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Publications (10 of 96) Show all publications
Melin, J. & Pendrill, L. (2019). Innovative measurements for improved diagnosis and management of neurodegenerative diseases. In: : . Paper presented at IAGG-ER: International Association of Gerontology and Geriatrics for the European Region.
Open this publication in new window or tab >>Innovative measurements for improved diagnosis and management of neurodegenerative diseases
2019 (English)Conference paper, Poster (with or without abstract) (Other academic)
Abstract [en]

Development of novel therapies for Alzheimer’s Disease (AD) is constrained by the lack of available methods for preclinical diagnosis, despite extensive research on biomarker identification. The EMPIR NeuroMET project unites National Measurement Laboratories, clinicians and academics, to overcome limitations in measurement methods and provide a better understanding of how to improve, combine and analyse measurements in AD diagnosis and treatment. Comparability through SI (System of International Units) traceability and uncertainty analysis is an, as yet, unmet requirement for regulatory approval of biomarkers, patient centred outcome measures, clinical thresholds and new therapeutic drugs. We will report on:

  • Multimodal statistical analysis on blood, CSF and saliva biomarkers data from the NeuroMET cohort generated by using mass spectroscopy and immunoassay platforms, including a novel immunoassay approach to overcome matrix effects when relative quantification is not sensitive enough. A new digital PCR approach was developed to assess microRNAs quantities in blood to compare with established biomarkers.
  • Progress towards the development of mass spectrometry reference measurement procedures traceable to the SI for t-tau and α-synuclein in cerebrospinal fluids.
  • Development of ultrahigh field Magnetic Resonance Imaging and Spectroscopy protocols for increased spatial and spectral resolution and decreased uncertainty, and their application to the NeuroMET cohort.
  • Improved cognitive assessment protocols, with improved metrological evaluation of cognitive performance scores and the development of construct specification equations for various cognitive protocols and biomarkers.
  • Potential relationships between volumes of AD-related brain structures and neurometabolite concentrations with measured cognitive function.

Improved reference methods to underpin the production of calibrators and improve measurement comparability of established biomarkers has the potential to further the understanding of AD and boost research for disease modifying therapies.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:ri:diva-39316 (URN)
Conference
IAGG-ER: International Association of Gerontology and Geriatrics for the European Region
Available from: 2019-07-03 Created: 2019-07-03 Last updated: 2019-11-14Bibliographically approved
Pendrill, L. & Melin, J. (2019). Measuring counted fractions in healthcare. TMQ Techniques, Methodologies and Quality (NÚMERO ESPECIAL), 60-69
Open this publication in new window or tab >>Measuring counted fractions in healthcare
2019 (English)In: TMQ Techniques, Methodologies and Quality, ISSN 2183-0940, no NÚMERO ESPECIAL, p. 60-69Article in journal (Refereed) Published
Abstract [en]

In establishing metrological quality assurance in healthcare, one major hurdle is the correct treatment ofordinal data typical of questionnaires, performance tests and other categorical data collected widely in care.Despite being known well over a century, there are still many examples of measurements in healthcare – forexample, (i) on-line tables of percentage performance indicators (e.g. fraction of patients seeing a doctorwithin seven days) and (ii) correlation plots for Alzheimer sufferers of cognitive scores against biomarkerconcentration – where the ‘counted fraction’ distortion of scales is not compensated for. The Rasch form ofgeneralised linear model not only handles counted fraction ordinality but also enables separation of objectand instrument attributes (such as task difficulty and patient ability) essential for metrological restitutionin measurement systems in healthcare. A perspective is given of a new kind of certified reference materialemploying causal Rasch models in terms of construct specification equations for metrological item bankingin the social sciences. This is part of the response to a recent call for: ‘a new international body to bringtogether metrology, psychometrics, philosophy, and clinical management to support the global comparabilityand equivalence of measurement results in patient centred outcome measurement to improve healthcare’.

