Risperidone reduces tic-like motor behaviors and linguistic dysfluencies in severe persistent developmental stuttering

Speech Fluency Improvement in Developmental Stuttering Using Non-invasive Brain Stimulation: Insights From Available Evidence

Developmental stuttering (DS) is a disturbance of the normal rhythm of speech that may be interpreted as very debilitating in the most affected cases. Interventions for DS are historically based on the behavioral modifications of speech patterns (e.g., through speech therapy), which are useful to regain a better speech fluency. However, a great variability in intervention outcomes is normally observed, and no definitive evidence is currently available to resolve stuttering, especially in the case of its persistence in adulthood. In the last few decades, DS has been increasingly considered as a functional disturbance, affecting the correct programming of complex motor sequences such as speech. Compatibly, understanding of the neurophysiological bases of DS has dramatically improved, thanks to neuroimaging, and techniques able to interact with neural tissue functioning [e.g., non-invasive brain stimulation (NIBS)]. In this context, the dysfunctional activity of the cortico-basal-thalamo-cortical networks, as well as the defective patterns of connectivity, seems to play a key role, especially in sensorimotor networks. As a consequence, a direct action on the functionality of "defective" or "impaired" brain circuits may help people who stutter to manage dysfluencies in a better way. This may also "potentiate" available interventions, thus favoring more stable outcomes of speech fluency. Attempts aiming at modulating (and improving) brain functioning of people who stutter, realized by using NIBS, are quickly increasing. Here, we will review these recent advancements being applied to the treatment of DS. Insights will be useful not only to assess whether the speech fluency of people who stutter may be ameliorated by acting directly on brain functioning but also will provide further suggestions about the complex and dynamic pathophysiology of DS, where causal effects and "adaptive''/''maladaptive" compensation mechanisms may be strongly overlapped. In conclusion, this review focuses future research toward more specific, targeted, and effective interventions for DS, based on neuromodulation of brain functioning.

Investigation of Risperidone Treatment Associated With Enhanced Brain Activity in Patients Who Stutter

Stuttering is a childhood onset fluency disorder that leads to impairment in speech. A randomized, double-blinded placebo-controlled study was conducted with 10 adult subjects to observe the effects of risperidone (a dopamine receptor 2/serotonin receptor 2 antagonist) on brain metabolism, using [¹⁸F] deoxyglucose as the marker. At baseline and after 6 weeks of taking risperidone (0.5–2.0 mg/day) or a placebo pill, participants were assigned to a solo reading aloud task for 30 min and subsequently underwent a 90-min positron emission tomography scan. Paired t-tests were performed to compare the pre-treatment vs. post-treatment in groups. After imaging and analysis, the blind was broken, which revealed an equal number of subjects of those on risperidone and those on placebo. There were no significant differences in the baseline scans taken before medication randomization. However, scans taken after active treatment demonstrated higher glucose uptake in the specific regions of the brain for those in the risperidone treatment group (p < 0.05). Risperidone treatment was associated with increased metabolism in the left striatum, which consists of the caudate and putamen, and the Broca’s area. The current study strengthens previous research that suggests the role of elevated dopamine activity and striatal hypometabolism in stuttering. We propose that the mechanism of risperidone’s action in stuttering, in part, involves increased metabolism of striatal astrocytes. We conclude that using neuroimaging techniques to visualize changes in the brain of those who stutter can provide valuable insights into the pathophysiology of the disorder and guide the development of future interventions.

Effect of muscular activation on surrounding motor networks in developmental stuttering: A TMS study

Previous studies regarding developmental stuttering (DS) suggest that motor neural networks are strongly affected. Transcranial magnetic stimulation (TMS) was used to investigate neural activation of the primary motor cortex in DS during movement execution, and the influence of muscle representations involved in movements on "surrounding" ones. TMS was applied over the contralateral abductor digiti minimi (ADM) motor representation, at rest and during the movement of homologue first dorsal interosseous muscles (tonic contraction, phasic movements cued by acoustic signalling, and "self-paced" movements). Results highlighted a lower cortico-spinal excitability of ADM in the left hemisphere of stutterers, and an enhanced intracortical inhibition in their right motor cortex (in comparison to fluent speakers). Abnormal intracortical functioning was especially evident during phasic contractions cued by "external" acoustic signals. An exaggerated inhibition of muscles not directly involved in intended movements, in stuttering, may be useful to obtain more efficient motor control. This was stronger during contractions cued by "external" signals, highlighting mechanisms likely used by stutterers during fluency-evoking conditions.

