"In their own words": delineating the contours of dyspnea invisibility in patients with advanced chronic obstructive pulmonary disease from quantitative discourse analysis.

BACKGROUND: Dyspnea conveys an upsetting or distressing experience of breathing awareness. It heavily weighs on chronic respiratory disease patients, particularly when it persists despite maximal treatment of causative abnormalities. The physical, psychological and social impacts of persistent dyspnea are ill-appreciated by others. This invisibility constitutes a social barrier and impedes access to care. This study aimed to better understand dyspnea invisibility in patients with chronic obstructive pulmonary disease (COPD) through quantitative discourse analysis. METHODS: We conducted a lexicometric analysis (lemmatization, descending hierarchical classification, multicomponent analysis, similarity analysis) of 11 patients' discourses (6 men, severe COPD; immediate postexacerbation rehabilitation) to identify semantic classes and communities, which we then confronted with themes previously identified using interpretative phenomenological analysis (IPA). RESULTS: Class#1 ("experience and need for better understanding"; 38.9% of semantic forms, 50% of patients) illustrates the gap that patients perceive between their experience and what others see, confirming the importance of dyspnea invisibility in patients' concerns. Class#2 ("limitations"; 28.7% of forms) and Class#3 (management"; 13.1% of forms) point to the weight of daily limitations in performing basic activities, of the need to accept or adapt to the constraints of the disease. These three classes matched previously identified IPA-derived themes. Class#4 ("hospitalization"; 18.2% of forms) points to the importance of interactions with the hospital, especially during exacerbations, which constitutes novel information. CONCLUSIONS: Lexicometry confirms the importance of dyspnea invisibility as a burden to COPD patients.

Lifting dyspnoea invisibility: COVID-19 face masks, the experience of breathing discomfort, and improved lung health perception - a French nationwide survey.

QUESTION ADDRESSED: In contrast with pain, dyspnoea is not visible to the general public, who lack the corresponding experiential baggage. We tested the hypothesis that the generalised use of face masks to fight severe acute respiratory syndrome coronavirus 2 dissemination could change this and sensitise people to respiratory health. METHODS: General population polling (1012-person panel demographically representative of the adult French population, quota sampling method; 517 (51%) female). 860 (85%) answered "no" to "treated for a chronic respiratory disease" ("respiratory healthy"), and 152 answered "yes" ("respiratory disease"). 14% of respiratory healthy respondents reported having a close family member treated for a chronic respiratory disease (RH-family+ ). Respondents described mask-related attitudes, beliefs, inconveniencies, dyspnoea and changes in their respiratory health vision . RESULTS: Compliance with masks was high (94.7%). Dyspnoea ranked first among mask inconveniencies (respiratory disease 79.3%, respiratory healthy 67.3%; p=0.013). "Air hunger" was the main sensory dyspnoea descriptor. Mask-related dyspnoea was independently associated with belonging to RH-family+ (OR 1.85, 95% CI 1.16-2.98) and removing masks to improve breathing (OR 5.21, 95% CI 3.73-7.28). It was negatively associated with considering masks effective to protect others (OR 0.42, 95% CI 0.25-0.75). Half the respondents were more concerned with their respiratory health since wearing masks; 41% reported better understanding patients' experiences. ANSWER TO THE QUESTION: Wearing protective face masks leads to the mass discovery of breathing discomfort. It raises public awareness of what respiratory diseases involve and sensitivity to the importance of breathing. These data should be used as the fulcrum of respiratory health oriented communication actions.

'You can't feel what we feel': Multifaceted dyspnoea invisibility in advanced chronic obstructive pulmonary disease examined through interpretative phenomenological analysis.

