Dysautonomia in narcolepsy: evidence by questionnaire assessment

Hyperhidrosis in sleep disorders - A narrative review of mechanisms and clinical significance

Hyperhidrosis is characterized by excessive sweating beyond thermoregulatory needs that affects patients' quality of life. It results from an excessive stimulation of eccrine sweat glands in the skin by the sympathetic nervous system. Hyperhidrosis may be primary or secondary to an underlying cause. Nocturnal hyperhidrosis is associated with different sleep disorders, such as obstructive sleep apnea, insomnia, restless legs syndrome/periodic limb movement during sleep and narcolepsy. The major cause of the hyperhidrosis is sympathetic overactivity and, in the case of narcolepsy type 1, orexin deficiency may also contribute. In this narrative review, we will provide an outline of the possible mechanisms underlying sudomotor dysfunction and the resulting nocturnal hyperhidrosis in these different sleep disorders and explore its clinical relevance.

Screening autonomic functions in patients with restless legs syndrome: A case-control study in a tertiary care hospital

PURPOSE

The clinical importance of autonomic involvement in patients with restless legs syndrome (RLS) remains unclear. To our knowledge, no study has explored the relationship between autonomic dysfunction and disease-related variables in patients with RLS. Therefore, this study aimed 1) to determine the presence of autonomic symptoms in drug-naïve patients with RLS in comparison with healthy controls using Scales for Outcomes in Parkinson's disease-Autonomic (SCOPA-AUT) questionnaire and 2) to evaluate the possible associations of autonomic dysfunction with clinical factors in RLS.

METHODS

A total of 70 drug-naïve patients with RLS and 85 healthy volunteers were enrolled. The SCOPA-AUT questionnaire and Epworth Sleepiness Scale (ESS) scores were used to determine autonomic functions and sleep propensity, respectively. Moreover, the International Restless Legs Syndrome Study Group rating scale was used to evaluate disease severity in the patient group.

RESULTS

Compared with the control group, the RLS group had significantly higher subscale scores (gastrointestinal, urinary, cardiovascular, thermoregulatory, pupillomotor, and sexual [women]) and total scores of the SCOPA-AUT questionnaire (p < 0.05). In the patient group, there was a significant correlation between the total scores and subscale scores (gastrointestinal, cardiovascular, and thermoregulatory subscales) of the SCOPA-AUT questionnaire and disease severity. Moreover, ESS was positively correlated with the total scores and subscale scores (urinary, cardiovascular, and pupillomotor) of the SCOPA-AUT questionnaire.

CONCLUSION

Disease severity and daytime sleepiness may be related to autonomic dysfunction in RLS. Further studies focusing on autonomic functions in RLS are required to improve management strategies and clinical outcomes.

TRIAL REGISTRATION

ClinicalTrials.gov. NCT04906486; May 28, 2021.

Narcolepsy: the impact of aging, hypocretin deficiency, and years of formal education in olfactory function and abdominal obesity

BACKGROUND

Narcolepsy is a disease resulting from the loss of hypocretin-producing cells or other dysfunctions of the hypocretinergic system. In addition to sleep disorders, affected patients may experience increased weight gain, olfactory changes, and poorer quality of life.

METHODS

This study aimed to investigate the relationship between narcolepsy and weight gain, years of study, sleep parameters, and olfactory dysfunction in patients with narcolepsy type 1 and narcolepsy type 2. Anthropometric, olfactory, socioeducational, and excessive daytime sleepiness evaluations were performed in 77 patients.

RESULTS

Greater weight gain and abdominal obesity were observed in patients with type 1 narcolepsy. Patients with higher education level had lower scores of daytime sleepiness, higher scores on the olfactory function test, and lower rates of abdominal obesity.

DISCUSSION

Patients with narcolepsy type 1 showed an increased body weight and abdominal obesity when compared to narcolepsy type 2. The patients with a higher schooling level showed a reduction of the daytime sleepiness scores, lower rates of abdominal obesity, and better scores on the olfactory function test.

CONCLUSION

Among all the patients with narcolepsy, the data indicated that aging and hypocretin deficiency are associated with abdominal obesity, while years of study is the variable that mostly influences olfaction function.

