Effects of haemodialysis and continuous ambulatory peritoneal dialysis on P300 cognitive potentials in uraemic patients

Evaluation of Event-Related Potentials in Somatic Diseases - Systematic Review

Many somatic illnesses (e.g. hypertension, diabetes, pulmonary and cardiac diseases, hepatitis C, kidney and heart failure, HIV infection, Sjogren's disease) may impact central nervous system functions resulting in emotional, sensory, cognitive or even personality impairments. Event-related potential (ERP) methodology allows for monitoring neurocognitive processes and thus can provide a valuable window into these cognitive processes that are influenced, or brought about, by somatic disorders. The current review aims to present published studies on the relationships between somatic illness and brain function as assessed with ERP methodology, with the goal to discuss where this field of study is right now and suggest future directions.

Comparison of P300 Cognitive-evoked Potentials and Visual and Auditory Reaction Time in Stage 5 Chronic Kidney Disease Patients on Different Treatment Modalities

Patients with chronic kidney disease (CKD) are at a higher risk of cognitive impairment. Poor quality of life and decreased compliance are frequently observed with cognitive decline among CKD patients. Cognitive impairment among Stage 5 CKD patients varies with different modalities of treatment, and contradicting results have been reported. Fifty-four medically stable Stage 5 CKD patients undergoing different modalities of treatment were recruited: Patients with Stage 5 CKD on maintenance hemodialysis (HD) (n = 18), continuous ambulatory peritoneal dialysis (CAPD) (n = 18), and conservative management (CM) (n = 18). Eighteen apparently healthy participants were recruited as a control group. The cognitive functions assessed were P300 event- related potential, auditory and visual reaction times (VRTs). Kidney function was assessed by serum creatinine and estimated glomerular filtration rate. Creatinine levels were significantly higher in all three treatment groups compared with the control group. Multivariate analysis revealed a significant association between the CKD groups (n = 54) and the parameters of cognitive function. P300 latency was prolonged in all treatment groups compared with the control group and was significantly prolonged in patients on CM compared with HD and CAPD patients. The VRT of CM patients was found to be significantly higher compared with the control group. The auditory reaction time was significantly prolonged in all treatment groups compared with the control group and in the CM group compared with the CAPD group. Cognitive function was more affected in Stage 5 CKD patients on CM compared with patients undergoing HD or CAPD.

Cognitive Dysfunction and Health-Related Quality of Life in Patients with End-Stage Renal Disease Undergoing Hemodialysis in Comparison with Patients Undergoing Peritoneal Dialysis: A Cross-Sectional Study

Background

This study compared the effects of peritoneal dialysis and hemodialysis on cognitive dysfunction and health-related quality of life (HRQOL) in end-stage renal disease (ESRD) patients and analyzed other potential influencing factors.

Material/Methods

A total of 265 patients who received dialysis at our hospital were included and divided into the hemodialysis group (n=115) and the peritoneal dialysis group (n=150). The cognitive performance was assessed by the Beijing version of the Montreal Cognitive Assessment. The Kidney Disease Quality of 36-Item Short Form Survey and a kidney disease-related quality of life assessment were used for evaluating HRQOL. Univariate and multivariate linear regression analyses were used to explore the effects of dialysis on cognitive dysfunction and HRQOL.

Results

As compared with the hemodialysis group, the peritoneal dialysis group had lower scores on the Montreal Cognitive Assessment (β=−8.35, 95% CI: −9.85 to −6.86), 36-Item Short Form Survey (β=−10.20, 95% CI: −11.94 to −8.45), and kidney disease-related quality of life assessment (β=−8.67, 95% CI: −10.10 to −7.23). After adjustment for sex, age, BMI, marital status, educational level, income level, presence of diabetes, duration of kidney disease, duration of dialysis, and dialysis frequency, the results were consistent with that of the crude model.

Conclusions

In the present study, patients receiving peritoneal dialysis had worse cognitive dysfunction and worse HRQOL compared to patients receiving hemodialysis, which might lead to poorer outcomes of ESRD patients. The related factors affecting cognitive dysfunction and HRQOL were also explored, which could help clinicians to determine the optimal treatment for ESRD patients.

Renal Contributions in the Pathophysiology and Neuropathological Substrates Shared by Chronic Kidney Disease and Alzheimer's Disease

Chronic kidney disease and Alzheimer’s disease are chronic conditions highly prevalent in elderly communities and societies, and a diagnosis of them is devastating and life changing. Demanding therapies and changes, such as non-compliance, cognitive impairment, and non-cognitive anomalies, may lead to supplementary symptoms and subsequent worsening of well-being and quality of life, impacting the socio-economic status of both patient and family. In recent decades, additional hypotheses have attempted to clarify the connection between these two diseases, multifactorial in their nature, but even so, the mechanisms behind this link are still elusive. In this paper, we sought to highlight the current understanding of the mechanisms for cognitive decline in patients with these concurrent pathologies and provide insight into the relationship between markers related to these disease entities and whether the potential biomarkers for renal function may be used for the diagnosis of Alzheimer’s disease. Exploring detailed knowledge of etiologies, heterogeneity of risk factors, and neuropathological processes associated with these conditions opens opportunities for the development of new therapies and biomarkers to delay or slow their progression and validation of whether the setting of chronic kidney disease could be a potential determinant for cognitive damage in Alzheimer’s disease.

