Potential immunological triggers for narcolepsy and idiopathic hypersomnia: Real-world insights on infections and influenza vaccinations.

OBJECTIVE: It is hypothesized that narcolepsy type 1 (NT1) develops in genetically susceptible people who encounter environmental triggers leading to immune-mediated hypocretin-1 deficiency. The pathophysiologies of narcolepsy type 2 (NT2) and idiopathic hypersomnia (IH) remain unknown. The main aim of this study was to collect all reported immunological events before onset of a central disorder of hypersomnolence. METHODS: Medical records of 290 people with NT1, and 115 with NT2 or IH were retrospectively reviewed to extract infection and influenza vaccination history. Prevalence, distribution of immunological events, and time until hypersomnolence onset were compared between NT1 and the combined group of NT2 and IH. RESULTS: Immunological events were frequently reported before hypersomnolence disorder onset across groups. Flu and H1N1 influenza vaccination were more common in NT1, and Epstein-Barr virus and other respiratory and non-respiratory infections in NT2 and IH. Distributions of events were comparable between NT2 and IH. Rapid symptom onset within one month of infection was frequent across groups, especially after flu infection in NT1. Hypersomnolence disorder progression after an immunological event was reported in ten individuals. CONCLUSIONS: Our findings suggest a variety of immunological triggers potentially related to NT1, including H1N1 influenza infection or vaccination, infection with other flu types, and other respiratory and non-respiratory infections. Frequent reports of immunological events (other than those reported in NT1) immediately prior to the development of NT2 and IH support the specificity of triggers for NT1, and open important new research avenues into possible underlying immunological mechanisms in NT2 and IH.

A prospective open label 2-8 year extension of the randomised controlled ICON trial on the long-term efficacy and safety of occipital nerve stimulation in medically intractable chronic cluster headache.

BACKGROUND: We demonstrated in the randomised controlled ICON study that 48-week treatment of medically intractable chronic cluster headache (MICCH) with occipital nerve stimulation (ONS) is safe and effective. In L-ICON we prospectively evaluate its long-term effectiveness and safety. METHODS: ICON participants were enrolled in L-ICON immediately after completing ICON. Therefore, earlier ICON participants could be followed longer than later ones. L-ICON inclusion was stopped after the last ICON participant was enrolled in L-ICON and followed for ≥2 years by completing six-monthly questionnaires on attack frequency, side effects, subjective improvement and whether they would recommend ONS to others. Primary outcome was the change in mean weekly attack frequency 2 years after completion of the ICON study compared to baseline. Missing values for log-transformed attack-frequency were imputed for up to 5 years of follow-up. Descriptive analyses are presented as (pooled) geometric or arithmetic means and 95% confidence intervals. FINDINGS: Of 103 eligible participants, 88 (85%) gave informed consent and 73 (83%) were followed for ≥2 year, 61 (69%) ≥ 3 year, 33 (38%) ≥ 5 years and 3 (3%) ≥ 8.5 years. Mean (±SD) follow-up was 4.2 ± 2.2 years for a total of 370 person years (84% of potentially 442 years). The pooled geometric mean (95% CI) weekly attack frequency remained considerably lower after one (4.2; 2.8-6.3), two (5.1; 3.5-7.6) and five years (4.1; 3.0-5.5) compared to baseline (16.2; 14.4-18.3). Of the 49/88 (56%) ICON ≥50% responders, 35/49 (71%) retained this response and 15/39 (38%) ICON non-responders still became a ≥50% responder for at least half the follow-up period. Most participants (69/88; 78% [0.68-0.86]) reported a subjective improvement from baseline at last follow-up and 70/88 (81% [0.70-0.87]) would recommend ONS to others. Hardware-related surgery was required in 44/88 (50%) participants in 112/122 (92%) events (0.35 person-year-1 [0.28-0.41]). We didn't find predictive factors for effectiveness. INTERPRETATION: ONS is a safe, well-tolerated and long-term effective treatment for MICCH. FUNDING: The Netherlands Organisation for Scientific Research, the Dutch Ministry of Health, the NutsOhra Foundation from the Dutch Health Insurance Companies, and Medtronic.

Clinical symptoms of androgen deficiency in men with migraine or cluster headache: a cross-sectional cohort study.

