Abnormal motor cortex excitability during linguistic tasks in adductor-type spasmodic dysphonia

作者：Suppa A; Marsili L; Giovannelli F; Di Stasio F; Rocchi L; Upadhyay N; Ruoppolo G; Cincotta M; Berardelli A^*

来源：European Journal of Neuroscience, 2015, 42(4): 2051-2060.

DOI：10.1111/ejn.12977

• botulinum toxin
• cepstral analysis
• human
• spasmodic dysphonia
• speech-related network
• transcranial magnetic stimulation

In healthy subjects (HS), transcranial magnetic stimulation (TMS) applied during linguistic' tasks discloses excitability changes in the dominant hemisphere primary motor cortex (M1). We investigated linguistic' task-related cortical excitability modulation in patients with adductor-type spasmodic dysphonia (ASD), a speech-related focal dystonia. We studied 10 ASD patients and 10 HS. Speech examination included voice cepstral analysis. We investigated the dominant/non-dominant M1 excitability at baseline, during linguistic' (reading aloud/silent reading/producing simple phonation) and non-linguistic' tasks (looking at non-letter strings/producing oral movements). Motor evoked potentials (MEPs) were recorded from the contralateral hand muscles. We measured the cortical silent period (CSP) length and tested MEPs in HS and patients performing the linguistic' tasks with different voice intensities. We also examined MEPs in HS and ASD during hand-related action-verb' observation. Patients were studied under and not-under botulinum neurotoxin-type A (BoNT-A). In HS, TMS over the dominant M1 elicited larger MEPs during reading aloud' than during the other linguistic'/non-linguistic' tasks. Conversely, in ASD, TMS over the dominant M1 elicited increased-amplitude MEPs during reading aloud' and syllabic phonation' tasks. CSP length was shorter in ASD than in HS and remained unchanged in both groups performing linguistic'/non-linguistic' tasks. In HS and ASD, linguistic' task-related excitability changes were present regardless of the different voice intensities. During hand-related action-verb' observation, MEPs decreased in HS, whereas in ASD they increased. In ASD, BoNT-A improved speech, as demonstrated by cepstral analysis and restored the TMS abnormalities. ASD reflects dominant hemisphere excitability changes related to linguistic' tasks; BoNT-A returns these excitability changes to normal.

• 出版日期2015-8