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Lenfeldt, Niklas
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Publications (10 of 20) Show all publications
Rönnqvist, L., Domellöf, E., Johansson, A.-M., Riklund, K., Warntjes, M. J. B. & Lenfeldt, N. (2019). Associations between brain volumes, myelin and upper-limb kinematics in children born preterm. Developmental Medicine & Child Neurology, 61(S2), 53-54, Article ID OP 130.
Open this publication in new window or tab >>Associations between brain volumes, myelin and upper-limb kinematics in children born preterm
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2019 (English)In: Developmental Medicine & Child Neurology, ISSN 0012-1622, E-ISSN 1469-8749, Vol. 61, no S2, p. 53-54, article id OP 130Article in journal, Meeting abstract (Refereed) Published
Abstract [en]

Introduction: Long-term outcomes linked to preterm (PT) births have generally found an increased amount of neuromotor-developmental delays and/or disabilities. Few studies have addressed how upper-limb kinematics associates with brain volumes and myelination. This study aimed to investigate such possible relationships within children born PT compared with term-born controls at early school age, in relation to gestational age (GA) and birth-weight (BW).

Material and methods: This sub-study, part of a multidisciplinary project exploring long-term effects of PT births, included 27 children (Mean age= 8.2y) born PT (Mean GA= 32-weeks, range 22-35), and 33 age-matched born term. Kinematics of task-specific head and bi-/uni-manual upper-limb-movements was measured by a 3D-registration system (ProReflex). Brain volumes and myelin content were investigated by a 3-Tesla, magnetic resonance imaging (MRI)-scanner with a 7-min Synthetic MRI (SyMRI) acquisition-sequence.

Results: Significantly (p < .05) less efficient upper-limb kinematics with more segmented and longer movement paths was found in PT-born compared with term-born, particularly evident for those extremely-/very PT-born (<32 GA). Smaller total brain volumes and regional white-matter reduction with less myelin were significantly correlated with more segmented and longer arm- and head-trajectories, and with lower GA and BW.

Discussion-conclusion: The present findings show that an extremely- and very-PT-birth may cause long-term effects on neuromotor-mechanisms involved in goal-directed movements and that these effects are associated with generally delayed brain development and myelination. Additionally, SyMRI stands out as a suitable and cost-effective method for longitudinal/follow-up of brain development and changes, reducing distress in children due to a decreased scan time.

Place, publisher, year, edition, pages
Wiley-Blackwell, 2019
Keywords
preterm, neuro-motor-mechanisms, myelin, SyMRI, kinematics
National Category
Social Sciences Neurosciences
Research subject
Psychology; Pediatrics; Radiology
Identifiers
urn:nbn:se:umu:diva-159820 (URN)10.1111/dmcn.14244 (DOI)
Funder
Swedish Research Council, 2011-179
Available from: 2019-06-09 Created: 2019-06-09 Last updated: 2019-06-13Bibliographically approved
Wåhlin, A., Fordell, H., Ekman, U., Lenfeldt, N. & Malm, J. (2019). Rehabilitation in chronic spatial neglect strengthens resting-state connectivity. Acta Neurologica Scandinavica, 139(3), 254-259
Open this publication in new window or tab >>Rehabilitation in chronic spatial neglect strengthens resting-state connectivity
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2019 (English)In: Acta Neurologica Scandinavica, ISSN 0001-6314, E-ISSN 1600-0404, Vol. 139, no 3, p. 254-259Article in journal (Refereed) Published
Abstract [en]

Objectives: Rehabilitation of patients with chronic visuospatial neglect is underexplored, and little is known about neural mechanisms that can be exploited to promote recovery. In this study, we present data on resting-state functional connectivity within the dorsal attention network (DAN) in chronic neglect patients as they underwent training in a virtual reality (VR) environment that improved left-side awareness.

Methods: The study included 13 patients with visuospatial neglect persisting more than six months after a right-sided stroke. The patients underwent resting-state functional magnetic resonance imaging (fMRI). Scans were collected at baseline and after five weeks of intense training. We specifically examined resting-state functional connectivity within the DAN. In addition, using spatial concordance correlation, we compared changes in the spatial topology of the DAN with that of other networks.

Results: We found a longitudinal increase in interhemispheric functional connectivity between the right frontal eye field and the left intraparietal sulcus following training (before: 0.33 +/- 0.17 [mean +/- SD]; after: 0.45 +/- 0.13; P = 0.004). The spatial concordance analyses indicated that training influenced the DAN connectivity more than any of the other networks.

