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  • 28701.
    Åström, Mattias
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology. Sapiens Steering Brain Stimulation B.V., The Netherlands .
    Functional brain atlas2014Conference paper (Other academic)
  • 28702.
    Åström, Mattias
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Modelling, Simulaltion, and Visualization of Deep Brain Stimulation2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Deep brain stimulation (DBS) is an effective surgical treatment for neurological diseases such as essential tremor, Parkinsonʹs disease (PD) and dystonia. DBS has so far been used in more than 70 000 patients with movement disorders, and is currently in trial for intractable Gilles de la Tourette’s syndrome, obsessive compulsive disorders, depression, and epilepsy. DBS electrodes are implanted with stereotactic neurosurgical techniques in the deep regions of the brain. Chronic electrical stimulation is delivered to the electrodes from battery-operated pulse generators that are implanted below the clavicle.

    The clinical benefit of DBS is largely dependent on the spatial distribution of the electric field in relation to brain anatomy. To maximize therapeutic benefits while avoiding unwanted side-effects, knowledge of the distribution of the electric field in relation anatomy is essential. Due to difficulties in measuring electric fields in vivo, computerized analysis with finite element models have emerged as an alternative.

    The aim of the thesis was to investigate technical and clinical aspects of DBS by means of finite element models, simulations, and visualizations of the electric field and tissue anatomy. More specifically the effects of dilated perivascular spaces filled with cerebrospinal fluid on the electrical field generated by DBS was evaluated. A method for patient-specific finite element modelling and simulation of DBS was developed and used to investigate the anatomical distribution of the electric field in relation to clinical effects and side effects. Patient-specific models were later used to investigate the electric field in relation to effects on speech and movement during DBS in patients with PD (n=10). Patient-specific models and simulations were also used to evaluate the influence of heterogeneous isotropic and heterogeneous anisotropic tissue on the electric field during DBS. In addition, methods were developed for visualization of atlas-based and patient-specific anatomy in 3D for interpretation of anatomy, visualization of neural activation with the activating function, and visualization of tissue micro structure. 3D visualization of anatomy was used to assess electrode contact locations in relation to stimulation-induced side-effects (n=331) during DBS for patients with essential tremor (n=28). The modelling, simulation, and visualization of DBS provided detailed information about the distribution of the electric field and its connection to clinical effects and side-effects of stimulation. In conclusion, the results of this thesis provided insights that may help to improve DBS as a treatment for movement disorders as well as for other neurological diseases in the future.

  • 28703.
    Åström, Mattias
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology. Sapiens Steering Brain Stimulation B.V., The Netherlands .
    Neuronmodeling and DBS electric field simulations2014Conference paper (Other academic)
  • 28704.
    Åström, Mattias
    et al.
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology. Sapiens Steering Brain Stimulation BV, NL-5656 Eindhoven, Netherlands.
    Diczfalusy, Elin
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Martens, Hubert
    Sapiens Steering Brain Stimulation B.V., Eindhoven, The Netherlands.
    Wårdell, Karin
    Linköping University, Department of Biomedical Engineering. Linköping University, The Institute of Technology.
    Relationship between Neural Activation and Electric Field Distribution during Deep Brain Stimulation2015In: IEEE Transactions on Biomedical Engineering, ISSN 0018-9294, E-ISSN 1558-2531, Vol. 62, no 2, p. 664-72Article in journal (Refereed)
    Abstract [en]

    Models and simulations are commonly used to study deep brain stimulation (DBS). Simulated stimulation fields are often defined and visualized by electric field isolevels or volumes of tissue activated (VTA). The aim of the present study was to evaluate the relationship between stimulation field strength as defined by the electric potential V, the electric field E, and the divergence of the electric field ∇(2) V, and neural activation. Axon cable models were developed and coupled to finite-element DBS models in three-dimensional (3-D). Field thresholds ( VT , ET, and ∇(2) VT ) were derived at the location of activation for various stimulation amplitudes (1 to 5 V), pulse widths (30 to 120 μs), and axon diameters (2.0 to 7.5 μm). Results showed that thresholds for VT and ∇(2) VT were highly dependent on the stimulation amplitude while ET were approximately independent of the amplitude for large axons. The activation field strength thresholds presented in this study may be used in future studies to approximate the VTA during model-based investigations of DBS without the need of computational axon models.

  • 28705.
    Åström, Mattias
    et al.
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Diczfalusy, Elin
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Wårdell, Karin
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Computational analysis of the electric field during deep brain stimulation (oral, invited)2010Conference paper (Refereed)
  • 28706.
    Åström, Mattias
    et al.
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Diczfalusy, Elin
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Wårdell, Karin
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Software for patient-specific modeling and simulation of deep brain stimulation (poster)2011Conference paper (Other academic)
  • 28707.
    Åström, Mattias
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Johansson, Johannes
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Hariz, Marwan
    Institute of Neurology London.
    Eriksson, Ola
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Wårdell, Karin
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    The effect of cystic cavities on deep brain stimulation in the basal ganglia: A simulation-based study2006In: Journal of Neural Engineering, ISSN 1741-2560, E-ISSN 1741-2552, Vol. 3, no 2, p. 132-138Article in journal (Refereed)
    Abstract [en]

