| 1. |
- Johansson, Mikael, et al.
(författare)
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Memory for perceived and imagined pictures : an event-related potential study
- 2002
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Ingår i: Neuropsychologia, vol. 40, no. 7. - : Elsevier. ; 40:7, s. 986-1002
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Konferensbidrag (refereegranskat)abstract
- Event-related potentials (ERPs) and behavioural measures were used to investigate recognition memory and source-monitoring judgements about previously perceived and imagined pictures. At study, word labels of common objects were presented. Half of these were followed by a corresponding picture and the other half by an empty frame, signalling to the participants to mentally visualise an image. At test, participants in a source-monitoring task made a three-way discrimination between new words and words corresponding to previously perceived and imagined pictures. Participants in an old/new-recognition task indicated whether test words were previously presented or not. In both tasks, correctly identified old items elicited more positive-going ERPs than correctly judged new items. This widely distributed old/new effect was found to have an earlier onset and to be of a greater magnitude for imagined than for perceived items. Task (source versus item-memory) affected the old/new effects over prefrontal areas and the reaction times to remembered old items. The present findings are consistent with the view that a greater amount, or a different type, of information is necessary for accurate source-memory judgements than for correct recognition, and moreover, that different types of source-specifying information revive at different rates. In addition, the results add weight to the view that the late widespread ERP-old/new effect is sensitive to the quality or the amount of information retrieved from memory.
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| 2. |
- Stenberg, Georg, 1947-, et al.
(författare)
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Conceptual and perceptual memory : retrieval orientations reflected in event-related potentials
- 2006
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Ingår i: Acta Psychologica. - : Elsevier. - 0001-6918 .- 1873-6297. ; 122:2, s. 174-205
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Tidskriftsartikel (refereegranskat)abstract
- In memory retrieval, search can be guided by mental sets towards different subsets of the available evidence. Such retrieval orientations have been suggested to leave an imprint on event-related potentials (ERPs). The present study aimed at characterizing orientations towards perceptual and conceptual evidence in a recognition task, where pictures and words were studied. In the recognition test, items were presented in either the same format as at study or in the opposite format. A between-subjects manipulation modified the task, instructing an Exclusion group to endorse only items that preserved their format from study, and an Inclusion group to endorse both formats of a studied item. It was hypothesized that exclusion instructions would instil a perceptual - and inclusion instructions a conceptual - orientation. As a corollary, instructions were expected to dissociate the high end from the low end of the picture-word mirror effect. This expectation was confirmed in a behavioural experiment. In an ERP experiment, retrieval orientations were examined in their effects on correct rejections of new pictures and words. Confirming earlier findings (Hornberger, Morcom, & Rugg, 2004), a perceptual orientation was accompanied by more positive-going amplitudes over widespread areas. The difference was larger for pictures than for words, supporting behavioural evidence that new pictures are more easily rejected on perceptual grounds than are new words. The Exclusion group showed no ERP evidence of cross-format old-new effects, despite reaction times indicative of involuntary conceptual recognition. The results indicate that perceptual and conceptual retrieval orientations imprint distinct signatures on ERPs. They further suggest that the examined old-new effects in ERPs are mainly linked to voluntary aspects of memory, even in a task where involuntary memory exerts effects on reaction times.
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| 3. |
- Stenberg, Georg, 1947-, et al.
(författare)
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Semantic priming effects in a second language : an event-related potential study
- 2004
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Ingår i: Bulletin of the Psychonomic Society, vol. 9. - : Psychonomic Society. ; 9:Nov Abstract Supplement, s. 105-105
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This study addressed the question whether the second language (L2) of bilinguals can access conceptual memory as directly as their first language (L1). Swedish undergraduates, with English as their second language, performed two tasks in both L1 and L2. Exp. 1 used a picture-name verification task, where pictures induced automatic semantic priming. Exp. 2 used a category-exemplar verification task, where pictures induced strategic priming. The primary measure was reduction of the N400 amplitude in the ERP. Experiment 1 showed a fronto-central priming effect that did not differ between L1 and L2 in amplitude, topographical distribution, or peak latency. Experiment 2 showed a different, centro-parietal priming effect that was similar in amplitude between L1 and L2, but differed in peak latency, and lateral distribution. The study indicates that L2 provides direct automatic access to conceptual memory, although strategic use may recruit partly different neuronal resources in L2 than in L1.
