The state of the art in non-pharmacological interventions for developmental stuttering. Part 1: a systematic review of effectiveness

Background The growing range of available treatment options for people who stutter presents a challenge for clinicians, service managers and commissioners, who need to have access to the best available treatment evidence to guide them in providing the most appropriate interventions. While a number of reviews of interventions for specific populations or a specific type of intervention have been carried out, a broad-based systematic review across all forms of intervention for adults and children was needed to provide evidence to underpin future guidelines, inform the implementation of effective treatments and identify future research priorities. Aims To identify and synthesize the published research evidence on the clinical effectiveness of the broad range of non-pharmacological interventions for the management of developmental stuttering. Methods & Procedures A systematic review of the literature reporting interventions for developmental stuttering was carried out between August 2013 and April 2014. Searches were not limited by language or location, but were restricted by date to studies published from 1990 onwards. Methods for the identification of relevant studies included electronic database searching, reference list checking, citation searching and hand searching of key journals. Appraisal of study quality was performed using a tool based on established criteria for considering risk of bias. Due to heterogeneity in intervention content and outcomes, a narrative synthesis was completed. Main Contribution The review included all available types of intervention and found that most may be of benefit to at least some people who stutter. There was evidence, however, of considerable individual variation in response to these interventions. The review indicated that effects could be maintained following all types of interventions (although this was weakest with regard to feedback and technology interventions). Conclusions This review highlights a need for greater consensus with regard to the key outcomes used to evaluate stuttering interventions, and also a need for enhanced understanding of the process whereby interventions effect change. Further analysis of the variation in effectiveness for different individuals or groups is needed in order to identify who may benefit most from which intervention

No evidence for dystonia-like sensory overflow of tongue representations in adults who stutter

Persistent developmental stuttering (PDS) disrupts speech fluency in about 1% of adults. Although many models of speech production assume an intact sensory feedback from the speech organs to the brain, very little is actually known about the integrity of their sensory representation in PDS. Here, we studied somatosensory evoked potentials (SEPs) in adults who stutter (AWS), with the aim of probing the integrity of sensory pathways. In addition, we tested the processing of dual sensory input to address a putative link between stuttering and focal dystonia. In 15 AWS (aged 15–55 years; three females) and 14 matched fluent speaking adults (ANS), we recorded SEPs at C5′ and C6′ induced by stimulating separately or simultaneously the tongue or the cheek at the corner of the mouth. We determined latencies (N13, P19, and N27) and peak-to-peak amplitudes (N13-P19, P19-N27). We divided amplitudes from simultaneous stimulation by the sum of those from separate stimulation. Amplitude ratios did not differ between groups, indicating normal processing of dual sensory input. This does not support a clinical analogy between focal dystonia and persistent stuttering. SEP latencies as a measure of transmission speed in sensory pathways were significantly shorter in stuttering subjects than in fluent speaking participants, however, this might have been related to a trend for a height difference between groups, and was not confirmed in a replication dataset. In summary, we did not find evidence for dystonia-like sensory overflow of tongue representations in AWS

Reduced intracortical inhibition and facilitation in the primary motor tongue representation of adults who stutter

Objective: We aimed at detecting neurophysiological changes, in the primary motor tongue representation in adults with persistent stuttering. Methods: Using transcranial magnetic stimulation in 12 patients and 14 controls, we examined motor threshold, motor-evoked potential (MEP) input–output curve, short-term intracortical inhibition (SICI) and intracortical facilitation (ICF), based on eight trials per conditioning-test interval. Results: In controls inhibition of the MEP-amplitude at short inter-stimulus intervals (ISI) and facilitation of the MEP-amplitude at long ISIs was evident. Patients showed an inhibition at ISI 3 ms and weaker nonsignificant inhibition at ISI 2 ms; this delay of inhibitory activity was especially prominent in the right hemisphere. Facilitation was reduced at ISI 10 and 15 ms in patients. Furthermore, MEP input–output curve was steeper in patients. Motor thresholds did not differ between groups. Conclusions: In persistent stuttering intracortical excitability of the primary motor tongue representation is altered with a deviant time course for inhibitory activity in the right hemisphere and reduced pairedpulse facilitation. Significance: These results specify changes in intracortical networks possibly mediated by altered GABAergic regulations in persistent stuttering. Thus, a better understanding of pathomechanisms and a potential role in understanding pharmacological treatment responses emerge by using transcranial magnetic stimulation

Speaking-related changes in cortical functional connectivity associated with assisted and spontaneous recovery from developmental stuttering

We previously reported speaking-related activity changes associated with assisted recovery induced by a fluency shaping therapy program and unassisted recovery from developmental stuttering (Kell et al., Brain 2009). While assisted recovery re-lateralized activity to the left hemisphere, unassisted recovery was specifically associated with the activation of the left BA 47/12 in the lateral orbitofrontal cortex. These findings suggested plastic changes in speaking-related functional connectivity between left hemispheric speech network nodes. We reanalyzed these data involving 13 stuttering men before and after fluency shaping, 13 men who recovered spontaneously from their stuttering, and 13 male control participants, and examined functional connectivity during overt vs. covert reading by means of psychophysiological interactions computed across left cortical regions involved in articulation control. Persistent stuttering was associated with reduced auditory-motor coupling and enhanced integration of somatosensory feedback between the supramarginal gyrus and the prefrontal cortex. Assisted recovery reduced this hyper-connectivity and increased functional connectivity between the articulatory motor cortex and the auditory feedback processing anterior superior temporal gyrus. In spontaneous recovery, both auditory-motor coupling and integration of somatosensory feedback were normalized. In addition, activity in the left orbitofrontal cortex and superior cerebellum appeared uncoupled from the rest of the speech production network. These data suggest that therapy and spontaneous recovery normalizes the left hemispheric speaking-related activity via an improvement of auditory-motor mapping. By contrast, long-lasting unassisted recovery from stuttering is additionally supported by a functional isolation of the superior cerebellum from the rest of the speech production network, through the pivotal left BA 47/12

Similarity in Programs

Abstract. An overview of the concept of program similarity is presented. It divides similarity into two types—syntactic and semantic— and provides a review of eight categories of methods that may be used to measure program similarity. A summary of some applications of these methods is included. The paper is intended to be a starting point for a more comprehensive analysis of the subject of similarity in programs, which is critical to understand if progress is to be made in fields such as clone detection