    Although the therapeutic effect of deep brain stimulation (DBS) is well recognized, a fundamental understanding of the mechanisms responsible is still not known. In this study finite element method (FEM) modelling and simulation was used in order to study relative changes of the electrical field extension surrounding a monopolar DBS electrode positioned in grey matter. Due to the frequently appearing cystic cavities in the DBS-target globus pallidus internus, a nucleus of grey matter with and without a cerebrospinal fluid filled cystic cavity was modelled. The position, size and shape of the cyst were altered in relation to the electrode. The simulations demonstrated an electrical field around the active element with decreasing values in the radial direction. A stepwise change was present at the edge between grey and white matters. The cyst increased the radial extension and changed the shape of the electrical field substantially. The position, size and shape of the cyst were the main influencing factors. We suggest that cystic cavities in the DBS-target may result in closely related unexpected structures or neural fibre bundles being stimulated and could be one of the reasons for suboptimal clinical effects or stimulation-induced side effects. © 2006 IOP Publishing Ltd.

  • 28708.
    Åström, Mattias
    et al.
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Johansson, Johannes
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Wårdell, Karin
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Modeling and simulation of electric fields generated by brain stimulation electrodes: the effect of cystic cavities in the basal ganglia2005In: Proceedings from the International IEEE EMBS Conference on Neural Engineering, IEEE , 2005, p. 198-201Conference paper (Refereed)
    Abstract [en]

    Deep brain stimulation (DBS) is an effective method for managing movement disorders. A small electrode is implanted in the basal ganglia and an electric potential is applied to one or more active elements of the electrode in order to simulate the neurons in the surrounding tissue. The fundamental understanding of the mechanisms responsible for the therapeutic DBS effects is unknown. A method to increase the knowledge is to use computer simulations. In this study the finite element method has been used for investigation of relative changes of the electrical field extension surrounding a monopolar DBS-electrode positioned in gray matter. Due to the frequently appearing cystic cavities in globus pallidus and putamen a nucleus of gray matter with and without a cerebrospinal fluid filled cystic cavity was modeled. The simulations demonstrated an electrical field around the active element with decreasing values in the radial direction. A stepwise change was present at the edge between gray and white matter. The cyst increased the radial extension and changed the shape of the field. This may result in closely related unexpected structures being stimulated and could be one of the reasons of reported postoperative complications.

  • 28709.
    Åström, Mattias
    et al.
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Lemair, Jean-Jaques
    Hôpital Gabriel Montpied, Service de Neurochirurgie, Clermont-Ferrand, France.
    Wårdell, Karin
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    The influence of brain tissue heterogeneity and anisotropy on deep brain stimulation in the subhalamic nucleus2009Conference paper (Refereed)
  • 28710.
    Åström, Mattias
    et al.
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Lemaire, Jean-Jacques
    Clermont Université, Université d'Auvergne, EA 3295, Equipe de recherche en signal et imagerie médicale, Image- Guided Clinical Neuroscience and Connectomics (IGCNC), BP 10448, F-63000 Clermont-Ferrand, France/CHU Clermont-Ferrand, Service de Neurochirurgie, F-63003 Clermont-Ferrand, France.
    Wårdell, Karin
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Influence of heterogeneous and anisotropic tissue conductivity on electric field distribution in deep brain stimulation2012In: Medical and Biological Engineering and Computing, ISSN 0140-0118, E-ISSN 1741-0444, Vol. 50, no 1, p. 23-32Article in journal (Refereed)
    Abstract [en]

    The aim was to quantify the influence of heterogeneous isotropic and heterogeneous anisotropic tissue on the spatial distribution of the electric field during deep brain stimulation (DBS). Three finite element tissue models were created of one patient treated with DBS. Tissue conductivity was modelled as I) homogeneous isotropic, II) heterogeneous isotropic based on MRI, and III) heterogeneous anisotropic based on diffusion tensor MRI. Modelled DBS electrodes were positioned in the subthalamic area, the pallidum, and the internal capsule in each tissue model. Electric fields generated during DBS were simulated for each model and target-combination and visualized in 3D with isolevels at 0.20 (inner), and 0.05 V m-1 (outer). F-test and vector analysis was used for statistical evaluation of the distribution of the electric field. Heterogeneous isotropic tissue altered the spatial distribution of the electric field by up to 4% at inner, and up to 10% at outer isolevel. Heterogeneous anisotropic tissue had a larger impact on the distribution of the electric field with an influence of up to 18% and 15% at each isolevel, respectively. The influence of heterogeneous and anisotropic tissue on the electric field may be clinically relevant in anatomic regions that are functionally subdivided and surrounded by multiple fibres of passage.

  • 28711.
    Åström, Mattias
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Tisch, Stephen
    Institute of Neurology University College, London, UK.
    Zrinzo, Ludvic U.
    Institute of Neurology University College, London, UK.
    Tripoliti, Elina
    University of Neurology University College, London, UK.
    Hariz, Marwan I.
    Department of Neurosurgery University Hospital, Umeå, Sweden.
    Wårdell, Karin
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    A model-Based analysis of deep brain stimulation2007Conference paper (Other academic)
    Abstract [en]

      