Single-Trial Mechanisms Underlying Changes in Averaged P300 ERP Amplitude and Latency in Military Service Members After Combat Deployment

Attenuation in P300 amplitude has been characterized in a wide range of neurological and psychiatric disorders such as dementia, schizophrenia, and posttraumatic stress disorder (PTSD). However, it is unclear whether the attenuation observed in the averaged event-related potential (ERP) is due to the reduction of neural resources available for cognitive processing, the decreased consistency of cognitive resource allocation, or the increased instability of cognitive processing speed. In this study, we investigated this problem by estimating single-trial P300 amplitude and latency using a modified Woody filter and examined the relation between amplitudes and latencies from the single-trial level to the averaged ERP level. ERPs were recorded from 30 military service members returning from combat deployment at two time points separated by 6 or 12 months. A conventional visual oddball task was used to elicit P300. We observed that the extent of changes in the within-subject average P300 amplitude over time was significantly correlated with the amount of change in three single-trial measures: (1) the latency variance of the single-trial P300 (r = -0.440, p = 0.0102); (2) the percentage of P300-absent trials (r = -0.488, p = 0.005); and (3) the consistent variation of the single-trial amplitude (r = 0.571, p = 0.0022). These findings suggest that there are multiple underlying mechanisms on the single-trial level that contribute to the changes in amplitudes seen at the averaged ERP level. The changes between the first and second assessments were quantified with the intraclass correlation coefficient, the standard error of measurement and the minimal detectable difference. The unique population, the small sample size and the large fraction of participants lost to follow up precludes generalizations of these measures of change to other populations.

Neuropsychiatric Disorders in Chronic Kidney Disease

Neuropsychiatric conditions including depression, anxiety disorders, and cognitive impairment are prevalent in patients with chronic kidney disease (CKD). These conditions often make worse the quality of life and also lead to longer hospitalizations and higher mortality. Over the past decades, some hypotheses have tried to explain the connection between CKD and neuropsychiatric disorders. The most common hypothesis is based on the occurrence of cerebrovascular disease and accumulated uremic toxins in adult patients with CKD. However, the lack of a direct association between known vascular risk factors (e.g., diabetes and hypertension) with CKD-related cognitive deficits suggests that other mechanisms may also play a role in the pathophysiology shared by renal and neuropsychiatric diseases. This hypothesis is corroborated by the occurrence of neuropsychiatric comorbidities in pediatric patients with CKD preceding vascular damage, and the inconsistent findings on neuroprotective effects of antihypertensives. The aim of this narrative review was to summarize clinical evidence and potential mechanisms that links CKD and brain disorders, specifically in regard to cognitive impairment, anxiety, and depression.

The comparison of cognitive function and risk of dementia in CKD patients under peritoneal dialysis and hemodialysis: A PRISMA-compliant systematic review and meta-analysis

BACKGROUNDS

Cognitive functions (CF) decline has been reported in end-stage renal disease (ESRD) patients. However, the influence of dialysis modalities on CF has not been investigated systematically.

METHODS

A systematic literature search was conducted in MEDLINE, Embase, Cochrane library and unpublished database Clinicaltrials.gov to identify the studies comparing the cognitive functions or risk of dementia between hemodialysis (HD) and peritoneal dialysis (PD). After data extraction, quality of studies was assessed using the Newcastle-Ottawa scale. Both qualitative and quantitative analyses were performed.

RESULTS

After study inclusion, totally 15 cohort or cross-sectional studies were included, comparing the cognitive functions using neuropsychological tests and covering the executive function, memory, orientation, attention, etc. By qualitative analysis, it showed that more studies are inclined to PD compared with HD with better cognitive functions. By quantitative analysis, it showed that PD showed better performance in the tests of Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), stroop interference test and exhibited lower risk of dementia compared with HD.

CONCLUSIONS

In this meta-analysis, we draw preliminary conclusion that patients treated with PD had better cognitive functions and lower dementia risk compared with patients with HD. Still more large-scale and well-conducted prospective cohort studies are needed to draw more convincing conclusions.

Screening of Cognitive Impairment in the Dialysis Population: A Scoping Review

BACKGROUND

Cognitive impairment in end-stage kidney disease patients on dialysis is increasingly common. This study aimed to review the practice of screening and to evaluate the evidence on cognitive impairment prevalence in this population.

METHODS

This scoping review of studies summarises the evidence on cognitive impairment in dialysis populations. The search included the Medline, CINAHL, Embase, PsycINFO, PubMed, and Cochrane Library databases for English-language articles published between 2000 and 2015. A total of 46 articles were reviewed.

RESULTS

The studies were of prospective observational design, with the majority conducted in the haemodialysis population. The reported prevalence of cognitive impairment ranged from 6.6 to 51%. Three screening tools were consistently used.

CONCLUSION

While cognitive impairment is recognised in the dialysis population, there is paucity of screening data. The design of prospective comparisons ideally includes established screening instruments, particularly the Montreal Cognitive Assessment, to determine the optimal results for this population. Translation of established screening tools to increase the inclusion of people from other cultural and language groups is required. Regular screening can enhance the timing to introduce home-based care support and advance care planning discussions.

