Correction: Liver enzymes.

In the article by Agganis B, Lee D, Sepe T (Liver enzymes: No trivial elevations, even if asymptomatic. Cleve Clin J Med 2018; 85(8):612-617, doi:10.3949/ccjm.85a.17103), an error occurred on page 613, in the second paragraph in the section about alcohol intake. The words ALT and AST were reversed. The paragraph should read as follows: The exact pathogenesis of alcoholic hepatitis is incompletely understood, but alcohol is primarily metabolized by the liver, and damage likely occurs during metabolism of the ingested alcohol. AST elevations tend to be higher than ALT elevations; the reason is ascribed to hepatic deficiency of pyridoxal 5'-phosphate, a cofactor of the enzymatic activity of ALT, which leads to a lesser increase in ALT than in AST. We thank Avinash Alexander, MD, Texas Tech University Health Sciences Center, for calling this to our attention. The correction has been made online.

Liver enzymes: No trivial elevations, even if asymptomatic.

Primary care physicians are at the forefront in screening for abnormal levels of liver enzymes and investigating the likely causes by obtaining a detailed history and physical examination, followed by appropriate laboratory and diagnostic workup. This review outlines common causes for the two main mechanisms of liver injury--cholestasis and hepatocellular insult--and explores the associated risk factors, methods of diagnosis, and management, with a focus on nonalcoholic fatty liver disease, one of the most often encountered causes of abnormal liver enzyme levels.

Measures of blood pressure and cognition in dialysis patients.

There are few reports on the relationship of blood pressure with cognitive function in maintenance dialysis patients. The Cognition and Dialysis Study is an ongoing investigation of cognitive function and its risk factors in six Boston area hemodialysis units. In this analysis, we evaluated the relationship between different domains of cognitive function with systolic and diastolic blood pressure, pulse pressure, and intradialytic changes in systolic blood pressure, using univariate and multivariable linear regression models adjusted for age, sex, race, education, and primary cause of end-stage renal disease. Among 314 participants, mean age was 63 years; 47% were female, 22% were African American, and 48% had diabetes. The mean (SD) of systolic blood pressure, diastolic blood pressure, pulse pressure, and intradialytic change in systolic blood pressure were 141 (21), 73 (12), 68 (15), and -10 (24) mmHg, respectively. In univariate analyses, the performance on cognitive tests primarily assessing executive function and processing speeds was worse among participants with lower diastolic blood pressure and higher pulse pressure. These relationships were not statistically significant, however, in multivariable analyses. There was no association between cognitive function and systolic blood pressure or intradialytic change in systolic blood pressure in either univariate or multivariable analyses. We found no association between different measures of blood pressure and cognitive function in cross-sectional analysis. Longitudinal studies are needed to confirm these results.

Cardiovascular disease and cognitive function in maintenance hemodialysis patients.

BACKGROUND: Cardiovascular disease (CVD) and cognitive impairment are common in dialysis patients. Given the proposed role of microvascular disease on cognitive function, particularly cognitive domains that incorporate executive functions, we hypothesized that prevalent systemic CVD would be associated with worse cognitive performance in hemodialysis patients. DESIGN: Cross-sectional cohort. SETTING & PARTICIPANTS: 200 maintenance hemodialysis patients without prior stroke from 5 Boston-area hemodialysis units. PREDICTOR: CVD, defined as history of coronary disease or peripheral vascular disease. OUTCOME: Performance on a detailed neurocognitive battery. Primary analyses quantified cognitive performance using principal components analysis to reduce cognitive tests to a processing speed/executive function domain and a memory domain. Multivariable linear regression models adjusted for age, sex, education, race, and other clinical and demographic characteristics. RESULTS: Mean age of participants was 62 ± 18 (standard deviation) years and 75 (38%) had CVD. Individuals with CVD were older and more likely to be men, have diabetes, and be current or former smokers. In adjusted models, individuals with CVD performed 0.50 standard deviation worse (P < 0.001) on tests assessing processing speed/executive function, whereas there was no difference in performance on tests of memory. Similar results were seen assessing individual tests, with performance on the Block Design, Digit Symbol Coding, and Trail Making Tests A and B significantly associated with CVD in age-, sex-, education-, and race-adjusted analyses and approaching significance in fully adjusted models. LIMITATIONS: CVD ascertainment dependent on patient recall and dialysis unit documentation. No brain imaging. CONCLUSIONS: The presence of CVD is associated with worse cognitive performance on tests of processing speed and executive functioning in hemodialysis patients and identifies a high-risk population for greater difficulty with complex tasks.

