Diagnostic and societal impact of implementing the syncope guidelines of the European Society of Cardiology (SYNERGY study)

BACKGROUND

Syncope management is fraught with unnecessary tests and frequent failure to establish a diagnosis. We evaluated the potential of implementing the 2018 European Society of Cardiology (ESC) Syncope Guidelines regarding diagnostic yield, accuracy and costs.

METHODS

A multicentre pre-post study in five Dutch hospitals comparing two groups of syncope patients visiting the emergency department: one before intervention (usual care; from March 2017 to February 2019) and one afterwards (from October 2017 to September 2019). The intervention consisted of the simultaneous implementation of the ESC Syncope Guidelines with quick referral routes to a syncope unit when indicated. The primary objective was to compare diagnostic accuracy using logistic regression analysis accounting for the study site. Secondary outcome measures included diagnostic yield, syncope-related healthcare and societal costs. One-year follow-up data were used to define a gold standard reference diagnosis by applying ESC criteria or, if not possible, evaluation by an expert committee. We determined the accuracy by comparing the treating physician's diagnosis with the reference diagnosis.

RESULTS

We included 521 patients (usual care, n = 275; syncope guidelines intervention, n = 246). The syncope guidelines intervention resulted in a higher diagnostic accuracy in the syncope guidelines group than in the usual care group (86% vs.69%; risk ratio 1.15; 95% CI 1.07 to 1.23) and a higher diagnostic yield (89% vs. 76%, 95% CI of the difference 6 to 19%). Syncope-related healthcare costs did not differ between the groups, yet the syncope guideline implementation resulted in lower total syncope-related societal costs compared to usual care (saving €908 per patient; 95% CI €34 to €1782).

CONCLUSIONS

ESC Syncope Guidelines implementation in the emergency department with quick referral routes to a syncope unit improved diagnostic yield and accuracy and lowered societal costs.

TRIAL REGISTRATION

Netherlands Trial Register, NTR6268.

Automated spike and seizure detection: Are we ready for implementation?

OBJECTIVE

Automated detection of spikes and seizures has been a subject of research for several decades now. There have been important advances, yet automated detection in EMU (Epilepsy Monitoring Unit) settings has not been accepted as standard practice. We intend to implement this software at our EMU and so carried out a qualitative study to identify factors that hinder ('barriers') and facilitate ('enablers') implementation.

METHOD

Twenty-two semi-structured interviews were conducted with 14 technicians and neurologists involved in recording and reporting EEGs and eight neurologists who receive EEG reports in the outpatient department. The study was reported according to the Consolidated Criteria for Reporting Qualitative Studies (COREQ).

RESULTS

We identified 14 barriers and 14 enablers for future implementation. Most barriers were reported by technicians. The most prominent barrier was lack of trust in the software, especially regarding seizure detection and false positive results. Additionally, technicians feared losing their EEG review skills or their jobs. Most commonly reported enablers included potential efficiency in the EEG workflow, the opportunity for quantification of EEG findings and the willingness to try the software.

CONCLUSIONS

This study provides insight into the perspectives of users and offers recommendations for implementing automated spike and seizure detection in EMUs.

Automated spike detection: Which software package?

PURPOSE

We assessed three commercial automated spike detection software packages (Persyst, Encevis and BESA) to see which had the best performance.

METHODS

Thirty prolonged EEG records from people aged at least 16 years were collected and 30-minute representative epochs were selected. Interictal epileptiform discharges (IEDs) were marked by three human experts and by all three software packages. For each 30-minutes selection and for each 10-second epoch we measured whether or not IEDs had occurred. We defined the gold standard as the combined detections of the experts. Kappa scores, sensitivity and specificity were estimated for each software package.

RESULTS

Sensitivity for Persyst in the default setting was 95% for 30-minute selections and 82% for 10-second epochs. Sensitivity for Encevis was 86% (30-minute selections) and 61% (10-second epochs). The specificity for both packages was 88% for 30-minute selections and 96%-99% for the 10-second epochs. Interrater agreement between Persyst and Encevis and the experts was similar than between experts (0.67-0.83 versus 0.63-0.67). Sensitivity for BESA was 40% and specificity 100%. Interrater agreement (0.25) was low.

CONCLUSIONS

IED detection by the Persyst automated software is better than the Encevis and BESA packages, and similar to human review, when reviewing 30-minute selections and 10-second epochs. This findings may help prospective users choose a software package.

Factors facilitating and hindering the implementation of the European Society of Cardiology Syncope Guidelines at the Emergency Department: A nationwide qualitative study

AIMS

Syncope care is often fragmented and inefficient. Structuring syncope care through implementation of guidelines and Syncope Units has been shown to improve diagnostic yield, reduce costs and improve quality of life. We implemented the European Society of Cardiology (ESC) 2018 syncope guidelines at the Emergency Departments (ED) and established Syncope Units in five Dutch hospitals. We evaluated the implementation process by identifying factors that hinder ('barriers') and facilitate ('facilitators') the implementation.

METHODS AND RESULTS

We conducted, recorded and transcribed semi-structured interviews with 19 specialists and residents involved in syncope care from neurology, cardiology, internal medicine and emergency medicine. Two researchers independently classified the reported barriers and facilitators, according to the framework of qualitative research (Flottorp), which distinguished several separate fields ('levels'). Software package Atlas.ti was used for analysis. We identified 31 barriers and 22 facilitators. Most barriers occurred on the level of the individual health care professional (e.g. inexperienced residents having to work with the guideline at the ED) and the organizational context (e.g. specialists not relinquishing preceding procedures). Participants reported most facilitators at the level of innovation (e.g. structured work-flow at the ED). The multidisciplinary Syncope Unit was welcomed as useful solution to a perceived need in clinical practice.

CONCLUSION

Implementing ESC syncope guidelines at the ED and establishing Syncope Units facilitated a structured multidisciplinary work-up for syncope patients. Most identified barriers related to the individual health care professional and the organizational context. Future implementation of the multidisciplinary guideline should be tailored to address these barriers.

[Long-term follow-up of psychogenic pseudosyncope]

BACKGROUND

Patients with psychogenic pseudosyncope (PPS) are frequently seen by neurologists and psychiatrists. As of yet, there has been no follow-up study of patients with PPS after communicating the diagnosis.

