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Pasculli G, Busan P, Jackson ES, Alm PA, De Gregorio D, Maguire GA, Goodwin GM, Gobbi G, Erritzoe D, Carhart-Harris RL. Psychedelics in developmental stuttering to modulate brain functioning: a new therapeutic perspective? Front Hum Neurosci 2024; 18:1402549. [PMID: 38962146 PMCID: PMC11221540 DOI: 10.3389/fnhum.2024.1402549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2024] [Accepted: 05/27/2024] [Indexed: 07/05/2024] Open
Abstract
Developmental stuttering (DS) is a neurodevelopmental speech-motor disorder characterized by symptoms such as blocks, repetitions, and prolongations. Persistent DS often has a significant negative impact on quality of life, and interventions for it have limited efficacy. Herein, we briefly review existing research on the neurophysiological underpinnings of DS -specifically, brain metabolic and default mode/social-cognitive networks (DMN/SCN) anomalies- arguing that psychedelic compounds might be considered and investigated (e.g., in randomized clinical trials) for treatment of DS. The neural background of DS is likely to be heterogeneous, and some contribution from genetically determinants of metabolic deficiencies in the basal ganglia and speech-motor cortical regions are thought to play a role in appearance of DS symptoms, which possibly results in a cascade of events contributing to impairments in speech-motor execution. In persistent DS, the difficulties of speech are often linked to a series of associated aspects such as social anxiety and social avoidance. In this context, the SCN and DMN (also influencing a series of fronto-parietal, somato-motor, and attentional networks) may have a role in worsening dysfluencies. Interestingly, brain metabolism and SCN/DMN connectivity can be modified by psychedelics, which have been shown to improve clinical evidence of some psychiatric conditions (e.g., depression, post-traumatic stress disorder, etc.) associated with psychological constructs such as rumination and social anxiety, which also tend to be present in persistent DS. To date, while there have been no controlled trials on the effects of psychedelics in DS, anecdotal evidence suggests that these agents may have beneficial effects on stuttering and its associated characteristics. We suggest that psychedelics warrant investigation in DS.
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Affiliation(s)
- Giuseppe Pasculli
- Department of Computer, Control, and Management Engineering (DIAG), La Sapienza University, Rome, Italy
- Italian Society of Psychedelic Medicine (Società Italiana di Medicina Psichedelica–SIMePsi), Bari, Italy
| | | | - Eric S. Jackson
- Department of Communicative Sciences and Disorders, New York University, New York, NY, United States
| | - Per A. Alm
- Department of Communicative Sciences and Disorders, New York University, New York, NY, United States
- Department of Public Health and Caring Sciences, Uppsala University, Uppsala, Sweden
| | - Danilo De Gregorio
- IRCCS, San Raffaele Scientific Institute, Milan, Italy
- Vita-Salute San Raffaele University, Milan, Italy
| | - Gerald A. Maguire
- School of Medicine, American University of Health Sciences, Signal Hill, CA, United States
- CenExel CIT Research, Riverside, CA, United States
| | - Guy M. Goodwin
- Department of Psychiatry, University of Oxford, Oxford, United Kingdom
| | - Gabriella Gobbi
- Neurobiological Psychiatry Unit, Department of Psychiatry, McGill University, Montreal, QC, Canada
| | - David Erritzoe
- Department of Medicine, Centre for Psychedelic Research, Imperial College London, London, United Kingdom
| | - Robin L. Carhart-Harris
- Department of Medicine, Centre for Psychedelic Research, Imperial College London, London, United Kingdom
- Psychedelics Division, Neuroscape, University of California, San Francisco, CA, United States
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Gastaldon S, Busan P, Arcara G, Peressotti F. Inefficient speech-motor control affects predictive speech comprehension: atypical electrophysiological correlates in stuttering. Cereb Cortex 2023:6995383. [PMID: 36682885 DOI: 10.1093/cercor/bhad004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 12/29/2022] [Accepted: 12/30/2022] [Indexed: 01/24/2023] Open
Abstract
Listeners predict upcoming information during language comprehension. However, how this ability is implemented is still largely unknown. Here, we tested the hypothesis proposing that language production mechanisms have a role in prediction. We studied 2 electroencephalographic correlates of predictability during speech comprehension-pre-target alpha-beta (8-30 Hz) power decrease and the post-target N400 event-related potential effect-in a population with impaired speech-motor control, i.e. adults who stutter (AWS), compared to typically fluent adults (TFA). Participants listened to sentences that could either constrain towards a target word or not, modulating its predictability. As a complementary task, participants also performed context-driven word production. Compared to TFA, AWS not only displayed atypical neural responses in production, but, critically, they showed a different pattern also in comprehension. Specifically, while TFA showed the expected pre-target power decrease, AWS showed a power increase in frontal regions, associated with speech-motor control. In addition, the post-target N400 effect was reduced for AWS with respect to TFA. Finally, we found that production and comprehension power changes were positively correlated in TFA, but not in AWS. Overall, the results support the idea that processes and neural structures prominently devoted to speech planning also support prediction during speech comprehension.