  • 28712.
    Åström, Mattias
    et al.
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Tripoliti, E
    n/a.
    Hariz, M I
    n/a.
    Zrinzo, L U
    n/a.
    Martinez-Torre, I
    n/a.
    Limousin, P
    n/a.
    Wårdell, Karin
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Swedish Movement Disorder Society, Umeå 15-16 october, 20092009In: The electric field during DBS, 2009Conference paper (Other academic)
  • 28713.
    Åström, Mattias
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Tripoliti, E.
    Institute of Neurology University College London.
    Zrinzo, U.
    Institute of Neurology University College London.
    Marinez-Torres, I.
    Institute of Neurology University College London.
    Limousin, P.
    Institute of Neurology University College London.
    Hariz, M. I.
    Institute of Neurology University College London.
    Wårdell, Karin
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Voltage steering to control deep brain stimulation-induced speech deficits2008In: XVIII Congress of the European Society for Stereotactic and Functional Neurosurgery,2008, 2008Conference paper (Other academic)
  • 28714.
    Åström, Mattias
    et al.
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Tripoliti, Elina
    University College, London.
    Hariz, Mawan I.
    University Hospital, Umeå .
    Zrinzo, Ludvig U.
    University College, London.
    Martinez-Torres, Irene
    University College, London.
    Limousin, Patricia
    University College, London.
    Wårdell, Karin
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Patient-Specific Model-Based Investigation of Speech Intelligibility and Movement during Deep Brain Stimulation2010In: Stereotactic and Functional Neurosurgery, ISSN 1011-6125, E-ISSN 1423-0372, Vol. 88, no 4, p. 224-233Article in journal (Refereed)
    Abstract [en]

    Background/Aims: Deep brain stimulation (DBS) is widely used to treat motor symptoms in patients with advanced Parkinson’s disease. The aim of this study was to investigate the anatomical aspects of the electric field in relation to effects on speech and movement during DBS in the subthalamic nucleus. Methods: Patient-specific finite element models of DBS were developed for simulation of the electric field in 10 patients. In each patient, speech intelligibility and movement were assessed during 2 electrical settings, i.e. 4 V (high) and 2 V (low). The electric field was simulated for each electrical setting. Results: Movement was improved in all patients for both high and low electrical settings. In general, high-amplitude stimulation was more consistent in improving the motor scores than low-amplitude stimulation. In 6 cases, speech intelligibility was impaired during high-amplitude electrical settings. Stimulation of part of the fasciculus cerebellothalamicus from electrodes positioned medial and/or posterior to the center of the subthalamic nucleus was recognized as a possible cause of the stimulation-induced dysarthria. Conclusion: Special attention to stimulation-induced speech impairments should be taken in cases when active electrodes are positioned medial and/or posterior to the center of the subthalamic nucleus.

  • 28715.
    Åström, Mattias
    et al.
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Tripoliti, Elina
    Institute of Neurology, Queen Square, University College London, UK.
    Martinez-Torres, Irene
    Institute of Neurology, Queen Square, University College London, UK.
    Zrinzo, Ludvic U.
    Institute of Neurology, Queen Square, University College London, UK.
    Limousin, Patricia
    Institute of Neurology, Queen Square, University College London, UK.
    Hariz, Marwan I.
    Institute of Neurology, Queen Square, University College London, UK; Dept of Neurosurgery, University Hospital, Umeå, Sweden.
    Wårdell, Karin
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Patient-specific models and simulations of deep brain stimulation for postoperative follow-up2009In: World Congress on Medical Physics and Biomedical Engineering / [ed] Olaf Dössel and Wolfgang C. Schlegel, Springer , 2009, p. 331-334Conference paper (Refereed)
    Abstract [en]

    Deep brain stimulation (DBS) is an established treatment for Parkinson’s disease (PD). The success of DBS is highly dependent on electrode location and electrical parameter settings. In this study patient-specific computer models of DBS were used for postoperative follow-up in three PD patients who suffered from stimulation induced hypomania, dysarthria, and uncontrollable laughter respectively. The overall aim of the study was to relate the anatomical aspect of the electric field to the effects and side effects of stimulation. The simulations showed the anatomical distribution of the electric field for all the patients and the results were in agreement with previous reports regarding these side effects of stimulation. It was demonstrated that patient-specific models and simulations of DBS may be useful for postoperative follow-up of DBS.

  • 28716.
    Åström, Mattias
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Tripoliti, Elina
    Institute of Neurology University College London, UK.
    Zrinzo, Ludvic U.
    Institute of Neurology University College London, UK.
    Martinez-Torres, Irene
    Institute of Neurology University College London, UK.
    Limousin, Patricia
    Institute of Neurology University College London, UK.
    Hariz, Marwan I.
    Institute of Neurology University College London, UK.
    Wårdell, Karin
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Voltage steering to control the effects and side effects of deep brain stimulation2008Conference paper (Other academic)
  • 28717.
    Åström, Mattias
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Tripoliti, Elina
    Institute of Neurology University College, London, UK.
    Zrinzo, Ludvic U
    Institute of Neuroligy University College, London, UK.
    Tisch, Stephen
    Institute of Neurology University College, London, UK.
    Martinez-Torres, Irene
    Institute of Neurology University College, London, UK.
    Limousin, Patricia
    Institute of Neurology University College, London, UK.
    Hariz, Marwan I.
    Department of Neurosurgery University Hospital, Umeå, Sweden.
    Wårdell, Karin
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Effects of bilateral subthalamic nucleus deep brain stimulation on speech intelligibillity and movement: A model-based case stydy.2007In: XVII WFN World Congress on Parkinson´s disease and related disorders,2007, 2007Conference paper (Other academic)
    Abstract [en]

      

