Event-related evoked potential P300 in frontotemporal dementia

The reduced left hippocampal volume related to the delayed P300 latency in amnestic mild cognitive impairment

BACKGROUND

Amnestic mild cognitive impairment (aMCI) is characterized by delayed P300 latency and reduced grey matter (GM) volume, respectively. The relationship between the features in aMCI is unclear. This study was to investigate the relationship between the altered P300 latency and the GM volume in aMCI.

METHODS

Thirty-four aMCI and 34 well-matched normal controls (NC) were studied using electroencephalogram during a visual oddball task and scanned with MRI. Both tests were finished in the same day.

RESULTS

As compared with the NC group, the aMCI group exhibited delayed P300 latency in parietal cortex and reduced GM volumes in bilateral temporal pole and left hippocampus/parahippocampal gyrus. A remarkable negative correlation was found between delayed P300 latency and reduced left hippocampal volume only in the aMCI group. Interestingly, the mediating analysis found P300 latency significantly mediated the association between right supramarginal gyrus volume and information processing speed indicated by Stroop Color and Word Test A scores.

CONCLUSIONS

The association between delayed P300 latency and reduced left hippocampal volume in aMCI subjects suggests that reduced left hippocampal volume may be the potential structural basis of delayed P300 latency.

Brain Oscillations and Their Implications for Neurorehabilitation

Neural oscillation is rhythmic or repetitive neural activities, which can be observed at all levels of the central nervous system (CNS). The large-scale oscillations measured by electroencephalography have long been used in clinical practice and may have a potential for the usage in neurorehabilitation for people with various CNS disorders. The recent advancement of computational neuroscience has opened up new opportunities to explore clinical application of the results of neural oscillatory activity analysis to evaluation and diagnosis; monitoring the rehab progress; prognostication; and personalized rehabilitation planning in neurorehabilitation. In addition, neural oscillation is catching more attention to its role as a target of noninvasive neuromodulation in neurological disorders.

Investigating Auditory Electrophysiological Measures of Participants with Mild Cognitive Impairment and Alzheimer's Disease: A Systematic Review and Meta-Analysis of Event-Related Potential Studies

BACKGROUND

Objectively measuring auditory functions has been proposed as an avenue in differentiating normal age-related cognitive dysfunction from Alzheimer's disease (AD) and its prodromal states. Previous research has suggested auditory event-related potentials (AERPs) to be non-invasive, cost-effective, and efficient biomarkers for the diagnosis of AD.

OBJECTIVE

The objective of this paper is to review the published literature on AERPs measures in older adults diagnosed with AD and those at higher risk of developing AD, i.e., mild cognitive impairment (MCI) and subjective cognitive decline.

METHODS

The search was performed on six major electronic databases (Ovid MEDLINE, OVID EMBASE, PsycINFO, PubMed, Scopus, and CINAHL Plus). Articles identified prior to 7 May 2019 were considered for this review. A random effects meta-analysis and analysis of between study heterogeneity was conducted using the Comprehensive Meta-Analysis software.

RESULTS

The search identified 1,076 articles; 74 articles met the full inclusion criteria and were included in the systematic review, and 47 articles were included into the analyses. Pooled analysis suggests that AD participants can be differentiated from controls due to significant delays in ABR, N100, P200, N200, and P300 latencies. P300 amplitude was significantly smaller in AD participants compared to controls. P300 latencies differed significantly between MCI participants and controls based on the pooled analysis.

CONCLUSION

The findings of this review indicate that some AERPs may be valuable biomarkers of AD. In conjunction with currently available clinical and neuropsychological assessments, AERPs can aid in screening and diagnosis of prodromal AD.

Anemia and Incident End-Stage Kidney Disease

Background

Chronic kidney disease (CKD) progression can be a cause and potentially a consequence of anemia. Previous studies suggesting that anemia is associated with CKD progression have not utilized methodologic approaches to address time-dependent confounding.

Methods

We evaluated the association of anemia (defined using World Health Organization criteria of hemoglobin <12 g/dL in women and <13 g/dL in men) with incident ESRD and all-cause death in individuals with CKD using data from the Chronic Renal Insufficiency Cohort Study. Marginal structural models were used to account for time-dependent confounding.

