Morten Engstrøm

The long-term effect of insomnia on primary headaches: a prospective population-based cohort study (HUNT-2 and HUNT-3).

(Headache 2011;51:570‐580)

Sleep quality, arousal and pain thresholds in migraineurs: a blinded controlled polysomnographic study

BackgroundOur aim was to compare subjective and objective sleep quality and arousal in migraine and to evaluate the relationship between sleep quality and pain thresholds (PT) in controls, interictal, preictal and postictal migraine.MethodsPolysomnography and PT (to pressure, heat and cold) measurements were done in 34 healthy controls and 50 migraineurs. Subjective sleep quality was assessed by sleep diaries, Epworth sleepiness scale, Karolinska sleep questionnaire and Pittsburgh sleep quality index. Migraineurs who had their sleep registration more than 48 h from an attack were classified as interictal while those who were less than 48 h from an attack were classified as either preictal or postictal.ResultsMigraineurs reported more insomnia and other sleep-related symptoms than controls, but the objective sleep differences were smaller and we found no differences in daytime sleepiness. Interictal migraineurs had more awakenings (p=0.048), a strong tendency for more slow-wave sleep (p=0.050), lower thermal pain thresholds (TPT) (heat pain thresholds p=0.043 and cold pain thresholds p=0.031) than controls. Migraineurs in the preictal phase had shorter latency to sleep onset than controls (p=0.003). Slow-wave sleep correlated negatively with pressure PT and slow bursts correlated negatively with TPT.ConclusionLower PT in interictal migraineurs seems related to increased sleep pressure. We hypothesize that migraineurs on the average suffer from a relative sleep deprivation and need more sleep than healthy controls. Lack of adequate rest might be an attack-precipitating- and hyperalgesia-inducing factor.

Interictal quantitative EEG in migraine: a blinded controlled study

Abnormal electroencephalography (EEG) in migraineurs has been reported in several studies. However, few have evaluated EEG findings in migraineurs during a time period when neither the last attack nor the next attack may interact with the results. We, therefore, compared interictal EEG in migraineurs and headache-free subjects with a design controlled for interference by pre-ictal changes. Pre-ictal EEG findings in the painful cranial side during the next attack after registration were also investigated. Correlations between clinical variables and EEG are reported as well. Interictal EEGs from 33 migraineurs (6 with and 27 without aura) and 31 controls were compared. Absolute power, asymmetry and relative power were studied for delta, theta and alpha frequency bands in parieto-occipital, temporal and fronto-central areas. EEG variables were correlated to attack frequency, headache duration, attack duration, pain intensity, photo- and phonophobia. Compared with controls, migraineurs had increased relative theta power in all cortical regions and increased delta activity in the painful fronto-central region. Absolute power and asymmetry were similar among groups. In age-adjusted analyses, headache intensity correlated with increased delta activity. In this blinded controlled study, we found globally increased relative theta activity in migraineurs. A slight interictal brain dysfunction is probably present between attacks.

The impact of headache and chronic musculoskeletal complaints on the risk of insomnia: longitudinal data from the Nord-Trøndelag health study

BackgroundA strong relationship between insomnia and painful disorders has been found, but it is still unclear whether chronic pain leads to insomnia. There is a need of large-scale prospective studies to evaluate if there is a causal relationship between painful disorders and insomnia.MethodsAll inhabitants aged ≥ 20 years in Nord-Trøndelag County of Norway were invited to participate in two surveys (n = 92,566 and 93,860, respectively). 27,185 subjects participated in both surveys, and 19,271 of these were insomnia-free at baseline (population at risk). Using logistic regression, we evaluated the influence of headache, CMSCs and coexisting headache and CMSCs on the subsequent risk of insomnia.ResultsCompared to subjects without headache and CMSCs, there was an increased risk of insomnia among those with headache, most pronounced among those with headache ≥ 7 days / month (OR = 2.2, 95% CI = 1.9 – 2.6). Similarly, an increased risk among those with CMSCs was found, most evident for those with widespread CMSCs (OR = 2.0, 95% CI = 1.8 – 2.2). Having coexistent CMSCs and headache (OR = 2.0, 95% CI = 1.8 – 2.2) predisposed more strongly to insomnia than having headache (OR = 1.5, 95% CI = 1.3 – 1.6) and CMSCs (OR = 1.6, 95% CI = 1.4 – 1.7) alone.ConclusionIn this prospective study headache and CMSCs were risk factors for insomnia 11 years later.