Keywords
Metrology; Quality assurance; Rasch Measurement Theory; Psychometrics
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:ri:diva-39317 (URN)
Available from: 2019-07-03 Created: 2019-07-03 Last updated: 2019-07-05Bibliographically approved
Melin, J., Pendrill, L. & Cano, S. (2019). NeuroMET Memory Metric version 0.1. In: : . Paper presented at IAGG-ER: International Association of Gerontology and Geriatrics for the European Region.
Open this publication in new window or tab >>NeuroMET Memory Metric version 0.1
2019 (English)Conference paper, Oral presentation with published abstract (Other academic)
Abstract [en]

Alongside a lack clinically validated, minimally invasive diagnostic tools for early diagnosis and/or monitoring of disease progression in Alzheimer’s Disease (AD), there are no sound metrological assessment protocols and measurements for cognition, nor measurement comparability through SI (System of International Units), traceability and uncertainty for regulatory approval of biomarkers. As part of the on-going EMPIR HLT04 NeuroMET project in which several national metrology institutes work together with clinicians and academics to overcome specific measurement issues to improve diagnosis and disease progression, we describe here the justification for and development of the ‘NeuroMET Memory Metric’ (version 0.1).

Re-examination of traditional widely used ‘legacy’ cognitive assessment protocols using invariant measurement theory aims at more accurately capturing the patient’s cognitive ability and improving the analysis of correlations with various AD biomarkers. Two principal elements provide sound metrological underpinnings: (i) a correct formulation of a measurement model; and (ii) proper handling of the ordinal cognitive data. In turn, this enables formulation of novel construct specification equations for patient cognitive ability as a function of diverse biomarkers (e.g., in plasma, CSF and saliva together with MRI/MRS data) as well as for cognitive task difficult as a function of test design.

To further improve the accuracy in patient’s cognitive ability work is now in progress to develop a NeuroMET Memory Metric based on legacy cognitive assessments (e.g., MMSE, Corsi Block Test, Digital Span Test). This work can be ascribed a level-5 construct theory. This means the realization of more fit-for-purpose, better targeted and better administered cognitive measurement systems. It will also enable traceable calibration of both additional cognitive tasks as well as the effects of intervention (or disease progression) on the cognitive ability of each individual patient.

National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:ri:diva-39315 (URN)
Conference
IAGG-ER: International Association of Gerontology and Geriatrics for the European Region
Available from: 2019-07-03 Created: 2019-07-03 Last updated: 2019-07-03Bibliographically approved
Melin, J. & Pendrill, L. (2019). Quality assurance of cognitive assessments and other categorical data. In: : . Paper presented at Charité lecture series,Thursday, 17.01.2019 CCM, Virchowweg 24, Aufgang B, Seminar Room 03.006.
Open this publication in new window or tab >>Quality assurance of cognitive assessments and other categorical data
2019 (English)Conference paper, Oral presentation with published abstract (Other academic)
Abstract [en]

Did you ever wonder how to account for biases such as ceiling eects in your (cognitive) data?

Metrological quality assurance of human-based responses is in its infancy and analyzing categorial data and other human responses is challenging. However, there is a need to tackle those challenges to ensure that decisions about health care are made correctly. Quality assured comparability, interoperability and decision-making can successfully be done by applying sound metrological approaches to enable traceability as well as stressing declaration of measurement uncertainties. In the seminar, we present metrological approaches to ensure quality assurance of categorical data,such as cognitive assessments and other human-reported responses. This is followed by a hands-onworkshop where you are welcome to bring your own or freely available data for analyses.