AIM

To determine the outcome of patients with psychogenic pseudosyncope (PPS) after communicatingthe diagnosis.

METHOD

A retrospective cohort study of patients with PPS referred to a tertiary referral center for syncope from 2007 to 2015. We reviewed patient records, studying attack frequency, factors possibly affecting attack frequency, health care use and quality of life using questionnaires. We explored influences on absence of attack and attack frequency in the six months before follow-up for age, sex, level of education, duration until a diagnosis was made, probability of diagnosis, additional syncope and acceptance of diagnosis.

RESULTS

47 out 57 PPS cases could be traced, of these 35 (74%) participated. Twelve (34%) were attack free for at least six months. The median time from diagnosis to follow-up was 50 months (range 6-103 months). Communication and explanation of the diagnosis resulted in immediate reduction of attack frequency (p=0.007) from the month before diagnosis (median one attack, range 0-156) to the month afterwards (median one attack, range 0-16). In the six months before follow-up the number of admissions decreased from 19/35 to 0/35 (p = 0.002). Furthermore, the demand for somatic health care shifted to psychiatric care (p < 0.0001). Quality of life at follow-up (Short Form Health Survey 36; SF-36) showed lower scores for seven of the eight domains compared to matched Dutch control values. The quality of life was not significantly influenced by absence of attack.

CONCLUSION

After communicating the diagnosis of PPS, attack frequency decreased and health care use shifted toward mental care. Low quality of life underlines the fact that PPS is a serious condition. Improvement of quality of life probably requires both a longer treatment and longer follow-up.

[Driving status of syncope patients is not part of standard advice]

OBJECTIVE

Some medical problems, such as syncope, have direct consequences for fitness to drive. Our objective was to discover if patients had been informed about their driving status after a syncopal episode by their physician, and if this advice was in line with current legislation.

DESIGN

Cross-sectional study.

METHOD

By means of a structured questionnaire, 150 patients referred to the syncope clinic at the Academic Medical Centre, Amsterdam, were asked about the advice they had received concerning their driving status during previous consultations with their general practitioner or specialists. A syncope expert then assessed the driving status of all patients in the light of the existing and new ruling.

RESULTS

In 121 of the 150 patients (81%), a certain or highly-likely cause for their loss of consciousness was determined: 68 patients had reflex syncope, 25 patients orthostatic hypotension, 20 patients psychogenic pseudosyncope, three patients cardiac syncope, three patients had epilepsy and two patients another diagnosis. Seven patients had experienced an episode while driving. Only 26/150 patients (17%) reported that the consequences of their episodes for their driving status had been discussed with them at earlier consultations. If driving was discussed, in only 31% had the current Dutch legislation on driving been followed. Over a third (38%) of the patients felt they should no longer drive.

CONCLUSION

Fewer than one in five patients reported that driving status was discussed by a physician after a syncope episode. If advice had been given, it was often not in line with current legislation.

Cardiovascular Autonomic Function Tests in Cluster Headache

While facial autonomic signs are prominent during cluster headache (CH) attacks, cardiovascular autonomic changes have been described in few CH patients. Cardiovascular autonomic function tests (AFT) can be used to assess general autonomic function in CH patients in different stages of the disease. We aimed to assess whether general autonomic function is changed in CH patients during a cluster period. AFT was performed both during a cluster period, but outside an actual attack, and outside a cluster period in 18 patients. Heart rate variability was studied at rest, during deep breathing, after standing up and during a Valsalva manoeuvre. Blood pressure (BP) changes were recorded at rest, during standing up and during sustained handgrip. Measurements during and outside the cluster period were compared using the paired t-test. AFT measurements revealed no significant differences between the two measurements, except for diastolic BP in rest, which was higher during the cluster period [80.3 (SD 12.2) vs. 74.8 (SD 9.0), P = 0.04]. Autonomic dysfunction during a cluster period, but outside an attack, does not include systemic cardiovascular control.

The Prevalence of Premonitory Symptoms in Migraine: A Questionnaire Study in 461 Patients

Migraine attacks are often preceded by premonitory symptoms. Prevalence rates of migraine patients reporting one or more premonitory symptoms show considerable variability and rates range between 12% and 79%. Sources of variability might be differences in study population or research design. Using a questionnaire, we retrospectively studied the prevalence of 12 predefined premonitory symptoms in a clinic-based population. Of 461 migraine patients, 374 (81%) responded. At least one premonitory symptom was reported by 86.9% and 71.1% reported two or more. The most frequently reported premonitory symptoms were fatigue (46.5%), phonophobia (36.4%) and yawning (35.8%). The mean number of premonitory symptoms per person was 3.2 (± 2.5). Women reported 3.3 premonitory symptoms compared with 2.5 symptoms in men ( P = 0.01). Age, education, migraine subtype (with or without aura) and mean attack frequency had no effect on the mean number of symptoms per individual. In conclusion, premonitory symptoms are frequently reported by migraine patients. Sensitivity and specificity of premonitory symptoms for migraine need to be assessed using prospective methods.

Effect of orthostatic hypotension on sustained attention in patients with autonomic failure

INTRODUCTION

Orthostatic hypotension has been associated with impaired cognitive function, but cognitive function during orthostatic hypotension has hardly been studied. We studied the effect of orthostatic hypotension, induced by head-up tilt (HUT), on sustained attention in patients with autonomic failure.

METHODS

We studied the sustained attention to response task (SART) in the supine position and during HUT in 10 patients with autonomic failure and 10 age-matched and sex-matched controls. To avoid syncope, the tilting angle was tailored to patients to reach a stable systolic blood pressure below 100 mm Hg. Controls were all tilted at an angle of 60°. Cerebral blood flow velocity, blood pressure and heart rate were measured continuously.

RESULTS

In patients, systolic blood pressure was 61.4 mm Hg lower during HUT than in the supine position (p<0.001). Patients did not make more SART errors during HUT than in the supine position (-1.3 errors, p=0.3). Controls made 2.3 fewer errors during SART in the HUT position compared to the supine position (p=0.020). SART performance led to an increase in systolic blood pressure (+11.8 mm Hg, p=0.018) and diastolic blood pressure (+5.8 mm Hg, p=0.017) during SART in the HUT position, as well as to a trend towards increased cerebral blood flow velocity (+3.8 m/s, p=0.101).