  • 28718.
    Åström, Mattias
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    U. Zrinzo, Ludvic
    Institute of Neurology, Queen Square, London, UK.
    I. Hariz, Marwan
    Inst. för Neurokirurgi Norrlands universitetssjukhus, Umeå samt Institute of Neurology, Queen Square, London, UK.
    Tisch, Stephen
    Institute of Neurology, Queen Square, London, UK.
    Limousin, Patricia
    Institute of Neurology, Queen Square, London, UK.
    Wårdell, Karin
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Patientspecifik modellering och simulering av djup hjärnstimulering2006In: Medicinteknikdagarna 2006,2006, 2006Conference paper (Other academic)
  • 28719.
    Åström, Mattias
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Zrinzo, L.U.
    Institute of Neurology Queen square, London, UK.
    Hariz, Marwan
    Institute of Neurology Queen square, London, UK.
    Tisch, Stephen
    Institute of Neurology Queen Square, London, UK.
    Limousin, Patricia
    Institute of Neurology Queens Square, London, UK.
    Wårdell, Karin
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation.
    Patient specific modelling and simulation of deep brain stimulation: A method for pre- and postoperative investigations2006Conference paper (Other academic)
  • 28720.
    Åström, Mattias
    et al.
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Zrinzo, Ludvic U
    University College London.
    Tisch, Stephen
    Linköping University, The Institute of Technology.
    Tripoliti, Elina
    University College London.
    Hariz, Marwan I
    University College London.
    Wårdell, Karin
    Linköping University, Department of Biomedical Engineering, Biomedical Instrumentation. Linköping University, The Institute of Technology.
    Method for patient-specific finite element modeling and simulation of deep brain stimulation2009In: Medical and Biological Engineering and Computing, ISSN 0140-0118, E-ISSN 1741-0444, Vol. 47, no 1, p. 21-28Article in journal (Refereed)
    Abstract [en]

    Deep brain stimulation (DBS) is an established treatment for Parkinsons disease. Success of DBS is highly dependent on electrode location and electrical parameter settings. The aim of this study was to develop a general method for setting up patient-specific 3D computer models of DBS, based on magnetic resonance images, and to demonstrate the use of such models for assessing the position of the electrode contacts and the distribution of the electric field in relation to individual patient anatomy. A software tool was developed for creating finite element DBS-models. The electric field generated by DBS was simulated in one patient and the result was visualized with isolevels and glyphs. The result was evaluated and it corresponded well with reported effects and side effects of stimulation. It was demonstrated that patient-specific finite element models and simulations of DBS can be useful for increasing the understanding of the clinical outcome of DBS.

  • 28721.
    Åström, Therese
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Betydelsen av skogskontinuitet och egenskaper hos gran för förekomst av Lecanactis abietina2013Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [sv]

    Skyddandet av gamla skogar med höga naturvärden är en viktig del i bevarandet av den biologiska mångfalden. För att kunna lokalisera och kvalitetsbedöma skogar med höga naturvärden används signalarter. En av dessa signalarter är Lecanactis abietina, gammelgranslav. Syftet med denna studie är att identifiera vilka faktorer som påverkar förekomst av signalarten L. abietina och täckningsgraden av apothecier. Studien utfördes i Ycke, Ullstämma och Säby Västerskog, vilka är naturreservat av olika ålder i Linköpings kommun, Östergötlands län. I de studerade områdena undersöktes samtliga granar med en diameter över 5 cm. Granarnas diameter och skuggning mättes, vid förekomst av L. abietina undersöktes förekomsten av apothecier, lavens täckningsgrad, maxhöjd och i vilka väderstreck laven förekom. Ett mindre urval av granarna borrades och ålderbestämdes. Resultatet visar att faktorerna som påverkar förekomst av L. abietina och täckningsgraden av apothecier främst är, skoglig kontinuitet i området, samt granarnas diameter och ålder. Resultaten från denna studie styrker användandet av L. abietina som lämplig indikatorart i Östergötland då lavens förekomst och spridning tydligt  speglade skogens kontinuitet (störst förekomst i de äldsta reservaten) och trädens egenskaper. Studien visar även att enbart förekomst inte räcker för att påvisa skog med höga naturvärden, utan de viktigaste faktorerna var förekomst av fertil lav, lavens täckningsgrad och frekvens på granar. Studien visar även att bevarandet av skogar med lång kontinuitet och förekomst av stora och gamla träd är viktigt för förekomsten av L. abietina.

  • 28722.
    Öberg, Birgitta
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Physiotherapy. Linköping University, Faculty of Health Sciences.
    Wåhlin, Charlotte
    Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
    Persson, Jan
    Linköping University, Department of Medical and Health Sciences, Division of Health Care Analysis. Linköping University, The Institute of Technology.
    Bernfort, Lars
    Linköping University, Department of Medical and Health Sciences, Division of Health Care Analysis. Linköping University, Faculty of Health Sciences.
    Ekberg, Kerstin
    Linköping University, Department of Medical and Health Sciences, Division of Community Medicine. Linköping University, Faculty of Health Sciences.
    A prospective cohort study on newly sick-listed patients with musculoskeletal disorders and sustainable return to work2013Conference paper (Other academic)
  • 28723.
    Öberg, Christina
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Economics, Industrial marketing.
    Accounting for Customer Relationship Changes2007In: 23rd IMP Conference,2007, 2007Conference paper (Refereed)
  • 28724.
    Öberg, Christina
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Economics, Industrial marketing.
    Accounting for Customer Relationship Dissolution - The Case of Arthur Andersen2006In: Nordic Workshop on Relationship Dynamics,2006, 2006Conference paper (Refereed)
    Abstract [en]

