| 1. |
- Brådvik, Björn, et al.
(författare)
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Disturbances of speech prosody following right hemisphere infarcts
- 1991
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Ingår i: Acta Neurologica Scandinavica. - 1600-0404. ; 84:2, s. 114-126
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Tidskriftsartikel (refereegranskat)abstract
- The ability to perceive and express emotional, as well as number of linguistic prosodic qualities of speech was tested in 20 Swedish-speaking patients with right-sided cortical, as well as purely subcortical brain infarcts, and in 18 normal controls. The infarcts were assessed by clinical neurological examination, and by CT, EEG, and measurements of regional cerebral blood flow (rCBF). In the patients the identification of emotional messages was disturbed, as well as the identification and production of several linguistic prosodic qualities. The study supports the claim that prosodic impairment could be linguistic in nature, and not secondary to affective disorder. The total degree of anatomical and functional disturbance of the right hemisphere played a role for both the ability to identify emotional messages and for identification of two of the linguistic prosodic qualities tested. However, it was not possible to find support for the hypothesis that the organization of prosody in the right hemisphere mirrors that of propositional speech on the left side.
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| 2. |
- Brådvik, Björn, et al.
(författare)
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Do single right hemisphere infarcts or transient ischaemic attacks result in aprosody?
- 1990
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Ingår i: Acta Neurologica Scandinavica. - 1600-0404. ; 81:1, s. 61-70
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Tidskriftsartikel (refereegranskat)abstract
- The ability to perceive and express prosodic qualities of speech was tested in 21 patients with a single focal ischaemic disturbance of the right hemisphere, 14 patients having an infarct and 7 transient ischaemic attacks, and in 21 age-matched normal controls. All patients were predominantly right-handed. None showed signs of aphasia. Pure tone audiometry showed acceptable hearing for speech. The cerebral lesions were assessed by clinical neurologic examination, and by CT, EEG and measurement of regional cerebral blood flow (rCBF) using intravenous 133-xenon. The prosodia test included items testing: the ability to perceive accentual and emotional qualities of speech, and the ability to express and vary such qualities. The test did not discriminate between the patients and the controls, although some patients had large right-sided lesions. This negative finding indicates that aprosody in patients with brain lesions appears more difficult to detect than has previously been assumed. Highly sensitive tests are most likely required.
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| 3. |
- Eckert, B., et al.
(författare)
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The recovery of brain function after hypoglycaemia in normal man
- 1992
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Ingår i: Diabetologia, 35, Suppl.1. ; , s. A43-
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The aim of the present study was to evaluate the recovery of brain function after moderate hypoglycaemla in normal man. Hypoglycaemia was induced by an intravenous infusion of insulin (2.5 mU/kg) in seven healthy right-handed men aged 25.4+1.1 years (Mean • SD). The brain function was evaluated with P300-amplitude after auditory stimulus, reaction time measurements and EEG before, during (2.4+0.44 mmol/l for 70 min) and three times in the recovery period following hypoglycaemia. Hypoglycaemia caused a reduction in the P300-amplitude, a prolongation in reaction time and minor changes in the EEG-activity. 15 min after normalisation of the blood glucose level, the P300-amplitude was lower than during hypoglycaemia and still 1,5 hrs after normalisation of the blood glucose level, there was a marked reduction in the P3OO-amplitude. 4 hrs after normalisation of the blood glucose, the P300-amplitude was restituted. The reaction time was shorter 15 min after normalisation of the blood glucose compared to hypoglycaemia, but was not nermalised until 1,5 hrs after of recovery following hypoglycaemia. The EEG-changes were normalised 15 min after hypoglycaemia. We conclude that moderate hypglycaemia causes marked effects in P300 and reaction time and that brain function measured as P300 is not restored after 1,5 hrs but at 4 hrs after normalisation of hypoglycaemia.
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| 4. |
- 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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| 5. |
- Hellström-Westas, Lena, et al.