BACKGROUND: More than a symptom, dyspnoea is an existential experience shaping the lives of those afflicted, particularly when its persistence despite maximal pathophysiological treatments makes it pervasive. It is, however, insufficiently appreciated by concerned people themselves, family members, healthcare professionals and the public (dyspnoea invisibility), limiting access to appropriate care and support. AIM: To provide a better understanding of dyspnoea experiences and its invisibility. DESIGN: Interpretative phenomenological analysis of data collected prospectively through in-depth semi-structured interviews. SETTING/PARTICIPANTS: Pulmonary rehabilitation facility of a tertiary care university hospital; 11 people (six men, five women) with severe chronic obstructive pulmonary disease (stages 3 and 4 of the 4-stage international GOLD classification) admitted for immediate post-exacerbation rehabilitation. RESULTS: We identified several types of dyspnoea invisibility depending on temporality and interlocutors: (1) invisibility as a symptom to oneself; (2) invisibility as a symptom to others; (3) invisibility as an experience that cannot be shared; (4) invisibility as an experience detached from objective measurements; (5) invisibility as an experience that does not generate empathic concern. The notion of invisibility was present in all the identified experiential dimensions of dyspnoea. It was seen as worsening the burden of the disease and as self-aggravating through self-isolation and self-censorship. CONCLUSIONS: The study confirmed that dyspnoea invisibility is a reality for people with advanced chronic obstructive pulmonary disease. It shows dyspnoea invisibility to be a multifaceted burden. Future research should aim at identifying individual and collective measures to overcome dyspnoea invisibility.

Awakening efficacy of a vibrotactile device in patients on home nocturnal ventilatory assistance and healthy subjects as family caregiver proxies.

The objective of this study was to test the capacity of vibrotactile stimulation transmitted to the wrist bones by a vibrating wristband to awaken healthy individuals and patients requiring home mechanical ventilation during sleep. Healthy subjects (n = 20) and patients with central hypoventilation (CH) (Congenital Central Hypoventilation syndrome n = 7; non-genetic form of CH n = 1) or chronic obstructive pulmonary disease (COPD) (n = 9), underwent a full-night polysomnography while wearing the wristband. Vibrotactile alarms were triggered five times during the night at random intervals. Electroencephalographic (EEG), clinical (trunk lift) and cognitive (record the time on a sheet of paper) arousals were recorded. Cognitive arousals were observed for 94% of the alarms in the healthy group and for 66% and 63% of subjects in the CH and COPD groups, respectively (p < 0.01). The percentage of participants experiencing cognitive arousals for all alarms, was 72% for healthy subjects, 37.5% for CH patients and 33% for COPD patients (ns) (94%, 50% and 44% for clinical arousals (p < 0.01) and 100%, 63% and 44% for EEG arousals (p < 0.01)). Device acceptance was good in the majority of cases, with the exception of one CH patient and eight healthy participants. In summary this study shows that a vibrotactile stimulus is effective to induce awakenings in healthy subjects, but is less effective in patients, supporting the notion that a vibrotactile stimulus could be an effective backup to a home mechanical ventilator audio alarm for healthy family caregivers.

HLA-DPB1 and HLA class I confer risk of and protection from narcolepsy.

Type 1 narcolepsy, a disorder caused by a lack of hypocretin (orexin), is so strongly associated with human leukocyte antigen (HLA) class II HLA-DQA1(∗)01:02-DQB1(∗)06:02 (DQ0602) that very few non-DQ0602 cases have been reported. A known triggering factor for narcolepsy is pandemic 2009 influenza H1N1, suggesting autoimmunity triggered by upper-airway infections. Additional effects of other HLA-DQ alleles have been reported consistently across multiple ethnic groups. Using over 3,000 case and 10,000 control individuals of European and Chinese background, we examined the effects of other HLA loci. After careful matching of HLA-DR and HLA-DQ in case and control individuals, we found strong protective effects of HLA-DPA1(∗)01:03-DPB1(∗)04:02 (DP0402; odds ratio [OR] = 0.51 [0.38-0.67], p = 1.01 × 10(-6)) and HLA-DPA1(∗)01:03-DPB1(∗)04:01 (DP0401; OR = 0.61 [0.47-0.80], p = 2.07 × 10(-4)) and predisposing effects of HLA-DPB1(∗)05:01 in Asians (OR = 1.76 [1.34-2.31], p = 4.71 × 10(-05)). Similar effects were found by conditional analysis controlling for HLA-DR and HLA-DQ with DP0402 (OR = 0.45 [0.38-0.55] p = 8.99 × 10(-17)) and DP0501 (OR = 1.38 [1.18-1.61], p = 7.11 × 10(-5)). HLA-class-II-independent associations with HLA-A(∗)11:01 (OR = 1.32 [1.13-1.54], p = 4.92 × 10(-4)), HLA-B(∗)35:03 (OR = 1.96 [1.41-2.70], p = 5.14 × 10(-5)), and HLA-B(∗)51:01 (OR = 1.49 [1.25-1.78], p = 1.09 × 10(-5)) were also seen across ethnic groups in the HLA class I region. These effects might reflect modulation of autoimmunity or indirect effects of HLA class I and HLA-DP alleles on response to viral infections such as that of influenza.