      

  • 28725.
    Öberg, Christina
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Engineering.
    BT Industries - A case study on acquisitions2007Report (Other academic)
  • 28726.
    Öberg, Christina
    Linköping University, Department of Management and Engineering, Industrial Marketing and Industrial Economics. Linköping University, The Institute of Technology.
    Co-ordinating for Creativity2010Conference paper (Other academic)
  • 28727.
    Öberg, Christina
    Linköping University, Department of Management and Engineering, Industrial Marketing and Industrial Economics. Linköping University, The Institute of Technology.
    Customer relationship dissolution following mergers and acquisitions – Reasons, counterforces and consequences2009In: Joint Ventures, Mergers and Acquisitions, and Capital Flow / [ed] J. B. Tobin & L. R. Parker, New York, USA: Nova Science Publishers, Inc., 2009, 1, p. 207-237Chapter in book (Other academic)
    Abstract [en]

    This book deals with 3 interrelated activities in business and finance: joint ventures, mergers and acquisitions, and capital flow.

  • 28728.
    Öberg, Christina
    Linköping University, Department of Management and Engineering, Industrial Marketing and Industrial Economics. Linköping University, The Institute of Technology.
    Customer roles in innovations2010In: The Dynamics of Innovation: Proceedings / [ed] K R E Huizingh; et al, Bilbao, Spain: International Society for Professional Innovation Management (ISPIM) , 2010Conference paper (Other academic)
    Abstract [en]

    The purpose of this paper is to discuss and classify the roles of customers in innovations. In literature on innovations, customers have been increasingly emphasised as a source for innovations and also in how they help developing ideas in their early phases. This paper exemplifies various customer roles in innovations through three case studies. These describe the customer as initiator, as co-producer and as central party for business development. Through using role theory to discuss customers in innovations, it becomes explicit how customers may act their traditional roles, add roles or transfer to new roles beyond the scope of being a customer. Furthermore, the paper shows that customer roles change during the innovation process, from added or transferred roles in early phases to more traditional ones i later phases of the innovation process

  • 28729.
    Öberg, Christina
    Linköping University, Department of Management and Engineering, Industrial Marketing and Industrial Economics. Linköping University, The Institute of Technology.
    Customer roles in innovations2010In: International Journal of Innovation Management, ISSN 1363-9196, E-ISSN 1757-5877, Vol. 14, no 6, p. 989-1011Article in journal (Refereed)
    Abstract [en]

    The purpose of this paper is to discuss and classify the roles of customers in innovations. In literature on innovations, customers have been increasingly emphasised as a source for innovations and also in how they help develop ideas in their early phases. This paper exemplifies various customer roles in innovations through three case studies. These describe the customer as initiator, as co-producer and as inspiration for business development. Through using role theory to discuss customers in innovations, it becomes explicit how customers may play their traditional roles, add roles or transfer to new roles beyond the scope of being a customer. Furthermore, the paper shows that customer roles change during the innovation process from added or transferred towards more traditional ones.

  • 28730.
    Öberg, Christina
    Linköping University, Department of Management and Engineering, Industrial Marketing and Industrial Economics . Linköping University, The Institute of Technology.
    Customers affecting M&A integration2010In: Proceedings from EURAM, Rome, 2010Conference paper (Refereed)
  • 28731.
    Öberg, Christina
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Engineering, Industrial Marketing and Industrial Economics .
    Hårda fakta och mjuka värden - Om årsredovisningar som underutnyttjad källa vid studier av affärsrelationer2008In: Workshop i kreativ metod,2008, 2008Conference paper (Refereed)
  • 28732.
    Öberg, Christina
    Linköping University, Department of Management and Engineering, Industrial Marketing and Industrial Economics . Linköping University, The Institute of Technology.
    Hårda fakta och mjuka värden: Årsredovisningar som underutnyttjad källa för studier av dynamik i affärsrelationer2009In: Nordiske organisasjonsstudier, ISSN 1501-8237, Vol. 4, p. 71-93Article in journal (Refereed)
  • 28733.
    Öberg, Christina
    Linköping University, Department of Management and Engineering, Industrial Marketing and Industrial Economics. Linköping University, The Institute of Technology.
    Identity in collaboration2010In: Abstracts from 26th Annual IMP Conference, Industrial Marketing and Purchasing Group , 2010Conference paper (Other academic)
    Abstract [en]

    Purpose: This paper targets the issue of multi-identities of companies in collaboration. Companies may participate in collaboration for various reasons and may also perceive the collaboration in different ways. What is more; companies in collaboration may to various extents regard themselves as, and be regarded as, individual companies or as part of the collaboration. Their views may in turn be reflected in how business partners of the collaborating companies perceive the collaboration. This paper builds on various actors’ perception of companies in collaboration. The paper uses the identity concept to capture the multi-identities of companies in collaboration. The purpose of the paper is to describe and discuss various actors’ perception in multi-identity settings.

    Research method: The paper is built on a case study describing three levels of identity: a company level, the level of a collaboration taking the form of a joint venture, and a contractual collaboration. These are in turn described from involved parties’ and their business partners’ perspectives.

