scholarly journals Choosing Strategies to Deal with Artifactual EEG Data in Children with Cognitive Impairment

Entropy ◽  
2021 ◽  
Vol 23 (8) ◽  
pp. 1030
Author(s):  
Ana Tost ◽  
Carolina Migliorelli ◽  
Alejandro Bachiller ◽  
Inés Medina-Rivera ◽  
Sergio Romero ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Energy Function ◽  
Data Distribution ◽  
Poor Performance ◽  
High Amplitude ◽  
Motion Artifacts ◽  
Motion Signal ◽  
Lower Amplitude ◽  
Artifact Rejection ◽  
Main Component

Rett syndrome is a disease that involves acute cognitive impairment and, consequently, a complex and varied symptomatology. This study evaluates the EEG signals of twenty-nine patients and classify them according to the level of movement artifact. The main goal is to achieve an artifact rejection strategy that performs well in all signals, regardless of the artifact level. Two different methods have been studied: one based on the data distribution and the other based on the energy function, with entropy as its main component. The method based on the data distribution shows poor performance with signals containing high amplitude outliers. On the contrary, the method based on the energy function is more robust to outliers. As it does not depend on the data distribution, it is not affected by artifactual events. A double rejection strategy has been chosen, first on a motion signal (accelerometer or EEG low-pass filtered between 1 and 10 Hz) and then on the EEG signal. The results showed a higher performance when working combining both artifact rejection methods. The energy-based method, to isolate motion artifacts, and the data-distribution-based method, to eliminate the remaining lower amplitude artifacts were used. In conclusion, a new method that proves to be robust for all types of signals is designed.

Analyses of Visuospatial and Visuoperceptual Errors as Predictors of Dementia in Parkinson’s Disease Patients with Subjective Cognitive Decline and Mild Cognitive Impairment

2020 ◽  
pp. 1-11
Author(s):  
Iván Galtier ◽  
Antonieta Nieto ◽  
María Mata ◽  
Jesús N. Lorenzo ◽  
José Barroso
Keyword(s):  
Risk Factors ◽  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Cognitive Impairment ◽  
Mild Cognitive Impairment ◽  
Cognitive Decline ◽  
Poor Performance ◽  
Subjective Cognitive Decline ◽  
Independent Risk Factors

ABSTRACT Objective: Subjective cognitive decline (SCD) and mild cognitive impairment (MCI) in Parkinson’s disease (PD) are considered as the risk factors for dementia (PDD). Posterior cortically based functions, such as visuospatial and visuoperceptual (VS-VP) processing, have been described as predictors of PDD. However, no investigations have focused on the qualitative analysis of the Judgment of Line Orientation Test (JLOT) and the Facial Recognition Test (FRT) in PD-SCD and PD-MCI. The aim of this work was to study the VS-VP errors in JLOT and FRT. Moreover, these variables are considered as predictors of PDD. Method: Forty-two PD patients and 19 controls were evaluated with a neuropsychological protocol. Patients were classified as PD-SCD and PD-MCI. Analyses of errors were conducted following the procedure described by Ska, Poissant, and Joanette (1990). Follow-up assessment was conducted to a mean of 7.5 years after the baseline. Results: PD-MCI patients showed a poor performance in JLOT and FRT total score and made a greater proportion of severe intraquadrant (QO2) and interquadrant errors (IQO). PD-SCD showed a poor performance in FRT and made mild errors in JLOT. PD-MCI and QO2/IQO errors were independent risk factors for PDD during the follow-up. Moreover, the combination of both PD-MCI diagnosis and QO2/IQO errors was associated with a greater risk. Conclusions: PD-MCI patients presented a greater alteration in VS-VP processing observable by the presence of severe misjudgments. PD-SCD patients also showed mild difficulties in VS-SP functions. Finally, QO2/IQO errors in PD-MCI are a useful predictor of PDD, more than PD-MCI diagnosis alone.

