Dream Analysis in COPD Patients

Sleep is a fundamental period for maintaining homeostasis and ensuring many vital functions. It is crucial for brain development, memory and the preservation of our cognitive abilities. It is essential for the adjustment of numerous hormonal secretions, for glycemic control and for the efficiency of our immune system. Today, it is assumed that the reduction of sleep time or the alteration of its quality favors weight gain and obesity, the appearance of diabetes or the development of cancerous diseases. This is a major issue for our modern societies

In patients with respiratory diseases, and in particular with chronic obstructive pulmonary disease (COPD), sleep complaints are extremely frequent. Thus, patients with COPD have subjectively and objectively impaired sleep quality with a lower efficiency and a decrease in the amount of deep slow wave sleep. Moreover, the alteration of the quality of sleep and the physiological modifications of the ventilation during it, worsen the respiratory state of these patients, with an increase of the alveolar hypoventilation, an alteration of the quality of life and an increased risk of exacerbation. A preliminary work of our team was interested in the study of this sleep-breathing relationship and its impact in COPD patients.

Twenty-nine COPD patients hospitalized after respiratory exacerbation were examined by polysomnography. The most striking features were the presence of short (median 328 min, IQR25-75 [299-414]) and poor quality sleep (median Efficiency at 66% IQR 28-75 [51-78]). The sleep architecture was extremely disturbed with notably a decrease in the duration of deep slow-wave sleep with 85 minutes of N3 in median, IQR 25-75 [62-111]. In 3 patients, there was even a complete absence of REM sleep (SP). However, these results only confirmed the data in the literature on the study of sleep in COPD patients.

However, this work has allowed us to highlight 2 other anomalies 1- the demonstration of an electromyographic activation of the cervical inspiratory muscles (MIC) (sternocleidomastoid and scalene) in 26 out of 29 patients during sleep. Activation which, for half of the cases, is not present during wakefulness and only appears during sleep. Moreover, this activation was even present during REM sleep in 9 patients, whereas REM sleep is defined by an abolition of muscle tone. 2- The presence of Alpha Delta on the EEG. This phenomenon has already been observed in patients with chronic pain and is, according to the authors, a sign of cortical integration of pain during sleep.

Dyspnea, or "unpleasant breathlessness", is an abnormal and uncomfortable perception of breathing. The experience of dyspnea is the result of multiple interactions between physiological and environmental factors: it is a complex symptom that signals a threat to homeostasis, frequently inducing an adaptive behavioral response, which is not always efficient. It is responsible for a suffering whose mechanisms and perception can be similar to those of pain. Dyspnea is a subjective sensation with a sensory component and an affective component.

Patients suffering from chronic respiratory disease and in particular COPD very frequently present this symptom of dyspnea on awakening. But during the night, several arguments plead for the persistence of this dyspnea: the activation of the accessory muscles at the cervical level is associated with this sensation of dyspnea and the presence of Alpha Delta at the EEG, known to be a sign of pain during sleep, could in this case be a sign of dyspnea, indeed, the mechanisms of the perception of pain and dyspnea are close.

Although it is often studied, especially in intensive care unit with sedated patients, there is no tool to evaluate dyspnea in non-awake patients. However, sleep is not a state similar to coma or sedation. As everyone knows, sleep is accompanied by a unique cognition: dreams. The scientific term dream includes thoughts, images, sounds, sensations or emotions occurring during sleep.

The link between dreams and breathing has already been established in 2 studies. In the first one, Oudiette et al. showed in lucid dreamers an interaction between the content of their dream (Crossing a nauseating city) and breathing (Apnea preceded by a deep inspiration, witnessing a cortical preparation). Carrasco et al. have shown that the quantity of dreams and their content were related to the effectiveness of the treatment in apneic subjects. The investigators can therefore hypothesize that if patients have respiratory abnormalities responsible for nocturnal dyspnea, these could be reflected in their dreams.

COPD is one of the most frequent respiratory pathologies in France and in the world. The WHO forecasts that it will be the 3rd cause of death in 2030. The study of COPD is therefore a priority, and it is one of the chronic diseases referenced by the Ministry of Solidarity and Health in its national health strategy 2018-2022.

In order to have a comparable control group, patients will be matched to a group of healthy subjects of the same sex and age.

The investigators dream all night long but there is still a difference between dream activity in MS and slow wave sleep. Thus, compared to slow wave sleep, dreams reported after waking up in MS are typically longer, more vivid, more animated (more movement), more emotionally charged and less related to waking experiences. In contrast to MS dreams, slow wave sleep dreams are more closely related to "thoughts" or representations of real life problems.

In this work, The investigators will study the dreams of the patients through 2 tools: a questionnaire of typical dreams in order to have an evaluation of the content of the dreams on the life of the patient (Cf Appendix) as well as a dream diary over 2 weeks to try to have a precise description of the dreams of the patients.

There are no studies that have looked at the dreams of COPD patients. However, it seems necessary to carry out a dream diary over several days in order to accustom the patient to remember his dreams and to succeed in telling them. A duration of 2 weeks seems to be an appropriate compromise between a sufficiently long time to allow relevant information to be collected, without being too long and discouraging for the patients.