Does Chronic Kidney Disease-Induced Cognitive Impairment Affect Driving Safety?

PURPOSE OF REVIEW

One of the principal mechanisms by which illness can affect driving safety is by impairing cognition. Nevertheless, despite the substantial evidence demonstrating cognitive impairment in chronic kidney disease (CKD), little is known about the effects of CKD on driving safety.

OBJECTIVE

Investigate the current national medical guidelines and research literature with respect to CKD and driving safety.

SOURCES OF INFORMATION

Medline, CINAHL, PEDro, Scopus as of August 2017. The most up to date national driving guidelines and available information provided by the provincial and territorial ministries of transportation across Canada.

FINDINGS

Fives studies of driving fitness in patients with CKD have been published with minimal data available for patients at early stages of the disease. Amongst these studies, only two come from an era when modern end stage renal disease therapies were routinely provided. The first study demonstrated that 40% of 186 surveyed patients on hemodialysis felt uncomfortable driving and that 1/3 of patients were involved in motor vehicle collisions (MVC) since starting dialysis. Of the patients who felt comfortable driving, more than 75% were found to be at increased driving risk. The second study reported that 15% of patients on hemodialysis were involved in MVCs over a three year span and that the "Am I A Safe Driver" assessment tool by the American Medical Association may not capture all patients at high driving risk. Despite these alarming numbers, national guidelines place few driving restrictions on this patient population and only 3 of 11 available provincial or territorial driving forms include kidney disease as a category that physicians should consider when assessing medical fitness to drive.

LIMITATIONS

Our review is limited by the lack of randomized control studies evaluating the effects of CKD on driving safety.

IMPLICATIONS

Our review demonstrates that driving safety in this patient population remains poorly understood. The limited evidence that does exist, however, suggests that these patients are at substantial risk for unsafe driving. Future research is necessary to determine the impact of CKD-associated cognitive impairment on driving risk, and to parse out the contributions of CKD and its various treatments to driving impairment.

Neurological complications of renal dialysis and transplantation

Neurological complications from renal replacement therapy contribute significantly to morbidity and mortality in patients with renal failure. Such complications can affect either the central or peripheral nervous systems. Most neurological disturbances associated with the uraemic state do not respond fully to renal replacement therapy. There are also complications specifically associated with dialysis and transplantation. A multidisciplinary approach, involving both nephrologists and neurologists, is critical for the diagnosis and effective management of these disorders.

Peritoneal dialysis is associated with better cognitive function than hemodialysis over a one-year course

Impaired cognitive functioning in patients with end-stage renal disease may reduce their capabilities to adhere to complex medical or dietary regimens and to fully participate in medical decisions. With decreasing renal function, cognitive abilities are likely to decline, with cognitive dysfunction improving after initiation of dialysis and even being generally reversible after successful renal transplantation. However, little is known about cognitive changes particularly regarding different treatment modalities. To gain further insight into this, we focused on a one-year course of cognitive functions, comparing peritoneal to hemodialysis patients. Within the CORETH-project, two validated neurocognitive tests, assessing executive functioning (Trail Making Test-B) and attention (d2-Revision-Test) and the self-reported Kidney Disease Quality of Life Short Form Cognitive Function-subscale, were administered to 271 patients at baseline and after one year. Subsamples were matched by propensity score, adjusting for age, comorbidity, education, and employment status for 96 hemodialysis and 101 peritoneal dialysis patients. The effects of time and treatment modality were investigated, controlling for well-known confounders. Both tests revealed improvement over one year. Peritoneal dialysis was associated with better outcomes than hemodialysis at baseline and follow-up, but comparability between groups may be limited. The opposite pattern applied to self-reporting. Hemodialysis patients had to be excluded from cognitive testing more often than peritoneal dialysis patients. As such, the number of exclusions may have biased the findings, limiting generalizability. Thus, our findings suggest an improvement of cognitive functioning and support previous indications for peritoneal dialysis being associated with better cognitive functions during a one-year course than hemodialysis.

Effect of renal transplantation on cognitive function in hemodialysis patients: a longitudinal study

BACKGROUND

The literature notes high prevalence of cognitive function (CF) impairment among hemodialysis patients. Renal transplantation by reversing metabolic factors should improve cognitive function; however, results in post-transplant patients are inconsistent. Lack of longitudinal studies, variable and small patient population, variable renal function and post-transplantation period and use of non-specific tests make results difficult to interpret. We looked at CF in stable hemodialysis patients just prior to live renal transplantation and approximately 3 months subsequently using well-validated electrophysiological study of P300 cognitive potential obtained by auditory oddball paradigm using multiple scalp electrodes.

METHODS

Ten healthy age- and gender-matched controls (group 1) and 20 end-stage kidney disease (ESKD) male patients on maintenance hemodialysis with no other comorbidities that affect CF were studied before (group 2) and 3 months after successful transplantation (group 3).