Conclusion: Intense VR training that improved left-sided awareness in chronic stroke patients also increased sporadic interhemispheric functional connectivity within the DAN. Specifically, a region responsible for saccadic eye movement to the left became more integrated with the left posterior parietal cortex. These results highlight a mechanism that should be exploited in the training of patients with chronic visuospatial neglect.

Place, publisher, year, edition, pages
John Wiley & Sons, 2019
Keywords
cognitive rehabilitation, functional magnetic resonance imaging, neuronal plasticity, spatial neglect, virtual reality
National Category
Neurology
Identifiers
urn:nbn:se:umu:diva-156864 (URN)10.1111/ane.13048 (DOI)000458682700006 ()30427058 (PubMedID)
Available from: 2019-03-13 Created: 2019-03-13 Last updated: 2019-03-13Bibliographically approved
Ekman, U., Fordell, H., Eriksson, J., Lenfeldt, N., Wåhlin, A., Eklund, A. & Malm, J. (2018). Increase of frontal neuronal activity in chronic neglect after training in virtual reality. Acta Neurologica Scandinavica, 138(4), 284-292
Open this publication in new window or tab >>Increase of frontal neuronal activity in chronic neglect after training in virtual reality
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2018 (English)In: Acta Neurologica Scandinavica, ISSN 0001-6314, E-ISSN 1600-0404, Vol. 138, no 4, p. 284-292Article in journal (Refereed) Published
Abstract [en]

Objectives: A third of patients with stroke acquire spatial neglect associated with poor rehabilitation outcome. New effective rehabilitation interventions are needed. Scanning training combined with multisensory stimulation to enhance the rehabilitation effect is suggested. In accordance, we have designed a virtual-reality based scanning training that combines visual, audio and sensori-motor stimulation called RehAtt((R)). Effects were shown in behavioural tests and activity of daily living. Here, we use fMRI to evaluate the change in brain activity during Posners Cuing Task (attention task) after RehAtt((R)) intervention, in patients with chronic neglect.

Methods: Twelve patients (mean age=72.7years, SD=6.1) with chronic neglect (persistent symptoms >6months) performed the interventions 3 times/wk during 5weeks, in total 15hours. Training effects on brain activity were evaluated using fMRI task-evoked responses during the Posners cuing task before and after the intervention.

Results: Patients improved their performance in the Posner fMRI task. In addition, patients increased their task-evoked brain activity after the VR interventions in an extended network including pre-frontal and temporal cortex during attentional cueing, but showed no training effects during target presentations.

Conclusions: The current pilot study demonstrates that a novel multisensory VR intervention has the potential to benefit patients with chronic neglect in respect of behaviour and brain changes. Specifically, the fMRI results show that strategic processes (top-down control during attentional cuing) were enhanced by the intervention. The findings increase knowledge of the plasticity processes underlying positive rehabilitation effects from RehAtt((R)) in chronic neglect.

Place, publisher, year, edition, pages
John Wiley & Sons, 2018
Keywords
cognitive rehabilitation, functional magnetic resonance imaging, neuronal plasticity, spatial neglect, virtual reality
National Category
Neurology
Identifiers
urn:nbn:se:umu:diva-152199 (URN)10.1111/ane.12955 (DOI)000443931400003 ()29770439 (PubMedID)
Available from: 2018-10-31 Created: 2018-10-31 Last updated: 2019-05-07Bibliographically approved
Fordell, H., Wahlin, A., Ekman, U., Lenfeldt, N. & Malm, J. (2018). Rehabilitation of chronic spatial neglect strengthens functional connectivity between nodes of the dorsal attention network. International Journal of Stroke, 13, 42-42
Open this publication in new window or tab >>Rehabilitation of chronic spatial neglect strengthens functional connectivity between nodes of the dorsal attention network
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2018 (English)In: International Journal of Stroke, ISSN 1747-4930, E-ISSN 1747-4949, Vol. 13, p. 42-42Article in journal, Meeting abstract (Other academic) Published
Place, publisher, year, edition, pages
Sage Publications, 2018
National Category
Neurology
Identifiers
urn:nbn:se:umu:diva-154840 (URN)000452504600182 ()
Note

Supplement: 3Special Issue: SIMeeting Abstract: 154

Available from: 2019-02-28 Created: 2019-02-28 Last updated: 2019-02-28Bibliographically approved
Lenfeldt, N., Johansson, A.-M., Domellöf, E., Riklund, K. & Rönnqvist, L. (2017). Alterations in white matter microstructure are associated with goal-directed upper-limb movement segmentation in children born extremely preterm. Human Brain Mapping, 38(10), 5051-5068
Open this publication in new window or tab >>Alterations in white matter microstructure are associated with goal-directed upper-limb movement segmentation in children born extremely preterm
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2017 (English)In: Human Brain Mapping, ISSN 1065-9471, E-ISSN 1097-0193, Vol. 38, no 10, p. 5051-5068Article in journal (Refereed) Published
Abstract [en]