    Research findings: The paper shows that pre-collaboration history greatly reflects the identity ascribed to the companies. This was the case both for the companies in the collaboration and their business partners’ perceptions. The more structured the collaboration, the more probable that a separate collaboration identity was established. A collaboration based on contracts merely meant that the company’s identity was affected by connections to collaboration parties, while a separate identity was not established.

    Main contribution: The paper contributes to literature on corporate identity through discussing them in relation to collaboration. It also contributes to research on perception in business relationships through pointing at differences in perception between parties, where this paper connects this to actor and relationship history along with the collaboration structure.

  • 28734.
    Öberg, Christina
    Linköping University, Department of Management and Engineering, Industrial Marketing and Industrial Economics . Linköping University, The Institute of Technology.
    Mergers and acquisitions: A network approach2009Conference paper (Refereed)
  • 28735.
    Öberg, Christina
    Linköping University, Department of Management and Economics, Industrial marketing. Linköping University, The Institute of Technology.
    On customers in mergers and acquisitions2004Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis focuses on how customers are perceived in mergers and acquisitions. Mergers and acquisitions (M&As) are frequent, yet complex, phenomena in business life. One dimension making M&As complex is that they can affect (the merging companies' relationships to) other companies. With an M&A being a potential source of, for example, customer losses, one must ask how, and indeed whether, customers are taken into account in the M&A process, and what are the merging parties' notions concerning customers in relation to an M&A.

    This thesis takes a triangulation approach to the subject, including a literature and press release review and two case studies. The following is concluded: Customers are seldom focused on in the M&A literature, though they are commonly referred to indirectly, in an unproblematised way. By not considering customers as part of an M&A, the literature is neglecting an important aspect - one that has been emphatically recognised in business experience. In actual M&A practice, customers figure prominently in the underlying motives of M&As, and also when determining the degree of integration. Notions concerning customers are malleable, shifting during the course of tl1e M&A process, and also differ between the official view articulated in press releases, and in intra-company discussions regarding reasons for merging or acquiring. The official discourse commonly refers to customers indirectly and as targets, whereas they are treated as actors in intra-company discussions. Once M&A intentions are realised, the focus shifts from creating value to keeping value, and at this stage, customer considerations constrain the degree of integration. While there is no clear-cutline between the integration itself and a possible post-M&A phase, when evaluating an M&A the evaluation tools correspond to how customers are defined in official M&A motives.

  • 28736.
    Öberg, Christina
    Linköping University, Department of Management and Engineering, Industrial Marketing and Industrial Economics . Linköping University, The Institute of Technology.
    Ownership transfer or integration: When is competition challenged in an M&A?2009Conference paper (Refereed)
  • 28737.
    Öberg, Christina
    Linköping University, Department of Management and Engineering, Industrial Marketing and Industrial Economics. Linköping University, The Institute of Technology.
    Pros and Cons of Long-Term Customer Relationships2010In: Customer relations / [ed] Victoria J. Farkas, Nova Science Publishers, Inc., 2010, p. 158-Chapter in book (Other academic)
    Abstract [en]

    Customer relations is a broadly recognised, widely-implemented strategy for managing and nurturing a companys interactions with clients and sales prospects. It involves using technology to organise, automate, and synchronise business processes -- principally sales activities, but also those for marketing, customer service, and technical support. This book presents topical research data in the study of customer relations, including how consumers use Alan P Fiske's relational models framework to construct their relationships with service organisations; measuring corporate Customer Relationship Management (CRM) strategy; and identifying the relational benefits influencing customer loyalty.

  • 28738.
    Öberg, Christina
    Linköping University, Department of Management and Engineering. Linköping University, The Institute of Technology.
    På jakt efter alternativa handledningsformer2007In: Pedagogiska utmaningar i tiden: 10:e universitetspedagogiska konferensen vid Linköpings universitet 8-9 november 2006 / [ed] H. Hård av Segerstad, Linköpings universitet , 2007, p. 61-72Chapter in book (Other academic)
    Abstract [sv]

    Vad är det vi vill att studenterna utvecklar under våra kurser? Hur formulerar vi mål för dessa avsedda kunskaper och förmågor? Hur kontrollerar vi om studenterna uppfyller målen? I samband med Bolognaprocessen har formuleringar av mål för kunskap, förståelse, färdigheter och förmågor kommit i förgrunden och tvingat kursansvariga till en nyttig eftertanke om vad vi avser att studenterna ska nå för resultat i sitt lärande. Men hur mäter vi på ett någorlunda meningsfullt sätt om de gör det? I anvisningarna för Bolognaprocessen framhålls den s.k. SOLO-taxonomin som det kriterium med vilket studenternas kunskaper ska mätas.  1 Det finns därför anledning att närmare studera SOLO-taxonomin, dess innebörd´samt dess för- och nackdelar. Syftet med detta papper är att bidra till en ökad förståelse för och möjliggöra tillämpning av SOLO-taxonomin som betygskriterium. Det ska ske för det första genom att förklara taxonomin i relation till alternativa metoder, för det andra genom att exemplifiera hur taxonomin använts i praktiken på en kurs samt kritiskt diskutera dess förtjänster och tillkortakommanden. Det visar sig att även om taxonomin rätt använd kan fungera som ett instrument att värdera nivån i studenternas kunskaper, så är metoden ofullständig.