National Category
Neurosciences
Identifiers
urn:nbn:se:ri:diva-37325 (URN)
Conference
Charité lecture series,Thursday, 17.01.2019 CCM, Virchowweg 24, Aufgang B, Seminar Room 03.006
Projects
EMPIR 15HLT04 NeuroMet
Funder
EU, FP7, Seventh Framework Programme, EMPIR 15HLT04
Available from: 2019-01-21 Created: 2019-01-21 Last updated: 2019-01-21Bibliographically approved
Melin, J., Fornazar, R., Spångfors, M. & Pendrill, L. (2019). Rasch analysis of the Patient Participation in Rehabilitation Questionnaire (PPRQ). Journal of Evaluation In Clinical Practice
Open this publication in new window or tab >>Rasch analysis of the Patient Participation in Rehabilitation Questionnaire (PPRQ)
2019 (English)In: Journal of Evaluation In Clinical Practice, ISSN 1356-1294, E-ISSN 1365-2753Article in journal (Refereed) Epub ahead of print
Abstract [en]

Objective: To evaluate the Patient Participation in Rehabilitation Questionnaire (PPRQ) according to Rasch measurement theory. Method: Five hundred twenty-two post-discharge patients from a neurological rehabilitation unit were included. The PPRQ questionnaire comprises 20 items rated by a cohort of 522 patients about their experiences of participating in rehabilitation. The measurement properties of the PPRQ were evaluated by Rasch analysis of the responses. Results: The Rasch analysis of 20 items showed some major misfits, particularly three items addressing the involvement of family members. After removing those items, the model fit improved and no significant DIF remained. Despite improvements, person values (−2.96 to 4.86 logits) were not fully matched by the item values (−0.61 to 0.77 logits). Neither did the t test for unidimensionality meet the criterion of 5%, and local dependency was present. The unidimensionality and local dependency could, however, be accommodated for by four testlets. Conclusion: The PPRQ-17 showed that a ruler with a reasonable and clinical hierarchy can be constructed, although the expectations of dimensionality and local dependency need to be evaluated further. Despite room for further development, PPRQ-17 nevertheless shows improved measurement precision in terms of patient leniency compared with previous evaluations with classical test theory. In turn, this can play a crucial role when comparing different rehabilitation programs and planning tailored care development activities.

Place, publisher, year, edition, pages
Blackwell Publishing Ltd, 2019
Keywords
patient-centred care, psychometrics, self-report, surveys and questionnaires, adult, article, cohort analysis, expectation, female, human, major clinical study, male, measurement precision, neurorehabilitation, patient care, patient participation, psychometry, questionnaire, Rasch analysis, self report
National Category
Natural Sciences
Identifiers
urn:nbn:se:ri:diva-38500 (URN)10.1111/jep.13134 (DOI)2-s2.0-85064053482 (Scopus ID)
Available from: 2019-05-03 Created: 2019-05-03 Last updated: 2019-05-09Bibliographically approved
Cano, S., Pendrill, L., Melin, J. & Fisher, W. (2019). Towards consensus measurement standards for patient-centered outcomes. Measurement, 141, 62-69
Open this publication in new window or tab >>Towards consensus measurement standards for patient-centered outcomes
2019 (English)In: Measurement, Vol. 141, p. 62-69Article in journal (Refereed) Published
Abstract [en]

Patient centered outcomes pertain to a patient's beliefs, opinions and needs in conjunction with a clinician's medical expertise and assessment. The rise of patient-centered outcome (PCO) measurement parallels increased interest in patient-centered care. PCO measures offer the opportunity for more meaningful measurement of health outcomes informative enough to guide treatment decisions. However, it has been suggested that, for practical and scientific reasons, existing PCO measures are currently not capable of delivering the kind of quality assured measurement required for high-stakes decision making. Potential solutions include: addressing the lack of units in PCO measurement through recourse to mathematical models devised to define meaningful, invariant, and additive units of measurement with known uncertainties; establishing coordinated international networks of key stakeholders guided by five principles (i.e., collaboration, alignment, integration, innovation and communication); better use of technology leveraging measurement through item banks linking PCO reports via common items, common patients, or specification equations based in strong explanatory theory. And finally ensuring PCO measurement always is associated with: (1) a clear definition of the measurand in regards to the intended clinical use; (2) a clear definition of the clinically allowable error of measurement; (3) international cooperation and consensus to navigate the complexities of the development of metrologically sound reference measurement systems; and (4) continued clinical validation of newly calibrated measures. In this article, we illustrate the principles to improve PCO measures with examples from breast cancer, vision-related patient-reported outcome measures, and dementia clinician-reported and performance outcome measures.

