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| 2. |
- Flisberg, Anders, 1958, et al.
(författare)
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Does indomethacin for closure of patent ductus arteriosus affect cerebral function?
- 2010
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Ingår i: Acta Paediatrica. - : Wiley. - 0803-5253 .- 1651-2227. ; 99:10, s. 1493-1497
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To study whether indomethacin used in conventional dose for closure of patent ductus arteriosus affects cerebral function measured by Electroencephalograms (EEG) evaluated by quantitative measures. Study design: Seven premature neonates with haemodynamically significant persistent ductus arteriosus were recruited. EEG were recorded before, during and after an intravenous infusion of 0.2 mg/kg indomethacin over 10 min. The EEG was analysed by two methods with different degrees of complexity for the amount of low-activity periods (LAP, "suppressions") as an indicator of affection of cerebral function. Results: Neither of the two methods identified any change in the amount of LAPs in the EEG as compared to before the indomethacin infusion. Conclusion: Indomethacin in conventional dose for closure of patent ductus arteriosus does not affect cerebral function as evaluated by quantitative EEG.
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| 3. |
- Flisberg, Anders, 1958, et al.
(författare)
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EEG and spectral edge frequency : analysis in posthypoxic newborn piglets
- 2010
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Ingår i: Neuro - endocrinology letters. - : Brain Research Promotion. - 0172-780X. ; 31:2, s. 181-186
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To evaluate the frequency content of the electroencephalogram (EEG) during recovery after a severe hypoxic insult in newborn piglets. METHODS: EEG was continuously monitored in nine newborn piglets exposed to a severe hypoxic period. Power spectra in five frequency bands were calculated using Fourier transformation. Spectral edge frequency 90 (SEF90) was defined as the frequency below which 90% of the power in the EEG was located. The piglets were divided into two groups; Group 1 represented piglets with some EEG recovery and Group 2 represented piglets without any EEG recovery. RESULTS: The recovery of the EEG in Group 1 had the same time course in all frequency bands. SEF90 indicates recovery earlier than the value of total power. But SEF90 also signals activity in the EEGs that were almost completely suppressed. When SEF90 was calculated during periods of periodic EEG activity during the very early phase of recovery, the values fell within the same range as during the control period. CONCLUSION: Spectral analysis of continuous EEG in newborn piglets exposed to very severe hypoxia showed that no specific frequency band of the EEG preceded the other ones during recovery. The results of the SEF90 measure, demonstrates the need for critical analysis of the raw EEG before any reliable estimation of cerebral function can be made.
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| 4. |
- Löfhed, Johan, et al.
(författare)
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Soft textile electrodes for EEG monitoring
- 2010
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Konferensbidrag (refereegranskat)abstract
- There is a need for long term monitoring of the brain during intensive care. This is e.g. the case for newborn babies that have been exposed to hypoxia during delivery. Electroencephalography (EEG) is the technique of choice. To get a clear and detailed view of the brain activity a large number of EEG electrodes should be used. Applying traditional electrodes one by one is a time-consuming and technically demanding work and therefore electrode caps are sometimes used. The existing caps have however been found to be suboptimal for long term monitoring because they may induce too high a pressure on the scalp of the babies. We have tested three different types of textile electrodes with regard to their potential use for EEG monitoring. The results show that soft conducting textile materials can indeed be used for EEG monitoring.
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| 5. |
- Löfhede, Johan, 1978, et al.
(författare)
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Automatic classification of background EEG activity in healthy and sick neonates
- 2010
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Ingår i: Journal of Neural Engineering. - : IOP Publishing. - 1741-2560 .- 1741-2552. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- The overall aim of our research is to develop methods for a monitoring system to be used at neonatal intensive care units. When monitoring a baby, a range of different types of background activity needs to be considered. In this work, we have developed a scheme for automatic classification of background EEG activity in newborn babies. EEG from six full-term babies who were displaying a burst suppression pattern while suffering from the after-effects of asphyxia during birth was included along with EEG from 20 full-term healthy newborn babies. The signals from the healthy babies were divided into four behavioural states: active awake, quiet awake, active sleep and quiet sleep. By using a number of features extracted from the EEG together with Fisher’s linear discriminant classifier we have managed to achieve 100% correct classification when separating burst suppression EEG from all four healthy EEG types and 93% true positive classification when separating quiet sleep from the other types. The other three sleep stages could not be classified. When the pathological burst suppression pattern was detected, the analysis was taken one step further and the signal was segmented into burst and suppression, allowing clinically relevant parameters such as suppression length and burst suppression ratio to be calculated. The segmentation of the burst suppression EEG works well, with a probability of error around 4%.
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| 6. |
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| 7. |
- Löfhede, Johan, 1978, et al.
(författare)
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Soft Textile Electrodes for EEG Monitoring
- 2010
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Ingår i: [12]10th IEEE International Conference on Information Technology and Applications.
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Konferensbidrag (refereegranskat)
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| 8. |
- Löfhede, Johan, 1980-, et al.
