RESUMEN
The aim of this study was to identify differences in functional and effective brain connectivity between persons who stutter (PWS) and typically developing (TD) fluent speakers, and to assess whether those differences can serve as biomarkers to distinguish PWS from TD controls. We acquired resting-state functional magnetic resonance imaging data in 44 PWS and 50 TD controls. We then used Independent Component Analysis (ICA) together with Hierarchical Partner Matching (HPM) to identify networks of robust, functionally connected brain regions that were highly reproducible across participants, and we assessed whether connectivity differed significantly across diagnostic groups. We then used Granger Causality (GC) to study the causal interactions (effective connectivity) between the regions that ICA and HPM identified. Finally, we used a kernel support vector machine to assess how well these measures of functional connectivity and granger causality discriminate PWS from TD controls. Functional connectivity was stronger in PWS compared with TD controls in the supplementary motor area (SMA) and primary motor cortices, but weaker in inferior frontal cortex (IFG, Broca's area), caudate, putamen, and thalamus. Additionally, causal influences were significantly weaker in PWS from the IFG to SMA, and from the basal ganglia to IFG through the thalamus, compared to TD controls. ICA and GC indices together yielded an accuracy of 92.7% in classifying PWS from TD controls. Our findings suggest the presence of dysfunctional circuits that support speech planning and timing cues for the initiation and execution of motor sequences in PWS. Our high accuracy of classification further suggests that these aberrant brain features may serve as robust biomarkers for PWS.
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Encéfalo/diagnóstico por imagen , Encéfalo/fisiopatología , Red Nerviosa/fisiopatología , Vías Nerviosas/fisiopatología , Tartamudeo/diagnóstico por imagen , Tartamudeo/fisiopatología , Adolescente , Adulto , Algoritmos , Ganglios Basales/fisiopatología , Mapeo Encefálico , Estudios de Casos y Controles , Niño , Femenino , Humanos , Aprendizaje Automático , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Corteza Motora/fisiopatología , Análisis de Componente Principal , Reproducibilidad de los Resultados , Habla , Adulto JovenRESUMEN
PURPOSE: In order to determine whether adults who stutter (AWS) would show changes in locus of causality during stuttering treatment and approximate those of adults who do not stutter (AWNS) this preliminary study compared the locus of causality as indicated by Origin and Pawn scaling procedures from two groups of young adults who do and do not stutter. METHOD: A total of 20 age- and gender-matched undergraduate and graduate students who did (n = 10) and did not (n = 10) stutter participated. The AWS took part in a three week intensive stuttering treatment provided by the American Institute for Stuttering (AIS). Along with measures of treatment outcome, writing samples were analyzed for Origin and Pawn statements that indicated the participant's locus of causality. RESULTS: At the outset of treatment the AWS showed significantly greater Pawn scores than the control group of AWNS and similar occurrences of Origin statements. The AWS showed a statistically significant increase in pre- to post-treatment Origin scores and a statistically significant decrease in Pawn scores. Following treatment the AWS showed the Origin and Pawn score ratios similar to those of AWNS. CONCLUSION: A pattern of increasing Origin and decreasing Pawn scores may indicate a pattern of increasing agency during successful stuttering treatment. Moreover the post-treatment Origin and Pawn score ratios of AWS, which were not significantly different from those of AWNS, may indicate a change trend toward normalization. Further research will determine whether such change patterns are predictive of long-term maintenance. EDUCATIONAL OBJECTIVES: By reading this article the reader will be able to: (a) describe advantages of content analysis measure such as the Origin and Pawn Scales; (b) discuss the purposes and procedures of the Origin and Pawn Scales; (c) describe typical change pattern of Origin and Pawn scores of adults who stutter while receiving treatment; (d) discuss how successful treatment for stuttering can result in the normalization of one's locus of causality.
