Approximately a year and a half after the first polysomnography, the child was already 6-years-old, and he maintained adequate neuropsychomotor development, had adequate social and affective behavior, and a good control of the allergic rhinitis. Another polysomnography was requested. This time, simultaneous sound and video monitoring were performed for all parameters analyzed in a complete polysomnography (6 EEG channels, 3 ECG channels, 2 EOG channels, 2 masseter electrodes, snoring sensor, nasal cannula, oronasal airflow sensor,
EMG sensor in one of the lower limbs). We observed that the child had 3 outbreaks of expiratory groans, all of them occurring in the second half of the nighttime sleep. The first outbreak started at 4.37 a.m. during the NREM sleep and presented an expiratory groan pattern, which lasted an average of 10 seconds followed by complete silence (Figure 1). The flow sensor and nasal cannula tracing in the polysomnography was compatible with central apnea (summation of groan and silence). The silence period usually lasted an average of 20 seconds, followed by a short period of inspiration, and was again followed by an episode of moaning with complete silence. This outbreak had a duration 4 minutes and 15 seconds. Afterwards, sleep remained still and no events were recorded for several minutes. At 5.26 a.m., there was another outbreak, also in NREM sleep, and it showed the same cyclic pattern as the previous one (Figure 2). This second outbreak lasted 4 minutes and 5 seconds. The final outbreak of the night started at 5.57 a.m. and lasted only 1 minute and 5 seconds, also during NREM sleep. This outbreak was followed by complete arousal, which lasted 1 minute. Then, the child began to make rhythmic movements with the hip together with the lower limbs. After 2 minutes, there was another episode of groaning/total silence, which lasted for 15 seconds.
It is necessary to emphasize that during the night the patient also presented episodes of hypopnea/obstructive apnea with mild inspiratory snoring in some moments, totaling an obstructive apnea/hypopnea index of 4.5 events per hour (slight increase for age group 6, without significant desaturation). There were no electroencephalographic changes suggestive of an epileptic seizure, nor cardiac alterations at any time during the night (respecting the method limitation).
Subsequently, the patient underwent cardiac evaluation with a specialist in the field. The cardiological evaluation with physical examination, electrocardiogram, echocardiogram, and chest radiography did not reveal any noteworthy changes in their findings.