@article {3400,
	title = {Dichotic and dichoptic digit perception in normal adults.},
	journal = {J Am Acad Audiol},
	volume = {22},
	year = {2011},
	month = {06/2011},
	pages = {332-41},
	abstract = {BACKGROUND:
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.},
	keywords = {Adolescent, Adult, Auditory Perception, Dichotic Listening Tests, Female, Functional Laterality, Humans, Male, Recognition (Psychology), Reference Values, Reproducibility of Results, Task Performance and Analysis, Visual Perception, Young Adult},
	issn = {1050-0545},
	doi = {10.3766/jaaa.22.6.3},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/21864471},
	author = {Lawfield, Angela and Dennis J. McFarland and Cacace, Anthony T}
}
@article {2136,
	title = {Overlap and refractory effects in a brain-computer interface speller based on the visual P300 event-related potential.},
	journal = {J Neural Eng},
	volume = {6},
	year = {2009},
	month = {04/2009},
	pages = {026003},
	abstract = {<p><span style="font-family: arial, helvetica, clean, sans-serif; font-size: 13px; line-height: 17px;">We reveal the presence of refractory and overlap effects in the event-related potentials in visual P300 speller datasets, and we show their negative impact on the performance of the system. This finding has important implications for how to encode the letters that can be selected for communication. However, we show that such effects are dependent on stimulus parameters: an alternative stimulus type based on apparent motion suffers less from the refractory effects and leads to an improved letter prediction performance.</span></p>},
	keywords = {Algorithms, Brain, Cognition, Computer Simulation, Electroencephalography, Event-Related Potentials, P300, Humans, Models, Neurological, Pattern Recognition, Automated, Photic Stimulation, Semantics, Signal Processing, Computer-Assisted, Task Performance and Analysis, User-Computer Interface, Writing},
	issn = {1741-2552},
	doi = {10.1088/1741-2560/6/2/026003},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/19255462},
	author = {Martens, S M M and Jeremy Jeremy Hill and Farquhar, Jason and Sch{\"o}lkopf, B}
}
@proceedings {2240,
	title = {Three cases of feature correlation in an electrocorticographic BCI.},
	year = {2008},
	month = {2008},
	pages = {5318-21},
	abstract = {Three human subjects participated in a closed-loop brain computer interface cursor control experiment mediated by implanted subdural electrocorticographic arrays. The paradigm consisted of several stages: baseline recording, hand and tongue motor tasks as the basis for feature selection, two closed-loop one-dimensional feedback experiments with each of these features, and a two-dimensional feedback experiment using both of the features simultaneously. The two selected features were simple channel and frequency band combinations associated with change during hand and tongue movement. Inter-feature correlation and cross-correlation between features during different epochs of each task were quantified for each stage of the experiment. Our anecdotal, three subject, result suggests that while high correlation between horizontal and vertical control signal can initially preclude successful two-dimensional cursor control, a feedback-based learning strategy can be successfully employed by the subject to overcome this limitation and progressively decorrelate these control signals.},
	keywords = {Adolescent, Adult, Algorithms, Electrocardiography, Evoked Potentials, Motor, Female, Humans, Male, Middle Aged, Motor Cortex, Pattern Recognition, Automated, Statistics as Topic, Task Performance and Analysis, User-Computer Interface},
	issn = {1557-170X},
	doi = {10.1109/IEMBS.2008.4650415},
	author = {Miller, John W and Blakely, Timothy and Gerwin Schalk and den Nijs, Marcel and Rao, Rajesh P N and Ojemann, J G}
}
@conference {3438,
	title = {Three cases of feature correlation in an electrocorticographic BCI.},
	booktitle = {Engineering in Medicine and Biology Society, 2008.},
	year = {2008},
	month = {08/2008},
	publisher = {IEEE},
	organization = {IEEE},
	address = {Vancouver, BC},
	abstract = {Three human subjects participated in a closed-loop brain computer interface cursor control experiment mediated by implanted subdural electrocorticographic arrays. The paradigm consisted of several stages: baseline recording, hand and tongue motor tasks as the basis for feature selection, two closed-loop one-dimensional feedback experiments with each of these features, and a two-dimensional feedback experiment using both of the features simultaneously. The two selected features were simple channel and frequency band combinations associated with change during hand and tongue movement. Inter-feature correlation and cross-correlation between features during different epochs of each task were quantified for each stage of the experiment. Our anecdotal, three subject, result suggests that while high correlation between horizontal and vertical control signal can initially preclude successful two-dimensional cursor control, a feedback-based learning strategy can be successfully employed by the subject to overcome this limitation and progressively decorrelate these control signals.},
	keywords = {Adolescent, Adult, Algorithms, automated pattern recognition, control systems, decorrelation, Electrocardiography, Electrodes, Electroencephalography, evoked motor potentials, Feedback, Female, frequency, hospitals, Humans, Male, Middle Aged, Motor Cortex, Signal Processing, Statistics as Topic, Task Performance and Analysis, Tongue, User-Computer Interface},
	doi = {10.1109/IEMBS.2008.4650415},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/19163918},
	author = {Miller, Kai J and Blakely, Timothy and Gerwin Schalk and den Nijs, Marcel and Rao, Rajesh PN and Ojemann, Jeffrey G}
}
@article {3334,
	title = {Correlations between task-related activity and responses to perturbation in primate sensorimotor cortex.},
	journal = {Journal of neurophysiology},
	volume = {44},
	year = {1980},
	month = {12/1980},
	pages = {1122{\textendash}1138},
	abstract = {1. Monkeys were trained to maintain hand position against a range of constant forces. Short-latency responses to passive wrist extension or flexion, as well as short-latency responses to stretch of a single wrist muscle, were recorded from units in areas 4, 3, 1, and 2. These responses were compared to unit activity during active holding and during active movement. 2. Units related to active holding and to active movement were most common in areas 4 and 2. Three-quarters of these units displayed a specific correlation between their passive and active behaviors. Thus, a unit excited by passive extension was excited during active holding against extension force and excited during an active flexion movement. This behavior is similar to the expected concurrent behavior of muscle stretch receptors. By demonstrating that a significant number of task-related units give qualitatively similar responses to passive extension and passive flexion, the results appear to explain the disagreement among previous studies (5, 9, 36) in regard to area 4 behavior during active and passive movements. 3. Area 4 units responded similarly to passive wrist extension and electromagnetic stretch of a single flexor muscle occurring in the absence of wrist extension, indicating that muscle stretch was important in determining area 4 unit responses to passive movements. 4. The similarity of area 4 behavior to area 2 behavior in active and passive situations, along with the observation that area 2 responses to passive movements occurred several milliseconds earlier than those of area 4, emphasizes the importance of area 2 in motor performance and is consistent with significant area 2 mediation of area 4 responses. 5. Results support the hypothesis of an oligosynaptic transcortical pathway (22, 32, 34), beginning in large part with muscle stretch receptors. Furthermore, the correlation noted between short-latency responses to passive movement and task-related activity suggests that this transcortical pathway not only mediates responses to passive movement but may be responsible, to a significant degree, for task-related activity during undisturbed performance. Thus, active position maintenance and active movement were probably accomplished, at least in part, by increasing and decreasing the influence of this pathway on specific area 4 neurons and thereby producing the patterns of area 4 activity responsible for task performance.},
	keywords = {Task Performance and Analysis},
	issn = {0022-3077},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/6450275},
	author = {Jonathan Wolpaw}
}