DISCUSSION

Orthostatic hypotension in patients with autonomic failure was not associated with impaired sustained attention. This might partly be explained by the observation that SART performance led to a blood pressure increase. Moreover, the upright position was associated with better performance in controls and, to a lesser extent, also in patients.

Local injection of autologous bone marrow cells to regenerate muscle in patients with traumatic brachial plexus injury: a pilot study

Objectives

Traumatic brachial plexus injury causes severe functional impairment of the arm. Elbow flexion is often affected. Nerve surgery or tendon transfers provide the only means to obtain improved elbow flexion. Unfortunately, the functionality of the arm often remains insufficient. Stem cell therapy could potentially improve muscle strength and avoid muscle-tendon transfer. This pilot study assesses the safety and regenerative potential of autologous bone marrow-derived mononuclear cell injection in partially denervated biceps.

Methods

Nine brachial plexus patients with insufficient elbow flexion (i.e., partial denervation) received intramuscular escalating doses of autologous bone marrow-derived mononuclear cells, combined with tendon transfers. Effect parameters included biceps biopsies, motor unit analysis on needle electromyography and computerised muscle tomography, before and after cell therapy.

Results

No adverse effects in vital signs, bone marrow aspiration sites, injection sites, or surgical wound were seen. After cell therapy there was a 52% decrease in muscle fibrosis (p = 0.01), an 80% increase in myofibre diameter (p = 0.007), a 50% increase in satellite cells (p = 0.045) and an 83% increase in capillary-to-myofibre ratio (p < 0.001) was shown. CT analysis demonstrated a 48% decrease in mean muscle density (p = 0.009). Motor unit analysis showed a mean increase of 36% in motor unit amplitude (p = 0.045), 22% increase in duration (p = 0.005) and 29% increase in number of phases (p = 0.002).

Conclusions

Mononuclear cell injection in partly denervated muscle of brachial plexus patients is safe. The results suggest enhanced muscle reinnervation and regeneration.

Cite this article: Bone Joint Res 2014;3:38–47.

Carotid body tumors are not associated with an increased risk for sleep-disordered breathing

PURPOSE

Tumors in the carotid bodies may interfere with their function as peripheral chemoreceptors. An altered control of ventilation may predispose to sleep-disordered breathing. This study aimed to assess whether patients with unilateral or bilateral carotid body tumors (uCBT or bCBT, respectively) or bilateral CBT resection (bCBR) display sleep-disordered breathing and to evaluate the global contribution of the peripheral chemoreceptor to the hypercapnic ventilatory response.

METHODS

Eight uCBT, eight bCBT, and nine bCBR patients and matched controls underwent polysomnography. The peripheral chemoreflex drive was assessed using euoxic and hyperoxic CO2 rebreathing tests. Daytime sleepiness and fatigue were assessed with the Epworth Sleepiness Scale and the Multidimensional Fatigue Index.

RESULTS

All patient groups reported significant fatigue-related complaints, but no differences in excessive daytime sleepiness (EDS) were found. The apnea/hypopnea index (AHI) did not differ significantly between patient groups and controls. Only in bCBT patients, a trend towards a higher AHI was observed, but this did not reach significance (p=0.06). No differences in the peripheral chemoreflex drive were found between patients and controls.

CONCLUSIONS

Patients with (resection of) CBTs have more complaints of fatigue but are not at risk for EDS. The presence or resection of CBTs is neither associated with an altered peripheral chemoreflex drive nor with sleep-disordered breathing.

At the heart of the arterial baroreflex: a physiological basis for a new classification of carotid sinus hypersensitivity

The aim of this review is to provide an update of the current knowledge of the physiological mechanisms underlying reflex syncope. Carotid sinus syncope will be used as the classical example of an autonomic reflex with relatively well-established afferent, central and efferent pathways. These pathways, as well as the pathophysiology of carotid sinus hypersensitivity (CSH) and the haemodynamic effects of cardiac standstill and vasodilatation will be discussed. We will demonstrate that continuous recordings of arterial pressure provide a better understanding of the cardiovascular mechanisms mediating arterial hypotension and cerebral hypoperfusion in patients with reflex syncope. Finally we will demonstrate that the current criteria to diagnose CSH are too lenient and that the conventional classification of carotid sinus syncope as cardioinhibitory, mixed and vasodepressor subtypes should be revised because isolated cardioinhibitory CSH (asystole without a fall in arterial pressure) does not occur. Instead, we suggest that all patients with CSH should be thought of as being 'mixed', between cardioinhibition and vasodepression. The proposed stricter set of criteria for CSH should be evaluated in future studies.

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. We studied 17 early HD subjects (mean age: 51 years), 12 premanifest HD subjects (mean age: 43 years), and 15 healthy controls (mean age: 51 years), using the sustained attention to response task (SART), a simple Go/No-go test reflecting attentional and inhibitory processes through reaction time (RT) and error rates. Simultaneously recorded EEG yielded P300 amplitudes and latencies. The early HD group made more Go errors (p < 0.001) and reacted slower (p < 0.005) than the other groups. The RT pattern during the SART was remarkably different for early HD subjects compared to the other two groups (p < 0.005), apparent as significant post-error slowing. P300 data showed that for early HD the No-go amplitude was lower than for the other two groups (p < 0.05). Subjects with early HD showed a reduced capacity to effectively control attention. They proved unable to resume the task directly after having made an error, and need more time to return to pre-error performance levels. No attentional control deficits were found for the premanifest HD group.

Disturbed subjective sleep characteristics in adult patients with long-standing type 1 diabetes mellitus

AIMS/HYPOTHESIS

Decreased sleep duration and/or impaired sleep quality negatively influence glucoregulation. The aim of this study was to assess subjective sleep characteristics in patients with type 1 diabetes, to relate sleep characteristics to long-term glycaemic control and to assess possible risk factors for impaired sleep.

METHODS

We studied 99 adult patients with type 1 diabetes (55 men, 44 women, duration of diabetes 26.9 ± 1.2 years) and 99 age-, sex- and BMI-matched non-diabetic controls. Subjective sleep characteristics were assessed by validated questionnaires, i.e. Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale and the Berlin Questionnaire. Glucoregulation was assessed by HbA(1c) values. Clinical variables were obtained from medical charts. Depression was assessed by the Hospital Anxiety and Depression Scale (HADS). Peripheral polyneuropathy was assessed by neurological examination and quantitative sensory testing.

