Stuttering as a matter of delay in neural activation: A combined TMS/EEG study

Pierpaolo Busan, Giovanni Del Ben, Lucia Roberta Russo, Simona Bernardini, Giulia Natarelli, Giorgio Arcara, Paolo Manganotti, Piero Paolo Battaglini

Research output: Contribution to journalArticlepeer-review


Objective: Brain dynamics in developmental stuttering (DS) are not well understood. The supplementary motor area (SMA) plays a crucial role, since it communicates with regions related to planning/execution of movements, and with sub-cortical regions involved in paced/voluntary acts (such as speech). We used TMS combined with EEG to shed light on connections in DS, stimulating the SMA. Methods: TMS/EEG was recorded in adult DS and fluent speakers (FS), stimulating the SMA during rest. TMS-evoked potentials and source distribution were evaluated. Results: Compared to FS, stutterers showed lower activity of neural sources in early time windows: 66–82 ms in SMA, and 91–102 ms in the left inferior frontal cortex and left inferior parietal lobule. Stutterers, however, showed higher activations in later time windows (i.e. from 260–460 ms), in temporal/premotor regions of the right hemisphere. Conclusions: These findings represent the functional counterpart to known white matter and cortico-basal-thalamo-cortical abnormalities in DS. They also explain how white matter abnormalities and cortico-basal-thalamo-cortical dysfunctions may be associated in DS. Finally, a mechanism is proposed in which compensatory activity of the non-dominant (right) hemisphere is recruited. Significance: DS may be a disorder of neural timing that appears to be delayed compared to FS; new mechanisms that support stuttering symptoms are inferred; the SMA may be a promising target for neuro-rehabilitation.

Original languageEnglish
Pages (from-to)61-76
Number of pages16
JournalClinical Neurophysiology
Issue number1
Publication statusPublished - Jan 1 2019


  • Combined TMS/EEG
  • Neural dynamics
  • Stuttering
  • Supplementary Motor Area
  • Transcranial Magnetic Stimulation

ASJC Scopus subject areas

  • Sensory Systems
  • Neurology
  • Clinical Neurology
  • Physiology (medical)


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