(författare)
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Cerebral function monitoring during the first week of life in extremely small low birthweight (ESLBW) infants
- 1991
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Ingår i: Neuropediatrics. - 0174-304X. ; 22:1, s. 27-32
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Tidskriftsartikel (refereegranskat)abstract
- In order to evaluate the usefulness of early continuous EEG-monitoring in very preterm neonates, recordings with a Cerebral Function Monitor (CFM) were made prospectively in 31 ESLBW infants with birthweights below 901 grams, during their first week of life. The CFM background activity was, as expected from EEG studies, dominated by a suppression-burst pattern in 94% of the infants. Some infants had periods with more continuous EEG activity or suppression-burst changing into continuous. Patterns similar to sleep-wake cycling (SWC) were identified in infants with gestational ages as low as 24 weeks. The level of the CFM-background activity was mainly influenced by the presence and severity of intracranial hemorrhage (ICH), but also by medications such as phenobarbital. Epileptiform activity (EPA) was only found in infants with ICH, and was identified in 75% of these infants. Of the infants with EPA, 87% had periods with subclinical EPA, although 47% had both clinical and subclinical seizures. The presence of more continuous activity and SWC were indicators of a favourable outcome, whereas electrocerebral inactivity predicted an unfavorable outcome. The prognostic estimates of mortality and neurologic outcome were similar for early CFM recording (positive predictive value 69-100%) and cranial ultrasound scan (positive predictive value 71-100%). The monitoring of cerebral electrical activity also provided immediate and clinically useful information during the intensive care of these ESLBW infants. Further studies on the causal relation between EPA and the development of ICH should be performed before definite conclusions can be drawn concerning any preventive effect from anticonvulsive treatment of clinical/subclinical seizures.
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| 6. |
- Hellström-Westas, Lena, et al.
(författare)
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Lidocaine for treatment of severe seizures in newborn infants. II. Blood concentrations of lidocaine and metabolites during intravenous infusion
- 1992
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Ingår i: Acta Pædiatrica. - : Wiley. - 1651-2227 .- 0803-5253. ; 81:1, s. 35-39
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Tidskriftsartikel (refereegranskat)abstract
- The blood concentrations of lidocaine and its main active metabolites, methylethylglycinexylidide (MEGX) and glycinexylidide (GX), were measured in 24 newborn infants during anticonvulsive treatment with an iv infusion of lidocaine. After a bolus dose of 1.5-2.2 mg/kg and continuous infusion of lidocaine (4.7-6.3 mg/kg/h) there was accumulation of the drug and MEGX within 24 h. After termination of the iv infusion, both lidocaine and the metabolites were eliminated within 24-48 h. The anticonvulsive effectiveness--estimated by clinical observation and continuous amplitude integrated EEG monitoring (cerebral function monitor)--was immediate in 15 infants (nine term and six preterm). There was no correlation between blood concentrations of lidocaine and metabolites, and anticonvulsive effect (i.e. good, intermediate or no response). No differences in blood concentrations were found between full-term and preterm babies, or between infants with or without birth asphyxia. In combination with a fast withdrawal of the drug, few adverse reactions were seen with the dosages used, even though blood concentrations were high. Routine measurements of lidocaine concentrations during anticonvulsive treatment in neonates seem to be of little clinical value. For evaluation of the anticonvulsive effect and for early detection of seizure activity during lidocaine withdrawal, continuous EEG monitoring is preferable.
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| 7. |
- Minthon, Lennart, et al.
