Endogenous pain modulation after sleep restriction in migraine: a blinded crossover study.

Background: Patients with migraine are vulnerable to insufficient sleep, but the impact of sleep restriction is largely unknown. In addition, the importance of sleep may be different in patients with migraine who mostly have attack onsets during sleep, so called sleep-related migraine, compared to patients with non-sleep-related migraine. In this study we investigate the effect of sleep restriction on endogenous pain modulation in patients with migraine and healthy controls.

Validation of Trøndelag Apnoea Score Proxy for Obstructive Sleep Apnoea in the General Population of Norway: The HUNT Study.

The aim was to validate a new seven-item "TASC" (Trøndelag Apnoea Score) proxy for obstructive sleep apnoea (OSA) against polysomnography in the general population. Objectives included validation against different polysomnographic criteria, stratification by age and gender, and estimation of OSA prevalence. From the fourth wave of the Trøndelag Health Study (HUNT4), 1,201 participants were randomly invited to a substudy focusing on sleep and headaches, of whom 232 accepted and 84 (64% women, mean age 55.

Retinal structure and visual pathway function at school age in children born extremely preterm: a population-based study.

Background: Children born extremely preterm (gestational age < 28 weeks) show reduced visual function even without any cerebral or ophthalmological neonatal diagnosis. In this study, we aimed to assess the retinal structure with optical coherence tomography (OCT) and visual function with pattern-reversal visual evoked potentials (PR-VEPs) in a geographically defined population-based cohort of school-aged children born extremely preterm. Moreover, we aimed to explore the association between measures of retinal structure and visual pathway function in this cohort.

Effects of insufficient sleep on sensorimotor processing in migraine: A randomised, blinded crossover study of event related beta oscillations.

Background: Migraine has a largely unexplained connection with sleep and is possibly related to a dysfunction of thalamocortical systems and cortical inhibition. In this study we investigate the effect of insufficient sleep on cortical sensorimotor processing in migraine.

Methods: We recorded electroencephalography during a sensorimotor task from 46 interictal migraineurs and 28 controls after two nights of eight-hour habitual sleep and after two nights of four-hour restricted sleep.

Insufficient sleep may alter cortical excitability near the migraine attack: A blinded TMS crossover study.

Background: Migraine is a brain disorder with a multifaceted and unexplained association to sleep. Brain excitability likely changes periodically throughout the migraine cycle. In this study we examine the effect of insufficient sleep on neuronal excitability during the course of the migraine cycle.

Sleep restriction alters cortical inhibition in migraine: A transcranial magnetic stimulation study.

Objective: Migraine is a primary headache disorder with a well-known association with insufficient sleep. However, both the underlying pathophysiology of the disease and the relationship with sleep is still unexplained. In this study, we apply transcranial magnetic stimulation to investigate possible mechanisms of insufficient sleep in migraine.

Validation of questionnaires for restless legs syndrome in the general population: the Trøndelag Health Study (HUNT).

Questionnaires for restless legs syndrome have rarely been validated against face-to-face interviews in the general population. We aimed to validate the modified Norwegian, seven-item Cambridge-Hopkins restless legs syndrome questionnaire and a single diagnostic question for restless legs syndrome. We also aimed to stratify validity at 65 years of age.

Pain thresholds and suprathreshold pain after sleep restriction in migraine - A blinded crossover study.

Objective: There is an unexplained association between disturbed sleep and migraine. In this blinded crossover study, we investigate if experimental sleep restriction has a different effect on pain thresholds and suprathreshold pain in interictal migraineurs and controls.

Methods: Forearm heat pain thresholds and tolerance thresholds, and trapezius pressure pain thresholds and suprathreshold pain were measured in 39 interictal migraineurs and 31 healthy controls after two consecutive nights of partial sleep restriction and after habitual sleep.

Validation of insomnia questionnaires in the general population: The Nord-Trøndelag Health Study (HUNT).