Impact of earplugs and eye mask on sleep in critically ill patients: a prospective randomized study.

BACKGROUND: Poor sleep is common in intensive care unit (ICU) patients, where environmental factors contribute to reduce and fragment sleep. The objective of this study was to evaluate the impact of earplugs and eye mask on sleep architecture in ICU patients. METHODS: A single-center randomized controlled trial of 64 ICU patients was conducted from July 2012 to December 2013. Patients were randomly assigned to sleep with or without earplugs and an eye mask from inclusion until ICU discharge. Polysomnography was performed on the first day and night following inclusion. The primary outcome was the proportion of stage N3 sleep over total sleep time. Secondary outcomes were other descriptors of sleep and major outcome variables. RESULTS: In the intervention group, nine (30%) patients did not wear earplugs all night long. The proportion of N3 sleep was 21 [7-28]% in the intervention group and 11 [3-23]% in the control group (p = 0.09). The duration of N3 sleep was higher among the patients in the intervention group who wore earplugs all night long than in the control group (74 [32-106] vs. 31 [7-76] minutes, p = 0.039). The number of prolonged awakenings was smaller in the intervention group (21 [19-26] vs. 31 [21-47] in the control group, p = 0.02). No significant difference was observed between the two groups in terms of clinical outcome variables. CONCLUSIONS: Earplugs and eye mask reduce long awakenings and increase N3 duration when they are well tolerated. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02292134 . Registered on 21 Nov 2013.

Kleine-Levin syndrome in 120 patients: differential diagnosis and long episodes.

OBJECTIVE: Kleine-Levin syndrome is a rare disease characterized by recurrent episodes of hypersomnia with behavioral and cognitive disturbances. We aimed at describing the diagnosis procedure, risk factors, and severe forms. METHODS: In consecutive patients referred for suspected Kleine-Levin syndrome, we detailed differential diagnoses, and atypical and secondary cases, compared typical patients with healthy subjects, and examined the characteristics of patients with prolonged (>30 days) episodes. RESULTS: Among 166 referred patients, 120 had typical primary Kleine-Levin syndrome (syndrome secondary to brain diseases; n = 4, atypical syndrome, n = 7; differential diagnoses that were mostly psychiatric, n = 29; incomplete information, n = 6). The prevalence in France was 1.8 per million. The patients were often male (64%) and had more frequent birth and developmental abnormalities (45%) than controls (despite normal karyotypes), and most (80%) had teenage onset, with no difference between patients with prolonged (n = 34) and short (n = 85) episodes. In patients with prolonged episodes, the durations of the first episode (32 ± 33 vs 11 ± 6 days) and subsequent episodes were longer (mean episode duration = 23 ± 19 vs 10 ± 3 days) and the disease course tended to be longer (9 ± 6 vs 6 ± 4 years). During episodes, patients with prolonged episodes had shorter sleep time, higher levels of anxiety, increased agitation, and more feelings of disembodiment and amnesia. Between episodes, they were more tired, needed more naps, fell asleep more rapidly, and had higher anxiety/depression scores. INTERPRETATION: Mental disorders are frequent differential diagnoses of Kleine-Levin syndrome. One-third of patients have prolonged (>1 month) episodes with more frequent immediate and long-term consequences of the disease, prompting therapeutic trials.

Impact of cytokine in type 1 narcolepsy: Role of pandemic H1N1 vaccination ?