RESULTS

ESKD population had mean age of 29.7 ± 7.5 years, with mean dialysis vintage and post-transplant period being 10.3 ± 6.9 and 3.2 ± 0.4 months, respectively. Mean P300 latencies in groups 1, 2 and 3 were 319 ± 33.6, 348.6 ± 27.8 and 316.4 ± 33.4 ms, respectively (P < 0.001 group 1 vs 2 and group 2 vs 3; group 1 vs 3 NS). Mean P300 amplitude in groups 1, 2 and 3 was 27.9 ± 12.8, 13.4 ± 8.6 and 14.6 ± 9.4 µV, respectively (P < 0.001 group 1 vs 2 and group 1 vs 3; group 2 vs 3 NS). P300 latencies correlated negatively with hemoglobin and serum albumin.

CONCLUSIONS

ESKD patients have impaired CF as documented by prolonged P300 latencies. There was normalization of P300 latencies post-transplantation indicating role of uremic toxins in CF impairment.

Cognitive Changes in Chronic Kidney Disease and After Transplantation

Cognitive impairment is very common in chronic kidney disease (CKD) and is strongly associated with increased mortality. This review article will discuss the pathophysiology of cognitive impairment in CKD, as well as the effect of dialysis and transplantation on cognitive function. In CKD, uremic toxins, hyperparathyroidism and Klotho deficiency lead to chronic inflammation, endothelial dysfunction and vascular calcifications. This results in an increased burden of cerebrovascular disease in CKD patients, who consistently have more white matter hyperintensities, microbleeds, microinfarctions and cerebral atrophy on magnetic resonance imaging scans. Hemodialysis, although beneficial in terms of uremic toxin clearance, also contributes to cognitive decline by causing rapid fluid and osmotic shifts. Decreasing the dialysate temperature and increasing total dialysis time limits these shifts and helps maintain cognitive function in hemodialysis patients. For many patients, kidney transplantation is the preferred treatment modality, because it reverses the underlying mechanisms causing cognitive impairment in CKD. These positive effects have to be balanced against the possible neurotoxicity of infections and immunosuppressive medications, especially glucocorticosteroids and calcineurin inhibitors. A limited number of studies have addressed the overall effect of transplantation on cognitive function. These have mostly found an improvement after transplantation, but have a limited applicability to daily practice because they have only included relatively young patients.

Cerebral blood flow changes in hemodialysis and peritoneal dialysis patients: an arterial-spin labeling MR imaging

We used arterial-spin labeling (ASL) MR imaging, a non-invasive technique to evaluate cerebral blood flow (CBF) changes in patients with end-stage renal disease (ESRD) undergoing peritoneal dialysis (PD) and hemodialysis (HD), and nondialysis ESRD patients compared with healthy cohort. Ninety seven ESRD patients including 32 PD patients (20 male, 12 female; mean age 33 ± 8 years), 33 HD patients (22 male, 11 female; mean age 33 ± 8 years) and 32 nondialysis patients (20 male, 12 female; mean age 35 ± 7 years) and 31 age- and gender-matched healthy controls (20 male, 11 female; mean age 32 ± 8 years) were included in this study. All subjects underwent ASL MR imaging, neuropsychologic tests, and ESRD patients underwent laboratory testing. CBF values were compared among PD, HD, nondialysis patients and control groups. Correlation analysis and multiple regression analysis were performed to investigate the association between CBF values and hemoglobin, neuropsychologic test results, serum creatinine, urea levels, disease duration, and dialysis duration. Elevated CBFs of whole brain region, gray matter, and white matter were found in all ESRD patient groups compared with healthy controls (all P < 0.001). However, compared with non-dialysis ESRD patients, both PD and HD patients had widespread regional CBF decline mainly in bilateral frontal and anterior cingulate cortices. There were no differences for CBF between PD and HD patient groups. Negative correlations were observed between mean CBFs of whole brain region, gray matter, and white matter and the hemoglobin level in all ESRD patients. Multiple linear regression showed elevated CBF of multiple brain areas correlated with some neuropsychological tests in ESRD patients (all P < 0.001, AlphaSim corrected), but the association was not present or shrank after adjusting hemoglobin level. This study found that mean CBF was predominantly increased in patients with ESRD, which correlated with their hemoglobin level and neurocognitive disorders. There were no differences of CBF change and cognitive function between PD and HD ESRD patients with long-term treatment. The degree of anemia may be a predominant risk factor for cognitive impairment in these ESRD patients.

Comparative study to evaluate the effects of peritoneal and hemodialysis on peripheral nerve function

INTRODUCTION

There is no specific treatment for neuropathy in chronic kidney disease (CKD). We compared nerve function across hemodialysis (HD) and peritoneal dialysis (PD).

METHODS

Subjects underwent neurological assessment and neurophysiological testing using nerve excitability studies. Pre- and postdialysis studies were undertaken in HD (n = 10) and PD (n = 10) patients and were compared with stage 4 CKD patients (n = 12) and healthy controls (n = 20).

RESULTS

There were prominent differences in nerve excitability between the groups (P <  0.001). The HD group was significantly abnormal compared with all groups for excitability parameters, while the PD group demonstrated results similar to the CKD group. Pre- and postdialysis fluctuations were pronounced in the HD group, while the PD group showed less severe fluctuations.