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Affiliation(s)
- Simone Gastaldon
- Dipartimento di Psicologia dello Sviluppo e della Socializzazione (DPSS), University of Padova, Via Venezia 8, Padova (PD) 35131, Italy.,Padova Neuroscience Center (PNC), University of Padova, Via Giuseppe Orus 2/B, Padova (PD) 35131, Italy
| | - Pierpaolo Busan
- IRCCS Ospedale San Camillo, Via Alberoni 70, Lido (VE) 30126, Italy
| | - Giorgio Arcara
- IRCCS Ospedale San Camillo, Via Alberoni 70, Lido (VE) 30126, Italy
| | - Francesca Peressotti
- Dipartimento di Psicologia dello Sviluppo e della Socializzazione (DPSS), University of Padova, Via Venezia 8, Padova (PD) 35131, Italy.,Padova Neuroscience Center (PNC), University of Padova, Via Giuseppe Orus 2/B, Padova (PD) 35131, Italy.,Centro Interdipartimentale di Ricerca "I-APPROVE-International Auditory Processing Project in Venice", University of Padova, Via Belzoni 160, Padova (PD) 35121, Italy
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Jannati A, Ryan MA, Kaye HL, Tsuboyama M, Rotenberg A. Biomarkers Obtained by Transcranial Magnetic Stimulation in Neurodevelopmental Disorders. J Clin Neurophysiol 2022; 39:135-148. [PMID: 34366399 PMCID: PMC8810902 DOI: 10.1097/wnp.0000000000000784] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
SUMMARY Transcranial magnetic stimulation (TMS) is a method for focal brain stimulation that is based on the principle of electromagnetic induction where small intracranial electric currents are generated by a powerful fluctuating magnetic field. Over the past three decades, TMS has shown promise in the diagnosis, monitoring, and treatment of neurological and psychiatric disorders in adults. However, the use of TMS in children has been more limited. We provide a brief introduction to the TMS technique; common TMS protocols including single-pulse TMS, paired-pulse TMS, paired associative stimulation, and repetitive TMS; and relevant TMS-derived neurophysiological measurements including resting and active motor threshold, cortical silent period, paired-pulse TMS measures of intracortical inhibition and facilitation, and plasticity metrics after repetitive TMS. We then discuss the biomarker applications of TMS in a few representative neurodevelopmental disorders including autism spectrum disorder, fragile X syndrome, attention-deficit hyperactivity disorder, Tourette syndrome, and developmental stuttering.
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Affiliation(s)
- Ali Jannati
- Neuromodulation Program and Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, MA, USA
- Berenson-Allen Center for Noninvasive Brain Stimulation and Division of Cognitive Neurology, Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
- F.M. Kirby Neurobiology Center, Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Mary A. Ryan
- Neuromodulation Program and Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, MA, USA
- Berenson-Allen Center for Noninvasive Brain Stimulation and Division of Cognitive Neurology, Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Harper Lee Kaye
- Behavioral Neuroscience Program, Division of Medical Sciences, Boston University School of Medicine, Boston, USA
| | - Melissa Tsuboyama
- Neuromodulation Program and Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Alexander Rotenberg
- Neuromodulation Program and Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, MA, USA
- Berenson-Allen Center for Noninvasive Brain Stimulation and Division of Cognitive Neurology, Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
- F.M. Kirby Neurobiology Center, Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, MA, USA
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Busan P, Moret B, Masina F, Del Ben G, Campana G. Speech Fluency Improvement in Developmental Stuttering Using Non-invasive Brain Stimulation: Insights From Available Evidence. Front Hum Neurosci 2021; 15:662016. [PMID: 34456692 PMCID: PMC8386014 DOI: 10.3389/fnhum.2021.662016] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 07/12/2021] [Indexed: 11/21/2022] Open
Abstract
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.
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Affiliation(s)
| | | | | | - Giovanni Del Ben
- Department of Life Sciences, University of Trieste, Trieste, Italy
| | - Gianluca Campana
- Department of General Psychology, University of Padua, Padua, Italy
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Corp DT, Bereznicki HGK, Clark GM, Youssef GJ, Fried PJ, Jannati A, Davies CB, Gomes-Osman J, Kirkovski M, Albein-Urios N, Fitzgerald PB, Koch G, Di Lazzaro V, Pascual-Leone A, Enticott PG. Large-scale analysis of interindividual variability in single and paired-pulse TMS data. Clin Neurophysiol 2021; 132:2639-2653. [PMID: 34344609 DOI: 10.1016/j.clinph.2021.06.014] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 06/22/2021] [Accepted: 06/29/2021] [Indexed: 01/01/2023]
Abstract
OBJECTIVE This study brought together over 60 transcranial magnetic stimulation (TMS) researchers to create the largest known sample of individual participant single and paired-pulse TMS data to date, enabling a more comprehensive evaluation of factors driving response variability. METHODS Authors of previously published studies were contacted and asked to share deidentified individual TMS data. Mixed-effects regression investigated a range of individual and study level variables for their contribution to variability in response to single and paired-pulse TMS data. RESULTS 687 healthy participant's data were pooled across 35 studies. Target muscle, pulse waveform, neuronavigation use, and TMS machine significantly predicted an individual's single-pulse TMS amplitude. Baseline motor evoked potential amplitude, motor cortex hemisphere, and motor threshold (MT) significantly predicted short-interval intracortical inhibition response. Baseline motor evoked potential amplitude, test stimulus intensity, interstimulus interval, and MT significantly predicted intracortical facilitation response. Age, hemisphere, and TMS machine significantly predicted MT. CONCLUSIONS This large-scale analysis has identified a number of factors influencing participants' responses to single and paired-pulse TMS. We provide specific recommendations to minimise interindividual variability in single and paired-pulse TMS data. SIGNIFICANCE This study has used large-scale analyses to give clarity to factors driving variance in TMS data. We hope that this ongoing collaborative approach will increase standardisation of methods and thus the utility of single and paired-pulse TMS.
