Publications by authors named "J Leo van Hemmen"

198 Publications

The Naming Assessment in Multicultural Europe (NAME): Development and Validation in a Multicultural Memory Clinic.

J Int Neuropsychol Soc 2022 Jan 18:1-13. Epub 2022 Jan 18.

Department of Neurology, Erasmus MC University Medical Center, Rotterdam, The Netherlands.

Objective: Traditional naming tests are unsuitable to assess naming impairment in diverse populations, given the influence of culture, language, and education on naming performance. Our goal was therefore to develop and validate a new test to assess naming impairment in diverse populations: the Naming Assessment in Multicultural Europe (NAME).

Method: We carried out a multistage pilot study. First, we generated a list of 149 potentially suitable items - e.g. from published cross-linguistic word lists and other naming tests - and selected those with a homogeneous age of acquisition and word frequency across languages. We selected three to four colored photographs for each of the 73 remaining items; 194 controls selected the most suitable photographs. Thirteen items were removed after a pilot study in 15 diverse healthy controls. The final 60-item test was validated in 39 controls and 137 diverse memory clinic patients with subjective cognitive impairment, neurological/neurodegenerative disease or psychiatric disorders in the Netherlands and Turkey (mean age: 67, SD: 11). Patients were from 15 different countries; the majority completed primary education or less (53%).

Results: The NAME showed excellent reliability (Spearman-Brown coefficient: 0.95; Kuder-Richardson coefficient: 0.94) and robust correlations with other language tests (ρ = .35-.73). Patients with AD/mixed dementia obtained lower scores on most (48/60) NAME items, with an area under the curve of 0.88. NAME scores were correlated with age and education, but not with acculturation or sex.

Conclusions: The NAME is a promising tool to assess naming impairment in culturally, educationally, and linguistically diverse individuals.
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http://dx.doi.org/10.1017/S135561772100148XDOI Listing
January 2022

Mathematization of nature: how it is done.

Authors:
J Leo van Hemmen

Biol Cybern 2021 Dec;115(6):655-664

Physik Department T35, Technische Universität München, 85747, Garching bei München, Germany.

Natural phenomena can be quantitatively described by means of mathematics, which is actually the only way of doing so. Physics is a convincing example of the mathematization of nature. This paper gives an answer to the question of how mathematization of nature is done and illustrates the answer. Here nature is to be taken in a wide sense, being a substantial object of study in, among others, large domains of biology, such as epidemiology and neurobiology, chemistry, and physics, the most outspoken example. It is argued that mathematization of natural phenomena needs appropriate core concepts that are intimately connected with the phenomena one wants to describe and explain mathematically. Second, there is a scale on and not beyond which a specific description holds. Different scales allow for different conceptual and mathematical descriptions. This is the scaling hypothesis, which has meanwhile been confirmed on many occasions. Furthermore, a mathematical description can, as in physics, but need not be universally valid, as in biology. Finally, the history of science shows that only an intensive gauging of theory, i.e., mathematical description, by experiment leads to progress. That is, appropriate core concepts and appropriate scales are a necessary condition for mathematizing nature, and so is its verification by experiment.
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http://dx.doi.org/10.1007/s00422-021-00914-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8642347PMC
December 2021

Caregiver Burden in a Culturally Diverse Memory Clinic Population: The Caregiver Strain Index-Expanded.

Dement Geriatr Cogn Disord 2021 26;50(4):333-340. Epub 2021 Oct 26.

Department of Neurology, Erasmus MC University Medical Center, Rotterdam, The Netherlands.

Introduction: Although qualitative studies have highlighted substantial barriers to dementia diagnosis and care in culturally diverse populations in Europe, quantitative studies examining the level of caregiver burden in these populations have been lacking thus far and are urgently needed.

Methods: We compared the caregiver burden levels on the Caregiver Strain Index (CSI)-Expanded of 63 culturally diverse patient-caregiver dyads from a multicultural memory clinic with 30 native Dutch patient-caregiver dyads and examined the association between caregiver burden and determinants of burden.

