| 1. |
- Blomstedt, Yulia, et al.
(författare)
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10 years follow-up of deep brain stimulation in the caudal zona incerta/posterior subthalamic area for essential tremor
- 2023
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Ingår i: Movement Disorders Clinical Practice. - : John Wiley & Sons. - 2330-1619. ; 10:5, s. 783-793
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Tidskriftsartikel (refereegranskat)abstract
- Background: Long-term data on the effects of deep brain stimulation (DBS) for essential tremor (ET) is scarce, especially regarding DBS in the caudal Zona incerta (cZi) and the posterior subthalamic area (PSA). Objectives: The aim of this prospective study was to evaluate the effect of cZi/PSA DBS in ET at 10 years after surgery.Methods: Thirty-four patients were included. All patients received cZi/PSA DBS (5 bilateral/29 unilateral) and were evaluated at regular intervals using the essential tremor rating scale (ETRS).Results: One year after surgery, there was a 66.4% improvement of total ETRS and 70.7% improvement of tremor (items 1–9) compared with the preoperative baseline. Ten years after surgery, 14 patients had died and 3 were lost to follow-up. In the remaining 17 patients, a significant improvement was maintained (50.8% for total ETRS and 55.8% for tremor items). On the treated side the scores of hand function (items 11–14) had improved by 82.6% at 1 year after surgery, and by 66.1% after 10 years. Since off-stimulation scores did not differ between year 1 and 10, this 20% deterioration of on-DBS scores was interpreted as a habituation. There was no significant increase in stimulation parameters beyond the first year.Conclusions: This 10 year follow up study, found cZi/PSA DBS for ET to be a safe procedure with a mostly retained effect on tremor, compared to 1 year after surgery, and in the absence of increase in stimulation parameters. The modest deterioration of effect of DBS on tremor was interpreted as habituation.
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| 2. |
- Persson, Rasmus
(författare)
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Downgrade
- 2023
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Ingår i: Encyclopedia of Terminology for Conversation Analysis and Interactional Linguistics. - : International Society for Conversation Analysis (ISCA).
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Bokkapitel (refereegranskat)
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| 3. |
- Persson, Rasmus, 1985
(författare)
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Qualitative molecular orbital theory suited for the high school student
- 2023
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Ingår i: African Journal of Chemical Education. - 2227-5835. ; 13:1, s. 162-177
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Tidskriftsartikel (refereegranskat)abstract
- We introduce and discuss a pedagogical approach to molecular orbital theory which, devoid of any mathematics beyond simple arithmetic on experimental data, is suitable as an introduction to chemical bonding concepts as a complement to Lewis theory in high-school chemistry. Examples are discussed that highlight the reasoning that could be imparted to students. This exercise may also give rise to discussions about scientific theories and “truth.” Notably, within the realm of our qualitative theory, we conclude that HF is a double-bonded diatomic.
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| 4. |
- Persson, Rasmus, 1985
(författare)
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Theoretical evaluation of partial credit scoring of the multiple-choice test item
- 2023
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Ingår i: Metron. - : Springer Science and Business Media LLC. - 0026-1424 .- 2281-695X. ; 81:1, s. 143-161
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Tidskriftsartikel (refereegranskat)abstract
- In multiple-choice tests, guessing is a source of test error which can be suppressed if its expected score is made negative by either penalizing wrong answers or rewarding expressions of partial knowledge. Starting from the most general formulation of the necessary and sufficient scoring conditions for guessing to lead to an expected loss beyond the test-taker’s knowledge, we formulate a class of optimal scoring functions, including the proposal by Zapechelnyuk (Econ. Lett. 132, 24–27 (2015)) as a special case. We then consider an arbitrary multiple-choice test taken by a rational test-taker whose knowledge of a test item is defined by the fraction of the answer options which can be ruled out. For this model, we study the statistical properties of the obtained score for both standard marking (where guessing is not penalized), and marking where guessing is suppressed either by expensive score penalties for incorrect answers or by different marking schemes that reward partial knowledge.