Altered Modulation of Silent Period in Tongue Motor Cortex of Persistent Developmental Stuttering in Relation to Stuttering Severity

Motor balance in developmental stuttering (DS) was investigated with Transcranial Magnetic Stimulation (TMS), with the aim to define novel neural markers of persistent DS in adulthood. Eleven DS adult males were evaluated with TMS on tongue primary motor cortex, compared to 15 matched fluent speakers, in a “state” condition (i.e. stutterers vs. fluent speakers, no overt stuttering). Motor and silent period thresholds (SPT), recruitment curves, and silent period durations were acquired by recording tongue motor evoked potentials. Tongue silent period duration was increased in DS, especially in the left hemisphere (P<0.05; Hedge’s g or Cohen’s d_unbiased = 1.054, i.e. large effect size), suggesting a “state” condition of higher intracortical inhibition in left motor cortex networks. Differences in motor thresholds (different excitatory/inhibitory ratios in DS) were evident, as well as significant differences in SPT. In fluent speakers, the left hemisphere may be marginally more excitable than the right one in motor thresholds at lower muscular activation, while active motor thresholds and SPT were higher in the left hemisphere of DS with respect to the right one, resulting also in a positive correlation with stuttering severity. Pre-TMS electromyography data gave overlapping evidence. Findings suggest the existence of a complex intracortical balance in DS tongue primary motor cortex, with a particular interplay between excitatory and inhibitory mechanisms, also in neural substrates related to silent periods. Findings are discussed with respect to functional and structural impairments in stuttering, and are also proposed as novel neural markers of a stuttering “state” in persistent DS, helping to define more focused treatments (e.g. neuro-modulation).

Premonitory Awareness in Stuttering Scale (PAiS)

Anticipation of stuttering events in persistent developmental stuttering is a frequent but inadequately measured phenomenon that is of both theoretical and clinical importance. Here, we describe the development and preliminary testing of a German version of the Premonitory Awareness in Stuttering Scale (PAiS): a 12-item questionnaire assessing immediate and prospective anticipation of stuttering that was translated and adapted from the Premonitory Urge for Tics Scale (PUTS) (Woods, Piacentini, Himle, & Chang, 2005). After refining the preliminary PAiS scale in a pilot study, we administered a revised version to 21 adults who stutter (AWS) and 21 age, gender and education-matched control participants. Results demonstrated that the PAiS had good internal consistency and discriminated the two speaker groups very effectively, with AWS reporting anticipation of speech disruptions significantly more often than adults with typical speech. Correlations between the PAiS total score and both the objective and subjective measures of stuttering severity revealed that AWS with high PAiS scores produced fewer stuttered syllables. This is possibly because these individuals are better able to adaptively use these anticipatory sensations to modulate their speech. These results suggest that, with continued refinement, the PAiS has the potential to provide clinicians and researchers with a practical and psychometrically sound tool that can quantify how a given AWS anticipates upcoming stuttering events.

Evaluating the effect of risperidone on speech: A cross-sectional study

Speech subsystems are susceptible to the effects of several factors including medications. The atypical antipsychotics can also adversely affect the speech because of its action on serotonin and dopamine neurotransmitters. The present study aims to analyze the speech characteristics associated with atypical antipsychotic risperidone. Speech of 92 patients on risperidone with or without trihexyphenidyl and/or clonazepam were compared with that of 31 persons who were not on any psychotropic medicines. Compared to control group, maximum phonation duration, sequential motion rate of diadochokinesia was reduced by about 3s and 1syllable/s respectively and s/z ratio was increased by 0.16 in patients with risperidone. Performance of larynx, lips and tongue sub-system and intelligibility of speech were also significantly reduced in risperidone group. Risperidone did impact the phonation and articulation sub-systems of speech mildly, which was independent of tardive dyskinesia and extrapyramidal symptoms. Randomized controlled prospective study looking into impact on speech and related effect on drug adherence, functioning and quality of life needs to be conducted with risperidone and other atypical antipsychotics.

Risperidone: Stuttering

This Hospital Pharmacy feature is extracted from Off-Label Drug Facts, a publication available from Wolters Kluwer Health. Off-Label Drug Facts is a practitioner-oriented resource for information about specific drug uses that are unapproved by the US Food and Drug Administration. This new guide to the literature enables the health care professional or clinician to quickly identify published studies on off-label uses and determine if a specific use is rational in a patient care scenario. References direct the reader to the full literature for more comprehensive information before patient care decisions are made. Direct questions or comments regarding Off-Label Drug Uses to jgeneral@ku.edu .

Anterior capsulotomy improves persistent developmental stuttering with a psychiatric disorder: a case report and literature review

Stuttering is characterized by disrupted fluency of verbal expression, and occurs mostly in children. Persistent developmental stuttering (PDS) may occur in adults. Reports of the surgical management of PDS are limited. Here we present the case of a 28-year-old man who had had PDS since the age of 7 years, was diagnosed with depression and anxiety disorder at the age of 24 years, and had physical concomitants. He underwent a bilateral anterior capsulotomy 4 years after the diagnosis. Over one year of follow-up, his physical concomitants resolved, and significant improvements in his psychiatric disorders and PDS were observed. To the best of our knowledge, this is the first report of simultaneous improvement in a patient's PDS and psychiatric disorder after a bilateral anterior capsulotomy.