Results

Among 3919 participants, 1859 (47.4%) had anemia at baseline. Over median follow up of 7.8 years, we observed 1,010 ESRD events and 994 deaths. In multivariable analyses, individuals with anemia had higher risk for ESRD compared to those without (HR 1.62, 95% CI 1.24-2.11). In stratified analyses, the increased risk for incident ESRD with anemia was observed in males (HR 2.15, 95% CI: 1.53-3.02) but not females (HR 1.20, 95% CI 0.82-1.78. The association between anemia and ESRD was significant among all racial/ethnic groups except non-Hispanic blacks (non-Hispanic white, HR 2.16, 95% CI 1.53-3.06; Hispanic, HR 1.92, 1.04-3.51; others, HR 2.94; 95% CI 1.16-7.44; non-Hispanic black, HR 1.39; 95% CI 0.95-2.02). There was no association between anemia and all-cause death.

Conclusions

In this cohort, anemia was independently associated with increased risk for incident ESRD. Future work is needed to evaluate the mechanisms by which anemia leads to CKD progression as well as the impact of novel therapeutic agents to treat anemia.

Effect of CPAP therapy on kidney function in patients with obstructive sleep apnoea and chronic kidney disease: a protocol for a randomised controlled clinical trial

INTRODUCTION

Obstructive sleep apnoea (OSA) is common in patients with chronic kidney disease (CKD) and may contribute to the progression of kidney disease either through direct effects of hypoxia on the kidney or indirectly through hypoxaemia-induced oxidative stress, endothelial dysfunction, inflammation, activation of the renin-angiotensin and sympathetic nervous systems, and hypertension. Treatment of OSA with continuous positive airway pressure (CPAP) improves many of these physiological abnormalities in patients with normal renal function, though to date there are no trials evaluating the effect of OSA treatment on kidney function in patients with CKD. The purpose of this study is to test the feasibility and efficacy of CPAP therapy in CKD patients with OSA.

METHODS AND ANALYSIS

The study is a randomised, controlled, non-blinded, parallel clinical trial in which patients with established CKD are screened for OSA. Patients with OSA are randomised to either conventional medical therapy (control group) or medical therapy and CPAP (CPAP group) and followed for 1 year. The primary outcome is the change in estimated glomerular filtration rate. Secondary outcomes are the change in the urinary albumin/creatinine ratio, the Epworth Sleepiness Scale , Pittsburgh Sleep Quality Index and Kidney Disease Quality of Life questionnaire.

ETHICS AND DISSEMINATION

Ethics approval has been obtained from the Conjoint Health Research Ethics Board (ID: REB15-0055). Results from this study will be disseminated through presentations at scientific conferences and publication in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT02420184; Pre-results.

[Post-stroke rehabilitation training with a brain-computer interface: a clinical and neuropsychological study]

AIM

To evaluate the efficacy of cytoflavin in the treatment of patients with chronic cerebral ischemia and mild cognitive impairment predominantly of vascular origin.

MATERIAL AND METHODS

Treatment results of 140 patients, aged 60-74, with chronic cerebral ischemia were analyzed. The main group included 77 patients (35 men and 42 women of average age 66.38±4.64 years) who received cytoflavin throughout the observation period: 2 tablets twice a day 30 minutes before meals. The comparison group included 63 patients (26 men and 37 women of average age 67.48±5.22 years) who during the whole period of observation received ethyl methyl hydroxypyridine succinate: 2 tablets (250 mg) twice a day, according to the same scheme as in the main group. Treatment efficacy was assessed by neuropsychological testing and P300 evoked potentials.

RESULTS AND CONCLUSION

During treatment, there was an improvement in neurophysiological parameters in both groups, which was more pronounced in patients treated with cytoflavin: their P300 amplitude increased by1.3 times in the left hemisphere (from 9.21 (8.36, 10.11) to 12.41 (10.23, 13.37 μV) and 1,7 times in the right hemisphere (from 6.48 (5.26, 7.35) to 11.04 (9.29, 12.18) μV). Our study confirms the advisability of using drugs that have complex cytoprotective and energy-correcting mechanism in patients with cognitive impairment. Cytoflavin has shown the high efficacy and safety and can be recommended as part of complex therapy for cognitive disorders. Using simple and inexpensive instrumental methods (assessment of cognitive P300 evoked potential) along with diagnostic scales in patients with cognitive impairment can significantly objectify the assessment of treatment dynamics.

Cortical function in Alzheimer's disease and frontotemporal dementia

Objectives

Alzheimer’s disease (AD) and the behavioral variant of frontotemporal dementia (bvFTD) are the most common causes of dementia; however, their overlapping clinical syndromes and involved brain regions make a differential diagnosis difficult. We aimed to identify the differences in the cognition and motor cortex excitability between AD and bvFTD patients.

Methods

Twenty-seven AD patients and 30 bvFTD patients were included in the study. Each participant received a neurological evaluation. Cognitive event-related potentials (P300) were recorded during an auditory oddball task. Next, the excitability of the motor cortex, including the resting, facilitated motor threshold (RMT and FMT) and cortical silent period (CSP), were assessed during transcranial magnetic stimulation (TMS).

