The relative contribution of hemodynamic parameters to blood pressure decrease in classical orthostatic hypotension.

Purpose: We studied the relative contributions of total peripheral resistance (TPR), stroke volume (SV) and heart rate (HR) to low blood pressure in classical orthostatic hypotension (cOH) on group and individual levels.

Methods: We retrospectively analyzed tilt test records from cOH patients and age/sex-matched controls. We quantified relative effects of HR, SV and TPR on mean arterial pressure (MAP) with the log-ratio method.

Orthostatic stress response in pediatric Fontan patients and the effect of ACE inhibition.

Background: Many cardiocirculatory mechanisms are involved in the adaptation to orthostatic stress. While these mechanisms may be impaired in Fontan patients. However, it is yet unclear how Fontan patients, who exhibit a critical fluid balance, respond to orthostatic stress.

The prevalence of pain in Huntington's disease in a large worldwide cohort.

Introduction: Pain could be an unknown non-motor symptom in Huntington's Disease (HD). The aim is therefore, to study the prevalence of pain interference, painful conditions and analgesic use across the different stages of HD and compare these levels to non-HD gene mutation carriers.

Methods: A cross-sectional analysis of the Enroll-HD study was conducted in premanifest, manifest HD gene mutation carriers (n = 3989 and n = 7,485, respectively) and in non-HD gene mutation carriers (n = 3719).

New hemodynamic criteria to separate classical orthostatic hypotension from vasovagal syncope.

Objective: To define and evaluate hemodynamic criteria to distinguish between classical orthostatic hypotension (cOH) and vasovagal syncope (VVS) in tilt table testing (TTT).

Methods: Inclusion criteria for VVS were a history of VVS and tilt-induced syncope defined as a blood pressure (BP) decrease and electroencephalographic changes during syncope with complaint recognition. Criteria for cOH were a history of cOH and a BP decrease meeting published criteria.

Deriving reference values for nerve conduction studies from existing data using mixture model clustering.

Objective: to obtain locally valid reference values (RVs) from existing nerve conduction study (NCS) data.

Methods: we used age, sex, height and limb temperature-based mixture model clustering (MMC) to identify normal and abnormal measurements on NCS data from two university hospitals. We compared MMC-derived RVs to published data; examined the effect of using different variables; validated MMC-derived RVs using independent data from 26 healthy control subjects and investigated their clinical applicability for the diagnosis of polyneuropathy.

Novel Methods for Quantification of Vasodepression and Cardioinhibition During Tilt-Induced Vasovagal Syncope.

Rationale: Assessing the relative contributions of cardioinhibition and vasodepression to the blood pressure (BP) decrease in tilt-induced vasovagal syncope requires methods that reflect BP physiology accurately.

Objective: To assess the relative contributions of cardioinhibition and vasodepression to tilt-induced vasovagal syncope using novel methods.

Methods And Results: We studied the parameters determining BP, that is, stroke volume (SV), heart rate (HR), and total peripheral resistance (TPR), in 163 patients with tilt-induced vasovagal syncope documented by continuous ECG and video EEG monitoring.

Progressive microstructural changes of the occipital cortex in Huntington's disease.

In this study we longitudinally investigated the rate of microstructural alterations in the occipital cortex in different stages of Huntington's disease (HD) by applying an automated atlas-based approach to diffusion MRI data. Twenty-two premanifest (preHD), 10 early manifest HD (early HD) and 24 healthy control subjects completed baseline and two year follow-up scans. The preHD group was stratified based on the predicted years to disease onset into a far (preHD-A) and near (preHD-B) to disease onset group.

Cognitive decline in Huntington's disease expansion gene carriers.

Background: In Huntington's Disease (HD) cognitive decline can occur before unequivocal motor signs become apparent. As cognitive decline often starts early in the course of the disease and has a progressive nature over time, cognition can be regarded as a key target for symptomatic treatment. The specific progressive profile of cognitive decline over time is unknown.

Core Body and Skin Temperature in Type 1 Narcolepsy in Daily Life; Effects of Sodium Oxybate and Prediction of Sleep Attacks.

Study Objectives: Previous laboratory studies in narcolepsy patients showed altered core body and skin temperatures, which are hypothesised to be related to a disturbed sleep wake regulation. In this ambulatory study we assessed temperature profiles in normal daily life, and whether sleep attacks are heralded by changes in skin temperature. Furthermore, the effects of three months of treatment with sodium oxybate (SXB) were investigated.

The Role of the Suprachiasmatic Nucleus in Cardiac Autonomic Control during Sleep.

