Comparison of PC and iPad administrations of the Cogstate Brief Battery in the Mayo Clinic Study of Aging: Assessing cross-modality equivalence of computerized neuropsychological tests.

Objective: Computerized neuropsychological assessments are increasingly used in clinical practice, population studies of cognitive aging and clinical trial enrichment. Subtle, but significant, performance differences have been demonstrated across different modes of test administration and require further investigation. Method: Participants included cognitively unimpaired adults aged 50 and older from the Mayo Clinic Study of Aging who completed the Cogstate Brief Battery and Cogstate's Groton Maze Learning Test (GMLT) on an iPad or a personal computer (PC) in the clinic. Mode of administration differences and test-retest reliability coefficients were examined across 3 cohorts: a demographically matched test-retest cohort completing PC and iPad administrations the same day (N = 168); a test naïve cohort comparing baseline PC (n = 1820) and iPad (n =605) performance; and a demographically matched longitudinal cohort completing 3 Cogstate visits over 15 months on either the PC (n =63) or iPad (n =63). Results: Results showed a small but statistically significant and consistent finding for faster performance on PC relative to iPad for several Cogstate Brief Battery measures. Measures of accuracy generally did not differ or differences were very small. The GMLT showed faster performance and higher total errors on iPad. Most Cogstate variables showed no difference in the rate of change across PC and iPad administrations. Conclusions: There are small, but significant, differences in performance when giving the same cognitive tests on a PC or an iPad. Future studies are needed to better understand if these small differences impact the clinical interpretation of results and research outcomes.

Subjective cognitive decline and risk of MCI: The Mayo Clinic Study of Aging.

OBJECTIVE: We investigated different dimensions of subjective cognitive decline (SCD) to determine which was the best prognostic risk factor for incident mild cognitive impairment (MCI) among cognitively unimpaired participants. METHODS: We included 1,167 cognitively unimpaired participants, aged 70 to 95 years, from the Mayo Clinic Study of Aging based on 2 concurrent SCD scales (part of the Blessed memory test and the 39-item Everyday Cognition [ECog] scale, which included a validated 12-item derivative) and a single question assessing worry about cognitive decline. We evaluated multiple ways to dichotomize scores. In continuous models, we compared average scores on 4 ECog domains and multidomain (39- and 12-item) ECog scores. Cox proportional hazards models were used to assess the association between each measure and risk of MCI in models adjusted for objective memory performance, depression, anxiety, sex, APOE ε4 carriership, and medical comorbidities. RESULTS: It was possible to select a substantial group of participants (14%) at increased risk of incident MCI based on combined baseline endorsement of any consistent SCD on the ECog (any item scored ≥3; 12-item ECog hazard ratio [HR] 2.17 [95% confidence interval 1.51-3.13]) and worry (HR 1.79 [1.24-2.58]) in an adjusted model combining these dimensions. In continuous models, all ECog domains and the multidomain scores were associated with risk of MCI with a small advantage for multidomain SCD (12-item ECog HR 2.13 [1.36-3.35] per point increase in average score). Information provided by the informant performed comparable to self-perceived SCD. CONCLUSION: Prognostic value of SCD for incident MCI improves when both consistency of SCD and associated worry are evaluated.

Performance of the CogState computerized battery in the Mayo Clinic Study on Aging.

INTRODUCTION: The feasibility and validity of brief computerized cognitive batteries at the population-level are unknown. METHODS: Nondemented participants (n = 1660, age 50-97 years) in the Mayo Clinic Study on Aging completed the computerized CogState battery and standard neuropsychological battery. The correlation between tests was examined and comparisons between CogState performance on the personal computer (PC) and iPad (n = 331), and in the clinic vs. at home (n = 194), were assessed. RESULTS: We obtained valid data on greater than 97% of participants on each test. Correlations between the CogState and neuropsychological tests ranged from -0.462 to 0.531. Although absolute differences between the PC and iPad were small and participants preferred the iPad, performance on the PC was faster. Participants performed faster on Detection, One Card Learning, and One Back at home compared with the clinic. DISCUSSION: The computerized CogState battery, especially the iPad, was feasible, acceptable, and valid in the population.

Relationship of genetic variation in the serotonin transporter gene (SLC6A4) and congenital and acquired cardiovascular diseases.