Keywords
Patient-centered outcome measurementPatient-centered careMetrologyPsychometrics
National Category
Medical and Health Sciences
Identifiers
urn:nbn:se:ri:diva-39314 (URN)10.1016/j.measurement.2019.03.056 (DOI)
Available from: 2019-07-03 Created: 2019-07-03 Last updated: 2019-07-05Bibliographically approved
Pendrill, L. (2018). Assuring measurement quality in person-centred healthcare. Measurement science and technology, 29(3), 034003
Open this publication in new window or tab >>Assuring measurement quality in person-centred healthcare
2018 (English)In: Measurement science and technology, ISSN 0957-0233, E-ISSN 1361-6501, Vol. 29, no 3, p. 034003-Article in journal (Refereed) Published
Abstract [en]

Is it realistic to aspire to the same kind of quality-assurance of measurement in person-centred care, currently being implemented in healthcare globally, as is established in the physical sciences and engineering? Ensuring metrological comparability (‘traceability’) and reliably declaring measurement uncertainty when assessing patient ability or increased social capital are however challenging for subjective measurements often characterised by large dispersion. Drawing simple analogies between ‘instruments’ in the social sciences – questionnaires, ability tests, etc.–  and  engineering instruments such as thermometers does not go far enough. A possible way forward apparently equally applicable to both physical and social measurement, seems to be to model inferences in terms performance metrics of a measurement system. Person-centred care needs person-centred measurement and a full picture of the measurement process when Man acts as a measurement instrument is given in the present paper. This complements previous work by presenting the process, step by step, from the observed indication (e.g. probability of success, Psuccess, of achieving atask), through restitution with Rasch Measurement Theory, to the measurand (e.g. task difficulty). Rasch invariant measure theory can yield quantities –‘latent’ (or ‘explanatory’) variables such as task challenge or person ability – with characteristics akin to those of physical quantities. Metrological references for comparability via traceability and reliable estimates ofuncertainty and decision risks are then in reach even for perceptive measurements (and other qualitative properties). As a case study, the person-centred measurement of cognitive ability is examined, as part of the EUproject EMPIR 15HLT04 NeuroMet, for Alzheimer’s, where better analysis of correlations with brain atrophy is enabled thanks to the Rasch metrological approach.

National Category
Neurosciences
Identifiers
urn:nbn:se:ri:diva-32801 (URN)10.1088/1361-6501/aa9cd2 (DOI)2-s2.0-85042552662 (Scopus ID)
Projects
EMPIR 15HLT04 NeuroMet
Funder
EU, Horizon 2020, EMPIR 15HLT04 NeuroMet
Available from: 2017-11-30 Created: 2017-11-30 Last updated: 2019-01-07Bibliographically approved
Quaglia, M., Bellotti, V., Cano, S., Cyrar, A., Deane, K., Divieto, C., . . . Pendrill, L. (2018). BETTER MEASUREMENT FOR IMPROVED DIAGNOSIS AND MANAGEMENT OF ALZHEIMER’S DISEASE: UPDATE ON THE EMPIR NEUROMET PROJECT. Alzheimer's & Dementia, 14, P759-P760, Article ID 7.
Open this publication in new window or tab >>BETTER MEASUREMENT FOR IMPROVED DIAGNOSIS AND MANAGEMENT OF ALZHEIMER’S DISEASE: UPDATE ON THE EMPIR NEUROMET PROJECT
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2018 (English)In: Alzheimer's & Dementia, ISSN 1552-5260, E-ISSN 1552-5279, Vol. 14, p. P759-P760, article id 7Article in journal (Other academic) Published
Abstract [en]

The development of novel therapies for Alzheimer’s Disease (AD) is constrained by the lack of available methods for preclinical diagnosis, despite extensive research on biomarker identification. Here, we present an update of progress from EMPIR NeuroMET, a project combining diverse expertise from five National Measurement Institutes (NMIs), with clinicians and academics, to overcome limitations in measurement methods in neurodegenerative disease diagnosis and treatment.

