Extraction of clinical phenotypes for Alzheimer\u27s disease dementia from clinical notes using natural language processing

OBJECTIVES: There is much interest in utilizing clinical data for developing prediction models for Alzheimer\u27s disease (AD) risk, progression, and outcomes. Existing studies have mostly utilized curated research registries, image analysis, and structured electronic health record (EHR) data. However, much critical information resides in relatively inaccessible unstructured clinical notes within the EHR. MATERIALS AND METHODS: We developed a natural language processing (NLP)-based pipeline to extract AD-related clinical phenotypes, documenting strategies for success and assessing the utility of mining unstructured clinical notes. We evaluated the pipeline against gold-standard manual annotations performed by 2 clinical dementia experts for AD-related clinical phenotypes including medical comorbidities, biomarkers, neurobehavioral test scores, behavioral indicators of cognitive decline, family history, and neuroimaging findings. RESULTS: Documentation rates for each phenotype varied in the structured versus unstructured EHR. Interannotator agreement was high (Cohen\u27s kappa = 0.72-1) and positively correlated with the NLP-based phenotype extraction pipeline\u27s performance (average F1-score = 0.65-0.99) for each phenotype. DISCUSSION: We developed an automated NLP-based pipeline to extract informative phenotypes that may improve the performance of eventual machine learning predictive models for AD. In the process, we examined documentation practices for each phenotype relevant to the care of AD patients and identified factors for success. CONCLUSION: Success of our NLP-based phenotype extraction pipeline depended on domain-specific knowledge and focus on a specific clinical domain instead of maximizing generalizability

Association between socioeconomic factors, race, and use of a specialty memory clinic

BACKGROUND AND OBJECTIVES: The capacity of specialty memory clinics in the United States is very limited. If lower socioeconomic status or minoritized racial group is associated with reduced use of memory clinics, this could exacerbate health care disparities, especially if more effective treatments of Alzheimer disease become available. We aimed to understand how use of a memory clinic is associated with neighborhood-level measures of socioeconomic factors and the intersectionality of race. METHODS: We conducted an observational cross-sectional study using electronic health record data to compare the neighborhood advantage of patients seen at the Washington University Memory Diagnostic Center with the catchment area using a geographical information system. Furthermore, we compared the severity of dementia at the initial visit between patients who self-identified as Black or White. We used a multinomial logistic regression model to assess the Clinical Dementia Rating at the initial visit and RESULTS: A total of 4,824 patients seen at the memory clinic between 2008 and 2018 were included in this study (mean age 72.7 [SD 11.0] years, 2,712 [56%] female, 543 [11%] Black). Most of the memory clinic patients lived in more advantaged neighborhoods within the overall catchment area. The percentage of patients self-identifying as Black (11%) was lower than the average percentage of Black individuals by census tract in the catchment area (16%) ( DISCUSSION: This study demonstrates that patients living in less affluent neighborhoods were less likely to be seen in one large memory clinic. Black patients were under-represented in the clinic, and Black patients had more severe dementia at their initial visit. These findings suggest that patients with a lower socioeconomic status and who identify as Black are less likely to be seen in memory clinics, which are likely to be a major point of access for any new Alzheimer disease treatments that may become available

A dual-role typology of multinational subsidiaries

This paper argues that, since a subsidiary is embedded in a dual context of both the MNE and the host environment, its strategic role should be assessed by its relative positions and contributions both within the knowledge networks of the MNE and the host country. Based on this, we develop a dual-role typology. The 369 multinational subsidiaries in our sample from China can be classified into as many as 12 out of the 16 conceptual groups of the typology. Our results indicate that dual activists (active both internally and externally) account for only 12% of the total sampled multinational subsidiaries while dual loners (inactive both internally and externally) reach 20%. The results from a larger sample by adding 113 minority foreign share firms show that external knowledge links are positively associated with local Chinese ownership. The central message from this paper is that a large proportion of foreign-invested firms in China are inactive in knowledge exchange either internally or externally or both. Managerial and policy implications are discussed

Tadpole Cancellation in Unoriented Liouville Theory

The tadpole cancellation in the unoriented Liouville theory is discussed. Using two different methods -- the free field method and the boundary-crosscap state method, we derive one-loop divergences. Both methods require two D1-branes with the symplectic gauge group to cancel the orientifold tadpole divergence. However, the finite part left is different in each method and this difference is studied. We also discuss the validity of the free field method and the possible applications of our result.Comment: 12 pages; v2: sign error in the crosscap state is corrected, some related argumets are modified and clarified; v3: minor corrections; v4:reference adde