The primary aim was to validate questionnaire-based insomnia diagnoses from a modified Karolinska Sleep Questionnaire (KSQ) and the Insomnia Severity Index (ISI), by age category (< or >65 years), against a semi-structured face-to-face interview. Secondary aims were to split validity by diagnostic certainty of the interview and to compare prevalence estimates of questionnaire- and interview-based diagnoses. A total of 232 out of 1,200 invited (19.

Fluctuations of sensorimotor processing in migraine: a controlled longitudinal study of beta event related desynchronization.

Background: The migraine brain seems to undergo cyclic fluctuations of sensory processing. For instance, during the preictal phase, migraineurs experience symptoms and signs of altered pain perception as well as other well-known premonitory CNS-symptoms. In the present study we measured EEG-activation to non-painful motor and sensorimotor tasks in the different phases of the migraine cycle by longitudinal measurements of beta event related desynchronization (beta-ERD).

Habituation of laser-evoked potentials by migraine phase: a blinded longitudinal study.

Background: Migraineurs seem to have cyclic variations in cortical excitability in several neurophysiological modalities. Laser-evoked potentials (LEP) are of particular interest in migraine because LEP specifically targets pain pathways, and studies have reported different LEP-changes both between and during headaches. Our primary aim was to explore potential cyclic variations in LEP amplitude and habituation in more detail with a blinded longitudinal study design.

Does pain sensitivity change by migraine phase? A blinded longitudinal study.

Objective Studies suggest that pain thresholds may be altered before and during migraine headaches, but it is still debated if a central or peripheral dysfunction is responsible for the onset of pain in migraine. The present blinded longitudinal study explores alterations in thermal pain thresholds and suprathreshold heat pain scores before, during, and after headache. Methods We measured pain thresholds to cold and heat, and pain scores to 30 seconds of suprathreshold heat four times in 49 migraineurs and once in 31 controls.

Visual evoked potentials in migraine: Is the "neurophysiological hallmark" concept still valid?

Objective: Lack of habituation is considered a neurophysiological hallmark of migraine. However, the results of visual evoked potential (VEP) studies have been discrepant, possibly because of different stimulation parameters and lack of blinding. Hence, there is a need for independent confirmation of lack of VEP habituation in migraine.

The effect of sleep restriction on laser evoked potentials, thermal sensory and pain thresholds and suprathreshold pain in healthy subjects.

Objective: Sleep restriction seems to change our experience of pain and reduce laser evoked potential (LEP) amplitudes. However, although LEP-habituation abnormalities have been described in painful conditions with comorbid sleep impairment, no study has previously measured the effect of sleep restriction on LEP-habituation, pain thresholds, and suprathreshold pain.

Method: Sixteen males and seventeen females (aged 18-31years) were randomly assigned to either two nights of delayed bedtime and four hours sleep (partial sleep deprivation) or nine hours sleep.

Modulation of visual evoked potentials by high-frequency repetitive transcranial magnetic stimulation in migraineurs.

Objective: High-frequency repetitive transcranial magnetic stimulation (rTMS) modulates cortical excitability. We investigated its effect on visual evoked potentials (VEPs) in migraine.

Methods: Thirty-two headache-free controls (CO), 25 interictal (MINT) and 7 preictal migraineurs (MPRE) remained after exclusions.

Visual evoked potentials in interictal migraine: no confirmation of abnormal habituation.

Objective: We intended to study the effect of check size on visual evoked potential habituation in interictal migraine, using the faster 3 per second reversal rate and an improved analytic procedure with block-number blinding.

Background: Habituation in migraineurs has been extensively studied with visual evoked potentials. Despite discrepant results, possibly related to the use of different stimulus conditions, lack of habituation in the period between attacks is presently considered to be a neurophysiological hallmark of migraine.

Habituation measured by pattern reversal visual evoked potentials depends more on check size than reversal rate.

Objective: Results have varied between studies of pattern-reversal visual evoked potential (PR-VEP) habituation, possibly caused by differences in stimulation parameters. Our aim was to estimate the interaction between check size and reversal rate on PR-VEP-habituation in healthy subjects.

Methods: Thirty-four healthy volunteers participated.