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Affiliation(s)
- Daniel T Corp
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, Geelong, Australia; Berenson-Allen Center for Non-Invasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
| | - Hannah G K Bereznicki
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, Geelong, Australia
| | - Gillian M Clark
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, Geelong, Australia
| | - George J Youssef
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, Geelong, Australia; Centre for Adolescent Health, Murdoch Children's Research Institute, Parkville, Australia
| | - Peter J Fried
- Berenson-Allen Center for Non-Invasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Ali Jannati
- Berenson-Allen Center for Non-Invasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA; Neuromodulation Program and Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Charlotte B Davies
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, Geelong, Australia
| | - Joyce Gomes-Osman
- Berenson-Allen Center for Non-Invasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA; Department of Physical Therapy, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Melissa Kirkovski
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, Geelong, Australia
| | - Natalia Albein-Urios
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, Geelong, Australia
| | - Paul B Fitzgerald
- Monash Alfred Psychiatry Research Centre, Central Clinical School, The Alfred and Monash University, Melbourne, Australia; Epworth Centre for Innovation in Mental Health, Epworth HealthCare and Central Clinical School, Melbourne, Australia
| | - Giacomo Koch
- Non-invasive Brain Stimulation Unit, Department of Clinical and Behavioral Neurology, IRCCS Santa Lucia Foundation, Rome, Italy; Department of Biomedical and Specialty Surgical Sciences, Section of Human Physiology, University of Ferrara, Italy
| | - Vincenzo Di Lazzaro
- Unit of Neurology, Neurophysiology and Neurobiology, Università Campus Bio-Medico, Rome, Italy
| | - Alvaro Pascual-Leone
- Hinda and Arthur Marcus Institute for Aging Research and Deanna and Sidney Wolk Center for Memory Health, Hebrew SeniorLife, Boston, MA, USA; Department of Neurology, Harvard Medical School, Boston, MA, USA; Guttmann Brain Health Institute, Institut Guttmann de Neurorehabilitació, Universitat Autonoma de Barcelona, Barcelona, Spain
| | - Peter G Enticott
- Cognitive Neuroscience Unit, School of Psychology, Deakin University, Geelong, Australia
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Herbert P, Burke JR. Characterization of stimulus response curves obtained with transcranial magnetic stimulation from bilateral anterior digastric muscles in healthy subjects. Somatosens Mot Res 2021; 38:178-187. [PMID: 34126860 DOI: 10.1080/08990220.2021.1914019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
PURPOSE The purpose of the study was to describe measurements of stimulus-response curves in the anterior digastric muscle (ADM) bilaterally following transcranial magnetic stimulation (TMS) to the right and left hemispheres. The first dorsal interosseous muscle (FDI) was the control muscle. MATERIALS AND METHODS The subjects were 20 healthy young adults. Test sessions determined motor thresholds (MT) and stimulus-response curves (1.0, 1.2, 1.4, 1.6 × MT) from either the FDI or ADM following TMS to left and right hemispheres using the double cone coil. Bilateral recordings of MEPs in the left and right ADM allowed us to generate stimulus response curves following ipsilateral and contralateral TMS. RESULTS Intraclass correlation coefficients (ICC) for MEP amplitudes from ipsilateral and contralateral ADMs were >0.60 at motor threshold (MT) and >0.90 at stimulus intensities above MT. There was a linear increase in MEP amplitudes across stimulus intensities for the FDI following contralateral TMS, while MEP amplitudes from the ADM following contralateral and ipsilateral TMS increased linearly across stimulus intensities [F(3, 57) [Muscle × Recording Site × Stim Intensity] = 33.57; p < 0.05]; (ηp2 = 0.64). The slopes of the stimulus-response curve of the contralateral FDI was greater than the slopes of the stimulus response curves of the ipsilateral and contralateral ADM (p < 0.05). CONCLUSIONS The current study provided insights on the methodology for recording stimulus response curves in the ADM with TMS. These findings may translate into a valid, reliable, and relevant clinical outcome to study the pathophysiology of the corticobulbar motor system.
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Busan P, Del Ben G, Tantone A, Halaj L, Bernardini S, Natarelli G, Manganotti P, Battaglini PP. Effect of muscular activation on surrounding motor networks in developmental stuttering: A TMS study. BRAIN AND LANGUAGE 2020; 205:104774. [PMID: 32135384 DOI: 10.1016/j.bandl.2020.104774] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 01/05/2020] [Accepted: 02/17/2020] [Indexed: 06/10/2023]
Abstract
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.
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Affiliation(s)
- Pierpaolo Busan
- IRCCS Ospedale San Camillo, via Alberoni 70, 30126 Venice, Italy.
| | - Giovanni Del Ben
- Department of Life Sciences, University of Trieste, via Fleming 22, 34100 Trieste, Italy.
| | - Antonietta Tantone
- Department of Life Sciences, University of Trieste, via Fleming 22, 34100 Trieste, Italy
| | - Livia Halaj
- Department of Life Sciences, University of Trieste, via Fleming 22, 34100 Trieste, Italy
| | | | - Giulia Natarelli
- Department of Developmental and Social Psychology, University of Padua, via Venezia 8, 35100 Padua, Italy.
| | - Paolo Manganotti
- Department of Medical, Surgical and Health Sciences, University of Trieste, Strada di Fiume 447, 34149 Trieste, Italy.
| | - Piero Paolo Battaglini
- Department of Life Sciences, University of Trieste, via Fleming 22, 34100 Trieste, Italy.
