Differentiation of epileptic regions from voluntary high-gamma activation via interictal cross-frequency windowed power-power correlation

2020 ◽  
Vol 133 (1) ◽  
pp. 43-53
Author(s):  
Michael Kogan ◽  
David J. Caldwell ◽  
Shahin Hakimian ◽  
Kurt E. Weaver ◽  
Andrew L. Ko ◽  
...  
Keyword(s):  
Cognitive Task ◽  
Motor Task ◽  
Electrode Site ◽  
Specific Marker ◽  
Epileptogenic Zone ◽  
Band Frequency ◽  
Window Method ◽  
High Gamma ◽  
Band Limited ◽  
Positive Correlations

OBJECTIVEElectrocorticography is an indispensable tool in identifying the epileptogenic zone in the presurgical evaluation of many epilepsy patients. Traditional electrocorticographic features (spikes, ictal onset changes, and recently high-frequency oscillations [HFOs]) rely on the presence of transient features that occur within or near epileptogenic cortex. Here the authors report on a novel corticography feature of epileptogenic cortex—covariation of high-gamma and beta frequency band power profiles. Band-limited power was measured from each recording site based on native physiological signal differences without relying on clinical ictal or interictal epileptogenic features. In this preliminary analysis, frequency windowed power correlation appears to be a specific marker of the epileptogenic zone. The authors’ overall aim was to validate this observation with the location of the eventual resection and outcome.METHODSThe authors conducted a retrospective analysis of 13 adult patients who had undergone electrocorticography for surgical planning at their center. They quantified the correlation of high-gamma (70–200 Hz) and beta (12–18 Hz) band frequency power per electrode site during a cognitive task. They used a sliding window method to correlate the power of smoothed, Hilbert-transformed high-gamma and beta bands. They then compared positive and negative correlations between power in the high-gamma and beta bands in the setting of a hand versus a tongue motor task as well as within the resting state. Significant positive correlations were compared to surgically resected areas and outcomes based on reviewed records.RESULTSPositive high-gamma and beta correlations appeared to predict the area of eventual resection and, preliminarily, surgical outcome independent of spike detection. In general, patients with the best outcomes had well-localized positive correlations (high-gamma and beta activities) to areas of eventual resection, while those with poorer outcomes displayed more diffuse patterns.CONCLUSIONSData in this study suggest that positive high-gamma and beta correlations independent of any behavioral metric may have clinical applicability in surgical decision-making. Further studies are needed to evaluate the clinical potential of this methodology. Additional work is also needed to relate these results to other methods, such as HFO detection or connectivity with other cortical areas.

Time series analysis of Holocene climate data

1990 ◽  
Vol 330 (1615) ◽  
pp. 601-616 ◽  
Keyword(s):  
Time Series ◽  
Time Series Analysis ◽  
Time Domain ◽  
Small Sample ◽  
Climate Data ◽  
Holocene Climate ◽  
Series Analysis ◽  
Window Method ◽  
Band Limited ◽  
Periodic Components

Holocene climate records are imperfect proxies for processes containing complicated mixtures of periodic and random signals. I summarize time series analysis methods for such data with emphasis on the multiple-data-window technique. This method differs from conventional approaches to time series analysis in that a set of data tapers is applied to the data in the time domain before Fourier transforming. The tapers, or data windows, are discrete prolate spheroidal sequences characterized as being the most nearly band-limited functions possible among functions defined on a finite time domain. The multiple-window method is a small-sample theory and essentially an inverse method applied to the finite Fourier transform. For climate data it has the major advantage of providing a narrowband F -test for the presence and significance of periodic components and of being able to separate them from the non-deterministic part of the process. Confidence intervals for the estimated quantities are found by jackknifing across windows. Applied to 14 C records, this method confirms the presence of the ‘Suess wiggles’ and give an estimated period of 208.2 years. Analysis of the thickness variations of bristlecone pine growth rings shows a general absence of direct periodic components but a variation in the structure of the time series with a 2360-year period.

scholarly journals Modifications in Prefrontal Cortex Oxygenation in Linear and Curvilinear Dual Task Walking: A Combined fNIRS and IMUs Study

Sensors ◽  
2021 ◽  
Vol 21 (18) ◽  
pp. 6159
Author(s):  
Valeria Belluscio ◽  
Gabriele Casti ◽  
Marco Ferrari ◽  
Valentina Quaresima ◽  
Maria Sofia Sappia ◽  
...  
Keyword(s):  
Prefrontal Cortex ◽  
Dual Task ◽  
Near Infrared ◽  
Cognitive Task ◽  
Real Life ◽  
Motor Task ◽  
Hemoglobin Concentration ◽  
Cortical Activation ◽  
Functional Near Infrared Spectroscopy ◽  
Gait Quality