Altered white matter microstructure is commonly found in children born preterm (PT), especially those born at an extremely low gestational age (GA). These children also commonly show disturbed motor function. This study explores the relation between white matter alterations and upperlimb movement segmentation in 41 children born PT (19 girls), and 41 children born at term (18 girls) at 8 years. The PT group was subdivided into extremely PT (E-PT; GA = 25–27 weeks, N = 10), very PT (V-PT; GA = 28–32 weeks, N = 13), and moderately PT (M-PT; GA = 33–35 weeks, N = 18). Arm/hand preference (preferred/non-preferred) was determined through object interactions and the brain hemispheres were designated accordingly. White matter alterations were assessed using diffusion tensor imaging in nine areas, and movement segmentation of the body-parts head, shoulder, elbow, and wrist were registered during a unimanual goal-directed task. Increased movement segmentation was demonstrated consistently on the preferred side in the E-PT group compared with the term born group. Also compared with the term born peers, the E-PT group demonstrated reduced fractional anisotropy (FA) in the cerebral peduncle (targeting the corticospinal tract) in the hemisphere on the non-preferred side and in the splenium of corpus callosum. In contrast, in the anterior internal capsule on the preferred side, the E-PT group had increased FA. Lower FA in the cerebral peduncle, but higher FA in the anterior internal capsule, was associated with increased movement segmentation across body-parts in a contralateral manner. The results suggest that impaired development of sensorimotor tracts in E-PT children could explain a sub-optimal spatiotemporal organization of upper-limb movements.

Place, publisher, year, edition, pages
Hoboken: Wiley-Blackwell, 2017
Keywords
diffusion tensor imaging, anisotropy, sensorimotor, corticospinal, internal capsule, laterality
National Category
Psychology
Research subject
Radiology; Psychology; Pediatrics
Identifiers
urn:nbn:se:umu:diva-139528 (URN)10.1002/hbm.23714 (DOI)000417002000017 ()28685893 (PubMedID)
Funder
Swedish Research Council, 2011-179
Available from: 2017-09-15 Created: 2017-09-15 Last updated: 2019-01-08Bibliographically approved
Lenfeldt, N., Åström, B., Forsgren, L. & Jakobson Mo, S. (2017). Fractional Anisotropy and Mean Diffusion as Measures of Dopaminergic Function in Parkinson's Disease: Challenging Results. Journal of Parkinson's Disease, 7(1), 129-142
Open this publication in new window or tab >>Fractional Anisotropy and Mean Diffusion as Measures of Dopaminergic Function in Parkinson's Disease: Challenging Results
2017 (English)In: Journal of Parkinson's Disease, ISSN 1877-7171, E-ISSN 1877-718X, Vol. 7, no 1, p. 129-142Article in journal (Refereed) Published
Abstract [en]

Background: Diffusion tensor imaging (DTI) has been purported as an imaging technique to assess dopaminergic degeneration in Parkinson’s disease.

Objective: To test if fractional anisotropy (FA) and mean diffusion (MD) in the basal ganglia as measured by DTI correlates with dopaminergic function as measured by dopamine transporter (DAT) and dopamine D2-receptor (D2R) SPECT.

Methods: One-hundred and eleven patients with Parkinson’s disease (71±10 years) and thirty-one controls (68±7 years) performed DTI, DAT and D2R SPECT at baseline and four follow-ups (1-year: 89 patients/zero controls; 3-year: 72/11; 5-year: 48/17; and 8-year: 13/13). Four equipment combinations of MRI scanners/SPECT gamma cameras were used during the study. Data from each combination were analyzed separately. Regions-of-interest were outlined in the substantia nigra (three subareas, DTI only) and in the striatum (putamen and caudate). Side differences and bilateral averages were correlated using linear regression. The significance threshold was set at P < 0.001 and 0.001 < P< 0.05 was defined as a trend towards significance.

Results: For side differences, no significant correlations were observed, but in patients, there was a trend towards a negative correlation between MD in the middle nigra and putaminal DAT uptake in two combinations (P = 0.04 and P = 0.03). For averages, in patients, striatal MD correlated negatively with striatal DAT uptake in one combination (P = 0.0005) and trended towards negative correlations with striatal D2R uptake (one combination, P = 0.03) and with the sum of striatal DAT and D2R uptake (two combinations P = 0.002 and P = 0.03). FA showed no correlations in patients, and no correlations were found in controls.