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| 5. |
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| 6. |
- Persson, Rasmus
(författare)
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Turn allocation
- 2023
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Ingår i: Encyclopedia of Terminology for Conversation Analysis and Interactional Linguistics. - : International Society for Conversation Analysis (ISCA).
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Bokkapitel (refereegranskat)
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| 7. |
- Persson, Rasmus
(författare)
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Turn holding
- 2023
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Ingår i: Encyclopedia of Terminology for Conversation Analysis and Interactional Linguistics. - : International Society for Conversation Analysis (ISCA).
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Bokkapitel (refereegranskat)
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| 8. |
- Persson, Rasmus
(författare)
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Turn-taking
- 2023
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Ingår i: Encyclopedia of Terminology for Conversation Analysis and Interactional Linguistics. - : International Society for Conversation Analysis (ISCA).
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Bokkapitel (refereegranskat)
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| 9. |
- Persson, Rasmus
(författare)
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Upgrade
- 2023
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Ingår i: Encyclopedia of Terminology for Conversation Analysis and Interactional Linguistics. - : International Society for Conversation Analysis (ISCA).
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Bokkapitel (refereegranskat)
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| 10. |
- Stenmark Persson, Rasmus, 1990-
(författare)
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Deep brain stimulation targeting the caudal zona incerta as a treatment for parkinsonian and essential tremor
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Deep brain stimulation (DBS) is used as a treatment for Parkinson’s disease (PD) and Essential tremor (ET) when medications are insufficient. The most common DBS-targets for PD and ET, the subthalamic nucleus (STN) and the ventral intermediate nucleus of the thalamus (Vim) respectively, have certain side effects and limitations. In the early 2000s, the posterior subthalamic area (PSA) was introduced as an alternative DBS-target with good results on PD and ET in non-blinded, non-randomised, short-term studies. Different structures in the PSA, such as the caudal zona incerta (cZi), have been used as targets but an optimal target within this area has not been established. Furthermore, there has been an increased interest in asleep DBS surgery but with a paucity of results of asleep surgery for ET, as the Vim is not visible on conventional MRI.Aims: To evaluate DBS targeting the cZi for PD in a blinded, randomised manner. To spatially map the effects of DBS within the PSA. To evaluate the long-term effects of cZi-DBS on PD tremor and ET. To analyse the outcome of awake and asleep cZi-DBS surgery for ET. Method: The thesis is based on five studies. Bilateral cZi-DBS was compared to Best Medical Treatment for PD in a randomised blinded trial. The long-term effects of unilateral cZi-DBS on PD tremor were evaluated retrospectively. Prospectively collected data on cZi-DBS for ET were used to evaluate long-term effects and compare awake and asleep surgery. The effects of cZi-DBS were spatially mapped within the PSA using electric field simulations and contact location in relation to the STN.Results: Bilateral cZi-DBS improved motor symptoms and quality of life in patients with PD in both blinded and non-blinded evaluations with a pronounced effect on tremor (90%) and a modest on bradykinesia (25-40%). The effects of unilateral cZi-DBS on PD tremor remained undiminished at a mean of five years after surgery. cZi-DBS significantly improved ET 10 years after surgery with a slight deterioration over time. Asleep surgery had similar effects and side effects as awake surgery for patients with ET. Electric field simulations did not reveal an optimal target but together with contact location analyses consistently found that the stimulation was concentrated within the PSA, overlapping the cZi and the cerebellothalamic tract. Conclusion: DBS targeting the cZi reliably achieved a pronounced effect on PD tremor and ET up to at least five and ten years after surgery respectively. In addition, cZi-DBS had a modest effect on bradykinesia and improved quality of life in patients with PD. Finally, targeting the cZi enabled asleep surgery with seemingly similar efficacy as awake surgery for ET.
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