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Busan P. Developmental stuttering and the role of the supplementary motor cortex. JOURNAL OF FLUENCY DISORDERS 2020; 64:105763. [PMID: 32361030 DOI: 10.1016/j.jfludis.2020.105763] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 04/05/2020] [Accepted: 04/08/2020] [Indexed: 06/11/2023]
Abstract
Developmental stuttering is a frequent neurodevelopmental disorder with a complex neurobiological basis. Robust neural markers of stuttering include imbalanced activity of speech and motor related brain regions, and their impaired structural connectivity. The dynamic interaction of cortical regions is regulated by the cortico-basal ganglia-thalamo-cortical system with the supplementary motor area constituting a crucial cortical site. The SMA integrates information from different neural circuits, and manages information about motor programs such as self-initiated movements, motor sequences, and motor learning. Abnormal functioning of SMA is increasingly reported in stuttering, and has been recently indicated as an additional "neural marker" of DS: anatomical and functional data have documented abnormal structure and activity of the SMA, especially in motor and speech networks. Its connectivity is often impaired, especially when considering networks of the left hemisphere. Compatibly, recent data suggest that, in DS, SMA is part of a poorly synchronized neural network, thus resulting in a likely substrate for the appearance of DS symptoms. However, as evident when considering neural models of stuttering, the role of SMA has not been fully clarified. Herein, the available evidence is reviewed, which highlights the role of the SMA in DS as a neural "hub", receiving and conveying altered information, thus "gating" the release of correct or abnormal motor plans.
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Ullman MT, Earle FS, Walenski M, Janacsek K. The Neurocognition of Developmental Disorders of Language. Annu Rev Psychol 2020; 71:389-417. [DOI: 10.1146/annurev-psych-122216-011555] [Citation(s) in RCA: 78] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Developmental disorders of language include developmental language disorder, dyslexia, and motor-speech disorders such as articulation disorder and stuttering. These disorders have generally been explained by accounts that focus on their behavioral rather than neural characteristics; their processing rather than learning impairments; and each disorder separately rather than together, despite their commonalities and comorbidities. Here we update and review a unifying neurocognitive account—the Procedural circuit Deficit Hypothesis (PDH). The PDH posits that abnormalities of brain structures underlying procedural memory (learning and memory that rely on the basal ganglia and associated circuitry) can explain numerous brain and behavioral characteristics across learning and processing, in multiple disorders, including both commonalities and differences. We describe procedural memory, examine its role in various aspects of language, and then present the PDH and relevant evidence across language-related disorders. The PDH has substantial explanatory power, and both basic research and translational implications.
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Affiliation(s)
- Michael T. Ullman
- Brain and Language Lab, Department of Neuroscience, Georgetown University, Washington, DC 20057, USA
| | - F. Sayako Earle
- Department of Communication Sciences and Disorders, University of Delaware, Newark, Delaware 19713, USA
| | - Matthew Walenski
- Department of Communication Sciences and Disorders, Northwestern University, Evanston, Illinois 60208, USA
| | - Karolina Janacsek
- Institute of Psychology, Eotvos Lorand University (ELTE), H-1071 Budapest, Hungary
- Brain, Memory, and Language Lab; Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, H-1117 Budapest, Hungary
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Sommer M, Omer S, Wolff von Gudenberg A, Paulus W. Hand Motor Cortex Excitability During Speaking in Persistent Developmental Stuttering. Front Hum Neurosci 2019; 13:349. [PMID: 31636556 PMCID: PMC6788188 DOI: 10.3389/fnhum.2019.00349] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 09/20/2019] [Indexed: 11/18/2022] Open
Abstract
Persistent developmental stuttering (PDS) is a speech fluency disorder characterized by intermittent involuntary breakdowns of speech motor control, possibly related to motor cortex excitability. Whether motor cortex dysfunction extends into hand representations is unclear. We here studied task-dependent modulations of hand motor cortex excitability in 10 right-handed adults who stutter (AWS) and 13 age- and sex-matched fluent speaking control participants (ANS), covering a wide range of tasks in an exploratory study. Before, during and after a null speech/rest task, spontaneous speech, solo reading, chorus reading, singing, and non-verbal orofacial movements, transcranial magnetic stimulation was applied over the primary motor cortex and motor evoked potentials (MEPs) were recorded from the abductor digiti minimi muscle of either hand. In both groups, motor threshold was lower in the left than in the right motor cortex. During task performance, MEP amplitudes increased in both groups. A post hoc comparison of spontaneous speech and non-verbal orofacial movements yielded an interaction of group by task with AWS showing larger than ANS MEP amplitude increase in spontaneous speech, but a smaller than ANS MEP amplitude increase in non-verbal orofacial movements. We conclude that hemispheric specialization of hand motor representation is similar for both groups. Spontaneous speech as well as non-verbal orofacial movements are the orofacial tasks that merit further study. The excessive motor cortex facilitation could be reflecting a stronger activation of non-speech muscles during AWS’s speech.