Recent reports have suggested an association between variation in the serotonin transporter and primary pulmonary hypertension and myocardial infarction. We set out to determine whether these associations were present in a population of patients who underwent SLC6A4 genotyping and to explore whether genetic variation in the serotonin transporter might be also associated with other cardiovascular functional and structural abnormalities. Included were 3473 patients who were genotyped for the SLC6A4 5HTTLPR polymorphism and a subset for rs25531 (n=816) and STin2 (n=819). An association was observed between 5HTTLPR and primary pulmonary hypertension (p=0.0130), anomalies of the cerebrovascular system (p<0.0001), and other anomalies of great veins (p=0.0359). The combined 5HTTLPR and rs25531 genotype was associated with tachycardia (p=0.0123). There was an association of the STin2 genotype with abnormal electrocardiogram (ECG) (p=0.0366) and abnormal cardiac study (0.0311). Overall, these results represent a step toward the understanding of the impact of SLC6A4 variation on cardiovascular pathology.

Modified Masaoka stage and size are independent prognostic predictors in thymoma and modified Masaoka stage is superior to histopathologic classifications.

INTRODUCTION: The prognostic value of histopathologic classifications of thymoma is debated. Problematic reproducibility might cause this controversy. We studied the prognostic significance of three histopathologic classifications of thymomas after three thoracic pathologists agreed upon thymoma subtype and invasion. We also compared the outcome to established prognostic parameters. METHODS: Patients, surgically treated for thymic epithelial neoplasm at Mayo Clinic (1942-2008), were staged according to the modified Masaoka staging and the recently proposed staging by Moran. Three thoracic pathologists independently classified all cases according to the World Health Organization, Bernatz, and proposed Suster and Moran classification. Only thymoma that all three pathologists diagnosed as the same histopathologic subtype and extent of invasion were included in outcome analysis. RESULTS: In 214 (proposed Suster and Moran classification), 145 (World Health Organization classification), and 120 cases (Bernatz classification), reviewers agreed upon subtype of thymoma and invasion and follow-up was available. Median follow-up time was 7.5-7.7 years (range between classifications). All histopathologic classifications were associated with overall survival (OS) and disease-free survival (p ≤ 0.0001 to p = 0.048); only Bernatz classification was independent of modified Masaoka staging associated with OS (p = 0.04). Modified Masaoka stage predicted outcome independent of all histopathologic classifications and resection status and strongly correlated with the proposed Moran stage (correlation coefficient, 0.95). Thymoma size and age were prognostic parameters for OS independent of any histopathologic classification. CONCLUSIONS: Histopathologic classifications of thymomas are associated with prognosis but are in general not independent predictors of outcome. Modified Masaoka stage and proposed Moran staging are independent prognostic parameters for thymoma and superior to histopathologic classifications.

Reproducibility of 3 histologic classifications and 3 staging systems for thymic epithelial neoplasms and its effect on prognosis.

Data regarding the prognostic significance of the histopathologic classifications of thymic epithelial neoplasms are contradictory, perhaps reflecting issues in reproducibility. We studied the effect of reproducibility of 3 histopathologic classifications on prognosis and investigated the interobserver agreement on invasion and its effect on staging and prognosis. A total of 456 patients who underwent surgery for thymic epithelial neoplasm at Mayo Clinic Rochester (1942 to 2008) were staged (modified Masaoka, proposed Moran, proposed IASLC/ITMIG) and independently classified by 3 thoracic pathologists (World Health Organization, proposed Suster & Moran [S&M], and Bernatz). Interobserver agreement was moderate to substantial for all histopathologic classifications (κ values: 0.65, 0.52, 0.74 for World Health Organization, Bernatz, and S&M, respectively). All histopathologic classifications were significant for overall survival (OS) and disease-free survival (DFS) (all reviewers). If adjusted for Masaoka, only Bernatz classification for one reviewer and all histopathologic classifications for another reviewer were significant for OS. Interobserver agreement for invasion was substantial (κ=0.61) and almost perfect for Masaoka, Moran, and IASLC/ITMIG stage (κ values: 0.85, 0.81, and 0.92, respectively). The correlation coefficient for Masaoka and Moran staging was 0.93. Masaoka and IASLC/ITMIG staging were significant for OS and DFS (all reviewers). If adjusted for any histopathologic classification, Masaoka was significant for OS and DFS (all reviewers). In conclusion, reproducibility of histopathologic classifications has some effect on outcome. S&M is the most reproducible classification. Reproducibility of invasion has no effect on the prognostic value of staging. Masaoka, Moran, and IASLC/ITMIG staging are almost perfectly reproducible. The strong correlation between Masaoka and Moran staging suggests similar prognostic strength.

Hypothyroidism and risk of mild cognitive impairment in elderly persons: a population-based study.