  • 28739.
    Öberg, Christina
    Linköping University, Department of Management and Economics, Industrial marketing. Linköping University, The Institute of Technology.
    På jakt efter alternativa handledningsformer2006In: Pedagogiska utmaningar i tiden / [ed] Helene Hård af Segerstad, Linköping: Linköping University Electronic Press , 2006, p. 61-69Conference paper (Other academic)
    Abstract [sv]

    Handledning kan ofta uppfattas som en fokuserad, men också resurskrävande undervisningsform. Förväntningar ställs inte bara på lärarens förmåga att stimulera till egentänkande, men också på att ofta kunna fatta snabba beslut och föra ett projekt framåt. Från studenter kan handledning uppfattas som ett tillfälle att få idéer bekräftade, en möjlighet att ställa specifika frågor och driva den egna lärprocessen framåt, eller som något nödvändigt ont där läraren förväntas vara den som tar initiativ.

    En kritik som därtill ofta riktas mot projekt härrör från grupprocesser och individens syn på sin roll i en gemensam uppgift. Ur lärarperspektivet ställs krav på att stimulera hela gruppen att känna ett gemensamt ansvar, bemöta eventuella gruppinterna konflikter, o s v.

    För att om möjligt komma förbi några av handledningens tillkortakommanden har en projektförberedande seminarieuppgift införts på grundläggande ekonomikurser (industriell ekonomi på ingenjörsutbildningar). Mer specifikt är avsikten med uppgiften att ge studenterna en första orientering och breddad förståelse för det ämne de senare ska fördjupa sig inom. Genom att besvara ett antal frågor och sedan diskutera dessa i tvärgrupper med andra studenter, där varje student individuellt får representera sin grupp, är avsikten att studenterna ska öka sin förmåga att självständigt reflektera och samtidigt lära sig genom att diskutera seminariesvaren med andra studenter.

    Arbetet baseras på studenters utvärdering av projektarbetet och intervjuer med handledare på kurserna. Avsikten med detta papper är att utvärdera om denna seminarieuppgift påverkat det slutliga projektet och kursen som helhet. En avslutande diskussion förs om huruvida denna typ av uppgifter utgör ett komplement till, eller en ersättning för, den traditionella handledningsformen, samt övriga lärdomar från införandet av uppgiften.

  • 28740.
    Öberg, Christina
    Linköping University, Department of Management and Engineering, Industrial Marketing and Industrial Economics. Linköping University, The Institute of Technology.
    The core customer concept2011In: Service Industries Journal, ISSN 0264-2069, E-ISSN 1743-9507, Vol. 31, no 16, p. 2677-2692Article in journal (Refereed)
    Abstract [en]

    The purpose of this paper is to define and discuss the core-customer concept. This concept examines how a company develops its operations around a single or only a few customers. The customer steers what products and services the supplier develops, which means that it is the customer that dictates the supplier's operations. The core-customer concept may be one method for designing a company's operations, but the paper also aims to challenge companies to consider how they think about customers. The paper contributes to research on customer value and extended service offerings by indicating a business-development strategy based on the customer rather than the supplier's operations. Building a company around a single customer, requires flexibility and competences in finding collaboration partners or in adjusting the organisation to new requirements. The paper refers to these as secondary/supporting competences, while the core competence upon which the company builds its operation is the customer.

  • 28741.
    Öberg, Christina
    Linköping University, Department of Management and Engineering, Industrial Marketing and Industrial Economics. Linköping University, The Institute of Technology.
    The Importance of Customers in Mergers and Acquisitions2008Doctoral thesis, monograph (Other academic)
    Abstract [en]

    The aim of the thesis is to identify categories and patterns of how customers impact and are impacted by an M&A. In M&A (merger and acquisition) research the focus is traditionally on the M&A parties alone, and while customers are important elements of the motives behind M&As, they are rarely seen as actors affecting and being affected by an M&A.

    This thesis researches M&As from M&A parties’ and customers’ perspectives. It categorises and connects M&A parties’ activities related to expectations and activities of customers, with customers’ activities at the acquisition point and at integration.

    Based on findings from eight M&As, the thesis concludes that customers may be the reasons why companies merge or acquire. Customers may react to the M&A announcement if it involves companies the customers do not want to have relationships with, or based on the fact that customers perceive the M&A as turbulent, for instance. Customer actions, and M&A parties reconsidering their initial intentions, affect integration strategies. The realisation of integration is in turn impacted by customers’ resistance to buy according to M&A parties’ intentions and by customers actively objecting to integration.

    In short, customers impact M&As through: (i) being a reason to merge or acquire, where the M&A aims at acquirer’s or acquired party’s customers, or markets/positions, and where the M&A is a responsive activity to customers’ previous activities or is based on expectations on customers; (ii) customer reactions or changed buying behaviour; (iii) M&A parties’ pre-integration reconsideration; and (iv) post-integration difficulties, whereby customers impact integration realisation through not seeing the benefit of the M&A and thereby continue to buy as previously, through objecting to integration or through dissolving relationships.

    Customers are impacted by M&As through: (i) the M&A as possibility for change; (ii) ownership changes, which may lead to changes in competition structures; and (iii) forced integration.

    This means that the impact that customers have on M&As are both results of their own actions, and also of the expectations that the M&A parties have on customers.

    Important findings from this thesis concern adjustments of initial M&A intentions, how integration may be resisted so as not to challenge ongoing relationships, and how customers (often) make it difficult to achieve initial M&A goals and integration as the customers do not act in accordance with the integration intentions of the parties involved in the M&A.

