the severity of the stuttering problem in the group of treated stutterers. Finally, implications for future research on therapy evaluation are discussed.     

Acoustics of stop consonant-vowel relationships during fluent and stuttered utterances

Acoustic duration measures were made on the stop-gap, voice onset time (VOT), and vowel portions of the utterance [tu] in the context “425” as spoken ten times or more by five normal speakers, four mild stutterers, and four severe stutterers. The fluent utterances of the severe stutterers were significantly longer than those of normal speakers on stop-gap and vowel durations but not on voice onset times. Despite the slower speech of the severe stutterers, indications of normalization were found in the relatively stable consonant-to-vowel ratios across groups and in the lack of any significant differences of segment durations as a percentage of total utterance times. Normal speakers and mild stutterers showed an inverse relationship between stop-gap and VOT measures across speakers, but severe stutterers did not maintain this relationship for either fluent or stuttered tokens, nor did a mild stutterer suspected of covert stuttering. Stop-gap durations increased while VOTs stayed within normal limits for fluent tokens. For stuttered tokens, some subjects increased the stop-gap and some the VOT depending upon the location of the block. Abnormal gap to VOT ratios may serve to detect convert stuttering.     

Some effects of the Edinburgh Masker on stuttering during oral reading and spontaneous speech

This study assessed the effect of a voice-activated masking unit, known as the Edinburgh Masker, on the speech of four stutterers during oral reading and spontaneous speech. The results show that one stutterer reduced stuttering almost completely whenever the masker was activated. Two subjects showed either marginal or temporary reductions of stuttering during one speaking condition but showed no change in the other condition. The other subject reduced stuttering only during spontaneous speech. No reduction in stuttering was associated with reduced speech rate. A perceptual analysis procedure conducted to assess for altered speech quality during masking conditions found changes in speech quality were evident in two subjects. The clinical implications of these findings are discussed.     

Adaptation effect in nonfluent speech behavior of controlled stutterers and nonstutterers

The adaptation effect in stuttering behavior has received considerable attention. Adaptation effect is defined as the reduction in the frequency of nonfluencies in the speech of subjects during successive readings of the same passage. The objective of this investigation was to assess the adaptation effect of nonfluent speech behavior of controlled stutterers and nonstutterers. The subjects included 35 controlled stutterers and 35 nonstutterers matched for factors of sex, grade level, and age. Results suggest a significant mean difference between the number of nonfluencies between trials of controlled stutterers with evidence of adaptation in the speech of nonstutterers. Nonstutterers demonstrate significant mean differences in nonfluencies among replicated testing occasions. Findings of this investigation suggest that both controlled stutterers and nonstutterers demonstrate similar adaptation regarding their nonfluent speech behavior. Issues and import for future research are offered.     

A comparison of syntax in young stutterers and nonstutterers

This study compares the syntactic structure of the spontaneous speech of a small group of stutterers and nonstutterers, using a method of constituent analysis. Speech samples were taped during play sessions with subjects, and the tapes were then transcribed and analyzed according to preselected constituent criteria. The stutterers were in the early stages of stuttering and had been diagnosed as stutterers by experienced clinicians. The method of analysis proved to be highly reliable. Differences were found in the number of complete clauses, the number of complex sentences, and in clause types between the two groups.     

Perceptual analyses of stuttering and nonstuttering children's fluent speech productions

Several investigators have reported a significant perceptual difference between adult stutterers' and nonstutterers' fluent speech productions. However, there is only limited information concerning the perceptual evaluation of stuttering and nonstuttering children's fluent speech. Therefore, in this study identical fluent sentences from nine stuttering children (mean age = 6 yrs, 8 mos) and nine nonstuttering children matched individually for sex and age (within 6 mos) were analyzed perceptually in both a paired- and single-stimulus paradigm by 12 sophisticated listeners. Individual subject analyses revealed that only one-half or fewer of the stutterers could be discerned in either paradigm. In the remaining cases, either no discrimination could be made or a nonstutterer was incorrectly identified as a stutterer. When averaged for subject group comparison, these findings indicated that listeners could not discriminate between the two groups. Possible explanations for this discrepancy in results between child and adult stutterers are proposed.     

Cluttering and stuttering exhibited in a young professional

S 18, a young adult professional, was self-referred for stuttering. Assessment indicated deficits consistent with both stuttering and cluttering, including prolongations, syllable repetitions, secondary escape behaviors, rapid speech rate, and poor expressive language. The client had no awareness of cluttering characteristics. Therapy goals included improved breath control, slowed rate, easier onset of articulation, and increased awareness of speech. Progress toward therapeutic goals was consistent. However, his motivation decreased as therapy progressed. He was discharged from direct treatment after 13 months, at which time he could employ therapeutic techniques to improve his fluency and intelligibility when speech was disordered.     

Onset and termination of accessory facial movements during stuttering

In this study the onset and offset times of seven types of accessory facial movements during oral and silent prolongations were described in three severe stutterers. For each observed facial movement the onset and offset times were determined by means of slow motion analysis of video-recorded speech samples. For two of the three subjects significant differences in the onset and offset times at the various facial movements were found; however, no consistent patterns in the separate facial movements could be observed. On the contrary, the onset of most facial movements appeared to be located at the very start and their offset at the end of the stuttering moment. The implications of these findings with respect to the function of accessory facial movements in stuttering are discussed.     