Recent advances in the identification of susceptibility genes and environmental exposures (pandemic influenza 2009 vaccination) provide strong support that narcolepsy type 1 is an immune-mediated disease. Considering the limited knowledge regarding the immune mechanisms involved in narcolepsy whether related to flu vaccination or not and the recent progresses in cytokine measurement technology, we assessed 30 cytokines, chemokines and growth factors using the Luminex technology in either peripheral (serum) or central (CSF) compartments in a large population of 90 children and adult patients with narcolepsy type 1 in comparison to 58 non-hypocretin deficient hypersomniacs and 41 healthy controls. Furthermore, we compared their levels in patients with narcolepsy whether exposed to pandemic flu vaccine or not, and analyzed the effect of age, duration of disease and symptom severity. Comparison for sera biomarkers between narcolepsy (n = 84, 54 males, median age: 15.5 years old) and healthy controls (n = 41, 13 males, median age: 20 years old) revealed an increased stimulation of the immune system with high release of several pro- and anti-inflammatory serum cytokines and growth factors with interferon-γ, CCL11, epidermal growth factor, and interleukin-2 receptor being independently associated with narcolepsy. Increased levels of interferon-γ, CCL11, and interleukin-12 were found when close to narcolepsy onset. After several adjustments, only one CSF biomarker differed between narcolepsy (n = 44, 26 males, median age: 15 years old) and non-hypocretin deficient hypersomnias (n = 57, 24 males, median age: 36 years old) with higher CCL 3 levels found in narcolepsy. Comparison for sera biomarkers between patients with narcolepsy who developed the disease post-pandemic flu vaccination (n = 36) to those without vaccination (n = 48) revealed an increased stimulation of the immune system with high release of three cytokines, regulated upon activation normal T-cell expressed and secreted, CXCL10, and CXCL9, being independently and significantly increased in the group exposed to the vaccine. No significant differences were found between narcoleptics whether exposed to flu vaccination or not for CSF biomarkers except for a lower CXCL10 level found in the exposed group. To conclude, we highlighted the role of sera cytokine with pro-inflammatory properties and especially interferon-γ being independently associated with narcolepsy close to disease onset. The activity of the interferon-γ network was also increased in the context of narcolepsy after the pandemic flu vaccination being a potential key player in the immune mechanism that triggers narcolepsy and that coordinates the immune response necessary for resolving vaccination assaults.

Feeling unreal: a functional imaging study in patients with Kleine-Levin syndrome.

Kleine-Levin syndrome is characterized by relapsing-remitting episodes of severe hypersomnia, cognitive impairment, apathy, derealization and behavioural disturbances. Between episodes, patients have normal sleep, mood and behaviour. Functional imaging studies performed in small series of patients with Kleine-Levin syndrome with visual or semi-quantitative, uncontrolled analysis yielded equivocal brain changes. Using whole brain voxel-based group analysis, we compared brain perfusion scintigraphy during and between episodes in consecutive patients with Kleine-Levin syndrome versus healthy control subjects and correlated perfusion changes with disease severity and symptoms, focusing on less studied but disabling symptoms, such as apathy and derealization. During asymptomatic periods, 41 patients (mean age of 22.3 ± 8.1 years, 56.1% male) and 15 age- and sex-matched healthy control subjects underwent single-photon emission computed tomography scanning with technetium-99m ethyl cysteinate dimer. Eleven patients repeated the test during a symptomatic period. Compared with controls, patients during asymptomatic periods had persistent hypoperfusion in the hypothalamus, the thalamus (mainly the right posterior part), the caudate nucleus, and cortical associative areas, including the anterior cingulate, (Brodmann area 25), the orbito-frontal (Brodmann area 11) and the right superior temporal cortices (Brodmann area 22), extending to the insula (P < 0.001 in all area). Two additional hypoperfused areas emerged during symptomatic periods (P < 0.001), located in the right dorsomedial prefrontal cortex (Brodmann area 8) and the right parieto-temporal junction (Brodmann areas 22 and 39). These two areas were more affected between episodes, when the mean episode duration was longer (r = -0.53; P < 0.001). The score for the Depersonalization/Derealization Inventory during symptomatic periods strongly correlated with the hypoperfusion of the right (r = -0.74, P < 0.001) and left (r = -0.59, P < 0.005) parieto-temporal junctions. No hyperperfusion was found. Because the parieto-temporal junction (including the angular gyrus) is involved in cross-modal association between somatosensory (body knowledge), auditory and visual information, the robust hypoperfusions and correlations observed in this area may underlie the striking derealization reported by patients during episodes. Defects in the dorsomedial prefrontal cortex may cause apathy. Persistent hypoperfusion in the diencephalic and associative cortical area during asymptomatic periods is a marker of the disease, suggestive of a scenario wherein patients compensate for these deficient circuitries.