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| 4. |
- Atroshi, Isam, et al.
(författare)
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Prevalence of carpal tunnel syndrome in a general population
- 1999
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Ingår i: JAMA: The Journal of the American Medical Association. - : American Medical Association (AMA). - 1538-3598. ; 282:2, s. 153-158
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Tidskriftsartikel (refereegranskat)abstract
- CONTEXT: Carpal tunnel syndrome (CTS) is a cause of pain, numbness, and tingling in the hands and is an important cause of work disability. Although high prevalence rates of CTS in certain occupations have been reported, little is known about its prevalence in the general population. OBJECTIVE: To estimate the prevalence of CTS in a general population. DESIGN: General health mail survey sent in February 1997, inquiring about symptoms of pain, numbness, and tingling in any part of the body, followed 2 months later by clinical examination and nerve conduction testing of responders reporting symptoms in the median nerve distribution in the hands, as well as of a sample of those not reporting these symptoms (controls). SETTING: A region in southern Sweden with a population of 170000. PARTICIPANTS: A sex- and age-stratified sample of 3000 subjects (age range, 25-74 years) was randomly selected from the general population register and sent the survey, with a response rate of 83% (n = 2466; 46% men). Of the symptomatic responders, 81% underwent clinical examination. MAIN OUTCOME MEASURES: Population prevalence rates, calculated as the number of symptomatic responders diagnosed on examination as having clinically certain CTS and/or electrophysiological median neuropathy divided by the total number of responders. RESULTS: Of the 2466 responders, 354 reported pain, numbness, and/or tingling in the median nerve distribution in the hands (prevalence, 14.4%; 95% confidence interval [CI], 13.0%-15.8%). On clinical examination, 94 symptomatic subjects were diagnosed as having clinically certain CTS (prevalence, 3.8%; 95% CI, 3.1%-4.6%). Nerve conduction testing showed median neuropathy at the carpal tunnel in 120 symptomatic subjects (prevalence, 4.9%; 95% CI, 4.1%-5.8%). Sixty-six symptomatic subjects had clinically and electrophysiologically confirmed CTS (prevalence, 2.7%; 95% CI, 2.1%-3.4%). Of 125 control subjects clinically examined, electrophysiological median neuropathy was found in 23 (18.4%; 95% CI, 12.0%-26.3%). CONCLUSION: Symptoms of pain, numbness, and tingling in the hands are common in the general population. Based on our data, 1 in 5 symptomatic subjects would be expected to have CTS based on clinical examination and electrophysiologic testing.
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| 5. |
- Atroshi, Isam, et al.
(författare)
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Prevalensen för kliniskt säkerställt karpaltunnelsyndrom 4 procent
- 2000
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Ingår i: Läkartidningen. - 0023-7205. ; 97:14, s. 1668-1670
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Tidskriftsartikel (refereegranskat)abstract
- This article summarizes the results of a large-scale population-based study conducted to determine the prevalence of carpal tunnel syndrome in the Swedish general population. The study utilized a health questionnaires as well as clinical and electrophysiological examinations. Population prevalence rates of carpal tunnel syndrome, based on clinical diagnosis and electrophysiological criteria, were calculated. Obesity and specific work-related hand activities were shown to be risk factors for carpal tunnel syndrome.
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| 6. |
- Bah Rösman, Jessica, 1975, et al.