CONCLUSIONS

PD patients demonstrated greater normality of nerve excitability compared with the HD group despite similar duration of dialysis. These results suggest PD may provide greater homeostatic stability and may be neurologically beneficial. Muscle Nerve 54: 58-64, 2016.

Cognition in People With End-Stage Kidney Disease Treated With Hemodialysis: A Systematic Review and Meta-analysis

BACKGROUND

Cognitive impairment is associated with poorer quality of life, risk for hospitalization, and mortality. Cognitive impairment is common in people with end-stage kidney disease treated with hemodialysis, yet the severity and specific cognitive deficits are uncertain.

STUDY DESIGN

Systematic review and meta-analysis.

SETTING & POPULATION

Adults receiving hemodialysis compared with the general population, people with non-dialysis-dependent chronic kidney disease (NDD-CKD), people receiving peritoneal dialysis, or people with nondialyzed chronic kidney failure.

SELECTION CRITERIA FOR STUDIES

Randomized controlled trials, cohort or cross-sectional studies without language restriction.

INDEX TESTS

Validated neuropsychological tests of cognition.

OUTCOMES

Cognitive test scores, aggregated by cognitive domain: orientation and attention, perception, memory, language, construction and motor performance, concept formation and reasoning, and executive functions.

RESULTS

42 studies of 3,522 participants. Studies were of high or uncertain risk of bias, assessed by the Newcastle-Ottawa Scale. People treated with hemodialysis had worse cognition than the general population, particularly in attention (n=22; standardized mean difference [SMD], -0.93; 95% CI, -1.18 to -0.68). Hemodialysis patients performed better than nondialyzed patients with chronic kidney failure in attention (n=6; SMD, 0.70; 95% CI, 0.45 to 0.96) and memory (n=6; SMD, 0.36; 95% CI, 0.08 to 0.63), but had poorer memory than the general population (n=16; SMD, -0.41; 95% CI, -0.91 to 0.09) and people with NDD-CKD (n=5; SMD, -0.40; 95% CI, -0.60 to -0.21). There were insufficient data to show other differences among people receiving hemodialysis and those receiving peritoneal dialysis or with NDD-CKD.

LIMITATIONS

Potentially biased studies, not wholly adjusted for education. High heterogeneity, mainly due to the large variety of tests used to assess cognition.

CONCLUSIONS

People treated with hemodialysis have impaired cognitive function compared to the general population, particularly in the domains of orientation and attention and executive function. Cognitive deficits in specific domains should be further explored in this population and should be considered when approaching education and chronic disease management.

The utility of P300 as a schizophrenia endophenotype and predictive biomarker: clinical and socio-demographic modulators in COGS-2

Reduced auditory P300 amplitude is a robust schizophrenia deficit exhibiting the qualities of a viable genetic endophenotype. These include heritability, test-retest reliability, and trait-like stability. Recent evidence suggests that P300 may also serve as a predictive biomarker for transition to psychosis during the schizophrenia prodrome. Historically, the utility of the P300 has been limited by its clinical nonspecificity, cross-site measurement variability, and required EEG expertise. The Consortium on the Genetics of Schizophrenia (COGS-2) study provided an opportunity to examine the consistency of the measure across multiple sites with varying degrees of EEG experience, and to identify important modulating factors that contribute to measurement variability. Auditory P300 was acquired from 649 controls and 587 patients at 5 sites. An overall patient deficit was observed with effect size 0.62. Each site independently observed a significant patient deficit, but site differences also existed. In patients, site differences reflected clinical differences in positive symptomatology and functional capacity. In controls, site differences reflected differences in racial stratification, smoking and substance use history. These factors differentially suppressed the P300 response, but only in control subjects. This led to an attenuated patient-control difference among smokers and among African Americans with history of substance use. These findings indicate that the P300 can be adequately assessed quantitatively, across sites, without substantial EEG expertise. Measurements are suitable for both genetic endophenotype analyses and studies of psychosis risk and conversion. However, careful attention must be given to selection of appropriate comparison samples to avoid misleading false negative results.

Risk of dementia in peritoneal dialysis patients compared with hemodialysis patients

BACKGROUND

Compared with similarly aged controls, patients with end-stage renal disease (ESRD) have a higher prevalence of cognitive impairment and more rapid cognitive decline, which is not explained by traditional risk factors alone. Since previous small studies suggest an association of cognitive impairment with dialysis modality, we compared incident dementia among patients initiating hemodialysis (HD) vs peritoneal dialysis (PD) in a large national cohort.

METHODS

This is a retrospective cohort study of incident dialysis patients in the United States from 2006 to 2008 with no diagnosis of dementia prior to beginning dialysis. We evaluated the effect of initial dialysis modality on incidence of dementia, diagnosed by Medicare claims data, adjusted for baseline demographic and clinical data from the USRDS registry.

RESULTS

Our analysis included 121,623 patients, of whom 8,663 initiated dialysis on PD. The mean age of our cohort was 69.2 years. Patients who initiated PD had a lower cumulative incidence of dementia than those who initiated HD (1.0% vs 2.7%, 2.5% vs 5.3%, and 3.9% vs 7.3% at 1, 2, and 3 years, respectively). The risk of dementia for patients who started on PD was lower compared with those who started on HD, with a hazard ratio (HR) = 0.46 [0.41, 0.53], in an unadjusted model and HR 0.74 [0.64, 0.86] in a matched model.