Results

The bvFTD patients exhibited significantly longer P300 latencies compared with AD patients. There was a significant negative correlation between cognition and P300 latency in the bvFTD group. The AD patients showed significantly reduced RMT and FMT values compared to the bvFTD group; however, no significant correlation was found between AD severity and the excitability of the motor cortex.

Conclusions

Cognition and motor cortical functions are different between AD and bvFTD patients. Noninvasive electrophysiological examinations have the potential to identify unique pathophysiological features that can be used to differentially diagnose AD and bvFTD patients.

The clinical utility of the auditory P300 latency subcomponent event-related potential in preclinical diagnosis of patients with mild cognitive impairment and Alzheimer's disease

The present meta-analysis investigated the clinical utility of the auditory P300 latency event-related potential in differentiating patients with Alzheimer's disease (AD), patients with mild cognitive impairment (MCI), and unaffected controls. Effect size estimates were computed from mean P300 latency measurements at midline electrodes between patients and unaffected controls using the random effects restricted maximum likelihood model. The effects of clinical and ERP/EEG methological variables were assessed in a moderator analysis. P300 latency was found to be significantly prolonged in patients with AD (and MCI) compared to unaffected controls. Shortened P300 latencies were observed when comparing patients with MCI to patients with AD. Clinically relevant differences in P300 latency effect sizes were associated with mean age, interstimulus interval, stimulus difference, target frequency, reference electrode, and sampling rate. The meta-analytic findings provide robust statistical evidence for the use of the auditory P300 latency subcomponent as a biological marker of prodromal AD.

Is the P300 deficit in alcoholism associated with early visual impairments (P100, N170)? An oddball paradigm

OBJECTIVE

Studies exploring chronic alcoholism with event-related potentials (ERPs) have shown delayed latency and reduced amplitude of the P300, a long-lasting positive potential reflecting decisional processing. This P300 deficit in alcoholism is generally interpreted as a disturbance in central nervous system inhibition or in memory/attention. The present study aimed at identifying if this electrophysiological deficit is already present on earlier components, and advances a new hypothesis concerning the interpretation of the P300 alteration.

METHODS

Patients suffering from alcoholism and matched healthy controls had to detect, in an oddball paradigm, emotional faces among a succession of neutral faces. Behavioral performance and ERP data (recorded from 32 electrodes) were analyzed.

RESULTS

In line with previous studies, data showed that alcoholism led to a P300 deficit. Moreover, we observed for the first time that this deficit begins at earlier visual (P100) and face-processing (N170) stages, and we found high positive correlations between P100, N170 and P300 for amplitude and latency values, suggesting cumulative deficits on the cognitive continuum.

CONCLUSIONS

We suggest that the P300 deficit observed in chronic alcoholism could be linked to earlier visuo-spatial deficits rather than being an impairment of the specific processes linked to the P300.

SIGNIFICANCE

These results call for reconsidering the interpretation of P300 impairments at a fundamental and clinical level, and shows that earlier ERP components must be taken into account in future studies.

Hyperlipidaemia, lack of sleep and smoking as risk factors for proteinuria among high altitude mountain trekkers

AIM

The number of alpine accidents has been increasing among trekkers in Japan. Some of the alpine accidents have been related to acute mountain sickness (AMS). At present, the mechanism of AMS is poorly clarified, however, it is well known that hypoxia at high altitudes plays an important role. A good relation exists between proteinuria, altitude and hypoxia. However, no reports are available concerned with the risk factors of proteinuria for trekkers at high altitudes.

METHODS

The authors evaluated 41 trekkers and 13 highlanders (cabin employees) through physical examinations and interviews held in a mountain cabin (2300 m above sea level) located in a mountain (2926 m above sea level) in the Japanese Alps. First, urine samples were collected and urinalysis was performed. Second, non-invasive blood pressure, heart rate, and arterial oxygen saturation (SpO2) were measured using a portable life monitor.

RESULTS

Proteinuria was present in 20 (49%) participants. Past history of hyperlipidaemia, amount of sleep, and smoking history are independently associated with proteinuria. Among the physiological examinations conducted at the cabin, only systolic blood pressure demonstrated strong association with proteinuria. Receiver operating characteristic curve analysis using a score combining past history of hyperlipidaemia, amount of sleep and smoking history revealed that the diagnostic accuracy of proteinuria at the cut-off score of 2 was 80%.

