02427nas a2200349   4500008004100000022001400041245011100055210006900166260001200235300001100247490000700258520132200265653001501587653002801602653003001630653003701660653002701697653002901724653001101753653001601764653001701780653001301797653003501810653003101845653003201876653004101908653002901949100001201978700001301990700002602003856004802029       2014                        eng d  a1558-021000aAdaptive spatio-temporal filtering for movement related potentials in EEG-based brain-computer interfaces.0 aAdaptive spatiotemporal filtering for movement related potential  c07/2014  a847-570 v223 aMovement related potentials (MRPs) are used as features in many brain-computer interfaces (BCIs) based on electroencephalogram (EEG). MRP feature extraction is challenging since EEG is noisy and varies between subjects. Previous studies used spatial and spatio-temporal filtering methods to deal with these problems. However, they did not optimize temporal information or may have been susceptible to overfitting when training data are limited and the feature space is of high dimension. Furthermore, most of these studies manually select data windows and low-pass frequencies. We propose an adaptive spatio-temporal (AST) filtering method to model MRPs more accurately in lower dimensional space. AST automatically optimizes all parameters by employing a Gaussian kernel to construct a low-pass time-frequency filter and a linear ridge regression (LRR) algorithm to compute a spatial filter. Optimal parameters are simultaneously sought by minimizing leave-one-out cross-validation error through gradient descent. Using four BCI datasets from 12 individuals, we compare the performances of AST filter to two popular methods: the discriminant spatial pattern filter and regularized spatio-temporal filter. The results demonstrate that our AST filter can make more accurate predictions and is computationally feasible.10aAlgorithms10aArtificial Intelligence10abrain-computer interfaces10aData Interpretation, Statistical10aElectroencephalography10aEvoked Potentials, Motor10aHumans10aImagination10aMotor Cortex10aMovement10aPattern Recognition, Automated10aReproducibility of Results10aSensitivity and Specificity10aSignal Processing, Computer-Assisted10aSpatio-Temporal Analysis1 aLu, Jun1 aXie, Kan1 aMcFarland, Dennis, J.  uhttp://www.ncbi.nlm.nih.gov/pubmed/2472363203784nas a2200337   4500008004100000022001400041245006200055210006100117260001200178300001100190490000700201520283200208653001503040653001003055653002403065653002903089653001103118653002603129653001103155653000903166653002903175653002103204653003103225653003403256653002203290653001603312100002103328700002603349700002303375856004803398       2011                        eng d  a1050-054500aDichotic and dichoptic digit perception in normal adults.0 aDichotic and dichoptic digit perception in normal adults  c06/2011  a332-410 v223 aBACKGROUND:
Verbally based dichotic-listening experiments and reproduction-mediated response-selection strategies have been used for over four decades to study perceptual/cognitive aspects of auditory information processing and make inferences about hemispheric asymmetries and language lateralization in the brain. Test procedures using dichotic digits have also been used to assess for disorders of auditory processing. However, with this application, limitations exist and paradigms need to be developed to improve specificity of the diagnosis. Use of matched tasks in multiple sensory modalities is a logical approach to address this issue. Herein, we use dichotic listening and dichoptic viewing of visually presented digits for making this comparison.
PURPOSE:
To evaluate methodological issues involved in using matched tasks of dichotic listening and dichoptic viewing in normal adults.
RESEARCH DESIGN:
A multivariate assessment of the effects of modality (auditory vs. visual), digit-span length (1-3 pairs), response selection (recognition vs. reproduction), and ear/visual hemifield of presentation (left vs. right) on dichotic and dichoptic digit perception.
STUDY SAMPLE:
Thirty adults (12 males, 18 females) ranging in age from 18 to 30 yr with normal hearing sensitivity and normal or corrected-to-normal visual acuity.
DATA COLLECTION AND ANALYSIS:
A computerized, custom-designed program was used for all data collection and analysis. A four-way repeated measures analysis of variance (ANOVA) evaluated the effects of modality, digit-span length, response selection, and ear/visual field of presentation.
RESULTS:
The ANOVA revealed that performances on dichotic listening and dichoptic viewing tasks were dependent on complex interactions between modality, digit-span length, response selection, and ear/visual hemifield of presentation. Correlation analysis suggested a common effect on overall accuracy of performance but isolated only an auditory factor for a laterality index.
CONCLUSIONS:
The variables used in this experiment affected performances in the auditory modality to a greater extent than in the visual modality. The right-ear advantage observed in the dichotic-digits task was most evident when reproduction mediated response selection was used in conjunction with three-digit pairs. This effect implies that factors such as "speech related output mechanisms" and digit-span length (working memory) contribute to laterality effects in dichotic listening performance with traditional paradigms. Thus, the use of multiple-digit pairs to avoid ceiling effects and the application of verbal reproduction as a means of response selection may accentuate the role of nonperceptual factors in performance. Ideally, tests of perceptual abilities should be relatively free of such effects.10aAdolescent10aAdult10aAuditory Perception10aDichotic Listening Tests10aFemale10aFunctional Laterality10aHumans10aMale10aRecognition (Psychology)10aReference Values10aReproducibility of Results10aTask Performance and Analysis10aVisual Perception10aYoung Adult1 aLawfield, Angela1 aMcFarland, Dennis, J.1 aCacace, Anthony, T  uhttp://www.ncbi.nlm.nih.gov/pubmed/2186447100559nas a2200157   4500008004100000022001400041245010000055210006900155260001200224300002900236490000700265653003100272100002600303700002400329856004800353       2002                        eng d  a1059-088900aFactor analysis in CAPD and the "unimodal" test battery: do we have a model that will satisfy?.0 aFactor analysis in CAPD and the unimodal test battery do we have  c06/2002  a7–9; author reply 9-120 v1110aReproducibility of Results1 aMcFarland, Dennis, J.1 aCacace, Anthony, T.  uhttp://www.ncbi.nlm.nih.gov/pubmed/12227358