BACKGROUND: To compare symptoms of clinical androgen deficiency between men with migraine, men with cluster headache and non-headache male controls. METHODS: We performed a cross-sectional study using two validated questionnaires to assess symptoms of androgen deficiency in males with migraine, cluster headache, and non-headache controls. Primary outcome was the mean difference in androgen deficiency scores. Generalized linear models were used adjusting for age, BMI, smoking and lifetime depression. As secondary outcome we assessed the percentage of patients reporting to score below average on four sexual symptoms (beard growth, morning erections, libido and sexual potency) as these items were previously shown to more specifically differentiate androgen deficiency symptoms from (comorbid) anxiety and depression. RESULTS: The questionnaires were completed by n = 534/853 (63%) men with migraine, n = 437/694 (63%) men with cluster headache and n = 152/209 (73%) controls. Responders were older compared to non-responders and more likely to suffer from lifetime depression. Patients reported more severe symptoms of clinical androgen deficiency compared with controls, with higher AMS scores (Aging Males Symptoms; mean difference ± SE: migraine 5.44 ± 0.90, p <  0.001; cluster headache 5.62 ± 0.99, p <  0.001) and lower qADAM scores (quantitative Androgen Deficiency in the Aging Male; migraine: - 3.16 ± 0.50, p <  0.001; cluster headache: - 5.25 ± 0.56, p <  0.001). Additionally, both patient groups more often reported to suffer from any of the specific sexual symptoms compared to controls (18.4% migraine, 20.6% cluster headache, 7.2% controls, p = 0.001). CONCLUSION: Men with migraine and cluster headache more often suffer from symptoms consistent with clinical androgen deficiency than males without a primary headache disorder.

Reward-seeking behavior in human narcolepsy.

STUDY OBJECTIVES: The hypocretin system enhances signaling in the mesolimbic pathways regulating reward processing and addiction. Because individuals with narcolepsy with cataplexy have low hypocretin levels, we hypothesized that they may be less prone to risk- and reward-seeking behaviors, including substance abuse. DESIGN: Endpoints were performance on an array of psychometric tests (including the Eysenck Impulsiveness Scale, the Zuckerman Sensation Seeking Scale, the Gormally Binge Eating Scale, and the Beck Depression and Anxiety Inventory) and on the Balloon Analogue Risk Task (BART). SETTING: Tertiary narcolepsy referral centers in Leiden (The Netherlands) and Boston (USA). PATIENTS: Subjects with narcolepsy with cataplexy (n = 30), narcolepsy without cataplexy (n = 15), and controls (n = 32) matched for age, sex, and smoking behavior. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: There was no difference in risk-taking behavior between narcolepsy with or without cataplexy and the control group, as measured using the BART and the array of questionnaires. However, subjects in the narcolepsy with cataplexy group had significantly higher scores on the Eysenck Impulsiveness Scale (p < 0.05), with 10.0% categorized as impulsive, compared to 6.7% of the narcolepsy without cataplexy group and none of the controls. Narcoleptics with cataplexy also scored significantly higher than controls on the Binge Eating Scale (p < 0.05), with moderate or severe binge eating in 23%. On the depression and anxiety scales, all narcolepsy patients, especially those with cataplexy, scored significantly higher than controls. CONCLUSIONS: We found that narcoleptics with or without cataplexy generally have normal risk-taking behavior, but narcoleptics with cataplexy were more impulsive and more prone to binge eating than patients without cataplexy and controls. Our findings shed new light on the relation between sleepiness and impulsiveness. Furthermore, rates of depression and anxiety were higher in all narcoleptic subjects. However, using the current methods, no evidence could be found to support the hypothesis that hypocretin deficiency would affect reward-processing in humans.

Evaluation of wireless determination of skin temperature using iButtons.

Measurements of skin temperatures are often complicated because of the use of wired sensors. This is so in field studies, but also holds for many laboratory conditions. This article describes a wireless temperature system for human skin temperature measurements, i.e. the Thermochron iButton DS1291H. The study deals with validation of the iButton and its application on the human skin, and describes clinical and field measurements. The validation study shows that iButtons have a mean accuracy of -0.09 degrees C (-0.4 degrees C at most) with a precision of 0.05 degrees C (0.09 degrees C at most). These properties can be improved by using calibration. Due to the size of the device the response time is longer than that of conventional sensors, with a tau in water of 19 s. On the human skin under transient conditions the response time is significantly longer, revealing momentary deviations with a magnitude of 1 degrees C. The use of iButtons has been described in studies on circadian rhythms, sleep and cardiac surgery. With respect to circadian rhythm and sleep research, skin temperature assessment by iButtons is of significant value in laboratory, clinical and home situations. We demonstrate that differences in laboratory and field measurements add to our understanding of thermophysiology under natural living conditions. The advantage of iButtons in surgery research is that they are easy to sterilize and wireless so that they do not hinder the surgical procedure. In conclusion, the application of iButtons is advantageous for measuring skin temperatures in those situations in which wired instruments are unpractical and fast responses are not required.