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Affiliation(s)
- Martin Sommer
- Department of Clinical Neurophysiology, University of Göttingen, Göttingen, Germany
| | - Sherko Omer
- Department of Clinical Neurophysiology, University of Göttingen, Göttingen, Germany
| | | | - Walter Paulus
- Department of Clinical Neurophysiology, University of Göttingen, Göttingen, Germany
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Busan P, Del Ben G, Russo LR, Bernardini S, Natarelli G, Arcara G, Manganotti P, Battaglini PP. Stuttering as a matter of delay in neural activation: A combined TMS/EEG study. Clin Neurophysiol 2019; 130:61-76. [DOI: 10.1016/j.clinph.2018.10.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Revised: 08/27/2018] [Accepted: 10/15/2018] [Indexed: 10/27/2022]
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Dinoto A, Busan P, Formaggio E, Bertolotti C, Menichelli A, Stokelj D, Manganotti P. Stuttering-like hesitation in speech during acute/post-acute phase of immune-mediated encephalitis. JOURNAL OF FLUENCY DISORDERS 2018; 58:70-76. [PMID: 30220403 DOI: 10.1016/j.jfludis.2018.09.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Revised: 08/08/2018] [Accepted: 09/05/2018] [Indexed: 06/08/2023]
Abstract
PURPOSE Neurogenic stuttering may be evident after a lesion/dysfunction of wider neural networks. Here we present a case of acquired stuttering as the consequence of immune-mediated encephalitis. METHODS The case of a 71-year old male who complained about the progressive onset of stuttering and disequilibrium as the consequence of immune-mediated encephalitis, is here reported. Administration of corticosteroid methylprednisolone was useful to recover from impairments. An in depth analysis of the electroencephalography (relative power of brain rhythms and source localization) during different phases of the disease/treatment was also realized. RESULTS The patient showed a stuttering-like slowed speech with blocks and repetitions, especially at the beginning of words/sentences, with associated movements of the oro-facial muscles. Speech and general motor skills resulted slowed in their preparation/execution phases. Electroencephalography showed a "slowed" pattern, with delta/theta waves mainly in the prefrontal cortex and in sensorimotor networks. CONCLUSION This case reports a probable immune-mediated encephalitis that resulted in acquired stuttering. The effect of "slowed" oscillatory brain activity on motor skills requesting sequencing and fine coordination (e.g. speech) could result in less "synchronized" systems, easily prone to disruptions.
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Affiliation(s)
- Alessandro Dinoto
- Department of Medical, Surgical, and Health Sciences, University of Trieste, Strada di Fiume 447, 34100, Trieste, Italy.
| | - Pierpaolo Busan
- Fondazione Ospedale San Camillo IRCCS, Via Alberoni 70, 30126, Venice, Italy.
| | - Emanuela Formaggio
- Fondazione Ospedale San Camillo IRCCS, Via Alberoni 70, 30126, Venice, Italy.
| | - Claudio Bertolotti
- Department of Medical, Surgical, and Health Sciences, University of Trieste, Strada di Fiume 447, 34100, Trieste, Italy.
| | - Alina Menichelli
- Neuropsychological Unit, Department of Rehabilitation Medicine, ASUI Trieste, Strada di Fiume 447, 34100, Trieste, Italy.
| | - David Stokelj
- Department of Medical, Surgical, and Health Sciences, University of Trieste, Strada di Fiume 447, 34100, Trieste, Italy.
| | - Paolo Manganotti
- Department of Medical, Surgical, and Health Sciences, University of Trieste, Strada di Fiume 447, 34100, Trieste, Italy.
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Whillier A, Hommel S, Neef NE, Wolff von Gudenberg A, Paulus W, Sommer M. Adults who stutter lack the specialised pre-speech facilitation found in non-stutterers. PLoS One 2018; 13:e0202634. [PMID: 30303960 PMCID: PMC6179203 DOI: 10.1371/journal.pone.0202634] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 08/07/2018] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVES Persistent developmental stuttering is a speech fluency disorder defined by its symptoms, where the underlying neurophysiological causes remain uncertain. This study examined the underlying neurophysiological mechanisms of the speech planning process, using facilitation in the motor cortex during speech preparation as an analogue. METHODS transcranial magnetic stimulation (TMS) pulses induced motor evoked potentials (MEPs), which were recorded from the tongue. Eighteen adults who stutter (AWS) and 17 adults who do not stutter (ANS) completed three experiments, which involved reading a German prefix+verb utterance from a screen. Each experiment involved 120 trials with three distinct levels of speech production: immediate speech, delayed speech without pacing and delayed speech with predefined pacing. TMS was applied shortly before speech onset. Trial MEPs were normalised to average non-speech MEPs. MEP amplitude, MEP facilitation ratio (amplitude: pre-speech offset) and group difference were the outcomes of interest analysed by multiple regression, as well as speech reaction time analysed by correlation. RESULTS MEP values were 11·1%-23·4% lower in AWS than ANS (by standardised Beta), across all three experiments. MEP facilitation ratio slopes were also 4·9%-18·3% flatter in AWS than ANS across all three experiments. Reaction times for AWS were only significantly slower than for ANS in immediate speech and predefined pacing experiments. No stuttering was detected during the trials. The group difference in immediate speech was 100% and 101% greater than the other two experiments respectively. DISCUSSION While performance of both ANS and AWS worsens under disturbed speech conditions, greater disturbance conditions affected controls worse than AWS. Future research and therapy in stuttering should focus on non-disturbed speech.