RESULTS

Of the patients with type 1 diabetes, 35% had subjective poor sleep quality compared with 20% of the control participants (p = 0.021). A higher proportion of the patients with type 1 diabetes were at increased risk for obstructive sleep apnoea (OSA) (17.2% vs 5.1%, p = 0.012). There was no significant association between individual sleep characteristics and HbA(1c) values. On logistic regression analysis, the HADS depression score, presence of peripheral polyneuropathy, habitual snoring and other sleep disturbances (e.g. hypoglycaemia) were independently associated with poor sleep quality.

CONCLUSIONS/INTERPRETATION

Adult patients with long-standing type 1 diabetes mellitus have disturbed subjective sleep quality and a higher risk for OSA compared with control participants. Subjective sleep disturbances are part of the complex syndrome of long-standing type 1 diabetes.

Patients previously treated for nonfunctioning pituitary macroadenomas have disturbed sleep characteristics, circadian movement rhythm, and subjective sleep quality

CONTEXT AND OBJECTIVE

Fatigue and excessive sleepiness have been reported after treatment of nonfunctioning pituitary macroadenomas (NFMA). Because these complaints may be caused by disturbed nocturnal sleep, we evaluated objective sleep characteristics in patients treated for NFMA.

DESIGN

We conducted a controlled cross-sectional study.

SUBJECTS AND METHODS

We studied 17 patients (8 women; mean age, 54 yr) in remission of NFMA during long-term follow-up (8 yr; range, 1-18 yr) after surgery (n = 17) and additional radiotherapy (n = 5) without comorbidity except for hypopituitarism and 17 controls matched for age, gender, and body mass index. Sleep was assessed by nocturnal polysomnography, sleep and diurnal movement patterns by actigraphy, and quality of life and subjective sleep characteristics by questionnaires.

RESULTS

Compared to controls, patients had reduced sleep efficiency, less rapid eye movement sleep, more N1 sleep, and more awakenings in the absence of excessive apnea or periodic limb movements. Actigraphy revealed a longer sleep duration and profound disturbances in diurnal movement patterns, with more awakenings at night and less activity during the day. Patients scored higher on fatigue and reported impaired quality of life.

CONCLUSION

Patients previously treated for NFMA suffer from decreased subjective sleep quality, disturbed distribution of sleep stages, and disturbed circadian movement rhythm. These observations indicate that altered sleep characteristics may be a factor contributing to impaired quality of life and increased fatigue in patients treated for NFMA.

Autonomic symptoms in patients and pre-manifest mutation carriers of Huntington's disease

BACKGROUND AND PURPOSE

Although autonomic function tests have revealed abnormalities of the autonomic nervous system in Huntington's disease (HD), autonomic symptoms and their association with other symptoms and signs of HD have not yet been assessed in large groups of patients or pre-manifest mutation carriers. Therefore, we aimed at delineating the characteristics and correlates of autonomic symptoms in HD.

METHODS

Using the scales for outcomes in Parkinson's disease-autonomic symptoms (SCOPA-AUT) and Beck Depression Inventory questionnaires, autonomic symptoms and depressed mood were assessed in 63 patients with HD, 21 pre-manifest mutation carriers, and 85 controls. The Unified Huntington's Disease Rating Scale was used to assess other HD symptoms and signs.

RESULTS

Relative to controls, patients with HD experienced significantly more gastrointestinal, urinary, cardiovascular and, in men, sexual problems. The most prevalent symptoms were swallowing difficulties, erection and ejaculation problems, dysphagia, sialorrhea, early abdominal fullness, straining for defecation, fecal and urinary incontinence, urgency, incomplete bladder emptying, and light-headedness whilst standing. Pre-manifest mutation carriers experienced significantly more swallowing difficulties and light-headedness on standing up compared with controls. In patients with HD, autonomic symptoms were associated with a greater degree of functional disability, more severe depression, and antidepressant drugs use. However, depression was the only independent predictor of autonomic dysfunction.

CONCLUSIONS

Autonomic symptoms are highly prevalent in patients with HD and may even precede the onset of motor signs. Moreover, autonomic dysfunction is related to functional disability and depression in HD.

Transient loss of consciousness through the eyes of a witness

OBJECTIVE

To assess the accuracy of eyewitness observations of transient loss of consciousness.

METHODS

Two sequential cohorts of psychology students unexpectedly viewed videos of a generalized tonic-clonic seizure (n = 125) and of reflex syncope (n = 104) during a lecture on an unrelated subject. Directly afterward, the students filled in a multiple-choice questionnaire regarding muscle tone, twitches, head deviation, eye closure, gaze deviation, drooling, and facial color. The consensus of experienced neurologists served as a gold standard. Even though not all items could be ascertained from the videos, the full range of questions was included to simulate clinical practice.

RESULTS

Of all responses to the observable items on the syncope video (flaccid limbs, twitches of one shoulder, head deviation), 44% were correct, 28% erroneous, and 29% had "I do not know" responses. The observable items on the epilepsy video (stiff limbs, twitches of all limbs, normal facial color, drooling, no head deviation) yielded 60% correct responses, 18% erroneous responses, and 22% "I do not know" responses. Regarding features that were not visible on the videos, 77% of the responses were accurate ("I do not know"), whereas 23% erroneously provided an observation. Of all items observable on both videos, muscle tone was the most accurately recalled item.

CONCLUSIONS

An eyewitness account of a single episode of transient loss of consciousness (TLOC) should be interpreted with caution because salient features are frequently overlooked or inaccurately recalled. However, the accuracy of the eyewitness observations of TLOC differs per item; muscle tone was reported with high accuracy.

Manipulation of skin temperature improves nocturnal sleep in narcolepsy

OBJECTIVE

Besides excessive daytime sleepiness, disturbed nocturnal sleep is a major complaint of patients with narcolepsy. Previously, alterations in skin temperature regulation in narcoleptic patients have been shown to be related to increased sleepiness. This study tests the hypothesis that direct control of nocturnal skin temperature might be applied to improve the disturbed sleep of narcoleptic patients.