Thermoacoustically-Based Combustion Oscillation in a Gas Turbine—A Brief Note

2003 ◽  
Vol 125 (4) ◽  
pp. 454-459 ◽  
Author(s):  
Frantisek L. Eisinger ◽  
Robert E. Sullivan
Keyword(s):  
Combustion Chamber ◽  
Gas Turbine ◽  
High Amplitude ◽  
Acoustic Mode ◽  
Cold Air ◽  
Amplitude Oscillation ◽  
Lower Amplitude ◽  
Second Mode ◽  
Combustion Oscillation

Thermoacoustic combustion oscillation and vibration experienced in a gas turbine at operation is reported. The oscillation manifested itself at two distinct frequencies representing the first and second mode frequencies of the combined hot and cold (combustion chamber/burner air) Rijke type thermoacoustic model. The first mode was a lower amplitude thermoacoustically driven free Rijke mode. The higher frequency second Rijke mode coupled with the second acoustic mode of the combustion chamber resulted in high amplitude oscillation. Modifications to the burner cold air components are considered which would eliminate the oscillation. The paper will present and discuss the principal parameters which caused the oscillation and changes which would eliminate it.

Significance of the Secretory Pattern of Growth Hormone

Physiology ◽  
1986 ◽  
Vol 1 (2) ◽  
pp. 44-47
Author(s):  
OGP Isakkson ◽  
J-O Jansson ◽  
RG Clark ◽  
I Robinson
Keyword(s):  
Growth Hormone ◽  
Plasma Concentration ◽  
High Amplitude ◽  
Female Rats ◽  
Healthy Children ◽  
Male And Female ◽  
Male And Female Rats ◽  
Low Concentrations ◽  
Lower Amplitude ◽  
Secretory Pattern

The plasma concentration of growth hormone fluctuates widely with pronounced peaks at intervals of a few hours and troughs of nearly vanishingly low concentrations in between. The pattern of secretion varies, and different patterns affect growth differently. Tall children usually have frequent growth hormone peaks of a high amplitude, whereas short, healthy children usually have fewer peaks of a lower amplitude. Male and female rats have different patterns, and a "masculine" pattern promotes growth more than a "feminine" pattern. If the same amount of growth hormone is administered in several pulses rather than continuously, the effect on growth is much greater.

scholarly journals A Multi-Sensor Approach to the Interpretation of Radar Altimeter Wave Forms from Two Arctic Ice Caps

1987 ◽  
Vol 9 ◽  
pp. 60-68 ◽  
Author(s):  
Mark R. Drinkwater ◽  
Julian A. Dowdeswell
Keyword(s):  
Surface Roughness ◽  
Leading Edge ◽  
High Amplitude ◽  
Wave Form ◽  
Radar Altimeter ◽  
Ice Caps ◽  
Lower Amplitude ◽  
Wet Snow ◽  
Radio Echo Sounding ◽  
Wave Forms

Data collected over Svalbard on 28 June 1984 by a 13.81 GHz airborne radar altimeter enabled analysis of signals returned from two relatively large ice masses. Wave forms received over the ice caps of Austfonna and Vestfonna are analysed with the aid of existing aerial photography, radio echo-sounding data, and Landsat MSS images acquired close to the date of the altimeter flight. Results indicate that altimeter wave forms are controlled mainly by surface roughness and scattering characteristics. Wet snow surfaces have narrow 3 dB back-scatter half-angles and cause high-amplitude signals, in contrast to relatively dry snow surfaces with lower-amplitude diffuse signals. Metre-scale surface roughness primarily affects wave-form amplitude and leading-edge slope, this becoming apparent over ice streams on Vestfonna.

The neuropsychological sequelae of delirium in elderly patients with hip fracture three months after hospital discharge

2013 ◽  
Vol 25 (9) ◽  
pp. 1521-1531 ◽  
Author(s):  
Joost Witlox ◽  
Chantal J. Slor ◽  
René W.M.M. Jansen ◽  
Kees J. Kalisvaart ◽  
Mireille F.M. van Stijn ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Hip Fracture ◽  
Episodic Memory ◽  
Hospital Discharge ◽  
Depressive Symptomatology ◽  
Poor Performance ◽  
Cognitive Outcome ◽  
Neuropsychological Sequelae ◽  
Global Cognition