Increased oxygenated hemoglobin concentration of the prefrontal cortex (PFC) has been observed during linear walking, particularly when there is a high attention demand on the task, like in dual-task (DT) paradigms. Despite the knowledge that cognitive and motor demands depend on the complexity of the motor task, most studies have only focused on usual walking, while little is known for more challenging tasks, such as curved paths. To explore the relationship between cortical activation and gait biomechanics, 20 healthy young adults were asked to perform linear and curvilinear walking trajectories in single-task and DT conditions. PFC activation was assessed using functional near-infrared spectroscopy, while gait quality with four inertial measurement units. The Figure-of-8-Walk-Test was adopted as the curvilinear trajectory, with the “Serial 7s” test as concurrent cognitive task. Results show that walking along curvilinear trajectories in DT led to increased PFC activation and decreased motor performance. Under DT walking, the neural correlates of executive function and gait control tend to be modified in response to the cognitive resources imposed by the motor task. Being more representative of real-life situations, this approach to curved walking has the potential to reveal crucial information and to improve people’ s balance, safety, and life’s quality.

scholarly journals Human Cognitive and Motor Abilities in the Aging Workforce: An Information-Based Model

2020 ◽  
Vol 10 (17) ◽  
pp. 5958
Author(s):  
Salvatore Digiesi ◽  
Daniela Cavallo ◽  
Andrea Lucchese ◽  
Carlotta Mummolo
Keyword(s):  
Information Content ◽  
Cognitive Abilities ◽  
Cognitive Task ◽  
Experimental Studies ◽  
Motor Task ◽  
Aging Workforce ◽  
Motor Abilities ◽  
Workforce Aging ◽  
And Performance

In the digital society, individuals are in charge of performing tasks based on the information gathered by huge amount of data and effectively use them to manifest their cognitive and motor abilities. In this paper, on the basis of experimental studies available in literature concerning lab tests on motor or cognitive abilities of differently aged subjects, an information-based theoretical model is proposed. The model allows to quantify the information content of a motor or a cognitive task and provides estimates of information processing time of individuals of different age and sex in accomplishing tasks with prevalent motor or cognitive nature, in spite of the fact that a “pure” cognitive or a “pure” motor task are rarely observed in practical cases. The model is then applied to a case study from automotive industry in which workforce aging phenomenon is experienced. Potential applications of the model go beyond the case study developed. Quantifying the information content of a general motor-cognitive task paves the way to new understanding and modelling of movements and performance time of both natural and artificial systems with applications in industrial robotics (e.g., human-robot cooperation), biomechanics, and neurorehabilitation.

scholarly journals A unifying principle underlying the extracellular field potential spectral responses in the human cortex

2015 ◽  
Vol 114 (1) ◽  
pp. 505-519 ◽  
Author(s):  
Ella Podvalny ◽  
Niv Noy ◽  
Michal Harel ◽  
Stephan Bickel ◽  
Gal Chechik ◽  
...  
Keyword(s):  
Field Potential ◽  
Neuronal Activation ◽  
Human Cortex ◽  
Neuronal Process ◽  
High Gamma ◽  
Neuronal Processes ◽  
Limited Power ◽  
Visuomotor Tasks ◽  
Band Limited ◽  
Spectrum Slope

Electrophysiological mass potentials show complex spectral changes upon neuronal activation. However, it is unknown to what extent these complex band-limited changes are interrelated or, alternatively, reflect separate neuronal processes. To address this question, intracranial electrocorticograms (ECoG) responses were recorded in patients engaged in visuomotor tasks. We found that in the 10- to 100-Hz frequency range there was a significant reduction in the exponent χ of the 1/ fχ component of the spectrum associated with neuronal activation. In a minority of electrodes showing particularly high activations the exponent reduction was associated with specific band-limited power modulations: emergence of a high gamma (80–100 Hz) and a decrease in the alpha (9–12 Hz) peaks. Importantly, the peaks' height was correlated with the 1/ fχ exponent on activation. Control simulation ruled out the possibility that the change in 1/ fχ exponent was a consequence of the analysis procedure. These results reveal a new global, cross-frequency (10–100 Hz) neuronal process reflected in a significant reduction of the power spectrum slope of the ECoG signal.