METHODS

Participants were eight patients (five males) diagnosed as having narcolepsy with cataplexy according to the ICSD-2 criteria, mean (SD) age 28.6 (6.4) years, range 18-35 years. During two nights, sleep was recorded polysomnographically while proximal and distal skin temperature were manipulated using a comfortable thermosuit that induced skin temperature to cycle slowly with an amplitude of only 0.4 degrees C within the comfortable range normally observed during sleep. Logistic regression was used to evaluate the effect of skin temperature manipulation on the probability of occurrence of different sleep stages and nocturnal wakefulness.

RESULTS

Proximal skin warming significantly suppressed wakefulness and enhanced slow wave sleep (SWS). In contrast, distal skin warming enhanced wakefulness and stage 1 sleep at the cost of SWS and REM sleep. The optimal combination of proximal skin warming and distal skin cooling led to a 160% increase in SWS, a 50% increase in REM sleep and a 68% decrease in wakefulness, compared with the least beneficial combination of proximal skin cooling and distal skin warming.

INTERPRETATION

Subtle skin temperature manipulations under controlled conditions significantly improved the typical nocturnal sleep problems in narcolepsy.

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.e. the percentual decrease in alpha power as compared to eyes closed) and alpha coherence during eyes closed and memory activation.

RESULTS

Theta relative power was increased in AD patients as compared with controls (p<0.001) and MCI patients (p<0.01) and related to decreased performance in all cognitive domains. Alpha reactivity was decreased in AD patients as compared with controls (p<0.005) and related to decreased performance on tests of global cognition, memory and executive functioning. Alpha coherence did not differ between groups and was unrelated to cognition.

CONCLUSIONS

EEG power measures were associated with decreased performance on tests of global cognition, memory, language and executive functioning, while coherence measures were not.

SIGNIFICANCE

The EEG yielded several power measures related to cognitive functions. These EEG power measures might prove useful in prospective studies aimed at predicting longitudinal cognitive decline and dementia.

EEG and MRI correlates of mild cognitive impairment and Alzheimer's disease

OBJECTIVE

To investigate whether cognitive function in the spectrum of normal aging to Alzheimer's disease is better reflected in MRI or EEG measures, or a combination of both.

METHODS

Cognitive functions were tested in 33 elderly subjects: 10 with probable Alzheimer's disease, 11 with mild cognitive impairment and 12 controls. Structural brain parameters were derived from conventional MRI and a quantitative MR technique called magnetization transfer imaging. The EEG provided measures of brain function. We performed multiple linear regression analyses to relate EEG and MRI parameters to global cognition, memory, language and psychomotor speed.

RESULTS

The model showed EEG alpha reactivity during eyes open to be the primary factor associated with global cognition, memory and language skills. Brain atrophy was the primary factor associated with psychomotor speed. Furthermore, EEG alpha reactivity during eyes open explained significant additional variability in psychomotor speed.

CONCLUSION

EEG and MRI are each associated with different aspects of cognitive function and complement each other in their relations to psychomotor speed.

Is stress a trigger factor for migraine?

BACKGROUND

Although mental stress is commonly considered to be an important trigger factor for migraine, experimental evidence for this belief is yet lacking.

OBJECTIVE

To study the temporal relationship between changes in stress-related parameters (both subjective and objective) and the onset of a migraine attack.

METHODS

This was a prospective, ambulatory study in 17 migraine patients. We assessed changes in perceived stress and objective biological measures for stress (saliva cortisol, heart rate average [HRA], and heart rate variability [low-frequency power and high-frequency power]) over 4 days prior to the onset of spontaneous migraine attacks. Analyses were repeated for subgroups of patients according to whether or not they felt their migraine to be triggered by stress.

RESULTS

There were no significant temporal changes over time for the whole group in perceived stress (p=0.50), morning cortisol (p=0.73), evening cortisol (p=0.55), HRA (p=0.83), low-frequency power (p=0.99) and high-frequency power (p=0.97) prior to or during an attack. Post hoc analysis of the subgroup of nine stress-sensitive patients who felt that >2/3 of their migraine attacks were triggered by psychosocial stress, revealed an increase for perceived stress (p=0.04) but no changes in objective stress response measures. At baseline, this group also showed higher scores on the Penn State Worry Questionnaire (p=0.003) and the Cohen Perceived Stress Scale (p=0.001) compared to non-stress-sensitive patients.

CONCLUSIONS

Although stress-sensitive patients, in contrast to non-stress-sensitive patients, may perceive more stress in the days before an impending migraine attack, we failed to detect any objective evidence for a biological stress response before or during migraine attacks.

[Narcolepsy: a new perspective on diagnosis and treatment]

The 5 classic symptoms of narcolepsy are excessive daytime sleepiness, cataplexy, sleep paralysis, hypnagogic hallucinations and disturbed nocturnal sleep. The presence of cataplexy is strongly associated with a deficiency of the neuropeptide hypocretin. This discovery has led to new diagnostic subclassifications: narcolepsy without cataplexy, which can be demonstrated by a multiple sleep latency test, and narcolepsy with cataplexy, which can be confirmed with a multiple sleep latency test or a cerebrospinal fluid deficiency of hypocretin I. Various treatment options are available, including psychostimulants and gamma hydroxybuterate.

Does modafinil enhance activity of patients with myotonic dystrophy?: a double-blind placebo-controlled crossover study

We performed a double-blind placebo-controlled crossover study in 13 patients with myotonic dystrophy to address the question whether modafinil, known to improve hypersomnolence in myotonic dystrophy, may improve levels of activity as well. We used the Epworth Sleepiness Scale as a measure of hypersomnolence and a structured interview of the patient and the partner or housemate as a measure of activity. We additionally used a restricted form of the RAND-36 to relate a possible improvement of activity to perceived general health. We confirmed earlier positive findings of modafinil regarding reduced somnolence (p = 0.015), but no significant effects were seen regarding activity levels (p = 0.2 for patients’ self-reports and 0.5 for partners’ reports).