Increased risk of narcolepsy in children and adults after pandemic H1N1 vaccination in France.

An increased incidence of narcolepsy in children was detected in Scandinavian countries where pandemic H1N1 influenza ASO3-adjuvanted vaccine was used. A campaign of vaccination against pandemic H1N1 influenza was implemented in France using both ASO3-adjuvanted and non-adjuvanted vaccines. As part of a study considering all-type narcolepsy, we investigated the association between H1N1 vaccination and narcolepsy with cataplexy in children and adults compared with matched controls; and compared the phenotype of narcolepsy with cataplexy according to exposure to the H1N1 vaccination. Patients with narcolepsy-cataplexy were included from 14 expert centres in France. Date of diagnosis constituted the index date. Validation of cases was performed by independent experts using the Brighton collaboration criteria. Up to four controls were individually matched to cases according to age, gender and geographic location. A structured telephone interview was performed to collect information on medical history, past infections and vaccinations. Eighty-five cases with narcolepsy-cataplexy were included; 23 being further excluded regarding eligibility criteria. Of the 62 eligible cases, 59 (64% males, 57.6% children) could be matched with 135 control subjects. H1N1 vaccination was associated with narcolepsy-cataplexy with an odds ratio of 6.5 (2.1-19.9) in subjects aged<18 years, and 4.7 (1.6-13.9) in those aged 18 and over. Sensitivity analyses considering date of referral for diagnosis or the date of onset of symptoms as the index date gave similar results, as did analyses focusing only on exposure to ASO3-adjuvanted vaccine. Slight differences were found when comparing cases with narcolepsy-cataplexy exposed to H1N1 vaccination (n=32; mostly AS03-adjuvanted vaccine, n=28) to non-exposed cases (n=30), including shorter delay of diagnosis and a higher number of sleep onset rapid eye movement periods for exposed cases. No difference was found regarding history of infections. In this sub-analysis, H1N1 vaccination was strongly associated with an increased risk of narcolepsy-cataplexy in both children and adults in France. Even if, as in every observational study, the possibility that some biases participated in the association cannot be completely ruled out, the associations appeared robust to sensitivity analyses, and a specific analysis focusing on ASO3-adjuvanted vaccine found similar increase.

Short-term cognitive loading deteriorates breathing pattern and gas exchange in adult patients with congenital central hypoventilation syndrome.

Question: Human PHOX2B mutations result in life-threatening sleep-related hypoventilation (congenital central hypoventilation syndrome, CCHS). Most patients retain ventilatory activity when awake through a respiratory-related cortical network. We hypothesised that this need to mobilise cortical resources to breathe would lead to breathing-cognition interferences during cognitive loading. Patients and methods: Seven adult CCHS patients (five women; median age 21) performed standard neuropsychological tests (paced auditory serial addition test - calculation capacity, working memory, sustained and divided attention; trail making test - visuospatial exploration capacity, cognitive processing speed, attentional flexibility; Corsi block-tapping test - visuospatial memory, short-term memory, working memory) during unassisted breathing and under ventilatory support. Ventilatory variables and transcutaneous haemoglobin oxygen saturation were recorded. Cortical connectivity changes between unassisted breathing and ventilatory support were assessed using electroencephalographic recordings (EEG). Results: Baseline performances were lower than expected in individuals of this age. During unassisted breathing, cognitive loading coincided with increased breathing variability, and decreases in oxygen saturation inversely correlated with an increasing number of apnoeic cycles per minute (rho -0.46, 95% CI -0.76 to -0.06, p=0.01). During ventilatory support, cognitive tasks did not disrupt breathing pattern and were not associated with decreased oxygen saturation. Ventilatory support was associated with changes in EEG cortical connectivity but not with improved test performances. Conclusions: Acute cognitive loads induce oxygen desaturation in adult CCHS patients during unassisted breathing, but not under ventilatory support. This justifies considering the use of ventilatory support during mental tasks in CCHS patients to avoid repeated episodes of hypoxia.