ABSTRACTBackground: Delirium is a risk factor for long-term cognitive impairment and dementia. Yet, the nature of these cognitive deficits is unknown as is the extent to which the persistence of delirium symptoms and presence of depression at follow-up may account for the association between delirium and cognitive impairment at follow-up. We hypothesized that inattention, as an important sign of persistent delirium and/or depression, is an important feature of the cognitive profile three months after hospital discharge of patients who experienced in-hosptial delirium.Methods: This was a prospective cohort study. Fifty-three patients aged 75 years and older were admitted for surgical repair of acute hip fracture. Before the surgery, baseline characteristics, depressive symptomatology, and global cognitive performance were documented. The presence of delirium was assessed daily during hospital admission and three months after hospital discharge when patients underwent neuropsychological assessment.Results: Of 27 patients with in-hospital delirium, 5 were still delirious after three months. Patients with in-hospital delirium (but free of delirium at follow-up) showed poorer performance than patients without in-hospital delirium on tests of global cognition and episodic memory, even after adjustment for age, gender, and baseline cognitive impairment. In contrast, no differences were found on tests of attention. Patients with in-hospital delirium showed an increase of depressive symptoms after three months. However, delirium remained associated with poor performance on a range of neuropsychological tests among patients with few or no signs of depression at follow-up.Conclusion: Elderly hip fracture patients with in-hospital delirium experience impairments in global cognition and episodic memory three months after hospital discharge. Our results suggest that inattention, as a cardinal sign of persistent delirium or depressive symptomatology at follow-up, cannot fully account for the poor cognitive outcome associated with delirium.

scholarly journals Which factors are associated with global cognitive impairment in Wilson's disease?

2016 ◽  
Vol 10 (4) ◽  
pp. 320-326 ◽  
Author(s):  
Norberto Anízio Ferreira Frota ◽  
Egberto Reis Barbosa ◽  
Claudia Sellitto Porto ◽  
Leandro Tavares Lucato ◽  
Carla Rachel Ono ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Globus Pallidus ◽  
Educational Level ◽  
Wilson’S Disease ◽  
Rating Scale ◽  
Poor Performance ◽  
Wisconsin Card Sorting Test ◽  
Wilson's Disease ◽  
Cognitive Test ◽  
Card Sorting

ABSTRACT Background: Patients with Wilson's disease (WD) present cognitive impairment, especially in executive functions. Which other factors might be associated with global cognitive decline in these patients remains unclear. Objective: To assess which factors are associated with worse performance on a global cognitive test in patients with WD. Methods: Twenty patients with WD underwent cognitive assessment with the following tests: the Mini-Mental State Examination (MMSE), Dementia Rating Scale (DRS), verbal fluency test, brief cognitive battery, clock drawing test, Frontal Assessment Battery, Stroop test, Wisconsin card sorting test, Hopper test, cubes (WAIS) and the Pfeffer questionnaire. MRI changes were quantified. Patients with poor performance on the DRS were compared to patients with normal performance. Results: Nine patients had a poor performance on the DRS. This group had lower educational level (9.11±3.58 × 12.82±3.06) and a greater number of changes on MRI (9.44±2.74 × 6.27±2.45). The presence of hyperintensity in the globus pallidus on MRI was more frequent in this group (66.6% vs 9.0%), with OR=5.38 (95% CI 0.85-33.86). Conclusion: Global cognitive impairment was prevalent in this sample of patients with WD and was associated with low educational level, number of changes on MRI and MRI hyperintensity in the globus pallidus.

scholarly journals Global Sea Ice Coverage from Satellite Data: Annual Cycle and 35-Yr Trends

2014 ◽  
Vol 27 (24) ◽  
pp. 9377-9382 ◽  
Author(s):  
Claire L. Parkinson
Keyword(s):  
Sea Ice ◽  
Annual Cycle ◽  
High Amplitude ◽  
Sea Ice Extent ◽  
Antarctic Sea Ice ◽  
Ice Coverage ◽  
High Magnitude ◽  
Lower Amplitude ◽  
Yearly Average ◽  
Lower Magnitude

Abstract Well-established satellite-derived Arctic and Antarctic sea ice extents are combined to create the global picture of sea ice extents and their changes over the 35-yr period 1979–2013. Results yield a global annual sea ice cycle more in line with the high-amplitude Antarctic annual cycle than the lower-amplitude Arctic annual cycle but trends more in line with the high-magnitude negative Arctic trends than the lower-magnitude positive Antarctic trends. Globally, monthly sea ice extent reaches a minimum in February and a maximum generally in October or November. All 12 months show negative trends over the 35-yr period, with the largest magnitude monthly trend being the September trend, at −68 200 ± 10 500 km2 yr−1 (−2.62% ± 0.40% decade−1), and the yearly average trend being −35 000 ± 5900 km2 yr−1 (−1.47% ± 0.25% decade−1).