Memory activation enhances EEG abnormality in mild cognitive impairment

This exploratory study investigated EEG power changes during memory activation in patients with amnestic mild cognitive impairment (MCI). Twelve MCI patients and 16 age-matched controls underwent EEG registration during two conventional EEG conditions ('eyes closed' and 'eyes open') and three memory conditions ('word memory', 'picture memory' and 'animal fluency'). For all conditions, EEG power in the theta (4-8 Hz), lower alpha (8-10.5 Hz) and upper alpha (10.5-13 Hz) bands were expressed as percentile changes compared to 'eyes closed'. MCI patients showed significantly less decrease in the lower alpha band than controls (p=0.04) during picture memory activation. The word memory task showed a trend towards a similar effect (p=0.09). This study suggests that memory activation reveals EEG differences between MCI patients and controls while conventional EEG conditions do not.

Interobserver variation in the interpretation of SSEPs in anoxic–ischaemic coma

OBJECTIVE

To study interobserver variation in the interpretation of median nerve SSEPs in patients with anoxic-ischaemic coma.

METHODS

SSEPs of 56 consecutive patients with anoxic-ischaemic coma were interpreted independently by 5 experienced clinical neurophysiologists using guidelines derived from a pilot study. Interobserver agreement was expressed as kappa coefficients.

RESULTS

Kappa ranged from 0.20 to 0.65 (mean 0.52, SD 0.14). Disagreement was related with noise level and failure to adhere strictly to the guidelines in 15 cases. The presence or absence of N13 and cortical peaks caused disagreement in 5 cases each. For recordings with a noise level of 0.25 microV or more, mean kappa was 0.34; for recordings with a noise level below 0.25 microV mean kappa was 0.74.

CONCLUSIONS

Interobserver agreement for SSEPs in anoxic-ischaemic coma was only moderate. Since the noise level strongly influenced interobserver variation, utmost attention should be given to its reduction. If an artefact level over 0.25 microV remains, absence of N20 cannot be judged with sufficient certainty and the SSEP should be repeated at a later stage.

SIGNIFICANCE

Because of its moderate interobserver agreement, great care has to be given to accurate recording and interpretation of SSEPs before using the recordings for non-treatment decisions.

Syncope in migraine: the population-based CAMERA study

OBJECTIVE

To examine the association between migraine and syncope-related autonomic nervous system (ANS) symptoms.

METHODS

A population-based study among migraineurs with and without aura (n = 323) and control subjects (n = 153) was conducted. A systematic questionnaire and cardiovascular measurements during rest, while standing, and after venipuncture addressed the prevalence of syncope, orthostatic intolerance, orthostatic hypotension (OH), and the postural tachycardia syndrome (POTS) in migraineurs and control subjects.

RESULTS

The lifetime prevalence of syncope in all participants was 41%, more often in women (45 vs 32%; p = 0.02). Compared with control subjects, migraineurs had a higher lifetime prevalence of syncope (46 vs 31%; p = 0.001), frequent syncope (five or more attacks) (13 vs 5%; p = 0.02), and orthostatic intolerance (32 vs 12%; p < 0.001). There was no association between ANS symptoms and the severity of migraine or migraine subtype. Cardiovascular measurements and the prevalence of POTS and OH did not differ significantly between migraineurs and control subjects.

CONCLUSION

This population-based study demonstrated an elevated prevalence of syncope and orthostatic intolerance in migraineurs without clear interictal signs of autonomic nervous system dysfunction.

Stress induced hypotension in pure autonomic failure

A 47 year old woman with pure autonomic failure complained of dizziness during emotional stress. Emotional stimuli have not previously been reported to cause hypotension in patients with autonomic failure. In the patient, ambulatory blood pressure recording revealed severe hypotension (50/30 mm Hg) after a stressful event. During a tilt table test, hyperventilation was shown to cause a significant fall of blood pressure. This suggests that emotional stress can induce hypotension, probably through hyperventilation, in subjects with autonomic failure.

Recognising F-response interference as a source of increased jitter in stimulated single fibre EMG

OBJECTIVE

To determine the source of an abnormal pattern of latency shifts leading to falsely high jitters in single fibre electromyography (SFEMG).

METHODS

We observed a sudden shortening of the latency to an individual single fibre spike component followed by a gradual return to baseline values during stimulation single fibre electromyography (SFEMG) of the facial muscle. The pattern could be reproduced in healthy controls.

RESULTS

The sudden decrease in latency proved to follow an additional discharge of the muscle fibre, not due to the external stimulus. This additional discharge was identified as an F-response.

CONCLUSIONS

The mechanism is thought to be a higher muscle fibre conduction velocity resulting from a temporary increase in stimulus frequency, in the form of an extra impulse along the muscle fibre represented by the F-response.

SIGNIFICANCE

The typical abnormal pattern should be recognised because it can falsely increase the mean jitter. We advice to increase the time base to 50 ms if this pattern is observed and to exclude the affected potentials from jitter measurements.

[Terms in use for transient loss of consciousness in the emergency ward; an inventory]

OBJECTIVE

To investigate the terminology for transient loss of consciousness in use in a Dutch emergency ward and to compare it with European definitions.

DESIGN

Descriptive.

METHOD

The records of all consecutive patients seen during an eight-week period in the Emergency Clinic of Leiden University Medical Centre, the Netherlands, were reviewed. Patients were enrolled in one of the following Dutch terms was encountered, expressing either a specific form or a general description of non-traumatic transient loss of consciousness (TLOC): 'collaps' (collapse), 'syncope' (syncope), 'flauwvallen' (fainting), 'wegraking' (TLOC) and 'insult' (seizure). The use of these terms was compared with the definitions of the European Society of Cardiology (ESC).

RESULTS

The prevalence of a non-traumatic TLOC diagnosis in the Emergency Clinic was 2.9% (123/4300). 'Collaps' was the most frequently used term (53%), followed by 'insult' (31%), 'wegraking' (11%), 'flauwvallen' (3%) and 'syncope' (2%). The term 'collaps' was found to have been used in the context of the ESC category 'syncope' (n=47), TLOC (n=5), 'no TLOC' (n=9) or for situations that could not be classified (n=4). The term 'insult' was used exclusively in the context of epilepsy and the term 'syncope' exclusively in the context of the ESC category 'syncope'. The term 'wegraking' proved to have been used in the context of the ESC category 'TLOC' (n=11), 'epilepsy' (n=1) or for situations that could not be classified (n=1). 'Flauwvallen' was used in the context of the ESC category 'syncope' (n=3) or the category 'no TLOC' (n=1).