Cardiovascular disorders in narcolepsy: Review of associations and determinants

Narcolepsy type 1 (NT1) is a lifelong disorder of sleep-wake dysregulation defined by clinical symptoms, neurophysiological findings, and low hypocretin levels. Besides a role in sleep, hypocretins are also involved in regulation of heart rate and blood pressure. This literature review examines data on the autonomic effects of hypocretin deficiency and evidence about how narcolepsy is associated with multiple cardiovascular risk factors and comorbidities, including cardiovascular disease. An important impact in NT1 is lack of nocturnal blood pressure dipping, which has been associated with mortality in the general population. Hypertension is also prevalent in NT1. Furthermore, disrupted nighttime sleep and excessive daytime sleepiness, which are characteristic of narcolepsy, may increase cardiovascular risk. Patients with narcolepsy also often present with other comorbidities (eg, obesity, diabetes, depression, other sleep disorders) that may contribute to increased cardiovascular risk. Management of multimorbidity in patients with narcolepsy should include regular assessment of cardiovascular health (including ambulatory blood pressure monitoring), mitigation of cardiovascular risk factors (eg, cessation of smoking and other lifestyle changes, sleep hygiene, and pharmacotherapy), and prescription of a regimen of narcolepsy medications that balances symptomatic benefits with cardiovascular safety.

Sleep-Wake Disorders in Childhood

PURPOSE OF REVIEW

The presentation of sleep issues in childhood differs from the presentation in adulthood and may be more subtle. Sleep issues may affect children differently than adults, and distinct treatment approaches are often used in children.

RECENT FINDINGS

Sodium oxybate was approved by the US Food and Drug Administration (FDA) in October 2018 for an expanded indication of treatment of sleepiness or cataplexy in patients with narcolepsy type 1 or narcolepsy type 2 aged 7 years or older, with side effect and safety profiles similar to those seen in adults. Restless sleep disorder is a recently proposed entity in which restless sleep, daytime sleepiness, and often iron deficiency are observed, but children do not meet the criteria for restless legs syndrome or periodic limb movement disorder.

SUMMARY

Children's sleep is discussed in this article, including normal sleep patterns and effects of insufficient sleep. Sleep disorders of childhood are reviewed, including insomnia, obstructive sleep apnea, restless legs syndrome, parasomnias, narcolepsy, and Kleine-Levin syndrome. Children with neurologic issues or neurodevelopmental disorders frequently have sleep disorders arising from an interaction of heterogeneous factors. Further attention to sleep may often be warranted through a polysomnogram or referral to a pediatric sleep specialist. Sleep disorders may cause indelible effects on children's cognitive functioning, general health, and well-being, and awareness of sleep disorders is imperative for neurologists who treat children.

The influence of narcolepsy on olfactory function: a review

INTRODUCTION

Narcolepsy is a sleep disorder associated with loss of hypocretin cells characterized by irrepressible need to sleep, often accompanied by cataplexy, sleep fragmentation, hypnagogical and hypnopompic hallucinations, and sleep paralysis. It is also correlated with alterations in the sleep-wake cycle, dysautonomia, olfactory dysfunction, and eating disorders.

METHODS

This is a review about influence of narcolepsy on human olfaction. Pubmed, Embase, Ovid and Cochrane databases were searched for articles on the evaluation of olfactory function in narcoleptic patients including terms as narcolepsy, olfaction disorder, amongst others.

RESULTS

Seven articles met the inclusion criteria. In five of them, the olfaction of narcoleptic patients was diminished in comparison with healthy control groups. The diagnosis of narcolepsy relates to worse performance in olfactory tests. Experimental researches showed that hypocretin and hypocretin receptors are present in the olfactory system, and this neuropeptide may have a role on olfactory sensitivity and on the olfactory modulation. The cause of hyposmia appears to be multifactorial. Among them, it stands out the hypocretin deficiency, therefore, that seems to be involved in the olfactory impairment in narcoleptic patients.

REM sleep behavior disorder in narcolepsy: A secondary form or an intrinsic feature?

