Pierpaolo Busan1, Giovanni Del Ben2, Lucia Roberta Russo3, Simona Bernardini4, Giulia Natarelli5, Giorgio Arcara6, Paolo Manganotti7, Piero Paolo Battaglini8. 1. Fondazione Ospedale San Camillo IRCCS, via Alberoni 70, 30126 Venice, Italy. Electronic address: pbusan@units.it. 2. B.R.A.I.N. Center for Neuroscience, Department of Life Sciences, University of Trieste, via Fleming 22, 34100 Trieste, Italy. Electronic address: giovanni.delben@phd.units.it. 3. B.R.A.I.N. Center for Neuroscience, Department of Life Sciences, University of Trieste, via Fleming 22, 34100 Trieste, Italy. 4. ABC(®) Balbuzie, Padua, Italy. 5. Department of Developmental and Social Psychology, University of Padua, via Venezia 8, 35100 Padua, Italy. Electronic address: giulia.natarelli@phd.unipd.it. 6. Fondazione Ospedale San Camillo IRCCS, via Alberoni 70, 30126 Venice, Italy. Electronic address: giorgio.arcara@ospedalesancamillo.net. 7. Department of Medical, Surgical and Health Sciences, University of Trieste, Strada di Fiume 447, 34100 Trieste, Italy. Electronic address: pmanganotti@units.it. 8. B.R.A.I.N. Center for Neuroscience, Department of Life Sciences, University of Trieste, via Fleming 22, 34100 Trieste, Italy. Electronic address: battagli@units.it.
Abstract
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.
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.
Authors: Nicole E Neef; Alexandra Korzeczek; Annika Primaßin; Alexander Wolff von Gudenberg; Peter Dechent; Christian Heiner Riedel; Walter Paulus; Martin Sommer Journal: Hum Brain Mapp Date: 2022-04-12 Impact factor: 5.399