IMPORTANCE: An association of clinical and subclinical hypothyroidism with mild cognitive impairment (MCI) has not been established. OBJECTIVE: To evaluate the association of clinical and subclinical hypothyroidism with MCI in a large population-based cohort. DESIGN, SETTING, AND PARTICIPANTS: A cross-sectional, population-based study was conducted in Olmsted County, Minnesota. Randomly selected participants were aged 70 to 89 years on October 1, 2004, and were without documented prevalent dementia [CORRECTED]. A total of 2050 participants were evaluated and underwent in-person interview, neurologic evaluation, and neuropsychological testing to assess performance in memory, attention/executive function, and visuospatial and language domains. Participants were categorized by consensus as being cognitively normal, having MCI, or having dementia according to published criteria. Clinical and subclinical hypothyroidism were ascertained from a medical records linkage system. MAIN OUTCOMES AND MEASURES: Association of clinical and subclinical hypothyroidism with MCI. RESULTS: Among 1904 eligible participants, the frequency of MCI was 16% in 1450 individuals with normal thyroid function, 17% in 313 persons with clinical hypothyroidism, and 18% in 141 individuals with subclinical hypothyroidism. After adjusting for covariates (age, educational level, sex, apolipoprotein E ε4, depression, diabetes mellitus, hypertension, stroke, body mass index, and coronary artery disease) we found no significant association between clinical or subclinical hypothyroidism and MCI (odds ratio [OR], 0.99 [95% CI, 0.66-1.48] and 0.88 [0.38-2.03], respectively). No effect of sex interaction was seen on these effects. In stratified analysis, the odds of MCI with clinical and subclinical hypothyroidism among men was 1.02 (95% CI, 0.57-1.82) and 1.29 (0.68-2.44) and, among women, was 1.04 (0.66-1.66) and 0.86 (0.37-2.02), respectively. CONCLUSIONS AND RELEVANCE: In this population-based cohort of elderly people, neither clinical nor subclinical hypothyroidism was associated with MCI. Our findings need to be validated in a separate setting using the published criteria for MCI and confirmed in a longitudinal study.

Methods for recovering Escherichia coli O157:H7 from cattle fecal, hide, and carcass samples: sensitivity and improvements.

The Meats Research Unit (MRU) methods, developed by MRU scientists of the U.S. Meat Animal Research Center, have been used to study the prevalence of Escherichia coli O157:H7 in cattle carcass, hide, and fecal samples. The sensitivity of these methods for recovery of injured E. coli O157:H7 cells from inoculated and uninoculated samples was determined, and potential improvements to these methods were evaluated. When using the conventional MRU methods, 91% of the pre-evisceration carcass samples tested positive for E. coli O157:H7 when inoculated with 5 to 10 CFU, 100% of hide samples tested positive for E. coli O157:H7 when inoculated with 30 to 50 CFU, and 96% of the fecal samples produced positive results when inoculated with 300 to 400 CFU per 10 g. The addition of a phosphate buffer to the tryptic soy broth enrichment improved recovery of E. coli O157:H7 from feces. Using the modified enrichment, 92% of the samples were identified as positive when inoculated with 10 to 30 CFU per 10 g. Substituting a commercially available wash buffer for the phosphate-buffered saline (PBS) plus Tween 20 wash buffer during immunomagnetic separation of hide samples improved recovery of the target organism at lower inoculum concentrations. When comparing uninoculated samples, substituting a PBS buffer plus a zwitterionic detergent for PBS plus Tween 20 also had a positive effect on recovery of E. coli O157:H7 from hide samples. Data presented here indicate that the MRU methods are highly effective at recovering injured E. coli O157:H7 from fecal, hide, and beef carcass samples; however, modifications can be added to increase the sensitivity.

DNA amplification and rearrangements in archival Salmonella enterica serovar Typhimurium LT2 cultures.

Variations in genome size and gene order were observed in archival Salmonella enterica serovar Typhimurium cultures stored for over 40 years. In one strain, microarray analysis revealed a large, stable amplification. PCR analysis of the same strain revealed a genomic duplication that underwent a translocation. Other strains had smaller duplications and deletions. These results demonstrate that storage in stabs over time at room temperature not only allows for further bacterial growth but also may produce an environment that selects for a variety of mutations, including genomic rearrangements.

Carbon and nitrogen substrate utilization by archival Salmonella typhimurium LT2 cells.

BACKGROUND: A collection of over 20,000 Salmonella typhimurium LT2 mutants, sealed for four decades in agar stabs, is a unique resource for study of genetic and evolutionary changes. Previously, we reported extensive diversity among descendants including diversity in RpoS and catalase synthesis, diversity in genome size, protein content, and reversion from auxotrophy to prototrophy. RESULTS: Extensive and variable losses and a few gains of catabolic functions were observed by this standardized method. Thus, 95 catabolic reactions were scored in each of three plates in wells containing specific carbon and nitrogen substrates. CONCLUSION: While the phenotype microarray did not reveal a distinct pattern of mutation among the archival isolates, the data did confirm that various isolates have used multiple strategies to survive in the archival environment. Data from the MacConkey plates verified the changes in carbohydrate metabolism observed in the Biolog system.