(författare)
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Textile Electrodes for EEG Recording : A Pilot Study
- 2012
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Ingår i: Sensors. - Basel : MDPI. - 1424-8220. ; 12:12, s. 16907-16919
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Tidskriftsartikel (refereegranskat)abstract
- The overall aim of our research is to develop a monitoring system for neonatal intensive care units. Long-term EEG monitoring in newborns require that the electrodes don’t harm the sensitive skin of the baby, an especially relevant feature for premature babies. Our approach to EEG monitoring is based on several electrodes distributed over the head of the baby, and since the weight of the head always will be on some of them, any type of hard electrode will inevitably cause a pressure-point that can irritate the skin. Therefore, we propose the use of soft conductive textiles as EEG electrodes, primarily for neonates, but also for other kinds of unobtrusive long-term monitoring. In this paper we have tested two types of textile electrodes on five healthy adults and compared them to standard high quality electrodes. The acquired signals were compared with respect to morphology, frequency distribution, spectral coherence, correlation and power line interference sensitivity, and the signals were found to be similar in most respects. The good measurement performance exhibited by the textile electrodes indicates that they are feasible candidates for EEG recording, opening the door for long-term EEG monitoring applications.
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| 9. |
- Persson, Mikael, 1959, et al.
(författare)
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Advances in Neuro Diagnostic based on Microwave Technology, Transcranial Magnetic Stimulation and EEG source localization
- 2011
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Ingår i: Asia Pacific Microwave Conference, (APMC 2011;Melbourne, VIC; 5 - 8 December 2011). - 9780858259744 ; , s. 469-472
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Konferensbidrag (refereegranskat)abstract
- Advances in neuro diagnostics based on microwave antenna system in terms of a helmet including a set of broad band patch antennas is presented. It is shown that classification algorithms can be used to detect internal bleeding in stroke patients. Transcranial magnetic stimulation has traditionally been used for brain mapping and treatment of depression. In this paper we discuss the use of the method for neuro diagnostics with the help of integrated image guidance. Surgical therapy has become an important therapeutic alternative for some patients with medically intractable epilepsy. Electroencephalography and the associated model based diagnostics as a non-invasive diagnostic tool is also discussed.
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| 11. |
- Thordstein, Magnus, et al.
(författare)
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Individual effects of varying stimulation intensity and response criteria on area of activation for different muscles in humans. A study using navigated transcranial magnetic stimulation
- 2013
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Ingår i: Brain Stimulation. - : Elsevier BV. - 1935-861X. ; 6:1, s. 49-53
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Tidskriftsartikel (refereegranskat)abstract
- Background When using transcranial magnetic stimulation, a stimulation intensity defined as a certain level above the threshold for activation of a hand muscle is commonly used, disregarding the fact that the areas of activation for different muscles may have varying response characteristics intra- and interindividually. Objective To study the response characteristics of different muscles and compare them within and between individuals. Also to investigate the effect of varying stimulation intensity (defined in two different ways) and amplitude criterion for response, on the sizes of the activation areas for different muscles. Methods A system of transcranial magnetic stimulation with navigation capacity where the stimulation intensity can be defined in terms of the electric field strength in the tissue was used. Four different muscles were investigated in healthy adults. The threshold for activation at rest (RMT) of the different muscles and their respective areas of activation were quantified using three different stimulus intensities (100, 110 and 120% RMT) and two criteria for response amplitude (20 and 50 μV). Results Responses could readily be determined using 20 μV as response limit. The RMTs for different muscles varied within and between individuals. The degree to which the area depended on stimulation intensity differed between muscles intra- and interindividually. All results were statistically significant (P < 0.05 or less). Conclusions The response characteristics vary between muscles within an individual and between individuals for a certain muscle. Thus, for optimal accuracy when delineating the activation area, the investigation should be adapted to each particular muscle.
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| 12. |
- Thordstein, Magnus, et al.
(författare)
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Possibly lifesaving, noninvasive, EEG-guided neuromodulation in anesthesia-refractory partial status epilepticus
- 2012
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Ingår i: Epilepsy & Behavior. - : Elsevier BV. - 1525-5050. ; 25:3, s. 468-472
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Tidskriftsartikel (refereegranskat)abstract
- This study aimed to investigate the effect of low frequency repetitive transcranial magnetic stimulation (rTMS) guided as to localization and effect by continuous EEG on a super-refractory status epilepticus unresponsive to conventional treatment for 44 days including repeated deep sedation. Repetitive transcranial magnetic stimulation was delivered for one-hour sessions to the most active of two EEG foci for 8 days. From the third day of stimulation, the EEG pathology markedly decreased in parallel to clinical improvement. The patient could be weaned off the respirator, transferred to an ordinary ward then to a rehabilitation clinic. This is the first report of a positive outcome of rTMS treatment in super-refractory status epilepticus. In the context of refractory partial status epilepticus, neuromodulation through rTMS is a safe treatment option. If performed along the lines herein described, it may also be more efficient than conventional treatment. Repetitive transcranial magnetic stimulation may be an underused treatment option for status epilepticus. (C) 2012 Elsevier Inc. All rights reserved.
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| 13. |
- Thordstein, Magnus, et al.
(författare)
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Transfer of cortical motor representation after a perinatal cerebral insult.
- 2011
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Ingår i: Pediatric neurology. - : Elsevier BV. - 1873-5150 .- 0887-8994. ; 44:2, s. 131-4
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Tidskriftsartikel (refereegranskat)abstract
- In a 16-year-old boy with hemiplegia and severe, intractable epilepsy after a neonatal cerebral ischemic insult, cortical motor control was only equivocally assessed by functional magnetic resonance imaging. Therefore, high-precision navigated transcranial magnetic stimulation was performed, which demonstrated that cortical control of muscles on the paretic side was selectively affected. Leg muscle control was located in the contralateral hemisphere, as expected in healthy individuals, whereas forearm muscles were controlled from both hemispheres, and hand muscles were controlled only from the hemisphere ipsilateral to the paresis.
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