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Affiliation(s)
- Alexander Whillier
- Department of Clinical Neurophysiology, University Medical Centre Göttingen, Göttingen, Germany
| | - Sina Hommel
- Department of Clinical Neurophysiology, University Medical Centre Göttingen, Göttingen, Germany
| | - Nicole E. Neef
- Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Science, Leipzig, Germany
| | | | - Walter Paulus
- Department of Clinical Neurophysiology, University Medical Centre Göttingen, Göttingen, Germany
| | - Martin Sommer
- Department of Clinical Neurophysiology, University Medical Centre Göttingen, Göttingen, Germany
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Chang SE, Angstadt M, Chow HM, Etchell AC, Garnett EO, Choo AL, Kessler D, Welsh RC, Sripada C. Anomalous network architecture of the resting brain in children who stutter. JOURNAL OF FLUENCY DISORDERS 2018; 55:46-67. [PMID: 28214015 PMCID: PMC5526749 DOI: 10.1016/j.jfludis.2017.01.002] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2016] [Revised: 12/28/2016] [Accepted: 01/14/2017] [Indexed: 05/14/2023]
Abstract
PURPOSE We combined a large longitudinal neuroimaging dataset that includes children who do and do not stutter and a whole-brain network analysis in order to examine the intra- and inter-network connectivity changes associated with stuttering. Additionally, we asked whether whole brain connectivity patterns observed at the initial year of scanning could predict persistent stuttering in later years. METHODS A total of 224 high-quality resting state fMRI scans collected from 84 children (42 stuttering, 42 controls) were entered into an independent component analysis (ICA), yielding a number of distinct network connectivity maps ("components") as well as expression scores for each component that quantified the degree to which it is expressed for each child. These expression scores were compared between stuttering and control groups' first scans. In a second analysis, we examined whether the components that were most predictive of stuttering status also predicted persistence in stuttering. RESULTS Stuttering status, as well as stuttering persistence, were associated with aberrant network connectivity involving the default mode network and its connectivity with attention, somatomotor, and frontoparietal networks. The results suggest developmental alterations in the balance of integration and segregation of large-scale neural networks that support proficient task performance including fluent speech motor control. CONCLUSIONS This study supports the view that stuttering is a complex neurodevelopmental disorder and provides comprehensive brain network maps that substantiate past theories emphasizing the importance of considering situational, emotional, attentional and linguistic factors in explaining the basis for stuttering onset, persistence, and recovery.
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Affiliation(s)
- Soo-Eun Chang
- Department of Psychiatry, University of Michigan, Ann Arbor, MI, United States.
| | - Michael Angstadt
- Department of Psychiatry, University of Michigan, Ann Arbor, MI, United States
| | - Ho Ming Chow
- Department of Psychiatry, University of Michigan, Ann Arbor, MI, United States
| | - Andrew C Etchell
- Department of Psychiatry, University of Michigan, Ann Arbor, MI, United States
| | - Emily O Garnett
- Department of Psychiatry, University of Michigan, Ann Arbor, MI, United States
| | - Ai Leen Choo
- Department of Communicative Sciences and Disorders, California State University East Bay, Hayward, CA, United States
| | - Daniel Kessler
- Department of Psychiatry, University of Michigan, Ann Arbor, MI, United States
| | - Robert C Welsh
- Department of Psychiatry, University of Utah, Salt Lake City, UT, United States
| | - Chandra Sripada
- Department of Psychiatry, University of Michigan, Ann Arbor, MI, United States
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15
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Etchell AC, Civier O, Ballard KJ, Sowman PF. A systematic literature review of neuroimaging research on developmental stuttering between 1995 and 2016. JOURNAL OF FLUENCY DISORDERS 2018; 55:6-45. [PMID: 28778745 DOI: 10.1016/j.jfludis.2017.03.007] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2016] [Revised: 01/25/2017] [Accepted: 03/06/2017] [Indexed: 05/14/2023]
Abstract
PURPOSE Stuttering is a disorder that affects millions of people all over the world. Over the past two decades, there has been a great deal of interest in investigating the neural basis of the disorder. This systematic literature review is intended to provide a comprehensive summary of the neuroimaging literature on developmental stuttering. It is a resource for researchers to quickly and easily identify relevant studies for their areas of interest and enable them to determine the most appropriate methodology to utilize in their work. The review also highlights gaps in the literature in terms of methodology and areas of research. METHODS We conducted a systematic literature review on neuroimaging studies on developmental stuttering according to the PRISMA guidelines. We searched for articles in the pubmed database containing "stuttering" OR "stammering" AND either "MRI", "PET", "EEG", "MEG", "TMS"or "brain" that were published between 1995/01/01 and 2016/01/01. RESULTS The search returned a total of 359 items with an additional 26 identified from a manual search. Of these, there were a total of 111 full text articles that met criteria for inclusion in the systematic literature review. We also discuss neuroimaging studies on developmental stuttering published throughout 2016. The discussion of the results is organized first by methodology and second by population (i.e., adults or children) and includes tables that contain all items returned by the search. CONCLUSIONS There are widespread abnormalities in the structural architecture and functional organization of the brains of adults and children who stutter. These are evident not only in speech tasks, but also non-speech tasks. Future research should make greater use of functional neuroimaging and noninvasive brain stimulation, and employ structural methodologies that have greater sensitivity. Newly planned studies should also investigate sex differences, focus on augmenting treatment, examine moments of dysfluency and longitudinally or cross-sectionally investigate developmental trajectories in stuttering.