(författare)
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Serotonin transporter gene polymorphisms: Effect on serotonin transporter availability in the brain of suicide attempters
- 2008
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Ingår i: Psychiatry Research: Neuroimaging. - : Elsevier BV. - 0925-4927 .- 0165-1781. ; 162:3, s. 221-229
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Tidskriftsartikel (refereegranskat)abstract
- The efficacy of serotonin reuptake inhibitors in depression and anxiety disorders suggests the gene coding for the serotonin transporter (5-HTT), SLC6A4, as a candidate of importance for these conditions. Positive findings regarding associations between polymorphisms in SLC6A4 have been reported, indicating that these polymorphisms may influence anxiety-related personality traits, as well as the risk of developing depression and suicidality. Serotonin 5-HTT availability was assessed with single photon emission computed tomography (SPECT), using I-123-beta-CIT as ligand, in a population of unmedicated male suicide attempters (n=9) and in matched controls (n=9). Two polymorphisms in SLC6A4 were assessed, including the 5-HTTLPR located in the promoter region and a variable number of tandem repeats (VNTR) polymorphism in intron 2 (STin2). In suicide attempters, but not in controls, low 5-HTT availability was associated with the S allele of 5-HTTLPR and with the 12 repeat allele of STin2. Data suggest that polymorphisms in SLC6A4 may influence the expression of the brain serotonin transporter in suicide attempters.
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| 7. |
- Elmståhl, Sölve, et al.
(författare)
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Autonomic cardiovascular responses to tilting in patients with alzheimer's disease and in healthy elderly women
- 1992
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Ingår i: Age and Ageing. - : Oxford University Press (OUP). - 0002-0729 .- 1468-2834. ; 21:4, s. 301-307
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Tidskriftsartikel (refereegranskat)abstract
- The cardiovascular responses to tilting and breathing were studied in 24 patients with late-onset Alzheimer's disease (AD) and 54 healthy control women aged between 75 and 96 years in order to study the parasympathetic and sympathetic heart-rate control. The cardiovascular response to tilting and breathing showed no age-associated decrease in the healthy control women. During rest, the AD patients had lower mean systolic and diastolic blood pressure but the same heart rate as the control patients. After tilting, the AD patients had a greater increase in heart rate, and the mean systolic blood pressure fell to 126 mmHg compared with 160 mmHg in the control women (p<0.001). After the initial acceleration, the following deceleration of the heart rate, an expression of parasympathetic nervous activity, was lower in the AD patients (p <0.001). The deep-breathing test showed no significant difference between the two groups, but the changes of acceleration and brake indices could indicate a dysfunction of the autonomic nervous system since the AD patients were not recumbent.
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| 8. |
- Greisen, G, et al.
(författare)
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EEG depression and germinal layer haemorrhage in the newborn
- 1987
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Ingår i: Acta Paediatrica Scandinavica. - : Wiley. - 0001-656X .- 0803-5253 .- 1651-2227. ; 76:3, s. 519-525
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Tidskriftsartikel (refereegranskat)abstract
- Amplitude integrated EEG (aEEG) recordings from 32 mechanically ventilated infants, gestational age 32 weeks or less, were analysed. All recordings were started within 24 h of birth and continued for at least 50 h. Germinal layer haemorrhage (GLH) was diagnosed by repeated ultrasonography. In six infants neither GLH nor hypocalcaemia were diagnosed; aEEG in these infants rapidly became more active after birth: at 30 h of age continuous background activity was present for more than 20% of the time, and a seizure-like pattern was exceptional. In seven infants without GLH but with hypocalcaemia and other signs of metabolic derangement, continuous background activity appeared later and seizure-like activity was frequent. In the infants with GLH, depression of the background activity was apparent. This finding was particularly distinct in the presence of severe haemorrhages. Four infants developed GLH after 30 h of age. All these infants had depressed aEEG before the development of GLH, with less than 20% continuous activity at 30 h of age. In ten infants an analysis of the aEEG during the occurrence of GLH was possible. In six of these, cortical electrical activity decreased. Due to the limitation of GLH timing, it was not possible to decide whether this decrease closely preceded or followed GLH. We suggest that GLH primarily occurs in brains with a preceding metabolic and neurophysiologic abnormality, and that further functional deterioration is caused by the most severe haemorrhages.
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| 9. |
- Hallböök, Tove, et al.