Conclusions: The poor correlations between MD and dopamine activity –and absent correlations for FA – imply that additional diffusion measures must be developed to reliably assess the dopaminergic degeneration in Parkinson’s disease.

Keywords
Parkinsonian disorders, anisotropy, Diffusion tensor imaging, dopamine, SPECT, basal ganglia
National Category
Neurology
Identifiers
urn:nbn:se:umu:diva-133249 (URN)10.3233/JPD-161011 (DOI)000395665200011 ()28106567 (PubMedID)
Available from: 2017-04-12 Created: 2017-04-12 Last updated: 2018-06-09Bibliographically approved
Lenfeldt, N., Holmlund, H., Larsson, A., Birgander, R. & Forsgren, L. (2016). Frontal white matter injuries predestine gait difficulties in Parkinson's disease. Acta Neurologica Scandinavica, 134(3), 210-218
Open this publication in new window or tab >>Frontal white matter injuries predestine gait difficulties in Parkinson's disease
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2016 (English)In: Acta Neurologica Scandinavica, ISSN 0001-6314, E-ISSN 1600-0404, Vol. 134, no 3, p. 210-218Article in journal (Refereed) Published
Abstract [en]

Objectives: This study applies diffusion tensor imaging (DTI) to determine differences in neuronal integrity between motor phenotypes in Parkinson's disease. Material and Methods: One hundred and twenty-two patients (47 females, mean age = 70.3 years) were included at baseline. Forty patients were tremor dominant (TD), 64 had postural imbalance and gait difficulty (PIGD), and 18 patients were indeterminate. The DTI was repeated after one, three and 5 years, including reassessment of phenotype. DTI was quantified using fractional anisotropy (FA), and mean, radial and axial diffusion. Targeted white matter involved six regions of interests (ROIs) in prefrontal cortex (PFC), the entrance to the external capsule (EEC) and lateral to the horn of the anterior ventricle (LVAH). Grey matter involved the basal ganglia. Data were analysed using mixed linear models with P < 0.05 (Bonferroni corrected) as significance threshold. Results: PIGD and Indeterminate had reduced FA and axial diffusion in PFC, EEC and LVAH compared to Tremor dominant (P < 0.05). Basal ganglia showed no differences. Post hoc analysis showed that FA correlated negatively, and mean and radial diffusion positively, to PIGD symptoms in EEC, LVAH and four ROIs in PFC (P < 0.05). Tremor symptoms showed no correlations. Patients converting to PIGD and Indeterminate had lower FA, and higher mean and radial diffusion, at baseline in EEC, LVAH and four areas in PFC compared to non-converting patients (P < 0.05). Conclusion: Degeneration in frontal white matter is connected to PIGD symptoms in Parkinson's disease and if present at an early stage, the risk for conversion to the PIGD phenotype increases.

Place, publisher, year, edition, pages
Wiley-Blackwell, 2016
Keywords
parkinsonism, diffusion tensor imaging, gait, tremor, anisotropy
National Category
Neurology Neurosciences
Identifiers
urn:nbn:se:umu:diva-125534 (URN)10.1111/ane.12532 (DOI)000381033500006 ()27465659 (PubMedID)
Available from: 2016-09-19 Created: 2016-09-13 Last updated: 2018-06-07Bibliographically approved
Lenfeldt, N., Larsson, A., Nyberg, L., Birgander, R. & Forsgren, L. (2015). Fractional anisotropy in the substantia nigra in Parkinson's disease: a complex picture. European Journal of Neurology, 22(10), 1410-1416
Open this publication in new window or tab >>Fractional anisotropy in the substantia nigra in Parkinson's disease: a complex picture
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2015 (English)In: European Journal of Neurology, ISSN 1351-5101, E-ISSN 1468-1331, Vol. 22, no 10, p. 1410-1416Article in journal (Refereed) Published
Abstract [en]