Bidirectional Interference Between Speech and Nonspeech Tasks in Younger, Middle-Aged, and Older Adults

2015 ◽  
Vol 58 (6) ◽  
pp. 1637-1653 ◽  
Author(s):  
Dallin J. Bailey ◽  
Christopher Dromey
Keyword(s):  
Divided Attention ◽  
Cognitive Task ◽  
Motor Task ◽  
Middle Aged ◽  
Cross Sectional ◽  
Semantic Decision ◽  
Motor Condition ◽  
Cross Sectional Design ◽  
Age Range ◽  
Speech Motor

Purpose The purpose of this study was to examine divided attention over a large age range by looking at the effects of 3 nonspeech tasks on concurrent speech motor performance. The nonspeech tasks were designed to facilitate measurement of bidirectional interference, allowing examination of their sensitivity to speech activity. A cross-sectional design was selected to explore possible changes in divided-attention effects associated with age. Method Sixty healthy participants were separated into 3 groups of 20: younger (20s), middle-aged (40s), and older (60s) adults. Each participant completed a speech task (sentence repetitions) once in isolation and once concurrently with each of 3 nonspeech tasks: a semantic-decision linguistic task, a quantitative-comparison cognitive task, and a manual motor task. The nonspeech tasks were also performed in isolation. Results Data from speech kinematics and nonspeech task performance indicated significant task-specific divided attention interference, with divided attention affecting speech and nonspeech measures in the linguistic and cognitive conditions and affecting speech measures in the manual motor condition. There was also a significant age effect for utterance duration. Conclusions The results increase what is known about bidirectional interference between speech and other concurrent tasks as well as age effects on speech motor control.

scholarly journals Nonuniform High-Gamma (60-500 Hz) Power Changes Dissociate Cognitive Task and Anatomy in Human Cortex

2011 ◽  
Vol 31 (6) ◽  
pp. 2091-2100 ◽  
Author(s):  
C. M. Gaona ◽  
M. Sharma ◽  
Z. V. Freudenburg ◽  
J. D. Breshears ◽  
D. T. Bundy ◽  
...  
Keyword(s):  
Cognitive Task ◽  
Human Cortex ◽  
High Gamma

scholarly journals Attention-Demanding Cognitive Tasks Worsen Postural Control in Patients With Cervical Dystonia: A Case-Control Study

2021 ◽  
Vol 12 ◽  
Author(s):  
Viola Baione ◽  
Gina Ferrazzano ◽  
Claudia Celletti ◽  
Matteo De Rosa ◽  
Daniele Belvisi ◽  
...  
Keyword(s):  
Postural Control ◽  
Cervical Dystonia ◽  
Case Control Study ◽  
Task Complexity ◽  
Cognitive Task ◽  
Motor Task ◽  
Case Control ◽  
Healthy Controls ◽  
Sensorimotor Disturbances ◽  
Control Study

Background: Patients with cervical dystonia (CD) show impaired postural control, balance, and gait, likely due to abnormal head postures and sensorimotor disturbances. However, until now no study has investigated whether attention-demanding activity worsens postural control and balance in CD patients.Objective: To investigate whether patients with CD show cognitive-motor interference (CMI), a specific kind of dual-task interference that occurs during the simultaneous execution of a cognitive and motor task. This information may be useful to determine whether performing activities of daily living worsens postural control and balance in CD patients.Methods: We performed a pilot case-control study. Twenty-two patients affected by CD and 19 healthy controls were enrolled in order to test CMI. Each subject was evaluated during the execution of a cognitive task while postural stability was assessed through a stabilometric platform.Results: CD patients showed impaired postural control compared to healthy controls, with instability increasing with increasing cognitive task complexity. No relationships were found between stabilometric parameters and clinical characteristics of CD.Conclusions: Our hypothesis is that CMI in CD patients derives from deranged network connectivity when activated simultaneously during the performance of two tasks that interfere with each other and “compete” for the same resources within the cognitive system.

scholarly journals Dual Task Effects on Speed and Accuracy During Cognitive and Upper Limb Motor Tasks in Adults With Stroke Hemiparesis

2021 ◽  
Vol 15 ◽  
Author(s):  
Hogene Kim ◽  
Hyun-Ki Kim ◽  
Nayoung Kim ◽  
Chang S. Nam
Keyword(s):  
Upper Limb ◽  
Dual Task ◽  
Word Association ◽  
Cognitive Task ◽  
Motor Task ◽  
Motor Speed ◽  
Dual Tasks ◽  
The Cross ◽  
Motor Accuracy ◽  
Speed And Accuracy