'Involve me and I learn': an experiential teaching approach to improve dyspnea awareness in medical residents.

BACKGROUND: Dyspnea is a frightening and debilitating experience. It attracts less attention than pain ('dyspnea invisibility'), possibly because of its non-universal nature. We tested the impact of self-induced experimental dyspnea on medical residents. MATERIALS AND METHODS: During a teaching session following the principles of experiential learning, emergency medicine residents were taught about dyspnea theoretically, observed experimental dyspnea in their teacher, and personally experienced self-induced dyspnea. The corresponding psychophysiological reactions were described. Immediate and 1-year evaluations were conducted to assess course satisfaction (overall 0-20 grade) and the effect on the understanding of what dyspnea represents for patients. RESULTS: Overall, 55 emergency medicine residents participated in the study (26 men, median age 26 years). They were moderately satisfied with previous dyspnea teaching (6 [5-7] on a 0-10 numerical rating scale [NRS]) and expressed a desire for an improvement in the teaching (8 [7-9]). Immediately after the course they reported improved understanding of patients' experience (7 [6-8]), which persisted at 1 year (8 [7-9], 28 respondents). Overall course grade was 17/20 [15-18], and there were significant correlations with experimental dyspnea ratings (intensity: r = 0.318 [0.001-0.576], p = 0.043; unpleasantness: r = 0.492 [0.208-0.699], p = 0.001). In multivariate analysis, the only factor independently associated with the overall course grade was 'experiential understanding' (the experimental dyspnea-related improvement in the understanding of dyspneic patients' experience). A separate similar experiment conducted in 50 respiratory medicine residents yielded identical results. CONCLUSIONS: This study suggests that, in advanced medical residents, the personal discovery of dyspnea can have a positive impact on the understanding of what dyspnea represents for patients. This could help fight dyspnea invisibility.

Impact of inspiratory threshold loading on brain activity and cognitive performances in healthy humans.

In healthy humans, inspiratory threshold loading deteriorates cognitive performances. This can result from motor-cognitive interference (activation of motor respiratory-related cortical networks vs. executive resources allocation), sensory-cognitive interference (dyspnea vs. shift in attentional focus), or both. We hypothesized that inspiratory loading would concomitantly induce dyspnea, activate motor respiratory-related cortical networks, and deteriorate cognitive performance. We reasoned that a concomitant activation of cortical networks and cognitive deterioration would be compatible with motor-cognitive interference, particularly in case of a predominant alteration of executive cognitive performances. Symmetrically, we reasoned that a predominant alteration of attention-depending performances would suggest sensory-cognitive interference. Twenty-five volunteers (12 men; 19.5-51.5 yr) performed the Paced Auditory Serial Addition Test (PASAT-A and B; calculation capacity, working memory, attention), the Trail Making Test (TMT-A, visuospatial exploration capacity; TMT-B, visuospatial exploration capacity, and attention), and the Corsi block-tapping test (visuospatial memory, short-term, and working memory) during unloaded breathing and inspiratory threshold loading in random order. Loading consistently induced dyspnea and respiratory-related brain activation. It was associated with deteriorations in PASAT-A [52 [45.5;55.5]; (median [interquartile range]) to 48 [41;54.5], P = 0.01], PASAT-B (55 [47.5;58] to 51 [44.5;57.5], P = 0.01), and TMT-B (44 s [36;54.5] to 53 s [42;64], P = 0.01), but did not affect TMT-A and Corsi. The concomitance of cortical activation and cognitive performance deterioration is compatible with competition for cortical resources (motor-cognitive interference), whereas the profile of cognitive impairment (PASAT and TMT-B but not TMT-A and Corsi) is compatible with a contribution of attentional distraction (sensory-cognitive interference). Both mechanisms are therefore likely at play.NEW & NOTEWORTHY To our knowledge, this is the first study exploring the interferences between inspiratory loading and cognition in healthy subjects with the concomitant use of neuropsychological tests and electroencephalographic recordings. Inspiratory loading was associated with dyspnea, respiratory-related changes in brain activation, and a pattern of deterioration of neuropsychological tests suggestive of attentional disruption. Inspiratory loading is therefore likely to impact cognitive performances through both motor-cognitive interference (engagement of cortical networks) and sensory-cognitive interference (dyspnea-related shift in attentional focus).