CONCLUSIONS

Dialysis modality is associated with incident dementia in a cohort of older ESRD patients. This finding warrants further investigation of the effect of dialysis modality on cognitive function and evaluation for possible mechanisms.

Comparison of dementia risk between end stage renal disease patients with hemodialysis and peritoneal dialysis--a population based study

A higher risk of dementia was reported in patients undergoing maintenance hemodialysis (HD) compared to those undergoing peritoneal dialysis (PD). Selection bias and competing risk of death were not considered in previous studies. The aim of this study was to investigate dementia risk in patients undergoing HD and PD by using the Taiwan Longitudinal Health Insurance Database. We enrolled 52,332 incident HD patients and 3292 incident PD patients who were older than 40 years between January 1, 1998 and December 31, 2007. During the study period, 3775 patients were diagnosed with dementia in the HD group (177.5 per 10,000 person-years incidence rate) and 181 patients in the PD group (145.9 per 10,000 person-years incidence rate). The results revealed that the higher hazard ratio of HD compared with PD for dementia disappeared after controlling for demographic characteristics, propensity score, and competing death risk (subdistribution hazard ratio was 1.086; 95% confidence interval, 0.940–1.255). In conclusion, HD did not increase the risk of dementia in dialysis-dependent patients compared to PD.

Relationship between cognitive impairment and depression in dialysis patients

PURPOSE

Patients with chronic kidney disease frequently show cognitive dysfunction. The association of depression and cognitive function is not well known in maintenance dialysis patients. We evaluated cognitive impairment and depression, as well as their relationship in regards to methods of dialysis, maintenance hemodialysis (MHD) and chronic peritoneal dialysis (CPD).

MATERIALS AND METHODS

Fifty-six maintenance dialysis patients were recruited and their clinical and laboratory data were collected. The Korean version of the mini-mental state exam (K-MMSE) was applied to screen the patient's cognitive function, while the Korean version of the Beck Depression Inventory (K-BDI) was used for depression screening.

RESULTS

The average age of the participants was 54.2±10.2 years; 29 (51.8%) were female. The average dialysis vintage was 4.2±3.8 years. The CPD group showed significantly higher K-MMSE score (27.8±2.9 vs. 26.1±3.1, p=0.010) and lower K-BDI score (12.0±8.4 vs. 20.2±10.4, p=0.003) compared with the MHD group. The percentage of patients with depression symptoms was higher in the MHD group (51.7% vs. 18.5%). There was a negative correlation between cognitive function and prevalence of depressive symptoms. Depression and education level were shown to be independent predictors for cognitive impairment in multivariate analysis.

CONCLUSION

Cognitive impairment was closely correlated with depression. It is important to detect cognitive impairment and depression early in maintenance dialysis patients with simple bedside screening tools.

Cognitive disorders and dementia in CKD: the neglected kidney-brain axis

Epidemiologic data suggest that individuals at all stages of CKD have a higher risk of developing cognitive disorders and dementia. This risk is generally explained by the high prevalence of both symptomatic and subclinical ischemic cerebrovascular lesions. However, other potential mechanisms, including direct neuronal injury by uremic toxins, could also be involved, especially in the absence of obvious cerebrovascular disease. We discuss the prevalence and characteristics of cognitive disorders and dementia in patients with CKD, brain imaging findings, and traditional and nontraditional risk factors. Understanding the pathophysiologic interactions between renal impairment and brain function is important in order to minimize the risk for future cognitive impairment.

Achados audiológicos em pacientes submetidos ao transplante renal

OBJETIVO: Investigar o comportamento auditivo de pacientes com insuficiência renal crônica submetidos ao transplante renal. MÉTODOS: Foram avaliados 30 pacientes, 10 do gênero feminino e 20 do gênero masculino, na faixa etária de 13 a 26 anos (média de idade 16,97 anos). Os sujeitos foram submetidos a anamnese, avaliação otorrinolaringológica, avaliação audiológica convencional e de altas frequências, medidas de imitância acústica e avaliação do processamento auditivo central. Para os resultados da audiometria de altas frequências foi utilizado um grupo controle. RESULTADOS: Os sujeitos não apresentaram queixas auditivas na anamnese. Os resultados da audiometria convencional demonstraram predomínio da normalidade; na audiometria de altas frequências, os pacientes apresentaram resultados piores do que os sujeitos do grupo controle. Na imitanciometria houve predomínio de curva tipo A bilateral. Na avaliação do processamento auditivo central, 14 sujeitos (46,67%) apresentaram resultados alterados no Staggered Spondaic Word Test (SSW). Houve diferença significativa entre a variável idade e o resultado da audiometria tonal limiar: quanto maior a idade, menor a sensibilidade auditiva nos limiares de 250 Hz a 8 kHz. Houve relação entre o tipo de doador (cadáver ou vivo) e o resultado do teste SSW: os índices de resultados alterados foram maiores quando o doador era cadáver, em comparação com casos de doador vivo. CONCLUSÃO: Houve alterações na avaliação audiológica convencional e de altas frequências e no processamento auditivo central de sujeitos com insuficiência renal crônica submetidos ao transplante renal, sugerindo a necessidade de orientação à equipe envolvida quanto aos cuidados, prevenção e identificação precoce de acometimentos audiológicos.

