000218946 001__ 218946
000218946 005__ 20181203024240.0
000218946 0247_ $$2doi$$a10.1038/srep25803
000218946 022__ $$a2045-2322
000218946 02470 $$2ISI$$a000375614700001
000218946 037__ $$aARTICLE
000218946 245__ $$aWord pair classification during imagined speech using direct brain recordings
000218946 260__ $$bNature Publishing Group$$c2016$$aLondon
000218946 269__ $$a2016
000218946 300__ $$a10
000218946 336__ $$aJournal Articles
000218946 520__ $$aPeople that cannot communicate due to neurological disorders would benefit from an internal speech decoder. Here, we showed the ability to classify individual words during imagined speech from electrocorticographic signals. In a word imagery task, we used high gamma (70–150 Hz) time features with a support vector machine model to classify individual words from a pair of words. To account for temporal irregularities during speech production, we introduced a non-linear time alignment into the SVM kernel. Classification accuracy reached 88% in a two-class classification framework (50% chance level), and average classification accuracy across fifteen word-pairs was significant across five subjects (mean = 58%; p < 0.05). We also compared classification accuracy between imagined speech, overt speech and listening. As predicted, higher classification accuracy was obtained in the listening and overt speech conditions (mean = 89% and 86%, respectively; p < 0.0001), where speech stimuli were directly presented. The results provide evidence for a neural representation for imagined words in the temporal lobe, frontal lobe and sensorimotor cortex, consistent with previous findings in speech perception and production. These data represent a proof of concept study for basic decoding of speech imagery, and delineate a number of key challenges to usage of speech imagery neural representations for clinical applications.
000218946 700__ $$aMartin, Stéphanie
000218946 700__ $$aBrunner, Peter
000218946 700__ $$0247943$$g212988$$aIturrate, Inaki
000218946 700__ $$0240030$$g149175$$aMillán, José del R.
000218946 700__ $$aSchalk, Gerwin
000218946 700__ $$aKnight, Robert T.
000218946 700__ $$aPasley, Brian N.
000218946 773__ $$j6$$tScientific Reports$$q25803
000218946 909C0 $$xU12103$$0252018$$pCNBI
000218946 909C0 $$xU12599$$0252517$$pCNP
000218946 909CO $$pSTI$$particle$$ooai:infoscience.tind.io:218946
000218946 917Z8 $$x149175
000218946 917Z8 $$x149175
000218946 937__ $$aEPFL-ARTICLE-218946
000218946 973__ $$rREVIEWED$$sPUBLISHED$$aEPFL
000218946 980__ $$aARTICLE