Voice reaction time of stuttering and nonstuttering children and adults

The voice reaction time (VRT) of 5-yr old, 9-yr old, and adult stutterers and nonstutterers was investigated. Subjects initiated the sound / Λ / in response to fifty-five 1000-Hz tones of 1 sec duration. The tones were presented in five equal sets of 11 tones each with the silent intervals between the tones randomly selected to be 3, 4, 5, or 6 sec. Data analysis was based on responses 2–11 for each set. The VRTs for both the stutterers and the nonstutterers decreased significantly as an inverse function of age, with the largest decrease in reaction time occuring between 5 and 9 yr. The VRTs for the stutterers, however, were significantly slower than those of the nonstutterers at each of the three age levels. The results suggest that observed disruption in the laryngeal behavior for at least some stutterers may not result from the development of stuttering with age, but may contribute to early difficulty in the child's ability to produce fluent speech. Consideration of central factors are discussed.     

Persistence and remission of incipient stuttering among high-risk children

This investigation concerns the persistence of stuttering and recovery from it among high-risk children. At the end of the second year of a 6-year prospective study, 26 of 93 preschool children with a parental history of stuttering were classified as stutterers. Four years later, seven of these children were classified as persistent stutterers, and 16 children were classified as recovered stutterers. The articulatory and linguistic skills of these two groups of children and the communicative and speaking behaviors of their mothers, were measured before and after the onset of stuttering. The analysis of these measures revealed that the articulatory skills of the children and the communicative style and language complexity of the mothers differentiated the incipient stutters whose stuttering subsequently became chronic from those who recovered.     

An evaluation of the effects of supplemental “fluency” training during maintenance

The voice onset time (VOT) of two groups of treated stutterers and a normal-speaking group was assessed by spectrographic analysis. Both groups of stutterers had significantly slower VOT than the normal speakers. The experimental group of stutterers was given 8 wk of “fluency” training designed to remediate characteristics of speech identified as related to “tenuous” fluency. The control group of stutterers received ongoing maintenance therapy. Posttreatment VOT was assessed. The experimental stuttering group had significantly decreased their VOT in the direction of the normal-speaking group, whereas the control group of stutterers had a greater VOT between pre- and posttreatment. The implication of these results for the maintenance of fluency are discussed.     

Visuoperceptual and visuomotor deficits in developmental stutterers: an exploratory study

Although the cause of stuttering is unknown, there is strong evidence for it being a neuromotor disorder characterised by an abnormality of higher control encompassing not only speech but other motor systems. The aim of this exploratory study was to look for the presence of non-speech/language deficits--in particular, visuomotor and visuoperceptual deficits--in persons who stutter. Twelve moderate to severe developmental stutterers were compared with a group of fluent speakers, matched for age and sex, on a range of computerized sensory-motor tasks. These tasks covered various aspects of visuomotor function--ballistic movement, dynamic steadiness, and several types of tracking--and visuoperceptual function--acuity, static perception, and dynamic perception. A novel technique was used to remove the visuospatial component from tracking performance. Stutterers had slower reaction times, less accurate random tracking, and impaired dynamic visual perception. Severity of stuttering correlated with reaction time and dynamic perception. Removal of the visuoperceptual component from tracking performance indicated that the impaired tracking in the stutterers was predominantly due to reduced dynamic perception. This is the first study to provide preliminary evidence for the presence of non-linguistic visuoperceptual and upper-limb visuomotor tracking deficits in people with moderate to severe stuttering. These findings support a neurogenic aetiology for stuttering and are compatible with evidence of an overactive dopamine system in stutterers.     

Bridging the divide between laboratory and "real world" in stuttering

Stutterers stutter significantly less in the laboratory and the clinic than in everyday speaking situations. This paper reviews pertinent literature to show that, in the outside world, stutterers have a stake in what they say and therefore message content and interpersonal dynamics command attention-relegating speech-motor planning and execution to an automatic, memory-based process called speech concatenation. In the laboratory and the clinic, content of communication and interpersonal dynamics are less important, allowing stutterers to concentrate on the motor planning of articulation and prosody. Evidence reviewed here suggests that speech construction (real time preparation of an utterance motor plan) is incompatible with stuttering. Evidence also suggests that a slight delay in retrieving motor plans from memory during speech concatenation is the immediate source of stuttering.     

发展性口吃的脑机制

口吃是一种常见的言语障碍,对此曾提出过大脑半球言语功能偏侧化异常假设。近期,发展性口吃的神经成像研究在支持这一经典假设的同时,还发现负责言语监控的颞叶系统和负责言语运动控制的额叶系统与皮层下脑结构存在功能失调,这可能损害言语产生时的精确时间控制。据此,研究者开始用神经网络的观点来解释发展性口吃产生的脑机制,认为患者可能存在由多个言语产生相关脑区构成的“双通路”网络的功能障碍