Is there differences in cognitive and motor functioning between hemodialysis and peritoneal dialysis patients?

OBJECTIVE

Change in cognitive function is one of the well-known consequences of the end-stage renal disease (ESRD). The aim of this study was to determine the effect of hemodialysis (HD) and continuous ambulatory peritoneal dialysis (CAPD) on cognitive and motor functions.

METHODS

In this cross-sectional study, cognitive and motor functions were investigated in a selected population of 42 patients with ESRD (22 patients on chronic HD and 20 patients on CAPD, aged 50.31 ± 11.07 years). Assessment of cognitive and motor functions was performed by Symbol Digit Modalities Test (SDMT) and Complex Reactiometer Drenovac (CRD-series), a battery of computer-generated psychological tests to measure simple visual discrimination of signal location, short-term memory, simple convergent visual orientation, and convergent thinking.

RESULTS

The statistically significant difference in cognitive-motor functions between HD and CAPD patients was not found in any of the time-related parameters in all CRD-series tests or SDMT score. Higher serum levels of albumin, creatinine, and calcium were correlated with better cognitive-motor performance among all patients regardless of dialysis modality. The significant correlation between ultrafiltration rate per HD and short-term memory actualization test score (CRD-324 MT) among HD patients was found (r = 0.434, p = 0.025).

CONCLUSION

This study has demonstrated that well-nourished and medically stable HD and CAPD patients without clinical signs of dementia or cognitive impairment and without significant difference in age and level of education performed all tests of cognitive-motor abilities without statistically significant difference.

Cognitive impairment in peritoneal dialysis patients

BACKGROUND

The prevalence of moderate to severe cognitive impairment in hemodialysis patients is more than double the prevalence in the general population. This study describes cognitive impairment occurrence in a peritoneal dialysis cohort compared with a cohort without chronic kidney disease (CKD).

STUDY DESIGN

Cross-sectional study.

SETTING & PARTICIPANTS

51 English-speaking peritoneal dialysis patients from 2 urban dialysis units compared with 338 hemodialysis patients from 16 urban dialysis units and 101 voluntary controls without CKD from urban general medicine clinics.

PREDICTOR

45-minute battery of 9 validated neuropsychological tests (cognitive domains memory, executive function, and language).

OUTCOMES

Mild, moderate, or severe cognitive impairment, classified according to a previously designed algorithm.

RESULTS

Of the peritoneal dialysis cohort, 33.3% had no or mild, 35.3% had moderate, and 31.4% had severe cognitive impairment; corresponding values were 60.4%, 26.7%, and 12.9% of the non-CKD cohort and 26.6%, 36.4%, and 37.0% of the hemodialysis cohort. A logistic regression model including age, sex, race, education, hemoglobin level, diabetes, and stroke showed that only nonwhite race (P = 0.002) and low education (P = 0.002) were associated with moderate to severe cognitive impairment in the peritoneal dialysis cohort. Compared with hemodialysis patients, more peritoneal dialysis patients had moderate to severe memory impairment (58% vs 51%), but fewer had impaired executive function (one-third vs one-half). Peritoneal dialysis was associated with a more than 2.5-fold increased risk of moderate to severe global cognitive impairment compared with no CKD (OR, 2.58; 95% CI, 1.02-6.53), as was hemodialysis (OR, 3.16; 95% CI, 1.91-5.24), in an adjusted logistic regression model.

LIMITATIONS

Small sample size, participation rate somewhat low.

CONCLUSIONS

Similar to hemodialysis patients, two-thirds of peritoneal dialysis patients had moderate to severe cognitive impairment, enough to interfere with safely self-administering dialysis and adhering to complex medication regimens. These patients could benefit from cognitive assessment before and periodically after dialysis therapy initiation.

[Cognitive impairment and chronic kidney disease: which links?]

Ageing of the population leads to an increase of cognitive disorders and chronic renal failure incidence. Compared to the general population, prevalence of cognitive impairment is more important in renal failure patients, especially in dialyzed patients. No direct link has been established between renal failure and cognitive impairment. The care of older and older patients and the high frequency of vascular risk factors, in particular hypertension and diabetes, partially explain the prevalence of vascular dementia and Alzheimer disease in this population. Other factors as the anemia, phosphocalcic metabolism disorders facilitate the cognitive impairment. The present work reviews the links existing between chronic renal failure and cognitive impairment.

Neuropsychiatric complications of chronic kidney disease

Evidence is emerging that cognitive impairment, delirium and depression are very common in patients with renal disease. All of these conditions are associated with prolonged hospitalization and an increased risk of mortality. A good understanding of these conditions is key to their prevention, early intervention and management. This Review summarizes the clinical features of various forms of cognitive dysfunction that occur in individuals with renal disease and describes the evidence for the high burden of disease in such patients.