Results: Informal caregivers in the multicultural memory clinic cohort experienced a high level of caregiver burden (mean CSI-score multicultural cohort: 6.1 [SD: 3.3]; mean CSI-score native Dutch cohort: 4.8 [SD: 3.2]). Burden was significantly associated with impairment on proxy-rated and objective measures of cognitive functioning, such as the Informant Questionnaire on Cognitive Decline and the Rowland Universal Dementia Assessment Scale, and with instrumental activities of daily living. Burden was the highest in spousal caregivers. The positive subscale of the CSI-Expanded provided limited additional information.

Conclusion: Caregivers of culturally diverse patients experience a high level of caregiver burden, in particular at more advanced disease stages. This study highlights the need to screen culturally diverse caregivers in European memory clinics on caregiver burden to identify those in need of caregiver support.
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http://dx.doi.org/10.1159/000519617DOI Listing
December 2021

Exploring Abstract Semantic Associations in the Frontotemporal Dementia Spectrum in a Dutch Population.

Arch Clin Neuropsychol 2022 Jan;37(1):104-116

Objective: To investigate the differential ability of the "Test Relaties Abstracte Concepten" (TRACE), a Dutch test for abstract semantic knowledge, in frontotemporal dementia (FTD).

Methods: The TRACE was administered in patients with behavioral variant FTD (bvFTD; n = 16), nonfluent variant (nfvPPA; n = 10), logopenic variant (lvPPA; n = 10), and semantic variant primary progressive aphasia (svPPA; n = 9), and controls (n = 59). We examined group differences, performed correlational analyses with other neuropsychological tests and investigated discriminative ability. We compared the TRACE with a semantic association test for concrete stimuli (SAT).

Results: All patient groups, except nfvPPA, performed worse on the TRACE than controls (p < .01). svPPA patients performed worse than the other patient groups (p < .05). The TRACE discriminated well between patient groups, except nfvPPA, versus controls (all p < .01) and between svPPA versus other patient groups with high sensitivity (75-100%) and specificity (86%-92%). In bvFTD and nfvPPA the TRACE correlated with language tests (ρ > 0.6), whereas in svPPA the concrete task correlated (ρ ≥ 0.75) with language tests. Patients with bvFTD, nfvPPA and lvPPA performed lower on the TRACE than the SAT (p < .05), whereas patients with svPPA were equally impaired on both tasks (p = .2).

Discussion: We demonstrated impaired abstract semantic knowledge in patients with bvFTD, lvPPA, and svPPA, but not nfvPPA, with svPPA patients performing worse than the other subtypes. The TRACE was a good classifier between each patient group versus controls and between svPPA versus other patient groups. This highlights the value of incorporating semantic tests with abstract stimuli into standard neuropsychological assessment for early differential diagnosis of FTD subtypes.
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http://dx.doi.org/10.1093/arclin/acab022DOI Listing
January 2022

Impaired Knowledge of Social Norms in Dementia and Psychiatric Disorders: Validation of the Social Norms Questionnaire-Dutch Version (SNQ-NL).

Assessment 2021 Apr 15:10731911211008234. Epub 2021 Apr 15.

Department of Neurology, Erasmus MC University Medical Center, Rotterdam, the Netherlands.

The Social Norms Questionnaire-Dutch version (SNQ-NL) measures the ability to understand and identify social boundaries. We examined the psychometric characteristics of the SNQ-NL and its ability to differentiate between patients with behavioral variant frontotemporal dementia (bvFTD; = 23), Alzheimer's dementia (AD; = 26), chronic psychiatric disorders ( = 27), and control participants ( = 92). Between-group differences in the Total score, Break errors, and Overadhere errors were examined and associations with demographic variables and other cognitive functions were explored. Results showed that the SNQ-NL Total Score and Break errors differed between patients with AD and bvFTD, but not between patients with bvFTD and psychiatric disorders. Modest correlations with age, sex, and education were observed. The SNQ-NL Total score and Break errors correlated significantly with emotion recognition and verbal fluency but not with processing speed or mental flexibility. In conclusion, the SNQ-NL has sufficient construct validity and can be used to investigate knowledge of social norms in clinical populations.
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http://dx.doi.org/10.1177/10731911211008234DOI Listing
April 2021
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