Sleep-related and non-sleep-related migraine: interictal sleep quality, arousals and pain thresholds

BackgroundThe mechanisms associating sleep and migraine are unknown. No previous polysomnographic (PSG) or pain-threshold (PT) study has compared patients with sleep-related migraine attacks (SM), non-sleep related migraine attacks (NSM) and healthy controls.MethodsWe have performed a blinded, prospective exploratory study with case–control design. Thirty-four healthy controls, 15 patients with SM and 18 patients with NSM had interictal PSG heat-, cold- and pressure PT (HPT, CPT, PPT) recordings and completed diary- and questionnaire on sleep and headache related aspects.ResultsNSM patients had more slow-wave sleep (SWS) and more K-bursts than SM patients (K-bursts: p = 0.023 and SWS: p = 0.030) and controls (K-bursts: p = 0.009 and SWS: 0.041). NSM patients also had lower HPT and CPT than controls (p = 0.026 and p = 0.021). In addition, SM patients had more awakenings and less D-bursts than controls (p = 0.025 and p = 0.041).ConclusionSM- and NSM patients differed in objective-, but not subjective sleep quality. NSM patients had PSG findings indicating foregoing sleep deprivation. As foregoing sleep times were normal, a relative sleep deficit might explain reduced PT among NSM patients. The SM patients had signs of slightly disturbed sleep.

Headache and insomnia in population-based epidemiological studies

Background Several epidemiological studies on the association between primary headaches and insomnia have been published in recent years. Both disorders are frequent, and our purpose was to review results from population-based studies exploring this association. Methods We performed a literature search in PubMed for “insomnia” (or sleep disturbance) and “headache” (or migraine) linked with “epidemiology.” Two hundred and eight records were identified. Three longitudinal and 10 cross-sectional studies met our inclusion criteria: population-based design with at least 200 participants including a numerical estimate of the association between headache and insomnia. Results and conclusions In nearly all studies, primary headaches, including migraine and tension-type headache, were significantly related to insomnia symptoms with OR estimates ranging from 1.4 to 1.7. The odds were even greater, from 2.0 to 2.6, for frequent, comorbid or severe headache. Recent large longitudinal studies from Norway found a bidirectional, possibly causal, association between headache and insomnia. However, not all studies used standardized diagnostic criteria for either headache or insomnia. Further research should use well defined and validated diagnostic criteria both for insomnia and headache types in order to improve the comparability between studies, investigate causality and clarify the relevance of the findings for clinical practice.

Sleep quality, arousal and pain thresholds in tension-type headache: A blinded controlled polysomnographic study

Introduction We aimed to compare subjective and objective sleep quality in tension-type headache (TTH) patients and to evaluate the relationship between sleep quality and pain thresholds (PT) in controls and TTH patients. Methods A blinded cross-sectional study where polysomnography (PSG) and PT (to pressure, heat and cold) measurements were done in 20 patients with TTH (eight episodic (ETTH) and twelve chronic (CTTH) TTH) and 29 healthy controls. Sleep diaries and questionnaires were applied. Results TTH patients had more anxiety (p = 0.001), insomnia (p < 0.0005), daytime tiredness (p < 0.0005) and reduced subjective sleep quality (p < 0.0005) compared to healthy controls. Sleep diaries revealed more long awakenings in TTH (p = 0.01) but no total sleep-time differences. TTH patients had more slow-wave sleep (p = 0.002) and less fast arousals (p = 0.004) in their PSGs. CTTH subjects had lower pressure PT (p = 0.048) and more daytime sleepiness than the controls (p = 0.039). Among TTH lower cold PT (CPT) correlated inversely with light sleep (N1) (r = −0.49, p = 0.003) while slow arousals correlated inversely with headache-frequency (r = −0.64, p = 0.003). Conclusions We hypothesize that TTH patients need more sleep than healthy controls and might be relatively sleep deprived. Inadequate sleep may also contribute to increased pain sensitivity and headache frequency in TTH.