Microemboli, developed during haemodialysis, pass the lung barrier and may cause ischaemic lesions in organs such as the brain

BACKGROUND

Chronic haemodialysis (HD) may relieve some medical problems of terminal uraemia, but the life expectancy of patients is still significantly shortened, and there is a greatly increased morbidity. This includes pulmonary morbidity and chronic central nervous system (CNS) abnormalities. Previous studies have shown that a considerable amount of air microbubbles emanate within the blood lines of the dialysis device and pass the air detector without sounding an alarm. The aim of this study was to investigate whether microemboli can pass to the patient and whether they could be detected in the carotid artery.

METHODS

A total of 54 patients on chronic HD (16 with central dialysis catheter) were investigated with an ultrasound detector (Hatteland, Røyken, Norway) for the presence of microemboli at the arteriovenous (AV) fistula/graft and at the common carotid artery before and during HD. Measurements were taken for 2 and 5 min, respectively. Non-parametric paired statistics were used (Wilcoxon).

RESULTS

The median number (range) and mean +/- SD of microembolic signals detected at the AV access site before commencing dialysis and during HD were 0 (0-3) and 0.2+/- 0.5 versus 4 (0-85) and 13.5 +/- 20 (P = 0.000); at the carotid artery, 1 (0-14) and 1.7 +/- 2.9 versus 2 (0-36) and 3.5 +/- 5.8 (P = 0.008).

CONCLUSIONS

The infused and returning fluid from HD devices contains air microbubbles that enter the patient without triggering any alarms. These small emboli pass the lung and may cause ischaemic lesions in organs supported by the arterial circuit, such as the brain.

Effect of Hemodialysis on Cognitive Function in ESRD Patients

BACKGROUND

Uremia is associated with impairment of different cognitive functions. However the pathogenesis of this cognitive dysfunction is unknown.

OBJECTIVE

In this study, long-latency event related potentials (ERPs) were used to assess changes in cortical function due to hemodialysis treatment.

METHODS

In this cross-sectional study, we measured event related potentials in 15 end stage renal disease (ESRD) patients maintained on hemodialysis, two hours before and two hours after they underwent hemodialysis and compared their data with a strictly age and sex matched healthy control group. The P3 was elicited by using standard auditory "odd-ball" paradigm and the data obtained was statistically analyzed (Wilcoxon signed ranks, Mann Whitney).

RESULTS

Before hemodialysis, the patients' P3 latency (347.73 +/- 39.47 ms) was significantly increased as compared with that of healthy control group (308.4 +/- 13.73 ms) (p = 0.001). After hemodialysis, P3 latency of the patients showed a significant decrease (347.73 +/- 39.47 ms to 325.20 +/- 37.15 ms, p = 0.001). P3 latency after dialysis was not significantly different from controls. No significant correlation was noted between various biochemical parameters (hemoglobin, blood urea, creatinine, uric acid and calcium) and P3 latency or amplitude.

CONCLUSIONS

Removal of uremic toxins by hemodialysis leads to an improvement in cognitive processing.

Cognitive function in chronic kidney disease

Chronic kidney disease (CKD) is a growing public health problem. The incidence of kidney failure is rising in all age groups but particularly in older adults. Individuals in all stages of CKD are at higher risk for development of cognitive impairment and this may be a major determinant in their quality of life. Furthermore, cognitive impairment is associated with an increased risk of death in dialysis patients. Cerebrovascular disease is a strong risk factor for development of cognitive impairment and vascular disease is a more likely cause of cognitive impairment than Alzheimer's disease in patients with CKD. Both traditional and nontraditional vascular risk factors are more common in CKD and dialysis patients may also be at risk for cognitive impairment via nonvascular risk factors and the hemodialysis procedure itself. Unfortunately, because risk factors for cognitive impairment in CKD have not been thoroughly ascertained, evaluation of potential treatments has been limited. Given the high prevalence of cognitive impairment in all stages of CKD, additional studies are needed to evaluate potential risk factors and treatments in this vulnerable population.

La population âgée hémodialysée : évaluer et prendre en charge le risque de déclin cognitif

Epidemiological data suggest a large prevalence of cognitive impairment in elderly patients on haemodialysis. They are frequently exposed to pathologies that affect the brain, and hold a plurality of risk factors for neurodegenerative and vascular dementia. Cognitive dysfunctions, because of their medical and socio-economical consequences, may led to discuss the indication for haemodialysis and its profit for the elderly patient. These facts highlight the advantage of a regular assessment of cognitive functions in this population. They also suggest the need in the future of a multidisciplinary intervention for these patients, for a better evaluation of interventions aimed on primary and secondary prevention of cognitive decline in the elderly group.

The central nervous system in childhood chronic kidney disease

Neurodevelopmental deficits in pediatric and adult survivors of childhood onset chronic kidney disease (CKD) have been documented for many years. This paper reviews the available literature on central nervous system involvement incurred in childhood CKD. The studies reviewed include recent work in neuroimaging, electrophysiology, and neuropsychology, along with commentary on school functioning and long-term outcomes. The paper concludes with suggestions for monitoring the neurodevelopmental status and pursuing appropriate early interventions for children with CKD.