  • 28742.
    Öberg, Christina
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Engineering, Industrial Marketing and Industrial Economics .
    The roles of customers in M&A integration2008In: IMP Conference,2008, Uppsala: Uppsala University , 2008, p. 99-Conference paper (Refereed)
  • 28743.
    Öberg, Christina
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Engineering, Industrial Marketing and Industrial Economics .
    The roles of customers in M&A integration2008In: IMP Seminar,2008, Lancaster: Lancaster University , 2008Conference paper (Refereed)
    Abstract [en]

      

  • 28744.
    Öberg, Christina
    Linköping University, Department of Management and Engineering, Industrial Marketing and Industrial Economics . Linköping University, The Institute of Technology.
    What happened with the grandiose plans? Strategic plans and network realities in B2B interaction2010In: INDUSTRIAL MARKETING MANAGEMENT, ISSN 0019-8501, Vol. 39, no 6, p. 963-974Article in journal (Refereed)
    Abstract [en]

    Research concerned with business relationships and organizational levels, respectively, has addressed companies difficulties in realizing their strategies. Studies of business relationships explain this through actions and reactions among business partners. Organizational studies note gaps between strategic and operational organizational levels in perceptions and goals. This paper combines these perspectives to obtain new insights into why company strategies may not materialize. The purpose of this paper is to describe and discuss how actor bonds on various organizational levels in business relationships affect strategy realization. The paper shows that actors on similar organizational levels representing different companies may actually share more understandings and activities than actors within the same company. The paper contributes to research on dyadic business relationships by highlighting differences in perspectives on various organizational levels, adds insights into research studying organizations by including a business-relationship aspect, and increases understanding of why strategic plans sometimes fail to succeed.

  • 28745.
    Öberg, Christina
    Linköping University, Department of Management and Engineering, Industrial Marketing and Industrial Economics . Linköping University, The Institute of Technology.
    Who owns a customer relationship following a merger or acquisition?2008In: Corporate Ownership and Control, Vol. 6, no 2, p. 212-221Article in journal (Refereed)
  • 28746.
    Öberg, Christina
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Economics, Industrial marketing.
    Anderson, Helén
    Linköping University, Department of Management and Economics.
    Do customers matter in mergers and acquisitions (literature)?2002In: Nordic Workshop onf Interorganisational Research,2002, 2002Conference paper (Refereed)
  • 28747.
    Öberg, Christina
    et al.
    Linköping University, Department of Management and Engineering, Industrial Marketing and Industrial Economics . Linköping University, The Institute of Technology.
    Brege, Staffan
    Linköping University, Department of Management and Engineering, Industrial Marketing and Industrial Economics . Linköping University, The Institute of Technology.
    What happened with the grandiose plans?: Strategic plans and network realities in B2B interaction2009Conference paper (Refereed)
  • 28748.
    Öberg, Christina
    et al.
    Linköping University, Department of Management and Engineering, Industrial Marketing and Industrial Economics. Linköping University, The Institute of Technology.
    Grundström, Christina
    Linköping University, Department of Management and Engineering, Industrial Marketing and Industrial Economics. Linköping University, The Institute of Technology.
    Challenges and opportunities in innovative firms' network development2009In: The Future of Innovation, Lappeenranta, Finland: Lappeenranta University of Technology Press , 2009Conference paper (Other academic)
    Abstract [en]

    The purpose of this paper is to describe and discuss challenges and opportunities related to the development of innovative firms' networks. The paper utilises four case studies based on interviews with representatives of young innovative firms and their present and previous network partners. The findings show that while early network partners often play several roles simultaneously, the roles of both the innovative firm and its network partners become increasingly distinct as the innovative firm develops. Such clarification of roles highlights competition between parties. For the innovative firm, the early phases are marked by innovativeness and problems related to growth and financial issues; later phases may include challenges of dependence, competition, exclusion of actors, decreased innovativeness and less innovative freedom.

  • 28749.
    Öberg, Christina
    et al.
    Linköping University, Department of Management and Engineering, Industrial Marketing and Industrial Economics. Linköping University, The Institute of Technology.
    Grundström, Christina
    Linköping University, Department of Management and Engineering, Industrial Marketing and Industrial Economics. Linköping University, The Institute of Technology.
    Challenges and opportunities in innovative firms' network development2009In: International Journal of Innovation Management, ISSN 1363-9196, E-ISSN 1757-5877, Vol. 13, no 4, p. 593-613Article in journal (Refereed)
    Abstract [en]

    The purpose of this paper is to describe and discuss challenges and opportunities related to the development of innovative firms' networks. The paper utilises four case studies based on interviews with representatives of young innovative firms and their present and previous network partners. The findings show that while early network partners often play several roles simultaneously, the roles of both the innovative firm and its network partners become increasingly distinct as the innovative firm develops. Such clarification of roles highlights competition between parties. For the innovative firm, the early phases are marked by innovativeness and problems related to growth and financial issues; later phases may include challenges of dependence, competition, exclusion of actors, decreased innovativeness and less innovative freedom.

  • 28750.
    Öberg, Christina
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Economics, Industrial marketing.
    Grundström, Christina
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Economics, Industrial marketing.
    Commercialisation via Acquistion? - A Literature Review2007In: 16th IPSERA Conference,2007, 2007Conference paper (Refereed)
    Abstract [en]

      

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