(författare)
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Oral tetrahydroaminoacridine treatment of Alzheimer's disease evaluated clinically and by regional cerebral blood flow and EEG
- 1993
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Ingår i: Dementia (Switzerland). - 1013-7424. ; 4:1, s. 32-42
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Tidskriftsartikel (refereegranskat)abstract
- Neurochemical evidence indicates that cognitive impairment in dementia of Alzheimer type (DAT) is related to degeneration of cholinergic neurons in the brain. A pharmacological approach is treatment with a cholinesterase inhibitor such as tetrahydroaminoacridine (THA). THA treatment of 17 patients with DAT was studied with a double-blind crossover design with three types of treatment, THA + lecithin, THA + placebo and placebo + placebo. Each treatment period was 6 weeks with wash out periods of 2 weeks. The treatment was evaluated with clinical ratings, psychometric testing, EEG and regional cerebral blood flow (rCBF) measurements. No significant clinical differences between treatment periods were found in the total sample, but marked individual differences were observed. The patients were subdivided into three outcome groups based on four clinical measures: 6 patients improved (responders), 5 patients were mainly unchanged, and 6 patients showed further deterioration during the trial period of 26 weeks. Pretreatment rCBF in responders differed significantly from that of the deteriorated patients. EEG showed more high frequency activity among responders. Hepatotoxic side effects were observed in several cases. Three subjects showed marked increases of liver enzymes, with normalization following dose reduction. The majority of patients who improved or remained unchanged during the study chose to continue THA treatment in an open trial.
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| 8. |
- Stenberg, Georg, 1947-, et al.
(författare)
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Attention and personality in augmenting/reducing of visual evoked potentials
- 1990
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Ingår i: Personality and Individual Differences. - 0191-8869 .- 1873-3549. ; 11:12, s. 1243-1254
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Tidskriftsartikel (refereegranskat)abstract
- Earlier research has shown that extraverts tend to increase their visual evoked potential amplitudes with increasing light intensity (augmenting), while introverts reach their maximum amplitude at lower intensities (reducing). The evoked response has normally been measured from association areas of the brain (at the vertex). The present study measured VEP amplitudes over visual cortex and at the vertex, using four light intensities in two conditions, where attention was either directed towards the light stimuli, or away from them by a concurrent auditory task. Forty subjects were classified as extraverts or introverts based on the Eysenck Personality Inventory. The results show that attention interacted significantly with extraversion. Introverts exhibited a narrower focus of attention, with higher amplitudes and amplitude-intensity functions when attending to the light flashes and lower when distracted. Extraverts showed smaller differences between conditions, indicating a more evenly distributed attention. Higher arousal in introverts is the probable cause of their narrower focus of attention. There were marked differences in the distribution of activity between vertex and occipital cortex. Introverts showed relatively stronger occipital responses and extraverts stronger vertex responses across all intensities and in both conditions. The predisposition for mainly perceptual responses to aversive stimuli in introverts, and for general alerting and motor preparatory responses in extraverts, are interpreted as supportive of Brebner & Cooper's hypothesis that introverts are "geared to inspect" and extraverts are "geared to respond".
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| 9. |
- Stenberg, Georg, 1947-, et al.
(författare)
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EEG topography of acute ethanol effects in resting and activated normals
- 1994
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Ingår i: Journal of Studies on Alcohol. - 0096-882X .- 1934-2683. ; 55:6, s. 645-656
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Tidskriftsartikel (refereegranskat)abstract
- Acute effects of ethanol on spectral characteristics of the EEG were studied using 18 recording sites and topographic mapping. The EEG was recorded both at rest and during a mental arithmetic task. Healthy young male volunteers were randomly assigned to an ethanol (n = 22) or a placebo (n = 15) group. The ethanol group received a total dose of 1.0 g/kg, divided into two equal doses given 75 minutes apart. and measurement sessions took place at baseline and after each dose. The placebo group underwent a similar schedule. Power in the theta, alpha and beta bands all increased in the ethanol group, but only the theta and beta bands clearly separated ethanol from placebo. Alpha increases were seen in the placebo group as well. The ethanol-induced changes were greater in the left hemisphere than in the right, having the effect of attenuating the right-over-left asymmetry seen at baseline. Differences between ethanol and placebo were more marked in the mentally activated condition, since the changes seen at rest were inhibited by the activation in the placebo group, but not in the ethanol group. The results indicate (1) that ethanol induces a less differentiated pattern of activity within the brain at rest, and (2) that it impairs the capacity to activate the brain under the challenge of a mental task.
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| 10. |
- Stenberg, Georg, 1947-, et al.
(författare)
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Extraversion and regional blood flow
- 1990
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Ingår i: Journal of Psychophysiology, vol. 4, no. 1. ; , s. 66-
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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