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Affiliation(s)
- Andrew C Etchell
- Department of Psychiatry, University of Michigan, MI, United States; Department of Cognitive Science, Macquarie University, Sydney, Australia.
| | - Oren Civier
- The Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan, Israel; Department of Computer Science and Applied Mathematics, Weizmann Institute of Science, Rehovot, Israel
| | - Kirrie J Ballard
- Faculty of Health Sciences, University of Sydney, Sydney, Australia
| | - Paul F Sowman
- Department of Cognitive Science, Macquarie University, Sydney, Australia
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16
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Busan P, Battaglini P, Sommer M. Transcranial magnetic stimulation in developmental stuttering: Relations with previous neurophysiological research and future perspectives. Clin Neurophysiol 2017; 128:952-964. [DOI: 10.1016/j.clinph.2017.03.039] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2016] [Revised: 03/14/2017] [Accepted: 03/22/2017] [Indexed: 10/19/2022]
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Busan P, Del Ben G, Bernardini S, Natarelli G, Bencich M, Monti F, Manganotti P, Battaglini PP. Altered Modulation of Silent Period in Tongue Motor Cortex of Persistent Developmental Stuttering in Relation to Stuttering Severity. PLoS One 2016; 11:e0163959. [PMID: 27711148 PMCID: PMC5053488 DOI: 10.1371/journal.pone.0163959] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 09/16/2016] [Indexed: 12/20/2022] Open
Abstract
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 dunbiased = 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).
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Affiliation(s)
- Pierpaolo Busan
- IRCCS Fondazione Ospedale San Camillo, Venice, Italy
- * E-mail:
| | - Giovanni Del Ben
- B.R.A.I.N. Center for Neuroscience, Department of Life Sciences, University of Trieste, Trieste, Italy
| | | | - Giulia Natarelli
- Department of Developmental and Social Psychology, University of Padua, Padua, Italy
| | - Marco Bencich
- B.R.A.I.N. Center for Neuroscience, Department of Life Sciences, University of Trieste, Trieste, Italy
| | - Fabrizio Monti
- Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy
| | - Paolo Manganotti
- Department of Medical, Surgical and Health Sciences, University of Trieste, Trieste, Italy
| | - Piero Paolo Battaglini
- B.R.A.I.N. Center for Neuroscience, Department of Life Sciences, University of Trieste, Trieste, Italy
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Rogić Vidaković M, Jerković A, Jurić T, Vujović I, Šoda J, Erceg N, Bubić A, Zmajević Schönwald M, Lioumis P, Gabelica D, Đogaš Z. Neurophysiologic markers of primary motor cortex for laryngeal muscles and premotor cortex in caudal opercular part of inferior frontal gyrus investigated in motor speech disorder: a navigated transcranial magnetic stimulation (TMS) study. Cogn Process 2016; 17:429-442. [PMID: 27130564 DOI: 10.1007/s10339-016-0766-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 04/18/2016] [Indexed: 11/24/2022]
Abstract
Transcranial magnetic stimulation studies have so far reported the results of mapping the primary motor cortex (M1) for hand and tongue muscles in stuttering disorder. This study was designed to evaluate the feasibility of repetitive navigated transcranial magnetic stimulation (rTMS) for locating the M1 for laryngeal muscle and premotor cortical area in the caudal opercular part of inferior frontal gyrus, corresponding to Broca's area in stuttering subjects by applying new methodology for mapping these motor speech areas. Sixteen stuttering and eleven control subjects underwent rTMS motor speech mapping using modified patterned rTMS. The subjects performed visual object naming task during rTMS applied to the (a) left M1 for laryngeal muscles for recording corticobulbar motor-evoked potentials (CoMEP) from cricothyroid muscle and (b) left premotor cortical area in the caudal opercular part of inferior frontal gyrus while recording long latency responses (LLR) from cricothyroid muscle. The latency of CoMEP in control subjects was 11.75 ± 2.07 ms and CoMEP amplitude was 294.47 ± 208.87 µV, and in stuttering subjects CoMEP latency was 12.13 ± 0.75 ms and 504.64 ± 487.93 µV CoMEP amplitude. The latency of LLR in control subjects was 52.8 ± 8.6 ms and 54.95 ± 4.86 in stuttering subjects. No significant differences were found in CoMEP latency, CoMEP amplitude, and LLR latency between stuttering and control-fluent speakers. These results indicate there are probably no differences in stuttering compared to controls in functional anatomy of the pathway used for transmission of information from premotor cortex to the M1 cortices for laryngeal muscle representation and from there via corticobulbar tract to laryngeal muscles.
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Affiliation(s)
- Maja Rogić Vidaković
- School of Medicine, Laboratory for Human and Experimental Neurophysiology (LAHEN), Department of Neuroscience, University of Split, Šoltanska 2, 21000, Split, Croatia.