National Category
Neurosciences
Identifiers
urn:nbn:se:ri:diva-36099 (URN)10.1016/j.jalz.2018.06.920 (DOI)
Projects
EMPIR 15HLT04 NeuroMet
Funder
EU, Horizon 2020, EMPIR 15HLT04
Available from: 2018-11-09 Created: 2018-11-09 Last updated: 2018-11-12Bibliographically approved
Pendrill, L. (2018). How to calibrate a questionnaire: quality-assuring categorical data with psychometric measurement theory. In: Charité (Ed.), : . Paper presented at BEMC Berlin Epidemiological Methods Colloquium. February 7th, 2018.
Open this publication in new window or tab >>How to calibrate a questionnaire: quality-assuring categorical data with psychometric measurement theory
2018 (English)In: / [ed] Charité, 2018Conference paper, Oral presentation only (Other academic)
Abstract [en]

Measurements in the social sciences – with ‘instruments’ such as questionnaires, ability tests, – in education, healthcare and so on, need metrological quality assurance. A patient, for instance, expects the same quality of care wherever and whenever provided. This is a challenge since the usual tools of statistics do not always work on the categorical scales typical of such measurements. Modelling a measurement system where the instrument is a human being, and where the output is a performance metric, i.e., how well the set-up performs an assessment, appears to be a way forward. This BEMC Colloquium will present the necessary tools, such as psychometric Rasch measurement theory, and will be followed by a hands-on workshop where you yourselves can analyse cases such as (i) the Quality of the BEMC Colloquium Series and (ii) a Healthy Lifestyle.

National Category
Other Medical Sciences
Identifiers
urn:nbn:se:ri:diva-33284 (URN)
Conference
BEMC Berlin Epidemiological Methods Colloquium. February 7th, 2018
Funder
EU, Horizon 2020, EMPIR 15HLT04
Available from: 2018-02-20 Created: 2018-02-20 Last updated: 2018-08-13Bibliographically approved
Mari, L., Ehrlich, C. & Pendrill, L. (2018). Measurement units as quantities of objects or values of quantities: a discussion. Metrologia, 55(5), 716-721
Open this publication in new window or tab >>Measurement units as quantities of objects or values of quantities: a discussion
2018 (English)In: Metrologia, ISSN 0026-1394, E-ISSN 1681-7575, Vol. 55, no 5, p. 716-721Article in journal (Refereed) Published
Abstract [en]

Measurement units have historically been defined as quantities (i.e., specific properties) of objects, such as the mass of a particular piece of metal or the length of a particular rod. While the current International System of Units (SI) Brochure endorses this position, the draft 9th SI Brochure proposes to change it, and instead define measurement units as values of quantities. The reason for this proposed change is not provided, but it does not seem plausible that it is related to the redefinition of the SI units in terms of fundamental constants of nature: the very concept of what a unit is does not depend on the concrete way any given unit is defined. This paper is intended to open a discussion of whether measurement units should be defined as quantities or as quantity values, and provides our rationale for maintaining the definition of units as quantities.

Keywords
foundations of measurement, measurement units, values of quantities
National Category
Other Natural Sciences
Identifiers
urn:nbn:se:ri:diva-34955 (URN)10.1088/1681-7575/aad8d8 (DOI)2-s2.0-85053877220 (Scopus ID)
Available from: 2018-08-27 Created: 2018-08-27 Last updated: 2019-01-09Bibliographically approved
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-4349-500x

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