Space headache on Earth: head-down-tilted bed rest studies simulating outer-space microgravity.

BACKGROUND: Headache is a common symptom during space travel, both isolated and as part of space motion syndrome. Head-down-tilted bed rest (HDTBR) studies are used to simulate outer space microgravity on Earth, and allow countermeasure interventions such as artificial gravity and training protocols, aimed at restoring microgravity-induced physiological changes. OBJECTIVES: The objectives of this article are to assess headache incidence and characteristics during HDTBR, and to evaluate the effects of countermeasures. METHODS: In a randomized cross-over design by the European Space Agency (ESA), 22 healthy male subjects, without primary headache history, underwent three periods of -6-degree HDTBR. In two of these episodes countermeasure protocols were added, with either centrifugation or aerobic exercise training protocols. Headache occurrence and characteristics were daily assessed using a specially designed questionnaire. RESULTS: In total 14/22 (63.6%) subjects reported a headache during ≥1 of the three HDTBR periods, in 12/14 (85.7%) non-specific, and two of 14 (14.4%) migraine. The occurrence of headache did not differ between HDTBR with and without countermeasures: 12/22 (54.5%) subjects vs. eight of 22 (36.4%) subjects; p = 0.20; 13/109 (11.9%) headache days vs. 36/213 (16.9%) headache days; p = 0.24). During countermeasures headaches were, however, more often mild (p = 0.03) and had fewer associated symptoms (p = 0.008). CONCLUSIONS: Simulated microgravity during HDTBR induces headache episodes, mostly on the first day. Countermeasures are useful in reducing headache severity and associated symptoms. Reversible, microgravity-induced cephalic fluid shift may cause headache, also on Earth. HDTBR can be used to study space headache on Earth.

Space headache: a new secondary headache.

Headache is a common, but rarely voiced, complaint during space flights, usually attributed to space motion sickness (SMS). We used a specifically designed questionnaire based on the criteria of the International Classification of Headache Disorders, 2nd edn (ICHD-II). Of the 16 male and one female astronauts who participated in the survey, 12 (71%) reported having experienced at least one headache episode while in space, whereas they had not suffered from headache when on earth. There were in total 21 space headache episodes, of moderate to severe intensity in 71%. In two astronauts (12%) the headache and associated symptoms would match the ICHD-II criteria for migraine and in three (18%) astronauts for tension-type headache; in 12 (70%) astronauts the headache was non-specific. The vast majority of headache episodes (76%) were not associated with symptoms of SMS. We conclude that space flights may trigger headaches without other SMS symptoms in otherwise 'super-healthy' male subjects. We propose to classify space headache as a separate entity among the secondary headaches attributed to disorders of homeostasis.

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.

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.

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.

Prediction of short-term neurological outcome in full-term neonates with hypoxic-ischaemic encephalopathy based on combined use of electroencephalogram and neuro-imaging.

BACKGROUND: In infants with hypoxic-ischaemic encephalopathy (HIE), prediction of the prognosis is based on clinical, neuro-imaging and neurophysiological parameters. METHODS: EEG, cranial ultrasound, MRI and follow-up findings of 23 infants (GA 35-42 weeks) with HIE were studied retrospectively to assess 1) the contribution of ultrasound, MRI and EEG in predicting outcome, 2) the accuracy of ultrasound as compared to MRI, and 3) whether patterns of brain damage and EEG findings are associated. RESULTS: An abnormal EEG background pattern was highly predictive of adverse outcome [positive predictive value (PPV) 0.88]. If combined with diffuse white and deep and/or cortical grey matter changes on ultrasound or MRI, the PPV increased to 1.00. Abnormal neuro-imaging findings were also highly predictive of adverse outcome. Abnormal signal intensity in the posterior limb of the internal capsule, and diffuse cortical grey matter damage were associated with adverse outcome. MRI showed deep grey matter changes more frequently than ultrasound. Severely abnormal neuro-imaging findings were always associated with abnormal EEG background pattern. CONCLUSIONS: Both early EEG and neuro-imaging findings are predictive of outcome in infants with HIE. The predictive value of EEG is strengthened by neuro-imaging.

[Nicolaas Bidloo, the Dutch director of the first hospital in Russia; a 300-year anniversary]. / Nicolaas Bidloo, de Nederlandse directeur van het eerste ziekenhuis in Rusland; een 300-jarig jubileum.

This year marks 300 years since the first Russian hospital opened its doors. The hospital was established by order of Tsar Peter the Great, and its leadership was given to a Dutchman, Nicolaas Bidloo. Bidloo came from a scientifically prominent Dutch family and was a student of Herman Boerhaave. He arrived in Russia as the personal physician of the Tsar Peter the Great. Besides directing the first Russian hospital, Bidloo also founded the first Russian medical school and authored the first Russian textbook on medical studies. In The Netherlands, little is known about Bidloo and his Russian ventures: he is viewed mainly as a nephew of Govard Bidloo, the renowned doctor and rector of Leiden University and author of a famous anatomical atlas. More attention is given to Bidloo in Russia, where he is considered one of the founders of Russian medicine.

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.

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.

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.

A Rett patient with a typical Angelman EEG.

PURPOSE: To draw attention to the phenomenon that EEG characteristics of both Angelman syndrome (AS) and Rett syndrome (RS) can be found in the same patient, as evidenced by the description of one case. There are specific EEG patterns in AS patients, in which the most frequently occurring EEG characteristics are rhythmic triphasic 2- to 3-Hz, high-voltage (200-500 microV) activity, mixed with spikes or sharp waves, with a maximum over the frontal regions. EEG changes in RS patients are less specific and can show multifocal, mostly central or centrotemporal epileptiform discharges in combination with slow background activity. METHODS: A 6-year-old girl with RS and a proven MECP2 mutation was described. RESULTS: She had an EEG pattern at age 2 years comparable with the clinical diagnosis of RS, and an EEG at age 6 years comparable with an AS EEG. CONCLUSIONS: We wish to draw attention to this phenomenon, although there is as yet no evident explanation for it. We advise MECP2 examination in AS patients of unknown genetic etiology whose EEG examinations are/were pathognomonic for AS to exclude RS.

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.

Clinical aspects of multifocal or generalized tonic dystonia in reflex sympathetic dystrophy.

The authors describe 10 patients with reflex sympathetic dystrophy that progressed to a multifocal or generalized tonic dystonia. The neuropsychologic profile was similar to that of other patients with chronic pain, irrespective of its cause. The distribution pattern of dystonia, the stretch reflex abnormalities, and the worsening of dystonia after tactile and auditory stimuli suggest impairment of interneuronal circuits at the brainstem or spinal level. Antibody titers for glutamic acid decarboxylase, tetanus, and Sjögren antigens were all normal.

[Neurohumoral correlations in lumbar pain syndromes]. / Neirogumoral'nye sootnosheniia pri poiasnichnykh bolevykh sindromakh.

The hemostasis system, activity of opioid peptides, hormonal status, vegetative and emotional parameters were studied in patients with lumbar pains of a vertebrogenic nature. The results obtained revealed a whole series of generalized shifts determining the reaction of the body to a local pain syndrome. These shifts were shown to exert an unfavourable effect on the course of a local pathological process. It is suggested that the generalized neurohumoral changes should be corrected by anti- and deaggregation agents, vasodilators, and a combination of psychotropic drugs.