Background: The suprachiasmatic nucleus (SCN) may play an important role in central autonomic control, since its projections connect to (para)sympathetic relay stations in the brainstem and spinal cord. The cardiac autonomic modifications during nighttime may therefore not only result from direct effects of the sleep-related changes in the central autonomic network, but also from endogenous circadian factors as directed by the SCN. To explore the influence of the SCN on autonomic fluctuations during nighttime, we studied heart rate and its variability (HRV) in a clinical model of SCN damage.

Microstructural brain abnormalities in Huntington's disease: A two-year follow-up.

Objectives: To investigate both cross-sectional and time-related changes of striatal and whole-brain microstructural properties in different stages of Huntington's disease (HD) using diffusion tensor imaging.

Experimental Design: From the TRACK-HD study, premanifest gene carriers (preHD), early manifest HD and controls were scanned at baseline and 2-year follow-up. Stratification of the preHD group into a far (preHD-A) and near (preHD-B) to predicted disease onset was performed.

Time- and state-dependent analysis of autonomic control in narcolepsy: higher heart rate with normal heart rate variability independent of sleep fragmentation.

Narcolepsy with hypocretin deficiency is known to alter cardiovascular control during sleep, but its aetiology is disputed. As cardiovascular control differs between sleep states, and narcolepsy affects sleep architecture, controlling for both duration and transitions of sleep states is necessary. This study therefore aimed to assess heart rate and its variability in narcolepsy during sleep taking these factors into account.

Sleep-mediated heart rate variability after bilateral carotid body tumor resection.

Study Objectives: The carotid bodies are thought to play an important role in sleep-dependent autonomic changes. Patients who underwent resection of bilateral carotid body tumors have chronically attenuated baroreflex sensitivity. These subjects provide a unique opportunity to investigate the role of the baroreflex during sleep.

The semiology of tilt-induced psychogenic pseudosyncope.

Objectives: To provide a detailed semiology to aid the clinical recognition of psychogenic pseudosyncope (PPS), which concerns episodes of apparent transient loss of consciousness (TLOC) that mimic syncope.

Methods: We analyzed all consecutive tilt-table tests from 2006 to 2012 showing proven PPS, i.e.

Deficient sustained attention to response task and P300 characteristics in early Huntington's disease.

Evidence for the extent and nature of attentional impairment in premanifest and manifest Huntington's disease (HD) is inconsistent. Understanding such impairments may help to better understand early functional changes in HD and could have consequences concerning care for HD patients. We investigated attentional control in both early and premanifest HD.

Basal ganglia volume is strongly related to P3 event-related potential in premanifest Huntington's disease.

Background:   The P3 event-related potential (ERP) is presumably partly generated by the basal ganglia. Because degeneration of these brain structures starts many years before clinical disease onset in Huntington's disease (HD), studying the interplay between P3 characteristics and basal ganglia volumes in 'premanifest' carriers might lead to new insights into the disease process.

Methods:   Fourteen premanifest\ HD mutation carriers and twelve non-mutation carriers underwent clinical, MRI and P3-ERP investigations.

Electromyographic activity in the EEG in Alzheimer's disease: noise or signal?

Many efforts have been directed at negating the influence of electromyographic (EMG) activity on the EEG, especially in elderly demented patients. We wondered whether these "artifacts" might reflect cognitive and behavioural aspects of dementia. In this pilot study, 11 patients with probable Alzheimer's disease (AD), 13 with amnestic mild cognitive impairment (MCI) and 13 controls underwent EEG registration.

Increased heart rate variability but normal resting metabolic rate in hypocretin/orexin-deficient human narcolepsy.

Study Objectives: We investigated autonomic balance and resting metabolic rate to explore their possible involvement in obesity in hypocretin/orexin-deficient narcoleptic subjects.

Methods: Resting metabolic rate (using indirect calorimetry) and variability in heart rate and blood pressure were determined in the fasted resting state. Subjects included 15 untreated, hypocretin-deficient male narcoleptics and 15 male controls matched for age and body mass index.

EEG markers of future cognitive performance in the elderly.

This exploratory follow-up study investigated whether EEG parameters can predict future cognitive performance. Forty elderly subjects, ranging from cognitively unimpaired to those with Alzheimer disease underwent EEG registration at baseline and neuropsychological examination at both baseline and follow-up. We assessed relations between EEG measures and future cognitive performance (i.

EEG correlates in the spectrum of cognitive decline.

Objective: To investigate relations between EEG measures and performance on tests of global cognition, memory, language and executive functioning.

Methods: Twenty-two controls, 18 patients with mild cognitive impairment (MCI) and 16 with probable Alzheimer's disease (AD) underwent neuropsychological and EEG investigations. We used the following EEG measures: theta relative power during eyes closed, alpha reactivity during memory activation (i.