Comparison of two brief neuropsychological batteries in people with multiple sclerosis

2002 ◽  
Vol 8 (2) ◽  
pp. 169-176 ◽  
Author(s):  
A Solari ◽  
L Mancuso ◽  
A Motta ◽  
L Mendozzi ◽  
C Serrati
Keyword(s):  
Multiple Sclerosis ◽  
Cognitive Impairment ◽  
Poor Performance ◽  
Clinical Variable ◽  
Impaired Performance ◽  
Selective Reminding ◽  
Administration Time ◽  
Serial Addition ◽  
The Relationship ◽  
Serial Evaluation

Background: We compared two brief neuropsychological batteries devised to assess people with multiple sclerosis (MS) and used them to assess the relationship between cognitive impairment and clinical characteristics. Methods: We administered either the Brief Repeatable Battery of Neuropsychological Tests (BRBNT) or the Screening Examination for Cognitive Impairment (SEFCI) to 213 consecutive MS outpatients and 213 individually matched controls. Results: Administration times were longer for BRBNT than SEFCI, for MS and controls (p=0.001). People with MS had lower scores in all individual tests than controls (p<0.001, BRBNT and SEFCI). By the criterion of poor performance on one or more tests, the sensitivity of BRBNT was 41.9% and that of SEFCI 31.5%. The corresponding figures by poor performance on two or more tests were 16.2% for BRBNT and 18.5% for SEFCI. The Buschke Selective Reminding and Paced Auditory Serial Addition were the tests best discriminating between people with MS and controls for BRBNT, and the Symbol Digit Modalities test for SEFCI. The only clinical variable independently associated with impaired performance on these batteries was EDSS. Conclusions: Both cognitive batteries were well accepted and easy to administer. Administration time for SEFCI was significantly shorter than for BRBNT; however, alternative forms for serial evaluation are available only for BRBNT. The BRBNT was slightly more sensitive in detecting impairment by the criterion of poor performance on one or more tests. EDSS score was the only clinical variable independently associated with cognitive impairment.

The seismic response of sediment-filled valleys. Part 2. The case of incident P and SV waves

1980 ◽  
Vol 70 (5) ◽  
pp. 1921-1941
Author(s):  
Pierre-Yves Bard ◽  
Michel Bouchon
Keyword(s):  
Seismic Response ◽  
Rayleigh Waves ◽  
High Amplitude ◽  
Ground Shaking ◽  
Resonance Modes ◽  
Long Duration ◽  
Time Domains ◽  
P And Sv Waves ◽  
Lateral Resonance ◽  
Main Component

abstract We present the extension to incident P and SV waves of our previous study (Bard and Bouchon, 1980) concerning the seismic response of sediment-filled bidimensional valleys to incident SH transient signals. The reliability of the Aki-Larner method is briefly discussed and the domain is estimated within which it provides accurate results. Then we investigate the response of three different valleys, having various geometrical and elastic parameters, to vertically incident P and SV waves, in both the frequency and time domains. The behavior of the valleys is shown to be qualitatively similar to their behavior for SH waves: the nonplanar interface causes surface waves (here Rayleigh waves) to be generated on valley edges, and to propagate laterally inside the basin. The amplitude of these Rayleigh waves depends greatly on the velocity contrast, the valley shape, and the incident wave type (P or SV), but it may be significantly higher than the disturbance associated with the direct incident signal. The frequency and direction of incident motion determine partly whether the fundamental or first higher mode will be predominantly excited, depending on the main component (vertical or horizontal) of the Rayleigh mode motion. Although the reflections of these Rayleigh waves on valley edges do not appear as clearly as in the SH case, a very long duration of the ground shaking inside the valley is still observed. In deep valleys, these laterally propagating Rayleigh waves may degenerate into a lateral resonance pattern, involving high-amplitude surface motion. These latter resonance modes, however, begin to appear in shallower valleys for incident SV waves than for incident P ones.

scholarly journals Cognitive function in schizophrenia: insights from intelligence research

2013 ◽  
Vol 203 (3) ◽  
pp. 161-162 ◽  
Author(s):  
Eileen M. Joyce
Keyword(s):  
Neural Network ◽  
Risk Factor ◽  
Cognitive Impairment ◽  
Cognitive Function ◽  
Fluid Intelligence ◽  
Poor Performance ◽  
Cognitive Tasks ◽  
Human Intelligence

SummarySchizophrenia is characterised by generalised cognitive impairment that is both a risk factor and a predictor of outcome. Recent research into human intelligence supports the view that, in schizophrenia, poor performance on disparate cognitive tasks can be explained by dysfunction of a frontoparietal neural network thought to support fluid intelligence.

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