CONCLUSIONS

This study indicated that these three variables were significantly and independently correlated with proteinuria: hyperlipidaemia, amount of sleep (night before) and smoking history. Improvement of these three variables might decrease the risk of alpine accidents including AMS.

Assessing neurocognitive dysfunction in cranial radiotherapy: can cognitive event-related potentials help?

Cognitive changes are common sequelae of cancer and cancer treatment, particularly in patients receiving cranial radiotherapy (RT). These effects are typically assessed by subjective clinical examination or using objective neuropsychological tests. Biologically based neurophysiological methods have been increasingly applied to the study of cognitive processing in neuropsychiatric and neurological disorders and as objective measures of cognitive status for patients with dementia. These methods detect the activation of neural circuits that directly mediate cognitive function in the human brain and include metabolic and electrophysiology based techniques. Neuroimaging procedures such as 18FDG PET and more recently fMRI, which detect metabolic activation associated with cognitive processing, provide excellent spatial resolution and can be directly correlated with neuroradiological findings associated with cranial RT neurotoxicity. Clinical electrophysiology procedures such as cognitive event-related potentials (ERP), which detect the neuronal electrical activity associated with cognitive processing, offer excellent temporal resolution at low cost. Cognitive ERP techniques are already being used to assess severity and progression of cognitive dysfunction in patients with vascular and degenerative dementias, but have been largely overlooked in studies of radiation-related cognitive impairments. We review these various electrophysiological methods in the context of their relevance to assessing cranial RT effects on cognitive function, and provide recommendations for a neurophysiological approach to supplement current neuropsychological tests for RT cognitive impairments. This technology is well suited for clinical assessment of neurocognitive sequelae of cancer and should provide new insights into the mechanism of RT-related cognitive dysfunction.

The N- and L-Type Calcium Channel Blocker Cilnidipine Suppresses Renal Injury in Dahl Rats Fed a High-Sucrose Diet, an Experimental Model of Metabolic Syndrome

BACKGROUND/AIMS

The L/N-type calcium channel blocker (CCB) cilnidipine has been demonstrated to suppress progressive renal disease in a variety of experimental models, but the characteristic effects of N-type calcium channel blocking action on renal injury have not been examined in detail. Therefore, we investigated the beneficial effects of cilnidipine on renal injury in Dahl salt-sensitive (Dahl S) rats fed a high-sucrose diet (HSD), which mimics metabolic syndrome, and compared them with the effects of an L-type CCB, amlodipine.

METHODS

Male Dahl S rats were divided into groups with similar blood pressure at 8 weeks of age and fed an HSD. They received vehicle, cilnidipine or amlodipine for 27 weeks. At 35 weeks of age, urine and blood samples were collected for physiological analysis, and the kidneys were removed for histopathological evaluation.

RESULTS

Cilnidipine reduced albuminuria, glomerular hypertrophy, glomerular expression of ICAM-1, ED-1-positive cell infiltration and interstitial fibrosis compared with vehicle-treated rats. In contrast, amlodipine had no effect on these parameters. Urinary norepinephrine excretion, renal expression of renin mRNA and renal tissue levels of angiotensin II were increased only in the amlodipine-treated group.

CONCLUSION

Cilnidipine provided superior protection against renal damage compared with amlodipine in Dahl S rats given an HSD. The different effects between these two drugs may be partly explained by their different actions on the renal sympathetic nerve activity and the renin-angiotensin system through the N-type calcium channel blocking action.

DIFFERENTIAL NEURAL CONTROL OF GLOMERULAR ULTRAFILTRATION

The renal nerves constrict the renal vasculature, causing decreases in renal blood flow (RBF) and glomerular filtration rate (GFR). Whether renal haemodynamics are influenced by changes in renal nerve activity within the physiological range is a matter of debate. We have identified two morphologically distinct populations of nerves within the kidney, which are differentially distributed to the renal afferent and efferent arterioles. Type I nerves almost exclusively innervate the afferent arteriole whereas type II nerves are distributed equally on the afferent and efferent arterioles. We have also demonstrated that type II nerves are immunoreactive for neuropeptide Y, whereas type I nerves are not. This led us to hypothesize that, in the kidney, distinct populations of nerves innervate specific effector tissues and that these nerves may be selectively activated, setting the basis for the differential neural control of GFR. In physiological studies, we demonstrated that differential changes in glomerular capillary pressure occurred in response to graded reflex activation of the renal nerves, compatible with our hypothesis. Thus, sympathetic outflow may be capable of selectively increasing or decreasing glomerular capillary pressure and, hence, GFR by differentially activating separate populations of renal nerves. This has important implications for our understanding of the neural control of body fluid balance in health and disease.