CONCLUSION

It would be advisable to give the terms mentioned above a specific meaning: reserve 'collaps' for a fall without an obvious external cause, 'wegraking' for transient loss of consciousness without a clear cause, and 'syncope' for loss of consciousness due to temporary low cerebral blood flow.

Diagnostic value of history taking in reflex syncope

The medical history, in combination with the physical examination and a 12-lead electrocardiogram, plays a key role in the diagnosis and risk stratification of patients with syncope. However, diagnostic clinical criteria are not uniformly applied. In older studies, the diagnostic criteria for vasovagal or reflex syncope often included typical precipitating events and warning symptoms. More recent studies have documented that a variety of unrecognized stressors can trigger reflex syncope and that warning signs and symptoms may be minimal. A characteristic medical history (a trigger and/or prodromi) is enough to diagnose reflex syncope if the risk for a cardiac cause of syncope is low (e. g. patients < 65 yrs, without a history of heart disease and no ECG abnormalities). In elderly subjects with a higher risk of cardiac syncope, the yield of the medical history is lower. However, a prospective study of the value of the medical history for the diagnosis of syncope with long-term follow-up has not been performed.

Gene dosage-dependent transmitter release changes at neuromuscular synapses of Cacna1a R192Q knockin mice are non-progressive and do not lead to morphological changes or muscle weakness

Ca(v)2.1 channels mediate neurotransmitter release at the neuromuscular junction (NMJ) and at many central synapses. Mutations in the encoding gene, CACNA1A, are thus likely to affect neurotransmitter release. Previously, we generated mice carrying the R192Q mutation, associated with human familial hemiplegic migraine type-1, and showed first evidence of enhanced presynaptic Ca(2+) influx [Neuron 41 (2004) 701]. Here, we characterize transmitter release in detail at mouse R192Q NMJs, including possible gene-dosage dependency, progression of changes with age, and associated morphological damage and muscle weakness. We found, at low Ca(2+), decreased paired-pulse facilitation of evoked acetylcholine release, elevated release probability, and increased size of the readily releasable transmitter vesicle pool. Spontaneous release was increased over a broad range of Ca(2+) concentrations (0.2-5mM). Upon high-rate nerve stimulation we observed some extra rundown of transmitter release. However, no clinical evidence of transmission block or muscle weakness was found, assessed with electromyography, grip-strength testing and muscle contraction experiments. We studied both adult ( approximately 3-6 months-old) and aged ( approximately 21-26 months-old) R192Q knockin mice to assess effects of chronic elevation of presynaptic Ca(2+) influx, but found no additional or progressive alterations. No changes in NMJ size or relevant ultrastructural parameters were found, at either age. Our characterizations strengthen the hypothesis of increased Ca(2+) flux through R192Q-mutated presynaptic Ca(v)2.1 channels and show that the resulting altered neurotransmitter release is not associated with morphological changes at the NMJ or muscle weakness, not even in the longer term.

Single-fiber EMG in familial hemiplegic migraine

Twelve familial hemiplegic migraine (FHM) patients (6 with the I1811L mutation in CACNA1A, 3 with M731T mutation in ATP1A2, and 3 without known mutations) and 10 control subjects underwent single-fiber EMG. Mean jitter did not differ significantly between patients and control subjects or among patients. No blocking was found. The results suggest that neuromuscular function is normal in FHM.

Neurophysiological tests and neuroimaging procedures in non-acute headache: guidelines and recommendations

The use of instrumental examinations in headache patients varies widely. In order to evaluate their usefulness, the most common instrumental procedures were evaluated, on the basis of evidence from the literature, by an EFNS Task Force (TF) on neurophysiological tests and imaging procedures in non-acute headache patients. The conclusions of the TF regarding each technique are expressed in the following guidelines for clinical use. 1 Interictal electroencephalography (EEG) is not routinely indicated in the diagnostic evaluation of headache patients. Interictal EEG is, however, indicated if the clinical history suggests a possible diagnosis of epilepsy (differential diagnosis). Ictal EEG could be useful in certain patients suffering from hemiplegic and basilar migraine. 2 Recording of evoked potentials is not recommended for the diagnosis of headache disorders. 3 There is no evidence to justify the recommendation of autonomic tests for the routine clinical examination of headache patients. 4 Manual palpation of pericranial muscles, with standardized palpation pressure, can be recommended for subdividing patient groups but not for diagnosis. Pressure algometry and electromyography (EMG) cannot be recommended as clinical diagnostic tests. 5 In adult and paediatric patients with migraine, with no recent change in attack pattern, no history of seizures, and no other focal neurological signs or symptoms, the routine use of neuroimaging is not warranted. In patients with atypical headache patterns, a history of seizures and/or focal neurological signs or symptoms, magnetic resonance imaging (MRI) may be indicated. 6 If attacks can be fully accounted for by the standard headache classification [International Headache Society (IHS)], a positron emission tomography (PET) or single-photon emission computerized tomography (SPECT) and scan will generally be of no further diagnostic value. 7 Nuclear medicine examinations of the cerebral circulation and metabolism can be carried out in subgroups of headache patients for diagnosis and evaluation of complications, when patients experience unusually severe attacks, or when the quality or severity of attacks has changed. 8 Transcranial Doppler examination is not helpful in headache diagnosis. Although many of the examinations described are of little or no value in the clinical setting, most of the tools have a vast potential for further exploring the pathophysiology of headaches and the effects of pharmacological treatment.

