Missing Data Analysis in Drug-Naive Alzheimer's Disease with Behavioral and Psychological Symptoms

PURPOSE: To clarify the effects of missing values due to behavioral and psychological symptoms in dementia (BPSD) in Alzheimer's disease (AD) patients on the neuropsychological tests, this study describes the pattern of missing values due to BPSD, and its influence on tests. MATERIALS AND METHODS: Drug-naive probable AD patients (n=127) with BPSD and without BPSD (n=32) were assessed with Seoul Neuropsychological Screening Battery including measures of memory, intelligence, and executive functioning. Moreover, patients were rated on Korean Neuropsychiatry Inventory (K-NPI). RESULTS: The more severe the K-NPI score, the less neuropsychological tests were assessable, leading to many missing values. Patients with BPSD were more severely demented than those without BPSD. K-NPI scores were significantly correlated with the number of missing values. The effect of BPSD was largest for tests measuring frontal functions. The replacement of the missing values due to BPSD by the lowest observed score also showed the largest effect on tests of frontal function. CONCLUSION: The global cognitive and behavior scales are related with missing values. Among K-NPI sub-domains, delusion, depressing, apathy, and aberrant motor behavior are significantly correlated for missing values. Data imputation of missing values due to BPSD provides a more differentiated picture of cognitive deficits in AD with BPSD.

Analysis of Oropharyngeal Microbiota between the Patients with Bronchial Asthma and the Non-Asthmatic Persons

Bronchial asthma can be triggered by microbial agents in the oropharynx. This study was designed to identify the differences in microbiota of oropharynx of bronchial asthmatic patients in contrast to normal controls. In order to resolve the qualitative and quantitative diversity of the 16S rRNA gene present in the oropharynx microbiota of 4 patients and 4 controls, we compared microbial communities using Sanger sequencing and 376 sequences of 16S rRNA gene were analyzed. Of the total microbial diversity detected in the oropharynx in asthmatic patients 45.6% comprised members of the Firmicutes. In contrast, Proteobacteria (44.0%) dominated the oropharyngeal microbiota in the normal control group. Members of the Bacteroidetes, Fusobacteria, Actinobacteria, TM7, Cyanobacteria and unclassified bacteria were present in both groups. In conclusion, the difference in the microbiota of the oropharynx between patients and normal individuals could trigger symptomatic attacks in bronchial asthma.