Disrupted nighttime sleep is one of the pentad of symptoms defining Narcolepsy. REM sleep behavior disorder (RBD) largely contributes to night sleep disruption and narcolepsy is the most common cause of secondary RBD. However, RBD linked to narcolepsy (N-RBD) has been insufficiently characterized, leaving unsolved a number of issues. Indeed, it is still debated whether N-RBD is an intrinsic feature of narcolepsy, as indubitable for cataplexy, and therefore strictly linked to the cerebrospinal fluid hypocretin-1 (CSF hcrt-1) deficiency, or an associated feature, with a still unclear pathophysiology. The current review aims at rendering a comprehensive state-of-the-art of N-RBD, highlighting the open and unsettled topics. RBD reportedly affects 30-60% of patients with Narcolepsy type 1 (NT1), but it may be seen also in Narcolepsy type 2 (NT2). When compared to idiopathic/isolated RBD (iRBD), N-RBD has been reported to be characterized by less energetic and quieter episode, which however occur with the same probability in the first and the second part of the night and sometime even subcontinuously. N-RBD patients are generally younger than those with iRBD. N-RBD has been putatively linked to wake-sleep instability due to CSF hcrt-1 deficiency, but this latter by itself cannot explain completely the phenomenon as N-RBD has not been universally linked to low CSF hcrt-1 levels and it may be observed also in NT2. Therefore, other factors may probably play a role and further studies are needed to clarify this issue. In addition, therapeutic options have been poorly investigated.

Clinical autonomic dysfunction in narcolepsy type 1

Study Objectives

(1) To compare the presence of autonomic symptoms using the validated SCOPA-AUT questionnaire in untreated patients with narcolepsy type 1 (NT1) to healthy controls, (2) to study the determinants of a high total SCOPA-AUT score in NT1, and (3) to evaluate the effect of drug intake on SCOPA-AUT results in NT1.

Methods

The SCOPA-AUT questionnaire that evaluates gastrointestinal, urinary, cardiovascular, thermoregulatory, pupillomotor, and sexual dysfunction was completed by 92 consecutive drug-free adult NT1 patients (59 men, 39.1 ± 15.6 years old) and 109 healthy controls (63 men, 42.6 ± 18.2 years old). A subgroup of 59 NT1 patients completed the questionnaire a second time, under medication (delay between two evaluations: 1.28 ± 1.14 years).

Results

Compared to controls, NT1 patients were more frequently obese, had more dyslipidemia, with no difference for age and gender. The SCOPA-AUT score of NT1 was higher than in controls in crude and adjusted models. Patients experienced more problems than controls in all subdomains. A higher score in NT1 was associated with older age, longer disease duration, altered quality of life and more depressive symptoms, but not with orexin levels and disease severity. Among patients evaluated twice, the SCOPA-AUT score total did not differ according to treatment status, neither did each subdomain.

Conclusion

We captured a frequent and large spectrum of clinical autonomic dysfunction in NT1, with impairment in all SCOPA-AUT domains, without key impact of medication intake. This assessment may allow physicians to screen and treat various symptoms, often not spontaneously reported but associated with poor quality of life.

Predictive markers for early conversion of iRBD to neurodegenerative synucleinopathy diseases

OBJECTIVE

To determine the predictive value of clinical assessment and dopamine transporter (DAT) uptake for the early development of neurodegenerative synucleinopathy diseases from idiopathic REM sleep behavior disorder (iRBD) over 5 years in a Chinese population.

METHODS

Forty-three patients with iRBD were administered clinical assessment tests, and 35 were examined by DAT-SPECT imaging during 2011. Cox proportional hazard and Kaplan-Meier analyses were used to evaluate the predictive value of the markers in a follow-up study over 5 years.

RESULTS

Eighteen patients (41.9%) developed neurodegenerative synucleinopathy diseases after a median of 4.1 years of prospective follow-up (median interval of 10.5 years from the estimated onset of iRBD symptoms). Patients with higher scores on the Nonmotor Symptom Questionnaire (hazard ratio [HR] 3.11, 95% confidence interval [CI] 1.15-8.40, p = 0.026) and Scale for Outcomes in Parkinson Disease-Autonomic questionnaire (HR 4.46, 95% CI 1.64-12.10, p = 0.003) were more likely to develop neurodegenerative synucleinopathy diseases. Furthermore, the population with decreased ^99mTc-TRODAT-1 binding in the left striatum (HR 2.7, 95% CI 1.02-7.14, p = 0.046) and putamen (HR 3.23, 95% CI 1.16-8.33, p = 0.024) had a relatively higher risk of developing neurodegenerative synucleinopathy diseases.

CONCLUSIONS

Our findings elucidate the predictive value of autonomic dysfunction and DAT uptake in identifying patients with iRBD at a high risk of progressing into neurodegenerative synucleinopathy diseases and could form a basis for future disease-prevention trials.