Background and purpose: This study employs magnetic resonance imaging (MRI) diffusion tensor imaging to compare diffusion measures in the brains of patients with Parkinson's disease (PD) with healthy controls using longitudinal data. Methods: One-hundred and twenty-two patients and 34 controls were included at baseline. The MRI investigations were repeated after 1, 3 and 5 years. The diffusion measures were quantified using fractional anisotropy and mean, radial and axial diffusion (FA, MD, RD, AD). Regions of interest included the anterior, middle and posterior substantia nigra (SN), but also other areas. Linear models were used to test for the effect of disease and hemispheric lateralization. The P value was set at 0.05 (Bonferroni corrected). Results: Fractional anisotropy and AD were increased in the three nigral subareas in PD (P < 0.01), but MD and RD were unaltered. The right SN had higher FA than the left in all subareas (P < 0.01). MD and AD were increased in the right anterior part (P < 0.04), whereas MD and RD were decreased in the right middle and posterior parts (P < 0.001). The left middle cerebellar peduncle had increased FA and AD (P < 0.001) and decreased MD and RD (P < 0.01) compared to the right. Diffusion measures did not progress over time and side differences were not related to disease or lateralization of symptoms. Conclusions: Increased FA in the SN in PD indicates gliosis and inflammation in the nuclei, but possibly also intrusion of surrounding fibres into the shrinking structure. The hemispheric side differences of diffusion might reflect natural lateralization of connectivity, but their relation to PD must be studied further.

Keywords
diffusion imaging, fractional anisotropy, lateralization, Parkinson, substantia nigra
National Category
Neurology
Identifiers
urn:nbn:se:umu:diva-111012 (URN)10.1111/ene.12760 (DOI)000362672700012 ()26118635 (PubMedID)
Available from: 2015-11-04 Created: 2015-11-02 Last updated: 2018-06-07Bibliographically approved
Behrens, A., Lenfeldt, N., Qvarlander, S., Koskinen, L.-O., Malm, J. & Eklund, A. (2013). Are intracranial pressure wave amplitudes measurable through lumbar puncture?. Acta Neurologica Scandinavica, 127(4), 233-241
Open this publication in new window or tab >>Are intracranial pressure wave amplitudes measurable through lumbar puncture?
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2013 (English)In: Acta Neurologica Scandinavica, ISSN 0001-6314, E-ISSN 1600-0404, Vol. 127, no 4, p. 233-241Article in journal (Refereed) Published
Abstract [en]

 Objective The aim of this study was to investigate whether pulsations measured in the brain correspond to those measured in lumbar space, and subsequently whether lumbar punctures could replace invasive recordings. Methods In ten patients with normal pressure hydrocephalus, simultaneous recordings of the intracranial pressure (ICP; intraparenchymal) and lumbar pressure (LP; cerebrospinal fluid pressure) were performed. During registration, pressure was altered between resting pressure and 45mmHg using an infusion test. Data were analyzed regarding pulsations (i.e., amplitudes). Also, the pressure sensors were compared in a bench test. Results The correlation between intracranial and lumbar amplitudes was 0.98. At resting pressure, and moderately elevated ICP, intracranial pulse amplitudes exceeded that of lumbar space with about 0.9mmHg. At the highest ICP, the difference changed to 0.2mmHg. The bench test showed that the agreement of sensor readings was good at resting pressure, but reduced at higher amplitudes. Conclusions Compared to intracranial registrations, amplitudes measured through lumbar puncture were slightly attenuated. The bench test showed that differences were not attributable to dissimilarities of the sensor systems. A lumbar pressure amplitude measurement is an alternative to ICP recording, but the thresholds for what should be interpreted as elevated amplitudes need to be adjusted.

Keywords
intracranial pressure, spinal puncture, cerebrospinal fluid pressure, hydrocephalus, normal pressure, pulse pressure waves
National Category
Neurology
Identifiers
urn:nbn:se:umu:diva-68250 (URN)10.1111/j.1600-0404.2012.01701.x (DOI)000316215900004 ()
Available from: 2013-04-18 Created: 2013-04-15 Last updated: 2018-06-08Bibliographically approved
Lenfeldt, N., Larsson, A., Nyberg, L., Birgander, R. & Forsgren, L. (2013). Diffusion measures in early stage parkinsonism: controversial findings including hemispheric lateralisation [Letter to the editor]. Parkinsonism & Related Disorders, 19(4), 469-471
Open this publication in new window or tab >>Diffusion measures in early stage parkinsonism: controversial findings including hemispheric lateralisation
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2013 (English)In: Parkinsonism & Related Disorders, ISSN 1353-8020, E-ISSN 1873-5126, Vol. 19, no 4, p. 469-471Article in journal, Letter (Refereed) Published
Keywords
Parkinson's disease, MRI, Anisotropy, Substantia nigra, Middle cerebellar peduncle
National Category
Neurology
Identifiers
urn:nbn:se:umu:diva-71098 (URN)10.1016/j.parkreldis.2012.10.003 (DOI)000317455600017 ()
Available from: 2013-06-12 Created: 2013-05-20 Last updated: 2018-06-08Bibliographically approved
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