Machine-learning based feature selection for a non-invasive breathing change detection.

BACKGROUND: Chronic Obstructive Pulmonary Disease (COPD) is one of the top 10 causes of death worldwide, representing a major public health problem. Researchers have been looking for new technologies and methods for patient monitoring with the intention of an early identification of acute exacerbation events. Many of these works have been focusing in breathing rate variation, while achieving unsatisfactory sensitivity and/or specificity. This study aims to identify breathing features that better describe respiratory pattern changes in a short-term adjustment of the load-capacity-drive balance, using exercising data. RESULTS: Under any tested circumstances, breathing rate alone leads to poor capability of classifying rest and effort periods. The best performances were achieved when using Fourier coefficients or when combining breathing rate with the signal amplitude and/or ARIMA coefficients. CONCLUSIONS: Breathing rate alone is a quite poor feature in terms of prediction of breathing change and the addition of any of the other proposed features improves the classification power. Thus, the combination of features may be considered for enhancing exacerbation prediction methods based in the breathing signal. TRIAL REGISTRATION: ClinicalTrials NCT03753386. Registered 27 November 2018, https://clinicaltrials.gov/show/NCT03753386.

Periodic leg movements and REM sleep without atonia in Parkinson's disease with camptocormia.

Camptocormia (a flexion of the trunk that only appears when standing or walking) affects a minority of patients with Parkinson's disease (PD). As it responds poorly to levodopa and is associated with reduced midbrain and pons volume, it may result from non-dopaminergic, brainstem lesions. As several sleep abnormalities in PD also result from non-dopaminergic brainstem lesions, we monitored sleep in 24 non-demented PD patients with (n = 12) and without (n = 12) camptocormia and in 12 controls. Nearly half (42%) patients with camptocormia had abnormal periodic leg movement indices (>15/h), versus 17% patients without camptocormia and 8% of controls (p = 0.02). In addition, the percentage of enhanced muscle activity during REM sleep (measured on the chin and on the limb muscles) tended to be higher in patients with than without camptocormia (51 +/- 39% vs. 20 +/- 25%, p = 0.06). The other sleep and REM sleep characteristics (sleep and REM sleep onset latencies, sleep time and sleep stage percentages, REMs density, arousal, and apnea-hypopnea indices) were not different between these two PD groups. Lesions causing this axial dystonia may spare the sleep systems but affect the control of movements during sleep.

Long-Term Cognitive Impairment in Kleine-Levin Syndrome.

STUDY OBJECTIVES: In Kleine-Levin syndrome (KLS), episodes of hypersomnia, cognitive, and behavioral disturbances alternate with asymptomatic periods. Because 50% of patients report decreased academic performances, we evaluated their cognitive status during asymptomatic periods, determinants of deficits, and changes during follow-up. METHODS: The cognitive assessment during asymptomatic periods in all consecutive patients with typical KLS and healthy controls included the non-verbal intelligence quotient (Raven Progressive Matrices), the Trail Making Test, the Stroop Color-Word Test, the Wechsler Memory Test, verbal fluencies, the Free and Cued Learning Memory Test, and the Rey-Osterreith Complex Figure. Cognitive status was reevaluated after 0.5 to 2 y in 44 patients. RESULTS: At baseline, compared with the 42 controls, the 122 patients with KLS exhibited lower non-verbal intelligence quotient, speed of processing, attention, and reduced retrieval strategies in episodic memory. Higher episode frequency, shorter episode duration, shorter time since last episode, deeper sleep, and megaphagia during episodes predicted impaired memory. The visuoconstructional abilities and non-verbal memory were intact. After a mean follow-up of 1.7 ± 1.0 y, the episode frequency decreased from 4.6 ± 4.8 to 1.7 ± 1.9/y. The logical reasoning and attention improved, the processing speed remained low, and the retrieval strategies in verbal memory further worsened. CONCLUSIONS: In this field study, one-third of patients with KLS have long-term cognitive deficits affecting retrieval and processing speed. Cognitive function should be systematically tested in patients with KLS, which appears important to help patients in their academic studies.