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Control Interno-Externo , Adulto , Estudios de Casos y Controles , Femenino , Humanos , Masculino , Lectura , Índice de Severidad de la Enfermedad , Logopedia/psicología , Tartamudeo/psicología , Tartamudeo/terapia , Resultado del Tratamiento , Adulto JovenRESUMEN
Developmental stuttering is a disorder of speech fluency with an unknown pathogenesis. The similarity of its phenotype and natural history with other childhood neuropsychiatric disorders of frontostriatal pathology suggests that stuttering may have a closely related pathogenesis. We investigated in this study the potential involvement of frontostriatal circuits in developmental stuttering. We collected functional magnetic resonance imaging data from 46 persons with stuttering and 52 fluent controls during performance of the Simon Spatial Incompatibility Task. We examined differences between the two groups of blood-oxygen-level-dependent activation associated with two neural processes, the resolution of cognitive conflict and the context-dependent adaptation to changes in conflict. Stuttering speakers and controls did not differ on behavioral performance on the task. In the presence of conflict-laden stimuli, however, stuttering speakers activated more strongly the cingulate cortex, left anterior prefrontal cortex, right medial frontal cortex, left supplementary motor area, right caudate nucleus, and left parietal cortex. The magnitude of activation in the anterior cingulate cortex correlated inversely in stuttering speakers with symptom severity. Stuttering speakers also showed blunted activation during context-dependent adaptation in the left dorsolateral prefrontal cortex, a brain region that mediates cross-temporal contingencies. Frontostriatal hyper-responsivity to conflict resembles prior findings in other disorders of frontostriatal pathology, and therefore likely represents a general mechanism supporting functional compensation for an underlying inefficiency of neural processing in these circuits. The reduced activation of dorsolateral prefrontal cortex likely represents the inadequate readiness of stuttering speakers to execute a sequence of motor responses.
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Encéfalo/fisiopatología , Imagen por Resonancia Magnética , Tartamudeo/diagnóstico , Tartamudeo/fisiopatología , Adolescente , Adulto , Mapeo Encefálico , Estudios de Casos y Controles , Niño , Preescolar , Femenino , Humanos , Masculino , Persona de Mediana Edad , Índice de Severidad de la Enfermedad , Adulto JovenRESUMEN
PURPOSE: To evaluate the effectiveness of behavioral interventions designed to treat stuttering in children. METHOD: Studies were included for review if (a) the treatment was a behavioral intervention, (b) participants were between 2 and 18 years old, (c) the design was an experimental or quasi-experimental group design, and (d) the reported outcome measure assessed stuttering. An electronic search of 8 databases yielded a total of 9 studies, representing 327 treated participants across 7 different intervention types. Data were extracted for participant, treatment, and outcome characteristics as well as for methodological quality. RESULTS: An analysis of the treatment effects yielded significant positive effects approaching 1 SD when compared with a nontreatment control group. No significant differences emerged for studies comparing 2 different treatments. CONCLUSION: Conclusions drawn from the extant research suggest that data to support the efficacy of behavioral intervention in children exists for a limited number of intervention strategies, based on a meager number of methodologically acceptable studies.
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Terapia Conductista/métodos , Conducta Infantil , Logopedia/métodos , Tartamudeo/terapia , Adolescente , Niño , HumanosRESUMEN
UNLABELLED: The concepts of locus of control and locus of causality are similar and refer to the degree to which a person perceives daily occurrences to be a consequence of his or her own behavior. Locus of control is considered to be a unidimensional construct indicating an inverse relationship between the polls of internality and externality. The locus of control is generally determined by using questionnaires with a limited number of items. Locus of causality is considered to be a two-dimensional construct where Origin and Pawn values, which are similar to internality and externality, respectively, are not necessarily inversely related. Locus of causality is determined by content analysis of freely spoken or written narratives. In the current study Origin and Pawn scores were obtained from twenty adults prior to and following a three-week intensive stuttering treatment program. Brief narratives written by the participants were analyzed to obtain Origin and Pawn values. These scores were compared with traditional measures of therapeutic outcome (Locus of Control, OASES, PSI, percentage of syllables stuttered). Results indicated statistically significant increases in pre- to post-treatment Origin scores (p=.001; Cohen's d=1.44) and statistically significant decreases in pre- to post-treatment Pawn scores (p=.003; Cohen's d=1.11). Origin and Pawn scores showed significant relationships with other measures of stuttering, indicating concurrent and construct validity. Origin and Pawn scaling procedures appear to provide a valid, sensitive, and nonreactive indicator of the speaker's locus of causality and ability to develop an autonomous and agentic lifestyle. EDUCATIONAL OBJECTIVES: After reading this article, the readers will be able to: (1) distinguish between the concepts of locus of control and locus of causality, (2) describe the characteristics of individuals behaving as an Origin and a Pawn, (3) differentiate patterns of change for Origin and Pawn scores prior to and following treatment, and (4) describe the clinical advantages using Origin and Pawn scaling procedures for individuals who stutter.