Cognitive function and dialysis adequacy: no clear relationship.

BACKGROUND/AIMS: Cognitive impairment is common in hemodialysis patients and may be impacted by multiple patient and treatment characteristics. The impact of dialysis dose on cognitive function remains uncertain, particularly in the current era of increased dialysis dose and flux. METHODS: We explored the cross-sectional relationship between dialysis adequacy and cognitive function in a cohort of maintenance hemodialysis patients. Adequacy was defined as the average of the 3 most proximate single pool Kt/V assessments. A detailed neurocognitive battery was administered during the 1st hour of dialysis. Multivariable linear regression models were adjusted for age, sex, education, race and other clinical and demographic characteristics. RESULTS: Among 273 patients who underwent cognitive testing, the mean (SD) age was 63 (17) years and the median dialysis duration was 13 months, 47% were woman, 22% were African American, and 48% had diabetes. The mean (SD) Kt/V was 1.51 (0.24). In univariate, parsimonious and multivariable models, there were no significant relationships between decreased cognitive function and lower Kt/V. CONCLUSION: In contrast to several older studies, there is no association between lower Kt/V and worse cognitive performance in the current era of increased dialysis dose. Future studies should address the longitudinal relationship between adequacy of dialysis and cognitive function to confirm these findings.

Depression and cognitive function in maintenance hemodialysis patients.

BACKGROUND: Both depression and cognitive impairment are common in hemodialysis patients, are associated with adverse clinical outcomes, and place an increased burden on health care resources. STUDY DESIGN: Cross-sectional cohort. SETTING & PARTICIPANTS: 241 maintenance hemodialysis patients in the Boston, MA, area. PREDICTOR: Depressive symptoms, defined as a Center for Epidemiological Studies Depression Scale (CES-D) score ≥16. OUTCOME: Performance on a detailed neurocognitive battery. RESULTS: Mean age was 63.8 years, 49.0% were women, 21.6% were African American, and median dialysis therapy duration was 13.8 months. There were 57 (23.7%) participants with significant depressive symptoms. In multivariable analysis adjusting for age, sex, education, and other comorbid conditions, participants with and without depressive symptoms performed similarly on the Mini-Mental State Examination (P = 0.4) and tests of memory. However, participants with greater depressive symptoms performed significantly worse on tests assessing processing speed, attention, and executive function, including Trail Making Test B (P = 0.02) and Digit-Symbol Coding (P = 0.01). Defining depression using a CES-D score ≥18 did not substantially change results. LIMITATIONS: Cross-sectional design, absence of brain imaging. CONCLUSIONS: Hemodialysis patients with a greater burden of depressive symptoms perform worse on tests of cognition related to processing speed and executive function. Further research is needed to assess the effects of treating depressive symptoms on cognitive performance in dialysis patients.

Visual biasing of auditory localization in azimuth and depth.

Correctly integrating sensory information across different modalities is a vital task, yet there are illusions which cause the incorrect localization of multisensory stimuli. A common example of these phenomena is the "ventriloquism effect". In this illusion, the localization of auditory signals is biased by the presence of visual stimuli. For instance, when a light and sound are simultaneously presented, observers may erroneously locate the sound closer to the light than its actual position. While this phenomenon has been studied extensively in azimuth at a single depth, little is known about the interactions of stimuli at different depth planes. In the current experiment, virtual acoustics and stereo-image displays were used to test the integration of visual and auditory signals across azimuth and depth. The results suggest that greater variability in the localization of sounds in depth may lead to a greater bias from visual stimuli in depth than in azimuth. These results offer interesting implications for understanding multisensory integration.