Impairment of trigeminal sensory pathways in cluster headache

Cluster headache (CH) typically presents in clusters of attacks of intense (peri)orbital, unilateral pain. The distribution of the pain implies involvement of central and/or peripheral trigeminal pathways. These can be investigated by means of trigeminal somatosensory evoked potentials (TSEP) and blink reflexes (BR). We aimed to relate functional changes in trigeminal sensory pathways to the presence of cluster periods. TSEP and BR were performed in 28 episodic CH patients during a cluster period and repeated in 22 outside a cluster period. TSEP latencies (N1, P1 and N2) and amplitude (N1-P1 and P1-N2) and BR latencies (R1, R2 ipsilateral and R2 contralateral) were compared between sides, during and outside a cluster period and with healthy control data (n = 22). During a cluster period, N2 TSEP latencies were longer on the symptomatic side compared with the non-symptomatic side (27.2 +/- 3.0 ms vs. 26.3 +/- 3.4 ms, P = 0.02), and compared with the same side outside the cluster period (26.7 +/- 3.1 ms vs. 25.1 +/- 3.0 ms, P = 0.01). N1, P1 and N2 latencies on the symptomatic side in patients during the cluster period (14.8 +/- 2.3 ms, 20.4 +/- 2.5 ms and 27.2 +/- 3.0 ms, respectively) were significantly longer than those of healthy controls (13.4 +/- 1.9 ms, 18.8 +/- 2.4 ms and 25.0 +/- 2.6 ms, respectively, P < 0.03). Outside the cluster period, N1 latencies of both sides (15.3 +/- 2.8 ms symptomatic side and 15.4 +/- 2.6 ms asymptomatic side) were longer compared with controls (13.4 +/- 1.9 ms, P < 0.04). TSEP amplitudes and BR latencies revealed no significant differences. We conclude that abnormalities of the afferent trigeminal pathway are present in patients with cluster headache, most prominent during the cluster period, and on the symptomatic side. This seems primarily due of changes within the higher cerebral regions of the system.

[Initial diagnostic strategy in the case of transient losses of consciousness: the importance of the medical history]

It is estimated that almost half of the people experience a transient loss of consciousness at some time during their life. In young patients (< 35 years) the cause is mostly a reflex syncope. In older patients the common causes are orthostatic and postprandial hypotension, sinus caroticus syndrome, cardiac arrhythmias and valvular disorders. The medical history can identify a probable cause of the transient loss of consciousness in almost all young patients (< 35 years) and in the majority of older patients. A physical examination and an ECG should be performed in all patients who have experienced a transient loss of consciousness, other than those with classical vasovagal syncope, in order to exclude orthostatic hypotension and dangerous cardiac causes.

Impaired antagonist inhibition may contribute to akinesia and bradykinesia in Huntington's disease

OBJECTIVE

To test the hypothesis that besides impaired agonist facilitation, impaired antagonist inhibition also contributes to delayed initiation (akinesia) and slow execution (bradykinesia) of voluntary movements in Huntington's disease.

METHODS

Fifteen patients with Huntington's disease and 11 age-matched controls participated in the study. The amount of agonist facilitation was measured as the increase in soleus H-reflex amplitude prior to ballistic voluntary plantar flexion (soleus contraction). Antagonist inhibition was measured as the decrease in soleus H-reflex prior to ballistic dorsiflexion (tibialis anterior (TA) contraction). The amount of agonist facilitation and antagonist inhibition was correlated with the time needed for motor initiation (reaction time) and movement execution (movement time).

RESULTS

Starting 50ms prior to soleus contraction, soleus H-reflex increased in control subjects but less so in patients. Soleus H-reflexes decreased in controls 25ms prior to TA contraction, while this antagonist inhibition was completely lacking in patients. Thus, patients with Huntington's disease not only displayed reduced agonist facilitation, but impaired antagonist inhibition as well. Moreover, more impairment of antagonist inhibition correlated significantly with more severe akinesia and bradykinesia.

CONCLUSIONS

Antagonist inhibition prior to and during agonist contractions is markedly impaired in Huntington's disease. This impairment might contribute to motor slowness in these patients.

Reproducibility and feasibility of neurophysiological assessment of the sensory trigeminal system for future application to paroxysmal headaches

As the distribution of pain in primary headaches suggests involvement of the trigeminal sensory pathways, trigeminal somatosensory evoked potentials (TSEP) and blink reflexes (BR) may provide important information about their functional integrity. Functional differences between symptomatic and non-symptomatic sides and between measurements during and outside attacks may be particularly informative. These tests should therefore be reproducible and should require a suitable number of patients for future studies in patients with primary, paroxysmal headaches. We performed TSEP and BR twice in 22 healthy volunteers, in order to calculate sample sizes based on reproducibility data. This is, to our knowledge, the first study investigating the reproducibility of TSEP and BR measurements. Latencies of TSEP and BR are appropriate for future studies, as their reproducibility allows practical sample sizes (less than 25 subjects). Duration, amplitude and area parameters of the BR responses were less appropriate for longitudinal studies.

Obstetric lesions of the brachial plexus

The few studies on prognosis of obstetric lesions of the brachial plexus that are not hampered by selection bias or a short follow-up suggest that functional impairment persists in 20-25% of cases, more than commonly thought. Electromyography (EMG), potentially useful for prognosis, is often considered of little value. Denervation in the first week of life has been interpreted as evidence of an antenatal lesion, but is the logical result of the short axonal length affected. EMG performed at close to the time of possible intervention (3 months) usually shows a discrepancy: motor unit potentials are seen in clinically paralyzed muscles. This can be explained in five ways: an overly pessimistic clinical examination; overestimation of EMG recruitment due to small muscle fibers; persistent fetal innervation; developmental apraxia; or misdirection, in which axons reach inappropriate muscles. Further research into the pathophysiology of obstetric lesions of the brachial plexus is needed to improve prognostication.

Patients with the major and minor form of hyperekplexia differ with regards to disynaptic reciprocal inhibition between ankle flexor and extensor muscles

The aim of the present study was to investigate the contribution of reciprocal inhibition to muscle tone by examining the transmission in the reciprocal inhibitory pathway in patients with a known defect in the glycine receptor. The study was performed in eight patients with hereditary hyperekplexia, six with the major form and two with the minor form of the disease. A mutation in the alpha1-subunit of the glycine receptor had been demonstrated in the patients with the major form, whereas no mutation was seen in the patients with the minor form. Disynaptic reciprocal inhibition, which is presumed to be mediated by glycine, was not seen in the patients with the major form of the disease, while it could be evoked in the patients with the minor form of the disease. Presynaptic inhibition, which is presumed to be mediated by GABA, was seen in both types of patients. It is concluded that the major form of hereditary hyperekplexia is associated with impaired transmission in glycinergic reciprocal inhibitory pathways. The findings demonstrate the importance of reciprocal inhibition for the muscle tone in man, and it is suggested that the impaired reciprocal inhibition seen in patients with a defect in the glycine receptor may contribute to the increased muscle stiffness that is observed in these patients.