BackgroundAdults with stroke need to perform cognitive–motor dual tasks during their day-to-day activities. However, they face several challenges owing to their impaired motor and cognitive functions.ObjectiveThis case-controlled pilot study investigates the speed and accuracy tradeoffs in adults with stroke while performing cognitive–upper limb motor dual tasks.MethodsTen adults with stroke and seven similar-aged controls participated in this study. The participants used a robotic arm for the single motor task and participated in either the serial sevens (S7) or the controlled oral word association test (COWAT) for single-cognitive task. For the dual task, the participants performed the motor and cognitive components simultaneously. Their speed and accuracy were measured for the motor and cognitive tasks, respectively.ResultsTwo-sample t-statistics indicated that the participants with stroke exhibited a lower motor accuracy in the cross task than in the circle task. The cognitive speed and motor accuracy registered by the subjects with stroke in the dual task significantly decreased. There was a negative linear correlation between motor speed and accuracy in the subjects with stroke when the COWAT task was performed in conjunction with the cross task (ρ = −0.6922, p = 0.0388).ConclusionsThis study proves the existence of cognitive–upper limb motor interference in adults with stroke while performing dual tasks, based on the observation that their performance during one or both dual tasks deteriorated compared to that during the single task. Both speed and accuracy were complementary parameters that may indicate clinical effectiveness in motor and cognitive outcomes in individuals with stroke.

Discrepancies Between the Rorschach Inkblot Method and Self-Report Measures of Personality

2005 ◽  
Vol 27 (1) ◽  
pp. 101-116 ◽  
Author(s):  
Jean-Michel Petot ◽  
Dragana Djurić Jočić
Keyword(s):  
Specific Pattern ◽  
Self Report ◽  
Specific Marker ◽  
Personality Psychology ◽  
Test Taking ◽  
Established Fact ◽  
Positive Correlations ◽  
Formal Properties ◽  
Rorschach Variables ◽  
Excessive Number

Because the quasi-absence of correlation between Rorschach variables and the dimensions described in academic psychology of personality is now a well-established fact, this paper reviews the main reasons which could account for this puzzling discrepancies. Some of these reasons are methodological or statistical ones, and they are linked to formal properties of variables to be correlated: raw scores, ratios, or percentages, or broader constructs operationalized by specific pattern of scores and ratios. It is emphasized that some difficulties are related to the excessive number of variables addressed in studies lacking theoretical hypotheses, as to the categorical nature of many Rorschach variables, which opposes the dimensional nature of the constructs of academic personality psychology. More fundamentally, it is suggested that, as exemplified by introversion and introversiveness, psychological realities assessed by the Rorschach differ from those conceptualized by personality psychology not only by their content but also by their structure. Finally, the authors discuss the hypothesis suggested by Ganellen and Meyer: the correlation between the Rorschach and self-report measures would be moderated by the patients’ response style or test-taking attitude; the absence of correlation in the studied samples would conceal strong positive correlations among subjects with the same attitude toward both tests, and strong negative correlations among subjects with test-taking attitude different toward each kind of instrument. It is suggested that this hypothesis is promising, but it will be illuminating only when a reliable and specific marker of attitude will be identified. To conclude, it is remembered that while these discrepancies between the two kinds of tests raise some problems at the theoretical level, at a clinical level they convey much valuable information about patient’s self-representation and defence mechanisms.

Postural control and executive functioning in patients with schizophrenia

2017 ◽  
Vol 41 (S1) ◽  
pp. S195-S195
Author(s):  
M. Yildirim ◽  
A. Elvan ◽  
G. Ercegil ◽  
I.E. Simsek ◽  
S. Savci ◽  
...  
Keyword(s):  
Executive Functioning ◽  
Postural Control ◽  
Verbal Fluency ◽  
Postural Sway ◽  
Cognitive Task ◽  
Motor Task ◽  
Executive Dysfunction ◽  
Proprioceptive Information ◽  
Healthy Controls ◽  
Eyes Closed

IntroductionPatients with schizophrenia commonly show deficits in executive functioning that allow a person to make plans, solve problems, do many tasks simultaneously and adapt to unexpected conditions. Executive dysfunction is associated with very simple and automatic activities, such as walking in schizophrenia patients. However, no study exists about its relation to postural control in these patients.AimTo investigate the effect of executive functioning on postural control using dual task paradigms.MethodsFifteen clinically stable schizophrenia outpatients and 15 healthy controls were enrolled in the study. Postural control was assessed with bilateral stance test using the Balance Master system under three different conditions with eyes open and eyes closed (EC): without a task, during a cognitive task (verbal fluency) and during a motor task (holding a cup of water).ResultsStanding on a foam surface with EC resulted in higher postural sway velocities in schizophrenia patients under all conditions (P = 0.009, P = 0.032, P = 0.013). During a cognitive task, both schizophrenia patients and healthy controls showed higher velocities on firm surface with EC in comparison to the condition without a task (P = 0.023). Both schizophrenia patients and healthy controls did not show higher postural sway velocities during the motor task.ConclusionThe effect of verbal fluency on postural sway shows the relationship between executive functioning and postural control in schizophrenia patients. Foam surface also higher postural sway velocities in schizophrenia patients in EC condition suggesting the difficulties in integrating the proprioceptive information in the absence of visual input.Disclosure of interestThe authors have not supplied their declaration of competing interest.

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