| 1. |
- Andreasson, Ann‐Charlotte, et al.
(author)
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Cortical excitability measured with transcranial magnetic stimulation in children with epilepsy before and after antiepileptic drugs
- 2020
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In: Developmental Medicine and Child Neurology. - : Wiley. - 0012-1622 .- 1469-8749. ; 62:7, s. 793-798
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Journal article (peer-reviewed)abstract
- Aim To evaluate cortical excitability with transcranial magnetic stimulation (TMS) in children with new-onset epilepsy before and after antiepileptic drugs (AEDs). Method Fifty-five drug-naive patients (29 females, 26 males; 3-18y), with new-onset epilepsy were recruited from 1st May 2014 to 31st October 2017 at the Child Neurology Department, Queen Silvia's Children's Hospital, Gothenburg, Sweden. We performed TMS in 48 children (23 females, 25 males; mean [SD] age 10y [3y], range 4-15y) with epilepsy (27 generalized and 21 focal) before and after the introduction of AEDs. We used single- and paired-pulse TMS. We used single-pulse TMS to record resting motor thresholds (RMTs), stimulus-response curves, and cortical silent periods (CSPs). We used paired-pulse TMS to record intracortical inhibition and facilitation at short, long, and intermediate intervals. Results There were no differences in cortical excitability between children with generalized and focal epilepsy at baseline. After AED treatment, RMTs increased (p=0.001), especially in children receiving sodium valproate (p=0.005). CSPs decreased after sodium valproate was administered (p=0.050). As in previous studies, we noted a negative correlation between RMT and age in our study cohort. Paired-pulse TMS could not be performed in most children because high RMTs made suprathreshold stimulation impossible. Interpretation Cortical excitability as measured with RMT decreased after the introduction of AEDs. This was seen in children with both generalized and focal epilepsy who were treated with sodium valproate, although it was most prominent in children with generalized epilepsy. We suggest that TMS might be used as a prognostic tool to predict AED efficacy.
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| 2. |
- Donadio, V., et al.
(author)
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Muscle sympathetic response to arousal predicts neurovascular reactivity during mental stress
- 2012
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In: Journal of Physiology-London. - : Wiley. - 0022-3751. ; 590:12, s. 2885-2896
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Journal article (peer-reviewed)abstract
- Key points Mental stress (MS) is often initiated by a sensory or cognitive stimulus, which induces a brief arousal reaction followed by a longer stress phase. Both phases induce blood pressure (BP) increases whereas effects on muscle sympathetic nerve activity (MSNA) vary: in approximately 50% of healthy subjects (responders) arousal induces a brief MSNA reduction, which is absent in the remaining 50% (non-responders). We now report a link between the arousal response and neurovascular effects of MS in healthy males. Our data show that during MS, responders to arousal exhibited a significant decrease of MSNA and a lesser BP increase compared to non-responders. The whole material displayed a positive correlation between MSNA responses induced by arousal and MS. In addition, arousal induced MSNA changes correlated positively with BP changes during MS. We conclude that the MSNA response to arousal predicts MSNA and BP responses to MS.
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| 3. |
- Krogstad, Anne-Lene, 1956, et al.
(author)
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Evaluation of objective methods to diagnose palmar hyperhidrosis and monitor effects of botulinum toxin treatment.
- 2004
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In: Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology. - : Elsevier BV. - 1388-2457. ; 115:8, s. 1909-16
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Journal article (peer-reviewed)abstract
- OBJECTIVE: To evaluate (1) if laboratory tests may be a useful complement in diagnosing palmar hyperhidrosis and (2) if such tests can be used in the follow up examination of treatment effects. METHODS: Repeated measurements of evaporation and conductance were made in glabrous skin on hands and compared with subjective estimates of the degree of sweating in 20 control subjects and 20 patients with a history of palmar hyperhidrosis. In addition, 17 patients were monitored for up to 6 months after treatment of the hands with botulinum toxin A. RESULTS: Before treatment, evaporation in the palms was higher in the patients than in the control subjects but skin conductance did not differ between the groups. After treatment both evaporation and skin conductance decreased markedly in the patients and then slowly returned towards pretreatment values. CONCLUSIONS: Measurements of evaporation, but not skin conductance, may be a useful objective adjunct when diagnosing palmar hyperhidrosis. Both methods can, however, be used to monitor intraindividual changes of sweating over time.