Sleep quality and arousal in migraine and tension-type headache: the headache-sleep study

The present paper summarizes and compares data from our studies on subjective and objective sleep quality and pain thresholds in tension‐type headache (TTH), migraine, and controls.

The Reliability of a New Sleep Screening Questionnaire for Large Population-Based Studies: The Third Nord-Trøndelag Health Study

The aim of the present study was to evaluate the reliability of a new sleep questionnaire (sHUNT-Q) used in the Nord Trondelag Health Study 3 (HUNT 3) performed between 2006 and 2008. Six of nine items were modified from a Norwegian version of the Karolinska Sleep questionnaire (KSQ). Overall, 50,839 (54%) out of 94,194 invited participated in HUNT 3. In a randomly selected group of participants, 297 (53%) out of 563 invited persons attended an interview by neurologists. The reliability of the sleep related questions was evaluated with Cohens kappa by blindly comparing the an- swers in the questionnaire with those from the semi-structured interview. Summary measure scores were calculated by summing the responses of the six modified KSQ questions, the three insomnia-related questions, and the two questions re- lated to respiratory disturbance during sleep. Agreement was calculated for dichotomized sum-score indexes based on 75% and 50% percentile cut-offs. Kappa values for the individual questions ranged from 0.35 to 0.52 in 3 x 3 tables while kappa for summary indexes in 2x2 tables ranged from 0.47 to 0.62. The best agreement between the interview and the questionnaire was found for respiratory disturbance defined as a summary measure score � 50 percentile (kappa value 0.62, 95% CI 0.51-0.74). Reliability did not depend on the time between the HUNT questionnaire and the interview. The KSQ-based summary measure scores from the new sHUNT-Q sleep screening questionnaire may become a useful tool in epidemiological studies for identifying individuals with a persistent sleep disturbance.

The impact of extended electrodiagnostic studies in ulnar neuropathy at the elbow.

BackgroundThis study aimed to explore the value of extended motor nerve conduction studies in patients with ulnar nerve entrapment at the elbow (UNE) in order to find the most sensitive and least time-consuming method. We wanted to evaluate the utility of examining both the sensory branch from the fifth finger and the dorsal branch of the ulnar nerve. Further we intended to study the clinical symptoms and findings, and a possible correlation between the neurophysiological findings and pain.MethodsThe study was prospective, and 127 UNE patients who were selected consecutively from the list of patients, had a clinical and electrodiagnostic examination. Data from the most symptomatic arm were analysed and compared to the departments reference limits. Students t - test, chi-square tests and multiple regression models were used. Two-side p-values < 0.05 were considered as significant.ResultsUlnar paresthesias (96%) were more common than pain (60%). Reduced ulnar sensitivity (86%) and muscle strength (48%) were the most common clinical findings. Adding a third stimulation site in the elbow mid-sulcus for motor conduction velocity (MCV) to abductor digiti minimi (ADM) increased the electrodiagnostic sensitivity from 80% to 96%. Additional recording of ulnar MCV to the first dorsal interosseus muscle (FDI) increased the sensitivity from 96% to 98%. The ulnar fifth finger and dorsal branch sensory studies were abnormal in 39% and 30% of patients, respectively. Abnormal electromyography in FDI was found in 49% of the patients. Patients with and without pain had generally similar conduction velocity parameter means.ConclusionWe recommend three stimulation sites at the elbow for MCV to ADM. Recording from FDI is not routinely indicated. Sensory studies and electromyography do not contribute much to the sensitivity of the electrodiagnostic evaluation, but they are useful to document axonal degeneration. Most conduction parameters are unrelated to the presence of pain.