| | - Ana Jerković
- Faculty of Philosophy, University of Zagreb, Ivana Lučića 3, 10000, Zagreb, Croatia
| | - Tomislav Jurić
- Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture, Department of Electronics, University of Split, R. Boškovića 32, Split, Croatia
| | - Igor Vujović
- Faculty of Maritime Studies, Signal Processing, Analysis and Advanced Diagnostics Research and Education Laboratory (SPAADREL), University of Split, Ruđera-Boškovića 37, Split, Croatia
| | - Joško Šoda
- Faculty of Maritime Studies, Signal Processing, Analysis and Advanced Diagnostics Research and Education Laboratory (SPAADREL), University of Split, Ruđera-Boškovića 37, Split, Croatia
| | - Nikola Erceg
- Faculty of Humanities and Social Sciences, University of Split, Put iza nove bolnice 10 C, Split, Croatia
| | - Andreja Bubić
- Faculty of Humanities and Social Sciences, University of Split, Put iza nove bolnice 10 C, Split, Croatia
| | - Marina Zmajević Schönwald
- Clinical Medical Centre "Sisters of Mercy", Department of Neurosurgery, Clinical Unit for Intraoperative Neurophysiologic Monitoring, Vinogradska 29 A, Zagreb, Croatia
| | - Pantelis Lioumis
- Bio Mag Laboratory HUS Medical Imaging center, Helsinki University Hospital, P.O. Box 340, 00029, HUS, Helsinki, Finland
| | - Dragan Gabelica
- School of Medicine, Laboratory for Human and Experimental Neurophysiology (LAHEN), Department of Neuroscience, University of Split, Šoltanska 2, 21000, Split, Croatia.,SGM Medical Monitoring, Grge Novaka 22A, 21000, Split, Croatia
| | - Zoran Đogaš
- School of Medicine, Laboratory for Human and Experimental Neurophysiology (LAHEN), Department of Neuroscience, University of Split, Šoltanska 2, 21000, Split, Croatia
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19
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Neef NE, Anwander A, Friederici AD. The Neurobiological Grounding of Persistent Stuttering: from Structure to Function. Curr Neurol Neurosci Rep 2015; 15:63. [PMID: 26228377 DOI: 10.1007/s11910-015-0579-4] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Nicole E Neef
- Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, Stephanstr. 1a, 04103, Leipzig, Germany,
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20
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Rabaeys H, Bijleveld HA, Devroey D. Influence of Methylphenidate on the Frequency of Stuttering. Ann Pharmacother 2015; 49:1096-104. [DOI: 10.1177/1060028015596415] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Background: Recently, a case report described a decrease in frequency of stuttering after intake of methylphenidate (MPH). Objective: This study was undertaken to investigate if this effect could again be reproduced in a population of young healthy male adult persons with developmental stuttering. Methods: A double-blind randomized crossover trial, with a 2-week washout period, including 15 Dutch-speaking young healthy persons with developmental stuttering, assessed the effects of a single dose of 20 mg MPH compared with placebo on stuttering. Dependent and 1-sample t tests were used to detect significant differences. The end point was the number of stutter moments and self-perceived improvement. Results: MPH yielded a significant decrease in the number of stutter moments when reading and speaking ( P = 0.002), which was not the case with placebo ( P = 0.090). There was a significant improvement from baseline after intake of MPH as compared with placebo ( P = 0.003). Self-perceived improvement with MPH was not significantly better as compared with placebo ( P = 0.28). Conclusions: This study showed that the participants had an objective statistically significant decrease in the frequency of stuttering with MPH, and this was not the case with placebo. This was also the case for a reduction in stutter moments when reading out loud and speaking spontaneously. However, this result was not subjectively perceived by the participants.
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21
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Neef NE, Hoang TNL, Neef A, Paulus W, Sommer M. Speech dynamics are coded in the left motor cortex in fluent speakers but not in adults who stutter. ACTA ACUST UNITED AC 2015; 138:712-25. [PMID: 25595146 DOI: 10.1093/brain/awu390] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The precise excitability regulation of neuronal circuits in the primary motor cortex is central to the successful and fluent production of speech. Our question was whether the involuntary execution of undesirable movements, e.g. stuttering, is linked to an insufficient excitability tuning of neural populations in the orofacial region of the primary motor cortex. We determined the speech-related time course of excitability modulation in the left and right primary motor tongue representation. Thirteen fluent speakers (four females, nine males; aged 23-44) and 13 adults who stutter (four females, nine males, aged 21-55) were asked to build verbs with the verbal prefix 'auf'. Single-pulse transcranial magnetic stimulation was applied over the primary motor cortex during the transition phase between a fixed labiodental articulatory configuration and immediately following articulatory configurations, at different latencies after transition onset. Bilateral electromyography was recorded from self-adhesive electrodes placed on the surface of the tongue. Off-line, we extracted the motor evoked potential amplitudes and normalized these amplitudes to the individual baseline excitability during the fixed configuration. Fluent speakers demonstrated a prominent left hemisphere increase of motor cortex excitability in the transition phase (P = 0.009). In contrast, the excitability of the right primary motor tongue representation was unchanged. Interestingly, adults afflicted with stuttering revealed a lack of left-hemisphere facilitation. Moreover, the magnitude of facilitation was negatively correlated with stuttering frequency. Although orofacial midline muscles are bilaterally innervated from corticobulbar projections of both hemispheres, our results indicate that speech motor plans are controlled primarily in the left primary speech motor cortex. This speech motor planning-related asymmetry towards the left orofacial motor cortex is missing in stuttering. Moreover, a negative correlation between the amount of facilitation and stuttering severity suggests that we discovered a main physiological principle of fluent speech production and its role in stuttering.
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Affiliation(s)
- Nicole E Neef
- 1 Department of Clinical Neurophysiology, Georg-August-University, Göttingen, Germany 2 Max Planck Institute for Human Cognitive and Brain Sciences, Department of Neuropsychology, Leipzig, Germany
| | - T N Linh Hoang
- 1 Department of Clinical Neurophysiology, Georg-August-University, Göttingen, Germany
| | - Andreas Neef
- 3 Max Planck Institute for Dynamics and Self-Organization, Department of Nonlinear Dynamics, Göttingen, Germany
| | - Walter Paulus
- 1 Department of Clinical Neurophysiology, Georg-August-University, Göttingen, Germany
| | - Martin Sommer
- 1 Department of Clinical Neurophysiology, Georg-August-University, Göttingen, Germany
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