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2002221 
Journal Article 
Reduced intracortical inhibition and facilitation in the primary motor tongue representation of adults who stutter 
Neef, NE; Paulus, W; Neef, A; von Gudenberg, AW; Sommer, M 
2011 
122 
9 
1802-1811 
English 
21377925 
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 non-significant 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 paired-pulse 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.