The relationship between obstructive sleep apnea and insomnia: a population-based cross-sectional polysomnographic study.

BACKGROUND: The relationship between insomnia and objectively measured obstructive sleep apnea (OSA) severity has not previously been investigated in both genders in the general population. The main aim of this population-based polysomnography (PSG) study was to evaluate the cross-sectional association between severity of OSA and DSM-V insomnia and insomnia severity. METHODS: A random sample of 1200 participants in the third Nord-Trøndelag Health Study (HUNT3) was invited and 213 (18%) aged between 21 and 82 years underwent an ambulatory PSG, a semi-structured interview, and a sleep-specific questionnaire. A proxy DSM-V insomnia diagnosis as well as an Insomnia Symptom Score (ISS, range 0-12) were calculated from three insomnia questions and one daytime sleepiness symptom question. Participants were then divided into three groups according to their apnea-hypopnea index (AHI): AHI < 5 (without OSA), AHI 5-14.9 (mild OSA), and AHI ≥ 15 (moderate-to-severe OSA). Associations between prevalence of insomnia and OSA groups were assessed by logistic regression models adjusted for age and gender. Associations between ISS and OSA were assessed in a general linear model with contrasts. RESULTS: A total of 25.2% (29.1% women, 12.5% men) had insomnia. Insomnia prevalence did not differ between subjects with and without OSA, but ISS differed significantly between OSA categories (ANCOVA df 2, F = 6.73, p = 0.001). ISS was lower in the moderate-to-severe OSA-group compared to those without OSA (mean difference -2.68; 95% [CI -4.33, -1.04]; p = 0.002). In subjects with moderate-to-severe OSA, ISS correlated negatively with age (Pearson r = -0.66, p = 0.015). CONCLUSION: In this population-based PSG study, no overall statistical association between OSA and insomnia prevalence was found. However, participants with moderate-to-severe OSA reported less insomnia symptoms than subjects without OSA, in particular in older individuals.

Non-invasive cortical modulation of experimental pain in migraine.

OBJECTIVE: To test the hypothesis that secondary somatosensory cortex (S2) is involved in the migraine pathogenesis, by exploring the effect of navigated repetitive transcranial magnetic stimulation (rTMS) to S2 on thermal perception and pain. METHODS: In this blinded sham-controlled case-control study of 26 interictal migraineurs and 31 controls, we measured thermal detection and pain thresholds on the hand and forehead, and pain ratings to heat stimulation on the forearm and temple, after real and sham 10Hz rTMS. RESULTS: rTMS increased cold and heat pain thresholds in controls as compared to interictal migraineurs (p<0.026). rTMS decreased forehead and arm pain ratings (p<0.005) and increased hand cool detection thresholds (p<0.005) in both interictal migraineurs and controls. CONCLUSIONS: The effects of rTMS to S2 on thermal pain measures differed significantly between migraine and control subjects, although the effects were generally low in magnitude and not present in pain ratings. However, the lack of cold and heat pain threshold increase in migraineurs may reflect a hypofunction of inhibitory pain modulation mechanisms. SIGNIFICANCE: The expected rTMS-induced cold and heat hypoalgesia was not found among migraineurs, possibly a reflection of reduced intracortical inhibition.

Increased baroreflex sensitivity and heart rate variability in migraine patients.

OBJECTIVES: We investigated whether spontaneous baroreflex sensitivity and heart rate variability (HRV) are different in migraine patients compared to healthy controls. MATERIAL AND METHODS: Sixteen female migraine patients without aura aged 18-30 years and 14 age-matched healthy female controls were included. Continuous finger blood pressure and ECG were measured supine during paced breathing in the laboratory. Continuous finger blood pressure was measured the following 24-h period. Spontaneous baroreflex sensitivity (time-domain cross correlation baroreflex sensitivity) as well as HRV parameters were calculated. RESULTS: Spontaneous baroreflex sensitivity measured in the 24-h period was increased in patients (20.6 ms/mmHg) compared to controls (15.7 ms/mmHg, P = 0.031). HRV parameters were increased during paced breathing in patients (P < 0.045). CONCLUSIONS: The results suggest that central hypersensitivity in migraine also includes cardiovascular reactivity and may be important for the understanding of the mechanisms for the effect of antihypertensive drugs for migraine prophylaxis.

Management of medication overuse headache: 1-year randomized multicentre open-label trial.

It is a general belief that patients with medication overuse headache (MOH) need withdrawal of acute headache medication before they respond to prophylactic medication. In this 1-year open-labelled, multicentre study intention-to-treat analyses were performed on 56 patients with MOH. These were randomly assigned to receive prophylactic treatment from the start without detoxification, undergo a standard out-patient detoxification programme without prophylactic treatment from the start, or no specific treatment (5-month follow-up). The primary outcome measure, change in headache days per month, did not differ significantly between groups. However, the prophylaxis group had the greatest decrease in headache days compared with baseline, and also a significantly more pronounced reduction in total headache index (headache days/month x headache intensity x headache hours) at months 3 (P = 0.003) and 12 (P = 0.017) compared with the withdrawal group. At month 12, 53% of patients in the prophylaxis group had > or = 50% reduction in monthly headache days compared with 25% in the withdrawal group (P = 0.081). Early introduction of preventive treatment without a previous detoxification programme reduced total headache suffering more effectively compared with abrupt withdrawal. (ClinicalTrials.gov number, NCT00159588).