(författare)
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Beneficial effects on sleep of vagus nerve stimulation in children with therapy resistant epilepsy.
- 2005
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Ingår i: European Journal of Paediatric Neurology. - : Elsevier BV. - 1090-3798. ; 9:6, s. 399-407
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Tidskriftsartikel (refereegranskat)abstract
- The study purpose was to evaluate sleep structure following Vagus Nerve Stimulation (VNS) in 15 children with therapy resistant epilepsy and to correlate possible alterations with changes in epileptiform activity and clinical effects. Fifteen children were examined with ambulatory polysomnographic recordings initially, and after 3 and 9 months of VNS-treatment. Sleep parameters, all-night delta power activity and movement times (MTs), used to account for arousals were estimated. Epileptiform activity was evaluated by spike detection. Seizure frequency was recorded in a diary. The severity of the seizures was scored with the National Hospital Seizure Severity Scale (NHS3). Quality of life (QOL) was assessed by a visual analogue scale. Behaviour problems were quantified by using the total score of the Child Behaviour Checklist (CBCL). VNS induces a significant increase in slow wave sleep (SWS) and a decrease in sleep latency and in stage 1 sleep. The number and density of MTs during total night sleep were significantly increased. There was also a significant increase in the number of MTs immediately related to the VNS stimulation periods. Of the 14 children with increased MTs, 10 had a reduction in epileptiform activity, and in clinical seizures, all had an improvement in NHS3, and 11 in QOL. Of the 10 children with increased SWS, eight also improved in QOL and eight in behaviour. Our findings indicate that VNS counteracts known adverse effects of epilepsy on sleep and increases slow wave sleep. This possibly contributes to the reported improvement in well-being. We also see an increase in MTs. This arousal effect seems to be of minor importance for QOL and could possibly be related to the antiepileptic mechanisms in VNS.
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| 10. |
- Hallböök, Tove, et al.
(författare)
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Effects of ketogenic diet on epileptiform activity in children with therapy resistant epilepsy
- 2007
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Ingår i: Epilepsy Research. - : Elsevier BV. - 1872-6844 .- 0920-1211. ; 77:2-3, s. 134-140
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: The purpose was to quantify changes of epileptiform activity during ketogenic diet (KD) treatment in children with therapy resistant epilepsy, and evaluate how these changes are related to activity stage and to clinical effects on seizure frequency, seizure severity, attentional behaviour, quality of life (QOL), and beta-hydroxybutyrate (betaOHb). METHODS: Eighteen children were investigated with 24h ambulatory EEG monitoring 1 week prior to KD initiation and, after 3 months of KD treatment. Epileptiform activity was evaluated by automated spike detection. This data was compared with data presented in a previous study published in Epilepsia 2006, on sleep structure and different activity stages, clinical data on seizure frequency, seizure severity, QOL and attentional behaviour on the same children [Hallbook, T., Lundgren, J., Rosen, I., 2007. Ketogenic diet improves sleep quality in children with therapy resistant epilepsy. Epilepsia 48, 59-65]. RESULTS: After 3 months of KD treatment the number of interictal epileptiform discharges (IEDs) was significantly reduced (p<0.001). When considering the four activity stages separately, the reduction was significant during non-rapid eye movement sleep stage 2, slow wave sleep (SWS) and rapid eye movement (REM) sleep (p=0.001, 0.001, 0.002), and not significantly so during awake (p=0.07). Beta-hydroxybutyrate was significantly increased (p<0.001). There was a significant correlation between the reduction in IEDs and clinical seizures (Spearman r=0.6, p=0.005) and between improvement in attentional behaviour and the increase in betaOHb (Spearman r=0.5, p=0.03). There was no significant correlation between changes in attentional behaviour and IEDs or clinical seizures. CONCLUSION: This study shows that KD reduces the number of IEDs, especially during sleep. It shows a correlation between reduction in epileptiform activity and clinical seizures. There were no correlations between reduction in epileptiform activity and clinical seizures and improvement in QOL or attention. The increase in betaOHb correlated with improvement in attention.
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