Lithium therapy in Kleine-Levin syndrome: An open-label, controlled study in 130 patients.

OBJECTIVE: To compare the benefits and risks of lithium therapy vs abstention/other treatments in Kleine-Levin syndrome (KLS). METHODS: In a KLS cohort followed in a single center, 130 patients regularly took lithium carbonate (median dose 1,000 mg/day; n = 71; 40 children), valproate (n = 5), contraceptive pill (n = 5), or no treatment (n = 49). The disease characteristics (frequency, mean, and longest durations of episodes, time incapacitated per year) were compared before and after follow-up in the lithium vs abstention groups. RESULTS: The time between KLS onset and therapeutic onset was 69 ± 92 months. The patients were then followed up for a mean of 21.5 ± 17.8 months. Before treatment, the 71 patients treated with lithium tended to have a higher frequency of episodes per year (3.8 ± 2.9 vs 2.9 ± 2.6) and had a longer time spent incapacitated (57 ± 51 vs 37 ± 35 days) than the untreated patients. The mean (-8 ± 20 vs 2 ± 13 days) and longest (-18 ± 35 vs -5 ± 13) episode duration, the time spent incapacitated (-37 ± 65 days vs -10 ± 38), as well as the frequency of episodes per year (-2.6 ± 2.9 vs 1.3 ± 2.78) decreased significantly more in the treated than in the untreated patients. Side effects (reported by 50% of the patients) were mild and classical with lithium (tremor, increased drinking, diarrhea, and subclinical hypothyroidism). CONCLUSIONS: In this large, prospective, open-label, controlled study, the benefit/risk ratio of lithium therapy is superior to that of abstention, supporting the concept that lithium has anti-inflammatory/neuroprotective effects. CLASSIFICATION OF EVIDENCE: This study provides Class IV evidence that for patients with KLS, lithium decreases the frequency and duration of KLS episodes.

Attention-Deficit/Hyperactivity Disorder (ADHD) Symptoms in Pediatric Narcolepsy: A Cross-Sectional Study.

STUDY OBJECTIVES: To evaluate the frequency, severity, and associations of symptoms of attention-deficit/hyperactivity disorder (ADHD) in children with narcolepsy with and without cataplexy. DESIGN: Cross-sectional survey. SETTINGS: Four French national reference centers for narcolepsy. PATIENTS: One hundred eight consecutively referred children aged younger than 18 y with narcolepsy, with (NwC, n = 86) or without cataplexy (NwoC, n = 22), and 67 healthy controls. INTERVENTIONS: The participants, their families, and sleep specialists completed a structured interview and questionnaires about sleep, daytime sleepiness, fatigue, and ADHD symptoms (ADHD-rating scale based upon Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision [DSM-IV-TR] symptoms), and use of psychostimulants for the treatment of narcolepsy (administered in 68.2%). Polysomnographic measures were collected. MEASUREMENTS AND RESULTS: Clinically significant levels of ADHD symptoms were found in 4.8% of controls compared with 35.3% in patients with NwoC (P < 0.001) and 19.7% in patients with NwC (P < 0.01). Total ADHD scores were 6.4 (95% confidence interval [CI]: 4.5, 9.0) in controls compared with 14.2 (95% CI: 10.6, 18.9; P < 0.001), in patients with NwoC and 12.2 (95% CI: 9.8, 15.3; P < 0.01) in patients with NwC; subscores of inattention and hyperactivity/impulsivity were also significantly higher in both narcolepsy groups compared with controls. No difference was found between the NwC and NwoC groups for any ADHD measure. ADHD symptom severity was associated with increased levels of sleepiness, fatigue, and insomnia. Compared with the 34 untreated patients, the 73 patients treated with psychostimulants (modafinil in 91%) showed a trend toward lower narcolepsy symptoms but not lower ADHD symptoms. CONCLUSIONS: Pediatric patients with narcolepsy have high levels of treatment-resistant attention-deficit/hyperactivity disorder (ADHD) symptoms. The optimal treatment for ADHD symptoms in these patients warrants further evaluation in longitudinal intervention studies.