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| 5. |
- Persson, Mikael, 1959, et al.
(author)
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Microwave-Based Stroke Diagnosis Making Global Prehospital Thrombolytic Treatment Possible
- 2014
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In: IEEE Transactions on Biomedical Engineering. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9294 .- 1558-2531. ; 61:11, s. 2806-2817
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Journal article (peer-reviewed)abstract
- Here, we present two different brain diagnostic devices based on microwave technology and the associated two first proof-of-principle measurements that show that the systems can differentiate hemorrhagic from ischemic stroke in acute stroke patients, as well as differentiate hemorrhagic patients from healthy volunteers. The system was based on microwave scattering measurements with an antenna system worn on the head. Measurement data were analyzed with a machine-learning algorithm that is based on training using data from patients with a known condition. Computer tomography images were used as reference. The detection methodology was evaluated with the leave-one-out validation method combined with a Monte Carlo-based bootstrap step. The clinical motivation for this project is that ischemic stroke patients may receive acute thrombolytic treatment at hospitals, dramatically reducing or abolishing symptoms. A microwave system is suitable for prehospital use, and therefore has the potential to allow significantly earlier diagnosis and treatment than today.
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| 6. |
- Rejnö-Habte Selassie, Gunilla, et al.
(author)
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Cortical mapping of receptive language processing in children using navigated transcranial magnetic stimulation.
- 2020
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In: Epilepsy & behavior : E&B. - : Elsevier BV. - 1525-5069. ; 103:A
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Journal article (peer-reviewed)abstract
- We used a stepwise process to develop a new paradigm for preoperative cortical mapping of receptive language in children, using temporary functional blocking with transcranial magnetic stimulation (TMS). The method combines short sentences with a lexical decision task in which children are asked to point at a picture that fits a short sentence delivered aurally. This was first tested with 24 healthy children aged 4-16years. Next, 75 sentences and 25 slides were presented to five healthy children in a clinical setting without TMS. Responses were registered on a separate computer, and facial expressions and hand movements were filmed for later offline review. Technical adjustments were made to combine these elements with the existing TMS equipment. The audio-recorded sentences were presented before the visual stimuli. Sentence lists were constructed to avoid similar stimuli in a row. Two different baseline lists were used before the TMS registration; the second baseline resulted in faster responses and was chosen as the reference for possible response delays induced by TMS. Protocols for offline reviews were constructed. No response, incorrect response, self-correction, delayed response, and perseveration were considered clear stimulation effects, while poor attention, discomfort, and other events were regarded as unclear. Finally, three children (6:2, 14:0, 14:10years) with epilepsy and expected to undergo neurosurgery were assessed using TMS (left hemisphere in one; both hemispheres in the other two). In the two assessed bilaterally, TMS effects indicated bilateral language processing. Delayed response was the most common error. This is a first attempt to develop a new TMS paradigm for receptive language mapping, and further evaluation is suggested.
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| 7. |
- Thordstein, Magnus, et al.
(author)
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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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In: Brain Stimulation. - : Elsevier BV. - 1935-861X. ; 6:1, s. 49-53
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Journal article (peer-reviewed)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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| 8. |
- Wallin, Gunnar B, 1936, et al.
(author)
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Sympathetic single axonal discharge after spinal cord injury in humans: activity at rest and after bladder stimulation
- 2014
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In: Spinal Cord. - : Springer Science and Business Media LLC. - 1362-4393 .- 1476-5624. ; 52:6, s. 434-438
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Journal article (peer-reviewed)abstract
- Study design: Clinical experimental mechanistic study. Objectives: (1) To determine in three spinal cord-injured patients whether individual muscle sympathetic nerve fibres below the level of the spinal lesion display spontaneous activity. (2) To determine in these patients if individual sympathetic vasoconstrictor fibres show a prolonged discharge following a bladder stimulus. Methods: Microneurographic recordings of action potentials from individual muscle nerve sympathetic fibres in a peroneal nerve. Recordings of skin blood flow and electrodermal responses in a foot. Results: In all patients, there was sparse ongoing spontaneous impulse traffic in individual sympathetic fibres. Brisk mechanical pressure over the urinary bladder evoked a varying number of action potentials in individual fibres, but the activity was brief and did not continue after the end of the evoked multiunit burst. Conclusion: Prolonged discharges in individual sympathetic fibres are unlikely to contribute to a long duration of blood pressure increases induced by brief bladder stimuli.
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